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Hypervitaminosis A in the cat: A case report and review of the literature
Abstract
A case of hypervitaminosis A with secondary entrapment and compression of the left brachial plexus nerve roots is described. A 9-year-old male castrated domestic shorthair, fed a home-made diet based on raw pork liver, was submitted for examination for a left forelimb lameness that evolved to paralysis over a 2-month period. Clinical examination revealed a flaccid paralysis and atrophy of all left forelimb muscles. An ipsilateral Horner's syndrome was also noted. Radiological examination of the cervical and thoracic spine showed massive new bone formation at the ventral aspect of the second cervical to sixth thoracic vertebra. The diagnosis of hypervitaminosis A was made, based on the clinical and radiographic findings, as well as the determination of serum vitamin A concentration, which was 630 microg/dl, three times above the upper normal limit for this species. Despite the unfavourable initial prognosis, the cat progressively regained function of the affected limb approximately 6 months after the diet was changed to a commercial canned food.
... Hypervitaminosis A. Another characteristic feline joint disease is hypervitaminosis A. It is caused by excessive vitamin A supply in the diet, typically affecting cats consuming large amounts of liver or receiving vitamin A diet supplements (52,53). The disease has been first described as metabolic osteopathy in the 1950s in cats fed exclusively with milk and raw liver (beef, poultry, pork) (52). ...
... Hypervitaminosis A. Another characteristic feline joint disease is hypervitaminosis A. It is caused by excessive vitamin A supply in the diet, typically affecting cats consuming large amounts of liver or receiving vitamin A diet supplements (52,53). The disease has been first described as metabolic osteopathy in the 1950s in cats fed exclusively with milk and raw liver (beef, poultry, pork) (52). It is most commonly diagnosed in cats aged between 2 and 9 years, without significant predilections in terms of sex or breed (52). ...
... The disease has been first described as metabolic osteopathy in the 1950s in cats fed exclusively with milk and raw liver (beef, poultry, pork) (52). It is most commonly diagnosed in cats aged between 2 and 9 years, without significant predilections in terms of sex or breed (52). For reasons yet to be discovered, it triggers periosteal response and formation of individual or multiple osteochondral outgrowths (exostoses, osteophytes, enthesophytes). ...
The aim of the review was to describe a complex microstructure and biomechanical properties of the articular cartilage as well as a current review of its pathologies encountered in veterinary practice. The articular cartilage with its unique features: complex microarchitecture, significant mechanical durability and elasticity, lacking blood, lymphatic vessels, and innervation, seems to stand in contradiction to the laws of biology. It can be involved in a vast majority of diseases, from osteoarthrosis as a result of natural aging process to more complex in nature like osteochondromatosis. The primary role of articular cartilage is to provide the surface for movement in any single joint in the body. Therefore, its diseases lead to physical impairment and deterioration of the quality of life. Treatment of articular cartilage poses a formidable challenge in both modern human and animal medicine.
... Hypervitaminosis A in cats was first reported in 1957 (Christi, 1957) and is mostly associated with the chronic consumption of large amounts of raw liver. The most common pathological findings of hypervitaminosis A in cats are vertebral and periarticular hyperostosis (Polizopoulou et al., 2005). In kittens, teratogenic effects of high vitamin A intake include cleft palate, craniofacial and pelvic abnormalities, shallow ophthalmic orbits, and vascular abnormalities (Freytag et al., 2003). ...
... However, excessive vitamin A intake alone for 2 years did not cause the typical skeletal new bone formation (Freytag et al., 2003). The consumption of raw liver, which contains high levels of vitamin A and more vitamin D than most other foods (Becker and Kienzle, 2013), or supplements containing vitamins A and D, were suggested to be the cause of this new bone formation (Goedegebuure and Hazewinkel, 1981;Polizopoulou et al., 2005). ...
... It is possible that a period of skeletal growth is required before the more severe skeletal effects of excess vitamin A and/or vitamin D ingestion occur. However, in most case reports of feline hypervitaminosis A, the cats were middle aged or older (Polizopoulou et al., 2005;Guerra et al., 2014). In adult cats, excessive intake of vitamin A might increase 24-hydroxylase, which stimulates bone resorption at the endosteum as well as mineralisation of newly formed osteoid (DeLuca, 1982). ...
The first aim of this study was to determine whether vitamin D supplementation influenced the effects of high vitamin A intake on new bone formation in adult cats. The second aim was to determine whether high vitamin A intake in cats caused liver pathology and, if so, whether the current upper limit for the dietary intake of vitamin A for healthy adult cats would be safe. Twenty-four healthy adult cats were divided into four groups that received a control diet supplemented with peanut oil (control), or peanut oil containing a 100-fold increase in vitamin A (HA), or a 100-fold increase in vitamin A and a 5-fold increase in vitamin D (HAMD), or a 100-fold increase in vitamin A and a 65-fold increase in vitamin D (HAHD) over a period of 18 months.
Cats did not show abnormal locomotion or clinical signs of liver failure after 18 months of supplementation, but did show subtle skeletal changes and liver pathology, suggesting that the current National Research Council (2006) safe upper limit for vitamin A for cats is too high. The addition of vitamin D did not seem to influence bone pathology. While moderately elevated dietary vitamin D levels (HAMD) seemed to protect cats against the liver pathology caused by the consumption of large amounts of vitamin A, higher dietary levels of vitamin D (HAHD) did not seem to be protective.
... Systemic diseases that can cause abnormal skeletal development in cats include nutritional imbalances such as nutritional secondary hyperparathyroidism of kittens on only meat diet, hypovitaminosis D (rickets in growing animals) (3), or hypervitaminosis A (4). There are several types of rickets in growing animals: hypophosphatemic due to loss via kidneys (5) and defects of metabolism of vitamin D-vitamin D-dependent rickets type 1 and type 2 (6), clinical signs are poor growth, soft bones, gait abnormalities, bowing of the legs, and enlarged growth plates, most commonly in the distal limbs (7). ...
... There are several types of rickets in growing animals: hypophosphatemic due to loss via kidneys (5) and defects of metabolism of vitamin D-vitamin D-dependent rickets type 1 and type 2 (6), clinical signs are poor growth, soft bones, gait abnormalities, bowing of the legs, and enlarged growth plates, most commonly in the distal limbs (7). Hypervitaminosis A is seen in cats fed excessive amounts of liver and causes multiple bone exostoses, joint laxity, and impingement on nerves causing spinal cord or peripheral nerve and plexus disorders (4). Osteogenesis imperfecta is an inherited bone disease characterized by poor mineralization and excessive bone fragility. ...
A 6-month-old kitten, male, domestic shorthair cat was presented with dwarfism, ocular and nasal discharge, and Ascaris infestation. Congenital hyposomatotropism was diagnosed on the basis of serum level of insulin-like growth factor-1 (IGF-I). The cat was treated with human recombinant growth hormone for 9 weeks. After that, his liver enzymes became elevated, and the therapy was discontinued. His IGF-I levels were normal at the end of the therapy. Normal IGF-I was present 3 months after discontinuation of therapy with human recombinant growth hormone and even half a year after the discontinuation. All other comorbidities were addressed with the therapy. The cat is now the size of normal cats, living with the first author.
