Veterinary Clinics of North America Small Animal Practice

Published by WB Saunders
Print ISSN: 0195-5616
Publications
For successful experimental therapy of canine hematopoietic tumors, one must have a randomized homogeneous population of patients in reasonably good condition. Drug combinations should contain several agents, each with antitumor effect, acceptable toxicity, and of reasonable cost. Other modalities include biological response modifiers, radiation, differentiation-inducing agents, and marrow transplantation. Ways must be found to prevent drug resistance of tumor cells.
 
This article discusses some of the basic issues concerning fluid therapy in small animals. It is hoped that the reader is able to assess the fluid needs of a dog or cat presented for veterinary treatment. The remaining articles address particular fluid compositions and fluid choices in patients with a variety of diseases and electrolyte imbalances.
 
Evaluating the evidence describes the scientific basis of evidence as presented in papers describing the results of clinical research. The types of errors that may lead to misinterpretation of evidence are discussed. This article includes descriptions of the main types of research performed in veterinary clinical research and notes on their advantages and disadvantages.
 
Hospital-associated infections, including those caused by zoonotic agents, represent an increasing concern in veterinary practice. Veterinarians and hospital staff are obligated and expected to provide education about and protection from transmission of pathogens among animal patients and between animal patients and human beings (eg, veterinary staff, volunteers, owners) who come into contact with infected animals. Patient management involves assessing risks of pathogen transmission, identification of animals either suspected of or proved to be infected with a transmissible infectious disease agent, and the implementation of measures that minimize the likelihood of transmission of the infectious agent. Copyright © 2015 Elsevier Inc. All rights reserved.
 
Otitis externa/media is commonly found in dogs with chronic ear diseases and in cats with upper respiratory disease and polyps. Diagnosis of otitis media requires attention to history and clinical signs, but it also requires other methods of determining disease within the bulla. If the integrity of the eardrum cannot be determined, assume that there is middle ear disease and proceed accordingly. It is prudent to take necessary precautions to avoid the use of potentially ototoxic ear cleaners or topical medications in suspected otitis media cases. Therapeutic success is possible using systemic and topical treatment within the cleaned bulla. Referral to a dermatology specialist or a radiologist for a CT scan may be indicated in some refractory cases. Surgical intervention may be required to cure these difficult cases.
 
Urolithiasis is a general term referring to the causes and effects of stones anywhere in the urinary tract. Urolithiasis should not be viewed conceptually as a single disease with a single cause, but rather as a sequela of multiple interacting underlying abnormalities. Thus, the syndrome of urolithiasis may be defined as the occurrence of familial, congenital, or acquired pathophysiologic factors that, in combination, progressively increase the risk of precipitation of excretory metabolites in urine to form stones (ie, uroliths). The following epidemiologic discussion is based on quantitative analysis of 350,803 canine uroliths, 94,778 feline uroliths, and 6310 feline urethral plugs submitted to the Minnesota Urolith Center from 1981 to 2007.
 
Knowledge of the mineral composition of uroliths in various species of animals can help veterinarians predict the mineral composition of stones in vivo. This information is important because dissolution of existing uroliths, or minimizing further growth of uroliths in situ, is dependent on knowledge of the mineral composition of uroliths. With this objective in mind, this report summarizes the results of quantitative mineral analysis of uroliths retrieved from 4468 animals sent to the Minnesota Urolith Center. It also encompasses the most extensive database about uroliths from animals other than domesticated dogs and cats found in the literature.
 
Geriatric health care remains a virtually untapped area in spite of changing public views and scientific knowledge on aging. The number of older dogs and cats will continue to grow into the next century. Owners of older dogs and cats are willing to invest in quality health care services. A geriatric health care program can expand veterinary services in a practice and is a natural extension of pediatric and adult maintenance programs.
 
Veterinary toxicology is a constantly evolving field. The authors use the ASPCA Animal Poison Control Center’s medical record database to examine recent trends in veterinary toxicology/animal poisoning incidents received from 2002 to 2010. The demographics of animals exposed to potentially harmful substances, the types of substances ingested, changes/emerging trends in substance exposures, and trends in therapies used to treat exposures are discussed.
 
Internal injuries are common and often life-threatening conditions that can be challenging to detect based on physical examination, radiographs, and centesis. Recently, ultrasound has been introduced and evaluated in human and veterinary emergency medicine as a point-of-care test for a variety of emergent conditions. This article discusses the indications for point-of-care emergency ultrasound of dogs and cats in the emergency and critical care setting. Techniques for performing focused emergency evaluations are described and the current veterinary and human literature is contrasted, with emphasis on abdominal, pleural, pericardial, and pulmonary evaluation.
 