... o Hip dysplasia (Keller et al., 1999, Langenbach et al., 1998, Loder and Todhunter, 2018 o Patellar luxation (Langenbach et al., 1998, Loughin et al., 2006, Smith et al., 1999 o Elbow dysplasia (Freire et al., 2014, Freire et al., 2011, Staiger and Beale, 2005 o Elbow luxation (Rossi et al., 2003, Valastro et al., 2005 • Traumatic o Cranial cruciate ligament injury (Harasen, 2005, Herzog et al., 1993, Leumann et al., 2019, Wessely et al., 2017, Wu et al., 2000 o Other trauma (Clarke and Bennett, 2006, Clarke et al., 2005, Godfrey, 2005, Hardie et al., 2002, Johnston, 1997 • Nutritional -Hypervitaminosis A (Polizopoulou et al., 2005) • Endocrine -Hypersomatotropism (Peterson et al., 1990, Wassenaar et al., 2009 • Neoplastic o Synovial osteochondromatosis (Tan et al., 2010, Tas et al., 2013 o Osteosarcoma (Godfrey, 2005) • Immune-mediated (Gao et al., 2013, Lemetayer and • Infectious (Lemetayer and Taylor, 2014) o Mycoplasma spp (Liehmann et al., 2006, Moise et al., 1983, Zeugswetter et al., 2007 o Bartonella spp (Tomas et al., 2015) o Histoplasma capsulatum (Wolf, 1987) o Cryptococcus neoformans (Tisdall et al., 2007) o Feline leukaemia virus (Oohashi et al., 2010, Pedersen et al., 1980 o Feline syncytia-forming virus (Inkpen, 2015, Pedersen et al., 1980 Primary or idiopathic DJD is suggested to occur without an apparent initiating cause. Scottish Fold osteochondrodysplasia (SFO) and mucopolysaccharidosis are considered primary forms of DJD in cats. ...
... Hypervitaminosis A has been reported in cats whose diet predominantly consists of liver and is rarely seen nowadays since most cats are mainly fed nutritionally complete commercial diets (Polizopoulou et al., 2005). ...
Degenerative joint disease (DJD) is one of the most common causes of chronic pain in cats. Two studies were designed to identify risk factors for DJD in 6-year-old cats by examining prospective data from a longitudinal cohort study, and compare the activity profiles and quality of life of cats with (cases) and without (controls) early owner-reported signs of impaired mobility using orthopaedic examination, accelerometry and owner-completed questionnaires (Feline Musculoskeletal Pain Index (FMPI), VetMetrica).
Binomial logistic regression using backwards elimination identified four risk factors for increased owner- reported mobility impairment score in 6-year-old cats: entire neuter status at six months of age (OR=1.97, 95%CI 1.26–3.07), sustained trauma before six years of age (OR=1.85, 95%CI 1.3–2.6), outdoor access at six years of age (OR=1.67, 95%CI 0.96–2.9), and overweight/obese status at six years of age (OR=1.62, 95%CI 1.13–2.33). Case cats scored significantly lower than control cats for the FMPI (p=0.003) and the VetMetrica domain of comfort (p=0.002), but not vitality (p=0.009) or emotional wellbeing (p=0.018). Total pain (p<0.0001), crepitus (p=0.002) and thickening (p=0.003) scores were higher in case cats. Accelerometry differentiated cases from controls with a 90.9% accuracy.
Risk factor analysis demonstrated that obesity, outdoor access, and a history of trauma predispose cats to developing DJD, whereas neutering appears to decrease that risk. Changes in joint health as detected by orthopaedic examination and accelerometry reflected owner-reported mobility changes, differentiating cats with early DJD-related signs from healthy cats, whilst the VetMetrica comfort domain score indicated an impaired quality of life of cats with early DJD compared to healthy cats. Being able to recognise signs of mobility impairment earlier would allow interventions aimed at slowing DJD progression, thereby improving feline health and welfare. These findings have identified that orthopaedic examination, FMPI and accelerometry are effective in identifying early DJD-related mobility changes in cats.
... Associations between nutrition and health are known regarding domestic cats. Not only do cats require a diet providing balanced nutrition in order to avoid adverse health outcomes, certain disease states are also known to be associated with imbalances or inappropriate provision of particular nutrients [12][13][14][15][16]. Considering this, the type of diet a cat is fed may influence their dayto-day health, disease status, and even their longevity. ...
... The proportion of respondents keeping cat(s) only (653/1325 49%) did not differ from those keeping dog(s) and cat(s) (672/1325, 51%). The median number of cats kept per respondent was two (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Most cats were acquired from shelters, rescues or veterinarians (664/1241, 54%), followed by tamed stray, feral or found cats (214/1241, 17%) or inherited or gifted from friends and family (167/1241, 13%). ...
Background
Cats, being obligate carnivores, have unique dietary requirements for nutrients most commonly found in dietary ingredients of animal origin. As such, feeding a diet devoid of animal-derived ingredients has been postulated as a possible cause of nutrient imbalances and adverse health outcomes. A small proportion of cat owners feed strictly plant-based diets to the cats in their care, yet the health and wellness of cats fed these diets has not been well documented.
Results
A total of 1325 questionnaires were complete enough for inclusion. The only exclusion criterion was failure to answer all questions. Most cats, 65% (667/1026), represented in the survey were fed a meat-based diet and 18.2% (187/1026) were fed a plant-based diet, with the rest fed either a combination of plant-based with meat-based (69/1026, 6.7%) or indeterminable (103/1026, 10%). Cat age ranged from 4 months to 23 years, with a median of 7 years, and was not associated with diet type. No differences in reported lifespan were detected between diet types. Fewer cats fed plant-based diets reported to have gastrointestinal and hepatic disorders. Cats fed plant-based diets were reported to have more ideal body condition scores than cats fed a meat-based diet. More owners of cats fed plant-based diets reported their cat to be in very good health.
Conclusions
Cat owner perception of the health and wellness of cats does not appear to be adversely affected by being fed a plant-based diet. Contrary to expectations, owners perceived no body system or disorder to be at particular risk when feeding a plant-based diet to cats. This study collected information from cat owners and is subject to bias, as well as methodological limitations. Further research is warranted to determine if these results are replicable in a prospective investigation.
... La hipervitaminosis A causa una osteopatía metabólica en gatos que se alimentan a base de hígado por períodos prolongados, de meses a años (Goldman 1992). Esta osteodistrofia metabólica se caracteriza por la presencia de osteofitos y exostosis alrededor de las articulaciones, tendones, ligamentos y cápsulas articulares, afectando más comúnmente a las vértebras cervicales y torácicas (Polizopoulou et al. 2005). Al principio, la hiperplasia ósea involucra las vértebras cervicales craneales, pero con la progresión de la enfermedad las articulaciones entre las vértebras cervicales y entre las vértebras torácicas craneales pueden coalescer y causar una anquilosis ósea completa. ...
... No existe tratamiento alguno, y la única forma de detener la progresión de la enfermedad es corregir la dieta. El pronóstico es grave para la recuperación funcional en los casos con lesiones más severas, aunque algunos signos neurológicos pueden llegar a atenuarse con la corrección dietética (Polizopoulou et al. 2005). ...
... 90 This metabolic osteodystrophy is characterized by bony osteophytes and exostosis around joints, and tendon, ligament, and joint capsule attachments, with the occipital bone and cervical and thoracic vertebrae the most commonly affected sites. 91 Initially, the osseous hyperplasia involves the cranial cervical vertebrae, then with progression of the disease the joints of the cervical and cranial thoracic vertebrae may coalesce and cause complete bony ankylosis. The pathophysiology of vitamin A toxicity is not well understood. ...
... 92 Vitamin A toxicity causes also an inhibition of the collagen synthesis and breakdown of musculotendinous insertions in the periosteum during muscular activity, therefore in cats the excessive muscular activity during grooming could explain the predisposition of the cervicothoracic spine to be more commonly affected. 91 Pain, reduced mobility of the neck, and forelimb lameness due to bony ankylosis and nerve root compression are the early clinical signs of vitamin A toxicity in cats. In some cases the lesions may progress to induce paralysis. ...
The objective of this article is to review the recent literature that reports on the most common diseases affecting the spinal cord of cats, and to draw some general conclusions that will be useful to formulate diagnosis and prognosis for feline spinal patients. The most common types of feline spinal cord diseases documented were inflammatory/infectious diseases, and feline infectious peritonitis was the most common disease, representing approximately 50% of all feline myelitis. Neoplasms were documented in approximately 25% of cases; lymphosarcoma was the most common tumor affecting the spinal cord of cats, with reported prevalence between 28% and 40%. Cats diagnosed with spinal lymphosarcoma were significantly younger (median age 4 years) than cats with other spinal cord tumors (median age 10 years). Cats with clinical signs of intervertebral disc disease had a median age of 8 years, and 67% had Hansen type I disc protrusions. The most commonly affected intervertebral disc was at the L4 to L5 intervertebral disc space. Fibrocartilaginous embolism-affected older cats (median age 10 years), seemed to predominate in the cervicothoracic intumescence, and clinical signs were markedly lateralized, especially when the cervical region was affected.
... Common symptoms are muscle soreness and hyperesthesia along the neck and forelimbs, and the diagnosis could be readily made from radiographs. If not chronic exposure, the recovery from the response to removal of vitamin A from the diet is generally rapid (Hayes and Sturman, 1982;Polizopoulou et al., 2005). Not only osteopathologic conditions but also liver symptoms due to hypervitaminosis A were reported with a case of hepatic stellate cell lipidosis and hepatic fibrosis in a domestic cat that had been fed a diet based on raw beef liver (Guerra et al., 2014). ...
Vitamin A, a fat-soluble vitamin, is necessary for the development and maintenance of the organism for differentiation, growth, embryonic development, and homeostasis. Many natural and synthetic compounds are developed as potential pharmacologic agents for use in treating ailments ranging from cancer to acne. The physiological role of vitamin A and retinoids in male and female reproduction is very complex and the relevant toxicity data are usually controversial. They are required for maintaining reproduction including spermatogenesis, oogenesis, conception, placenta formation, and embryogenesis. Deficiencies are accompanied by embryonic defects, yet excessive intake/intoxications induce teratogenic effects and skeletal disorders. As it is now widely acknowledged that retinoid signaling is a target for endocrine disruption, new bioinformatics tools are expected to provide predictive toxicology in mixed exposure and multiple pathways.
... This problem not an extremely rare health disorder of cats, as they can get used to a certain type of food easily. Fortunately, the animals can recover when the diet is restored to commercially canned food (Polizopoulou et al., 2005). However, recently the regulation (EU) No 2016/429 forbids to give any pork meat to carnivore pets (More et al., 2017;Lazić et al., 2017). ...
Keeping and feeding of companion carnivores (dogs and cats) appear to be a simple activity for a shallow observer. By a multidimensional approach, all three domains of health can be analysed in the course of pet-feeding. The interest of animal health requires healthy, nutritious, and non-infectious pet food. At the same time, public health necessitates safety for pet owners and their families. By going much deeper, the environmental impacts of pets and pet foods can be identified. This review gathers the animal and human health and environmental aspects of domestic carnivore feeding. Based on the literature, it can be claimed that for the present, few data are available to determine the right way of feeding to reach the balance between all three domains of health.
... Le plus souvent, elle est causée par l'ajout dans l'alimentation de cou ou de trachée dont les glandes thyroïdiennes n'ont pas été enlevées, ou dans les aliments industriels tout-viande contaminés par ces glandes. -Hypervitaminose A 34 . Elle est consécutive le plus souvent d'une consommation excessive de foie. ...
Par défiance des aliments industriels, à la suite d'informations trouvées sur internet, à des croyances, à une réflexion éthique.. . les propriétaires d'animaux se tournent, pour une part non négligeable, vers des rations que nous qualifierons de non conventionnelles. Cette qualification est mal définie, et regroupe plusieurs grands « types" de rations, des rations crues aux rations sans céréales en passant par les rations végétariennes. Mais, l'un des points communs à toutes ces rations est la motivation du propriétaire. Ainsi, dans le cadre des rations non conventionnelles, il y a une recherche d'alternative aux rations industrielles ou ménagères, non pas avec comme premier objectif d'avoir un apport équilibré en nutriments, mais de répondre à une certaine croyance ou orthodoxie alimentaire. Cette doctrine peut trouver son origine dans la recherche d'une alimentation plus saine ou plus adaptée à l'image que le propriétaire se fait de son animal. Ainsi, dans l'accompagnement et le conseil du propriétaire, dans l'intérêt de l'animal, il est essentiel de comprendre la base des motivations du propriétaire, afin d'identifier les leviers d'action. En effet, la motivation derrière le choix d'une ration n'est pas toujours rationnelle. Et quand elle l'est, le raisonnement sous-jacent n'est pas toujours soutenu par des preuves scientifiques, mais, le plus souvent, par des sophismes et arguments fallacieux. La discussion avec le propriétaire peut aussi être perturbée par un effet Dunning-Kruger. De plus, il existe un fort engagement de la part des propriétaires et des promoteurs de ce genre de pratique tenant de la conviction et laissant peu de place à l'argumentation. Par exemple, l'un des premiers articles sur l'équilibre des rations BARF en 2001 a fait l'objet de nombreuses lettres à l'éditeur. L'un des arguments les plus avancés est que les auteurs de ces études sont "contre" ces pratiques non conventionnelles, déplaçant ainsi la discussion du registre scientifique à celui d'opinion. De la vision de l'auteur, le conseil et l'accompagnement du propriétaire doivent se baser sur son information par la présentation de preuves apportées par la science, sans juger, ni nécessairement tenter de convaincre, ce qui est souvent contre-productif. Ce chapitre présente les deux types de rations non conventionnelles les plus communes, celles à base de viande crue et le sans céréales.
... However, this ingredient must be used in formulation of diets with a clear understanding of its nutritional profile to avoid causing development of hypervitaminosis A, which has been detected in cats consuming homeprepared diets containing high amounts of liver. 40 It is important to emphasize that even when a detailed and balanced recipe is used by pet owners, inherent variability in ingredients, differences in interpretations of the ingredients or instructions, or other food and owner-related factors likely lead to differences in the nutritional profile of the resulting diet. 41 Further, long-term compliance with regard to nutritional management plans that incorporate homeprepared diets is generally poor. ...
Objective:
To evaluate home-prepared maintenance diet (HPMD) recipes for cats and compare the nutritional profiles with National Research Council (NRC) recommended allowances (RAs) for essential nutrients for adult cats.
Design:
Evaluation study.
Sample:
114 recipes (obtained from books and online sources) for HPMDs for cats.
Procedures:
Computer software was used to determine nutrient concentrations of HPMD recipes for comparison with NRC RAs for essential nutrients for adult cats. Effects of recipe authorship (veterinarian vs nonveterinarian) and supplementation on the number of nutrient concentrations below RAs were evaluated.
Results:
Of the 114 HPMD recipes, 113 contained vague instructions regarding preparation, and 46 did not provide feeding directions. Only 94 recipes provided adequately detailed information for computerized nutritional analysis, although most (93/94) still required assumptions regarding ingredients, preparation, or supplementation. Nonveterinarian-authored recipes and recipes without supplement-type products had more nutrient concentrations below NRC RAs, but no recipe met all RAs. With assumptions, 5 veterinarian-authored recipes met NRC RAs for all assessed nutrients except choline; however, taurine adequacy in 2 of those recipes could not be confirmed. Crude protein concentration was below the RA in 6 of 94 (6.4%) recipes. Nutrients most frequently below RAs included choline, iron, thiamine, zinc, manganese, vitamin E, and copper (in 89.7%, 76.6%, 62.8%, 61.7%, 57.4%, 57.4%, and 45.7% of recipes, respectively).
Conclusions and clinical relevance:
Problems with nutritional adequacy were identified in all evaluated HPMD recipes. Appropriate formulation of HPMDs requires specialized knowledge of nutrition and use of computer software to avoid potentially harmful nutrient deficiencies.
... Furthermore, dogs and cats may react adversely to food supplements, both natural and synthetic, given by wellmeaning pet owners (Miller & Cullor 2000). Supplements containing fat-soluble vitamins should be used with care because of the potential for hypervitaminosis syndromes, particularly hypervitaminosis A in cats (Polizopoulou et al. 2005) and hypercalcaemia following hypervitaminosis D in dogs (Nakamura et al. 2004, Mellanby et al. 2005. ...
Food intolerance refers to any abnormal physiological response to a food or food additive, believed not to be immunological in nature. Mechanisms include food toxicity, pharmacological reactions, metabolic reactions, dysmotility, dysbiosis, physical effects and non‐specific dietary sensitivity. Food intolerance reactions are variable, typically dose‐dependent, and can occur at any age. Signs may arise at any time, sometimes several hours or days after consumption of the offending food item, and can last for hours or days. Dietary indiscretion and non‐immunological food intolerance are probably more common in dogs than true dietary hypersensitivity. Hopefully, with a greater knowledge of the different pathophysiological mechanisms involved, we will become better at recognising, preventing and managing adverse food reactions.
... However, the true story builds a much more complex picture. Namely, even natural sources of vitamin A in unnatural quantities produce problems for species with particularly high susceptibility to vitamin A toxicity, like metabolic osteopathy (Polizopoulou et al., 2005). For precursors to vitamin A, the carotenoids, as many as nine factors influence their bioavailability when ingested in food (Van het Hof et al., 2000). ...
... Common symptoms are muscle soreness and hyperesthesia along the neck and forelimbs, and the diagnosis could be readily made from radiographs. If not chronic exposure, the recovery from the response to removal of vitamin A from the diet is generally rapid (Hayes, 1982;Polizopoulou et al., 2005). Not only osteopathologic conditions but also liver symptoms due to hypervitaminosis A were reported with a case of hepatic stellate cell lipidosis and hepatic fibrosis in a domestic cat that had been fed a diet based on raw beef liver (Guerra et al., 2014). ...
Vitamin A, a fat-soluble vitamin, is necessary for the development and maintenance of the organism for differentiation, growth, embryonic development, and homeostasis. Many natural and synthetic compounds are developed as potential pharmacologic agents for use in treating ailments ranging from cancer to acne. The physiological role of vitamin A and retinoids in male and female reproduction is very complex and the relevant toxicity data are usually controversial. They are required for maintaining reproduction including spermatogenesis, oogenesis, conception, placenta formation, and embryogenesis. Deficiencies are accompanied by embryonic defects, yet excessive intake/intoxications induce teratogenic effects and skeletal disorders. Relationship between the toxicity of environmental contaminants, such as endocrine disruptors and retinoids, is yet to be elucidated through retinoid-dependent pathways.
... There are many case reports on dogs or cats fed home-made diets and displaying clinical signs of shortage or excess of nutrients. Cats fed a diet based on pork or beef liver developed intoxication of vitamin A and showed paralysis, malformation of the neck vertebrae and chronic liver disease (21,22). Diets consisting mainly of oily fish or pig's brain caused primary and/or secondary vitamin E deficiency in cats, leading to inflammation of adipose tissue (23). ...
Home-prepared pet diets Anyone can have her or his opinion about dog and cat nutrition and put it into practice, provided no harm is done. Some owners make their own pet diets which they believe to be healthier than commercial foods. There is no objective evidence that adequate, self-prepared diets have health advantages when compared with industrially produced, complete petfood. In principle, people can prepare nutritionally appropriate diets for their pets. However, home-made diets entail a certain risk of malnutrition. Practical examples are shortage of calcium and vitamin D in dogs and excess of vitamin A in cats. There is no feeding practice with zero risk. The health risks of home-made diets and industrially produced dog and cat foods cannot be compared directly, but it is likely that commercial foods are safer. Nutrient deficiency hazards in adult animals put on home-made diets can be minimized by including complete, commercial food at one-third of the total diet. Diets containing raw animal ingredients potentially cause human infections through pathogenic bacteria or parasites, but the risk magnitude is unknown.
... The chronic form is more common in cats, where it is reported as a deforming metabolic osteopathy, associated with a diet based on raw liver (Seawright et al. 1964). The long-term effects of vitamin A are characterised by the formation of extensive bony osteophytes and exostoses around joints at the site of tendon, ligament and joint capsule attachments (Polizopoulou et al. 2005). Primary affected structures include the occipital bone and cervical and thoracic vertebrae. ...
A nine-year-old intact female domestic shorthair cat was evaluated for paraparesis, ataxia and severe spinal hyperaesthesia. Neurological examination indicated a T3-L3 spinal cord segment lesion. Computed tomography of the thoracolumbar and lumbosacral vertebral column was performed. This showed contiguous smooth new bone formation ventral and lateral to the vertebrae extending from the cranial thoracic area to the lumbosacral junction and appearing similar to canine diffuse idiopathic skeletal hyperostosis. There was also marked dorsolateral stenosis of the vertebral canal at the level of T4-T5 because of degenerative changes of the facet joints. To the authors' knowledge, this is the first published report of feline diffuse idiopathic skeletal hyperostosis.
© 2015 British Small Animal Veterinary Association.
... Each of these areas of concerns have been reported to cause malnutrition in pets. [25][26][27][28][29][30][31] Checking the nutritional adequacy of recipes is not a simple task and is most often beyond the skill set and time available to most practitioners. To correctly assess the nutrient profile of a homemade diet requires software, formulation skills, nutritional knowledge, and access to databases of available ingredients. ...
The goal of this article was to provide veterinary practitioners with an overview of the types of alternative dietary options available to pet owners and a practical method by which to evaluate the nutritional adequacy of these various options. Our approach to categorizing the alternative dietary options is based on the nutritional adequacy of these dietary options, because patients will be at risk for nutrition-related diseases if fed a nutritionally incomplete or improperly balanced diet long term.
... [10][11][12][13][14][15][16][17][18][19][20] Currently, the documented secondary causes of DJD in cats are nutritional, hip dysplasia, the non-infectious polyarthropathies and infectious arthropathies. [21][22][23][24][25][26][27][28][29][30][31] Obesity has also been suggested as a driving or confounding factor. Despite this information, the etiology of the vast majority of feline DJD seen in practices is unknown. ...
The underlying disease mechanisms for feline degenerative joint disease (DJD) are mostly unidentified. Today, most of what is published on mammalian arthritis is based on human clinical findings or on mammalian models of human arthritis. However, DJD is a common occurrence in the millions of domestic felines worldwide. To get a better understanding of the changes in biological pathways that are associated with feline DJD, this study employed a custom-designed feline GeneChip, and the institution's unique access to large sample populations to investigate genes and proteins from whole blood and serum that may be up- or down-regulated in DJD cats. The GeneChip results centered around three main pathways that were affected in DJD cats: immune function, apoptosis and oxidative phosphorylation. By identifying these key disease-associated pathways it will then be possible to better understand disease pathogenesis and diagnose it more easily, and to better target it with pharmaceutical and nutritional intervention.
... In addition, these vitamin A concentrations were in moderate excess of values previously reported in captive cheetahs fed commercially prepared raw meat diets and supplemented meat diets [Bechert et al., 2002]. Excessive vitamin A intake may interfere with vitamin D metabolism, resulting in skeletal deformations [Polizopoulou et al., 2005]. Since slight elevations above feline serum reference values were observed in cheetahs consuming a diet of WR for only 1 month, studies with long-term exclusive feeding of such whole prey items are warranted to evaluate the risk of hypervitaminosis A. Overall, despite the low number of animals studied here, significant differences in metabolic blood parameters or circulating nutrients were observed following a 1-month feeding period. ...
... 24 Serum VA concentration measured herein in lions is within the serum reference ranges reported in most mammals, which range from 700 to 1,700 nmol/L as well as in a group of 60 free-ranging Florida panthers (350-1,300 nmol/L). 10,24,25,29 As no reference interval for serum or hepatic VA have been reported in lions, it should be established. The latter should be based on a considerably larger number of healthy animals and should be established using the needle biopsy technique as the sampling method before this technique can be applied to evaluate clinical cases and before a true state of VA deficiency can be declared. ...
Hypovitaminosis A (HA)-related skull malformations resulting in neurologic abnormalities and death have been, and still are, reported in captive lions (Panthera leo) worldwide. Liver vitamin A (VA) concentration is the most reliable indicator of animals' VA status, and its assessment is essential in prevention and treatment of HA in lions. A percutaneous needle liver biopsy using high-performance liquid chromatography ultraviolet retinoid analysis for VA concentration measurement was validated. It was first assessed in vitro using chicken liver. Later, the safety and feasibility of ultrasound-guided percutaneous needle liver biopsy was assessed in living lions. Hepatic VA concentrations in lion liver were measured using the above laboratory method. Mean chicken hepatic VA concentration in needle biopsy (NB) and wedge biopsy (WB) of the same liver lobes were 108.66 and 60.89 microg/g wet tissue, respectively, and were significantly (P = 0.03) correlated (r = 0.74). The calculated linear regression for predicting VA concentration in WB using NB VA for chicken liver was 25.194 + 0.3234x NB (microg/g). Four ultrasound-guided percutaneous needle liver biopsies were obtained from each of the four lions under general anesthesia. Mean hepatic VA concentration was 8.25 microg/g wet tissue (range 1.43-25.29 microg/g). Mean serum VA concentration, measured in these four lions was 1,011.1 nmol/L with a standard deviation of 337.91 nmol/L (range 590.26-1,077.2 nmol/L). The lions recovered uneventfully, and no complications were observed during a 4-yr follow-up period. In conclusion, the percutaneous needle liver biopsy technique is a reliable, practical, safe tool for obtaining liver tissue samples antemortem for assessment of the VA status in lions and can be used in future studies.
... Hypervitaminosis A in cats and dogs causes osteopathy, commonly affecting the axial skeleton, and often presents as lameness, paresis, or paralysis due to entrapment of spinal nerves. 30,31 Some animals with hypervitaminosis A, even those severely affected, recover in the long term after they are placed on a new diet. ...
Most pet foods are safe, but incidents of chemical contamination occur and lead to illness and recalls. There were 11 major pet food recalls in the United States between 1996 and 2010 that were due to chemical contaminants or misformulations: 3 aflatoxin, 3 excess vitamin D3, 1 excess methionine, 3 inadequate thiamine, and 1 adulteration with melamine and related compounds and an additional 2 warnings concerning a Fanconilike renal syndrome in dogs after ingesting large amounts of chicken jerky treat products. This article describes clinical findings and treatment of animals exposed to the most common pet food contaminants.
... In addition, these vitamin A concentrations were in moderate excess of values previously reported in captive cheetahs fed commercially prepared raw meat diets and supplemented meat diets [Bechert et al., 2002]. Excessive vitamin A intake may interfere with vitamin D metabolism, resulting in skeletal deformations [Polizopoulou et al., 2005]. Since slight elevations above feline serum reference values were observed in cheetahs consuming a diet of WR for only 1 month, studies with long-term exclusive feeding of such whole prey items are warranted to evaluate the risk of hypervitaminosis A. ...
This study evaluated nutrient intake and relevant blood parameters of 14 captive cheetahs, randomly assigned to a meat-only diet (supplemented beef, SB) or a whole prey diet (whole rabbit, WR) for 4 weeks each. Despite a higher food intake, daily metabolizable energy intake was lower when fed WR (308 kJ BW(-1) ) compared with SB (347 kJ BW(-1) ) (P = 0.002). The ratio of protein to fat was markedly lower for WR (2.3:1) compared with SB (8.8:1), which was reflected in higher serum urea levels when fed SB (P =0.033), and a tendency for elevated cholesterol levels when fed WR (P =0.055). Taurine intake of cheetahs fed WR was low (0.06% on DM basis); however, analytical error during taurine analysis cannot be ruled out. Feeding WR resulted in a well-balanced mineral intake, in contrast to SB. The latter provided a low calcium:phosphorus ratio (1:2.3), thereby increasing the risk of metabolic bone disease. The high zinc content of SB (200 mg/kg DM), compared with WR (94 mg/kg DM), was reflected in higher serum zinc concentrations (P =0.011). Feeding WR resulted in an increase in serum vitamin A (P =0.011). Therefore, the risk of hypervitaminosis A in captive cheetahs when fed WR exclusively on a long-term basis should be evaluated. Our findings suggest that neither diet is likely to provide appropriate nutrition to captive cheetahs when fed exclusively. Zoo Biol 30:1-13, 2011. © 2011 Wiley Periodicals, Inc.
An understanding of normal radiographic anatomy and the pathogenesis of disease conditions is imperative when evaluating young dogs and cats for developmental orthopedic disease. Developmental orthopedic disease can be broken down into three major categories: dysplasia, osteochondrosis, and miscellaneous idiopathic diseases that are often polyostotic and involve specific anatomic regions of the long bones. Hip dysplasia is a developmental abnormality associated with the soft tissues and osseous structures of the coxal joint. Osteochondrosis is the general term used to describe a failure of endochondral ossification, the normal bone growth process by which the cartilarge model is replaced by bone. Hypertrophic osteodystrophy is a spontaneously occurring, self‐limiting disease of young, large‐breed dogs involving the metaphyses of long bones. Retained cartilage core is a failure of endochondral ossification that may occur at any physis, though most commonly it is bilateral and affects the distal ulnar physis.
Objectives:
The aim of this case-control study was to identify early-life risk factors associated with the occurrence of owner-reported mobility changes in 6-year-old cats by examining prospective data from a longitudinal cohort study of pet cats, the Bristol Cats study.
Methods:
Data on potential risk factors were obtained from seven sequential questionnaires completed between the ages of 2-4 months and 5 years. Mobility-related questions from the study questionnaire distributed at the age of 6 years were used to calculate each cat's mobility score. Cats with mobility scores of ⩾2 and 0 were allocated to the case and control groups, respectively, and the cat's status was the outcome variable.
Results:
Of the 799 cats included for analysis, 238 (29.8%) had owner-reported mobility changes. Binomial logistic regression using backwards elimination identified four risk factors for owner-reported mobility changes at 6 years of age: entire neuter status at 6 months of age (odds ratio [OR] 1.97; 95% confidence interval [CI] 1.26-3.07), sustained trauma before 6 years of age (OR 1.85; 95% CI 1.30-2.60), outdoor access at 6 years of age (OR 1.67; 95% CI 0.96-2.90) and overweight/obese status at 6 years of age (OR 1.62; 95% CI 1.13-2.33).
Conclusions and relevance:
Risk factor analysis demonstrated that obesity, outdoor access and a history of trauma may predispose cats to developing owner-reported mobility changes associated with degenerative joint disease, whereas neutering before 6 months of age appears to decrease that risk.
Background
Pet owners have many feeding options, some may be considered unconventional by veterinary practitioners. Provision of appropriate nutrition is a basic requirement, with adverse health outcomes possible when a pet diet is inadequate.
Objective
To capture dog and cat feeding practices, with a special focus on countries with large English-speaking populations, and to compare with data published over the previous 10 years.
Methods
An electronic questionnaire was provided for dog and cat owners online. Responses were analysed using descriptive statistics, and comparisons made with data from nine peer-reviewed articles published over the previous 10 years.
Results
Responses from 3673 English-speaking dog and cat owners in Australia, Canada, New Zealand, the UK and the USA were included. In previous publications, conventional (commercial, heat-processed) products were the predominant method of feeding. In recent publications, feeding unconventional (raw, homemade, vegetarian) diets appeared more prevalent. In the present study, most (79 per cent dogs, 90 per cent cats) pets were offered conventional food. However a few (13 per cent dogs, 32 per cent cats) pets were fed conventional foods exclusively. Many pets were offered homemade (64 per cent dogs, 46 per cent cats) and/or raw (66 per cent dogs, 53 per cent cats) foods. Different feeding practices were associated with geographical location.
Conclusion
As an increased risk of nutrient insufficiency and associated conditions have been attributed to unconventional feeding practices, veterinarians must be aware of pet feeding trends and educate clients about the nutritional needs of companion animals.
A seven-month-old male entire Bulldog presented for a three-week history of progressive lethargy, exercise intolerance, hindlimb paresis, muscle atrophy and hyperaesthesia. The dog had initially been raised on the bitch’s milk before maternal illness resulted in him transitioning onto milk replacer. He was weaned onto commercial puppy food until four months of age before being transitioned onto a homecooked diet. This diet comprised of raw meat, collected weekly from a local abattoir, homecooked cereals and vegetables. The patient was oxygen-dependent on presentation, requiring 40 per cent inspired oxygen concentration to maintain normoxaemia. Investigations revealed marked osteopenia with concurrent severe hypovitaminosis D, hypocalcaemia and hyperparathyroidism; hypovitaminosis A; hypothyroidism and concurrent severe pneumonia. Despite intensive medical care, nutritional interventions and escalating oxygen therapy, the dog was euthanased due to a deterioration in respiratory function. This case report highlights the severe clinical complications associated with the consumption of a nutritionally incomplete diet.
Patient posture is the visually apparent by‐product of skeletal stability, muscle tone, and neuromuscular innervation. Abnormal presentations that involve posture may be suggestive of underlying pathology, particularly when certain regions of the body are involved. Cervical ventroflexion is a commonly described presentation in clinical practice. The patient's nose points ventrally as the chin dips to the thoracic inlet. When the head and neck are flaccid, cervical ventroflexion is indicative of generalized weakness, particularly in cats. This may point to such conditions as hereditary myopathies, including muscular dystrophy, “spasticity syndromes” of Devon Rex and Sphynx cats, and periodic hypokalemic polymyopathy of Burmese cats and related breeds. Hypokalemia may also be secondary to gastrointestinal losses or potassium wasting in the urine. Certain medications promote potassium excretion, as do those diseases that cause polyuria. Primary hyperaldosteronism also encourages the excretion of potassium by the kidneys, thereby inducing cervical ventroflexion. Note that cervical ventroflexion, when it occurs, is not always flaccid. Other forms of cervical ventroflexion are described in the veterinary medical literature in which the head and neck are more rigidly positioned in space. This is most often observed in cases involving thiamine deficiency. Hypervitaminosis A also causes rigidity of the cervicothoracic spine in such a way that the chin drops to the thoracic inlet. However, this rigidity results from the development of extensive bony exostoses and osteophytes that fuse the cervicothoracic vertebrae. When a patient presents for cervical ventroflexion, it is important to perform a complete physical examination. Rarely does this postural change occur in isolation. More often than not, cervical ventroflexion is one of many clinical signs that collectively paint a portrait of disease.
As frustration with conventional medicine deepens, people are seeking novel approaches to health care for themselves and their pets. Not only are many alternative therapies comparatively inexpensive and readily available, they offer owners an opportunity to actively contribute to their pets’ health. Hope surrounding alternative veterinary medicine is understandable, but for most modalities there is little evidence to support efficacy, and some pose significant risks to both humans and companion animals. Although there is little scientific research to report, this paper aims to inform on the safety and efficacy of select alternative modalities, with a focus on feline medicine.
Commercial pet foods are usually safe, but incidents of contamination can have a devastating impact on companion animals and their owners. There are numerous possible contaminants ranging from natural contaminants to nutrient imbalances to chemical adulteration, making it impossible to predict what will cause the next pet food recall. Veterinarians involvement with pet food recalls includes examining and treating affected animals, documentation and sample collection, and communicating with pet food manufacturers and regulatory agencies.
Objective:
To evaluate commercial complete canned cat foods according to their composition, labeling and nutritional characteristics.
Materials and methods:
A total of 21 commercial complete canned compound feeds for adult cats were analyzed for crude nutrients, minerals, vitamins, selected amino acids and taurine. The analyzed parameters were compared to the internal set of standards of the European Pet Food Industry Federation (FEDIAF). The energy content was calculated and compared with the labeled recommendations regarding the amounts of diet that should be fed. Analyzed nutrients were compared with the labeled nutrients according to the regulations of the EU food and feed law (directive EU regulation 767/2009).
Results:
In many cases, the labeled feeding protocols did not match the calculated daily energy requirements. In eight complete foods, the recommended daily feed amounts were underestimated and four recommendations exceeded energy requirements of adult cats. In 12 complete foods, the calcium and phosphorus contents were threefold higher than the respective requirement. In 16 of 21 complete foods, substantial discrepancies were observed between the recommendations and the analyzed trace elements. In particular, selenium contents exceeded the selenium requirement more than threefold. The vitamin, arginine and taurine contents showed no significant discrepancies to the recommendations. With respect to the labeled nutrients, there were only minor deviations from the regulations of the European law.
Conclusion and clinical relevance:
In general, healthy adult cats are adequately supplied with energy and nutrients when feeding commercial canned complete diets for cats. In cases of body weight loss or gain, the labelled feed amounts should be questioned. The high phosphorus contents are an issue of concern, because a high phosphorus intake can potentially increase the risk for urinary stones and particularly for older cats the risk for renal insufficiency. Furthermore, it is recommended to decrease the high selenium levels by the reduction of selenium-rich feed materials such as offal.
The Handbook of Small Animal Radiology and Ultrasound: Techniques and Differential Diagnoses provides a user-friendly reference for a wide range of radiographic and ultrasonographic findings in dogs and cats. Key features Enables successful and clear interpretation of radiographs and ultrasonograms Offers clearly sequenced text arrangement from the identification of the radiographic or sonographic abnormalities to a list of subsequent considerations for each sign Prioritizes different clinical findings to tailor further diagnostic tests or therapeutic interventions Takes imaging abnormalities from the descriptive to the interpretative New to this edition Colour throughout enhances user-friendliness Many new conditions Extra illustrations show techniques and normal anatomy Additional information on techniques, normal appearance and disease processes Expanded Further Reading sections This book is intended for all users of small animal diagnostic imaging, from radiologists through to general practitioners to veterinary students, and will be an invaluable supplement to existing references in the subject.
Many pet owners seek advice from veterinary nurses and technicians on all aspects of nutrition from how to feed to what to feed; ranging from commercial diets to feeding raw diets, natural diets and home-cooked/prepared foods. Good sound evidence-based knowledge should be utilised in order to convey the advice given on all aspects of nutrition.
In this report, a clinical case of dietary hyperthyroidism in a dog is described. An eleven-month-old, male, intact Rottweiler was presented because of panting, weight loss and increased serum total thyroxine concentration. A complete history revealed that the dog was fed a bone and raw food diet, which made dietary induced hyperthyroidism very likely. Other possible differentials were excluded after a thorough diagnostic work-up. Finally, after changing towards a traditional commercial maintenance diet, the clinical symptoms resolved and thyroid blood values normalized. In every dog with an increased serum total thyroxine concentration, with or without clinical signs of hyperthyroidism, a thorough dietary history should be obtained. Owners should be informed that raw food diets tend to be nutritionally imbalanced, carry the risk of bacterial contamination, and have other safety problems. Therefore, veterinarians should recommend against feeding these diets.
In recent years, there has been growing interest in the feeding of unconventional diets such as raw, vegetarian and home prepared diets to companion animals. BARF diets, often referred to as 'Biologically Appropriate Raw Food' or 'Bones And Raw Food,' were popularised by Billinghurst in 1993. Such diets typically consist of 60-80% raw meaty bones and 20-40% a wide variety of foods including fruit and vegetables, offal, meat, eggs, or dairy foods.
Prior to domestication, the diet of dogs and cats consisted largely of raw food. Once cohabiting with humans, raw food remained the staple diet for cats whereas dogs survived on by-products of human consumption, i.e. table scraps. The nutritional inadequacy of these diets is cited as being responsible for the shortened life span and nutritionally-related digestive, musculoskeletal problems encountered at that time. Yet, current justification for the feeding of this diet stems from the belief that these species are healthier when fed as if still in the wild.
This article explores the nutritional adequacy and food safety issues related to feeding raw meat-based diets to companion animals and considers approaches for communicating with pet owners about the concerns regarding these unconventional diets.
Neck pain is commonly seen in small animal practice. Pain may arise from the nervous system itself or its surrounding structures. Identification of the origin of pain determines the diagnostic tests required in order to reach a diagnosis and decide on the right therapy. This article discusses differential diagnoses, management and treatment of some common cervical and neck conditions in small animals.
This month we have another in our occasional ‘Points of view’ series exploring a single issue from two perspectives. Here Vicky Payne, a veterinary surgeon who works in general practice combining conventional with alternative approaches to the care of her patients, and Nicola Ackerman, a veterinary nurse from Plymouth who was SQP Nutritional Advisor of the Year in 2013, debate the issues surrounding the feeding of conventional as opposed to raw and natural diets.
Objective:
Horse meat is often used in the context of an elimination diet. For reasons of practicability some pet owners feed canned horse meat, which is commercially available. Based on a report of a cat with food allergy that displayed cervical spondylosis, the vitamin A content was analyzed in various horse meat products.
Material and methods:
The vitamin A (retinol) content was analyzed in 14 commercially available horse meat products. The content of metabolizable energy was calculated on the basis of the declaration by using estimation equations.
Results:
High amounts of vitamin A were found in some products for which liver, offal or animal by-products were labelled as contents. When feeding exclusively with one of these products, the vitamin A supply was just below the safe upper limit for cats while above the safe upper limit for dogs.
Conclusion:
Labelling and content of all-meat-products should be thoroughly checked to identify products with high liver percentages.
Clinical relevance:
An excessive vitamin A intake can occur when feeding with horse-meat products with a high liver content over a long period.
To evaluate recipes of diets recommended for animals with chronic kidney disease (CKD), compare nutritional profiles for those recipes to requirements for adult dogs and cats, and assess their appropriateness for the management of CKD.
Evaluation study.
Recipes of 67 home-prepared diets promoted for use in dogs (n = 39 recipes) and cats (28) with CKD.
Recipes were analyzed with computer software to determine calories, macronutrient calorie distribution, and micronutrient concentrations and were assessed for appropriateness for the management of CKD.
Assumptions were required for the analysis of every recipe, and no recipe met all National Research Council nutrient recommended allowances (RA) for adult animals. Compared with RAs, concentrations of crude protein or at least 1 amino acid were low in 30 of 39 (76.9%) canine recipes and 12 of 28 (42.9%) feline recipes. Choline was most commonly below the RA in both canine (37/39 [94.9%]) and feline (23/28 [82.1%]) recipes; selenium (34/39 [87.2%] canine and 9/28 [32.1 %] feline recipes), zinc (24/39 [61.5%] canine and 19/28 [67.9%] feline recipes), and calcium (22/39 [56.4%] canine and 7/28 [25.0%] feline recipes) concentrations were also frequently below recommendations. The median phosphorus concentration in canine and feline recipes was 0.58 and 0.69 g/1,000 kcal, respectively.
Many problems with nutritional adequacy were detected, and use of the recipes could result in highly variable and often inappropriate diets. Many recipes would not meet nutritional and clinical needs of individual patients and should be used cautiously for long-term feeding.
Practical relevance:
Cats, both young and old, can suffer a variety of weird and wonderful musculoskeletal conditions that are a cause of lameness. These include developmental, metabolic and nutritional bone diseases, ectopic mineralisation disorders, conditions that cause lameness or exercise intolerance and primarily or secondarily affect muscle, and lastly pad conditions.
Clinical challenges:
These conditions are mostly rare and can be challenging to diagnose. The aim of this review is to bring these conditions to the attention of practitioners so that, if they are encountered, further research around the topic can be undertaken. Radiographic changes and diagnostic tests that can be used to try to confirm diagnoses are described.
Evidence base:
These unusual causes of lameness are the subject of multiple single case reports or small case series, many of which are relatively old. The evidence presented here is drawn from these articles. However, it is not possible within the scope of this review to discuss all the conditions in as much detail as they may warrant, or to make reference to every article relating to them.
Feeding of raw meat-based diets to pets has become an increasingly popular trend amongst pet owners. Owners, who desire to provide the best for their pets, seek veterinary opinions about food options. This paper reviews and applies standards of evidence-based medicine to grade the available scientific literature that addresses the nutritional benefits or risks, infectious disease risks, and public health implications of raw, meat-based pet diets. Although there is a lack of large cohort studies to evaluate risk or benefit of raw meat diets fed to pets, there is enough evidence to compel veterinarians to discuss human health implications of these diets with owners.
Between October 2003 and May 2004, seven cats were diagnosed with severe and extensive hypertrophic osteopathy of the appendicular skeleton without detectable underlying causes. All cats showed similar clinical signs of pain with progressive lameness of the limbs. One cat died shortly after presentation, whereas conditions of the others resolved after medical treatment and a change in diet. Regression of the bone lesions was observed radiographically in all surviving six cases. J Am Anim Hosp Assoc 2010;46:346-352.
Two nutritional problems of the cat are reviewed. One represents a deficiency of taurine, the other vitamin A toxicity. Taurine deficiency in cats is insidious because the progressive retinal degeneration induced may go unnoticed until the damage is advanced and irreversible. Both rods and cones undergo degeneration along with the underlying tapetum lucidum. The hyperreflective focal lesion is easily observed in the area centralis with an ophthalmoscope and has been previously identified as feline central retinal degeneration. This lesion is not reversed by taurine supplementation, even though the remaining retina may be saved from further degeneration. The cat requires dietary taurine, found in meat and fish, because it cannot synthesize enough to meet demands for bile acid conjugation and tissue metabolism, especially those of muscle and central nervous system. Vitamin A toxicity is not commonly observed in cats but may occur if cats are fed beef liver in which appreciable vitamin A is stored. Cats exhibit muscle soreness and hyperesthesia, especially along the neck and forelimbs where bony exostoses of cervical verterbrae and longbones are common. The diagnosis is readily made from radiographs. The response to removal of vitamin A from the diet is generally rapid and, unless the toxicity has been chronic in young kittens, recovery is generally satisfactory.
The aspect of calcified tissues involved in fracture healing was studied by means of backscattered electron imaging. Bilateral transverse midshaft osteotomies were performed in the tibiae of 16 dogs. The osteotomies were reduced by means of a type II external skeletal fixator, and the clinical and radiographic course was assessed weekly until the moment of euthanasia, one, two, four and eight weeks after the operations. The osteotomized areas were removed and their structure examined in the scanning electron microscope, using backscattered electron images, to determine the general aspect of the extracellular matrix of the calcified tissues present. Four different tissues were observed: lamellar bone, woven bone, calcified cartilage and chondroid tissue. The backscattered electron contrast and fibre arrangement of the matrix, as well as the size and shape of the cellular lacunae, allow identification of the tissue. Chondroid tissue, which seems to have a leading role in the early phases of fracture healing, shows a characteristic pattern of a highly calcified and fibrous matrix with a large number of irregular and confluent cell lacunae.
The morphological characteristics of the calcified tissues involved in fracture healing were studied by means of backscattered electron imaging. Lamellar bone, woven bone, calcified cartilage and chondroid tissue were the four calcified tissues observed during the healing process of canine midshaft tibial experimental fractures.
Toxic effects of excessive vitamin A and of excessive vitamin ADE were studied in 9 mixed Labrador Retriever pups. Clinical signs were loss of body weight, dullness, emaciation, roughened coat, evident pain in limb joints, and retarded growth. Radiologic changes were decreases in overall length and thickness of long bones, development of osteophytes, periosteal reaction, and premature closure of epiphyses. Pathologic changes were degenerative epiphyseal plate, hemorrhage and exostotic proliferation of periosteum, fatty liver, and microcalculi in kidney. Toxic effects of excessive vitamin A did not appear to be so great when it was administered as vitamin ADE.
The influence of an excess of retinol on bone formation was studied by using cultures of embryonic-chick calvaria. Retinol decreased collagen synthesis in a dose-dependent manner, non-collagenous protein synthesis being relatively unaffected. Collagen synthesis was significantly inhibited after 24 h of culture with retinol and was progressively decreased, compared with control cultures containing no retinol, as the period of culture was increased. The effect of retinol on collagen synthesis could be reversed by incubation of calvaria for further periods in retinol-free medium. Incorporation of [3H]thymidine and [3H]uridine into DNA and RNA respectively was not altered by culturing calvaria with retinol for 22 h. These latter findings, and the selectivity for collagen synthesis, all suggested that the effect observed was not a cell-toxicity phenomenon. The effect of retinol on collagen synthesis by chick calvarial osteoblasts was probably direct and not mediated by osteoclasts, since a negligible number of the latter cells is present in chick calvaria. In cultures of neonatal murine calvaria, which contain many osteoclasts, retinol similarly inhibited synthesis of collagen, but not of non-collagenous protein; the concentrations of retinol necessary to produce the response were similar to those required to stimulate bone resorption in vitro.
The brachial plexus and its associated structures demonstrate a propensity for certain disease processes not common to other areas of the nervous system. Brachial plexus disease produces a gait disturbance that may mimic musculoskeletal disease. When evaluating a case with possible traumatic brachial plexus disease, one relies heavily on historical, physical, and neurologic information when differentiating musculoskeletal disorders, although both may sometimes be present simultaneously in the same limb. With inflammatory disease, electromyography is extremely helpful, although an empiric dietary change may help confirm a suspicion. Brachial plexus surgery requires careful planning and meticulous technique. Attempts to remove malignant schwannomas have not been as successful as one would hope (Table 2). To a large extent, these dogs are treated late in the course of their disease because they are often treated for extended periods of time for musculoskeletal disease first. Early diagnosis and prompt surgical intervention would help many of these dogs. New histopathologic techniques, electrodiagnostic equipment, and radiographic techniques are helping to define peripheral nerve disease in the companion animal. These techniques will help us categorize and treat these diseases with greater success in the future.
Vitamin A toxicity has been associated with alterations in mineral metabolism and may result in osteopenia, fractures, deformities, and growth arrest. The pathogenesis of the bone lesions that occur in vitamin A toxicity is, however, ill defined and was examined in the present study. The administration of pharmacological doses of vitamin A to growing male rats resulted in weakness and spontaneous fractures. Undecalcified bone histology of vitamin A toxic animals was characterized by increased bone resorption, osteoclastosis, a paucity of trabecular surfaces covered with osteoid, and lesions which appear to be pathognomonic of hypervitaminosis A. The serum calcium and magnesium levels of vitamin A-toxic animals were unremarkable, but serum phosphate levels were significantly higher than control values. Urinary hydroxyproline excretion reflected bone histology and was significantly increased in experimental rats. Circulating levels of the potent bone resorbers, PTH, 1,25-dihydroxyvitamin D, and 25-hydroxyvitamin D, were, however, comparable in vitamin A-toxic and control animals, suggesting a possible direct effect of vitamin A on bone. Subsequently, the effects of vitamin A (retinol) on in vitro collagen synthesis (incorporation of [3H]proline into collagen) and bone resorption (45Ca release from bone) were examined using a fetal rat calvarial culture. Retinol added to the culture medium for 20-24 h in concentrations ranging from 0.5-10 micrograms/ml selectively inhibited collagen synthesis in a dose-dependent fashion. Higher concentrations of retinol were toxic and resulted in a general inhibition of protein synthesis. Bone resorption was stimulated by 0.5 and 2.5 micrograms/ml retinol. We conclude that vitamin A toxicity in rats causes bone lesions, the genesis of which can be explained, at least in part, by a direct effect of the vitamin on skeletal tissue.
The growth and structure of epiphyseal plates was studied in normal kittens, and in kittens given an excess of vitamin A for 7 days prior to necropsy. Growth measurements were made on 10 different epiphyseal plates from each animal by means of in vivo labelling with a fluorescentdye. It was found that the growth of all plates was retarded in kittens which had received an excess of vitamin A. The absolute retardation of growth of each plate was directly proportional to its normal rate of growth as assessed in the control animals.
HYPERVITAMINOSIS A causes extensive confluent exostosis formation of the cervical spine in adult cats1,2. It was initially reported that no juvenile osteodystrophy occurred in this disease1, but an abnormal hindquarter gait was described later in a group of young cats receiving large daily doses of vitamin A (ref. 2). No explanation of this abnormal gait was given and the condition was therefore studied further.
An investigation of the aetiology and pathology of deforming cervical spondylosis was carried out in 19 normal, newly-weaned kittens divided into 6 groups. Four groups were fed lean beef and milk. One group served as a control and the remainder were supplemented with vitamin A daily at the rate of 15, 30 and 150 μg./g. body weight, respectively. Two other groups were fed raw liver and milk providing average daily intakes of vitamin A of 17 and 35 μg./g. body weight, respectively. After 24 to 41 weeks, primary lesions developed mainly about the first three diarthrodial joints of the cervical vertebrae in all except the controls and the lowest vitamin A supplemented groups. These consisted of an extensive osseocartilagenous hyperplasia, mainly at the margins of the joints. The trauma resulting from normal head and neck movements of coat licking was regarded as the basis of this predilection site for the lesions. There was marked lipid infiltration involving mainly the reticulohistiocytic cells of the liver, lungs, spleen and hepatic lymph node and of the tubular epithelium of the renal cortex in all cats in the experimental groups. Prominent fading, pale green fluorescence attributable to vitamin A was observed in these organs. Plasma levels and liver and kidney concentrations and reserves of vitamin A were very high. The percentage of the vitamin A stored was highest in the groups fed liver. The vitamin A intake of cats fed raw liver was comparable to that reported to produce chronic hypervitaminosis A in laboratory animals. It is concluded that hypervitaminosis A is the cause of naturally-occurring, deforming cervical spondylosis of the cat.
Craniomandibular osteopathy was diagnosed in two Pyrenean mountain dogs with a history of mandibular swelling, pain, fever and, in dog 1, lameness. Radiographs demonstrated extensive, active new bone formation on the ventral aspect of the mandibular bodies of both dogs. Dog 2 responded well to treatment but dog 1 was euthanased owing to severe pain, dysphagia and unsuccessful treatment. The mandibles were examined by means of back-scattered scanning electron microscopy and a well arranged mineralised trabecular network of chondroid tissue and woven bone was observed. The mandibular cortical bone under the areas of periosteal proliferation was also affected, showing a looseness of the characteristic compact appearance of lamellar bone. This is the first report of craniomandibular osteopathy in this breed.
Feline joint disorders are often overlooked, possibly because cats are extremely agile and appear to cope with pathologic changes within their joints better than their canine counterparts. There is a growing awareness that osteoarthritis occurs more frequently than previously anticipated in cats, and recently we have seen the emergence of hip dysplasia as an entity of concern in some purebred cats. There are also several poorly understood conditions that affect the joints of cats, such as synovial osteochondromatosis, that invite further study. In recent years we have seen an expansion in the knowledge of immune-mediated and infectious arthropathies and their inter-relationship with infective agents. This article describes the radiographic changes seen in many of the currently recognized joint disorders of domestic cats.
We describe a clinical case of hypervitaminosis A in a cat. The main lesions were bony fusions of both the hip and stifle joints, without spinal involvement. A post-mortem study using back-scattered scanning electron microscopy (BEI-SEM) revealed that exostoses had formed around the joints without articular surface involvement. The more recently formed areas of bony proliferation were composed mainly of chondroid tissue surrounded by different degrees of woven bone. As the bony reaction occurred, remodelling of the trabeculae was observed which lead to progressive substitution of chondroid tissue by woven bone surrounded by apposition of lamellar bone. No traces of calcified cartilage were observed in any of the bone sections evaluated.
Holstein suckling calves on a farm manifested severe emaciation, generalized alopecia, dome-like cranial deformation, and high mortality (Case 1). Metaphyseal growth plates of the femur were achondroplastic; segmented, partially resorped, and replaced with immature bony trabeculae containing degenerated chondrocytes. The skull was thin and partially replaced with connective tissue. Diffuse and severe fatty degeneration was observed in the hepatic stellate (Ito') cells. After 6 mo, surviving calves manifested unthrifty with short and irregular hindquarters (Case 2). The metaphyseal growth plates were poorly formed, irregular, partially disappeared centrally, and often sealed with thin bony trabeculae. The cartilage matrix was not homogeneous but was finely fibrous, and chondrocytes were flat and degenerated. The bone lesion was diagnosed as chondrodysplasia due to premature physeal closure. These calves had been administered excessive amounts of vitamins A, D3 and E, and blood chemistry of acute case showed hypervitaminosis A and E. Case I demonstrated acute disease, while Case 2 demonstrated chronic sequelae. Hypervitaminosis A was the suspected cause.
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