Motivation in writing this article stems from many things: a lack of time spent in the veterinary curriculum discussing vaccines, a growing concern(by the general public and the veterinary community) regarding adverse reactions associated with vaccines, and a desire to prevent a recurrence of preventable infectious diseases resulting from a fear-driven cessation of vaccine administration. The objectives of this article are to present a basic review of immunology as related to vaccines, to discuss general guidelines for pediatric vaccines in canine and feline patients,and to offer suggestions as to how we can most positively influence our patients' health from the first visit.
 
Evidence-based veterinary medicine relies critically on the scientific validity of research. A component of validity is the statistical design and subsequent analysis of data collected during the study. Correct statistical design reduces bias and improves generalizability, and correct analysis leads to appropriate inferences. Inference is the art and science of making correct decisions based on data. Because veterinarians are responsible for the medical care of their patents, it is also their responsibility to understand inferences about treatments presented in papers. This article is designed to assist veterinarians with the interpretation and understanding of statistics presented in papers.
 
Because of the role of the kidneys in maintaining homeostasis in the body, kidney failure leads to derangements of fluid, electrolyte, and acid-base balance. The most effective therapy of a uremic crisis is careful management of fluid balance, which involves thoughtful assessment of hydration, a fluid treatment plan personalized for the specific patient, repeated and frequent reassessment of fluid and electrolyte balance, and appropriate changes in the treatment plan in response to the rapidly changing clinical situation of the patient that has renal failure. Disorders of sodium, chloride, potassium, calcium, and phosphorus are commonly encountered in renal failure and may be life threatening. Treatment of metabolic acidosis and nutritional support are frequently needed.
 
Chemoimmunotherapy with adjuvant CL/MAb 231 offers an alternative treatment approach for canine lymphoma. Results of treatment and prognostic factors are discussed and compared with previously published chemotherapy results.
 
The cytochrome P-450 (CYP) drug metabolizing enzymes are essential for the efficient elimination of many clinically used drugs. These enzymes typically display high interindividual variability in expression and function resulting from enzyme induction, inhibition, and genetic polymorphism thereby predisposing patients to adverse drug reactions or therapeutic failure. There are also substantial species differences in CYP substrate specificity and expression that complicate direct extrapolation of information from humans to veterinary species. This article reviews the available published data regarding the presence and impact of genetic polymorphisms on CYP-dependent drug metabolism in dogs in the context of known human-dog CYP differences.
 
A commonly recognized dental problem in cats is the resorption of tooth structure and subsequent loss of the tooth. These tooth defects are often very painful, because the sensitive dentin layer is exposed. The destruction of the tooth through odontoclastic resorption is considered a consequence of inflammatory resorption, probably secondary to periodontal inflammation. Because these resorptive lesions are progressive in nature, it is best to stage this progression of resorption in order to address treatment planning. The purpose of this study was to evaluate a group of 58 cats with resorptive lesions to determine the outcome of treatment 6 months or longer after restoration. In 81% of the cats, there was loss of the tooth, evidence of further resorption, or loss of the restoration at one or more resorption sites. Of the 154 teeth restored, only 33% showed no further evidence of loss of tooth structure.
 
Of the hundreds of minerals that are found in the earth, most canine uroliths are comprised of only six types: (1) magnesium ammonium phosphate, (2) calcium oxalate, (3) calcium phosphates, (4) ammonium urate and other salts or uric acid, (5) cystine, or (6) silica. Each type has characteristics that allow its identification. During the past two decades, the prevalence of calcium oxalate canine uroliths has dramatically increased, while struvite has decreased. The most effective treatment and prevention protocols are based on knowledge of the primary mineral type comprising the urolith.
 
This article contains an analysis of data compiled from 813 specimens of canine uroliths submitted to the Urinary Stone Analysis Laboratory at University of California School of Veterinary Medicine.
 
The American Animal Hospital Association Computer Program should benefit all small animal practitioners. Through the availability of well-researched and well-developed certified software, veterinarians will have increased confidence in their purchase decisions. With the expansion of computer applications to improve practice management efficiency, veterinary computer systems will further justify their initial expense. The development of the Association's veterinary computer network will provide a variety of important services to the profession.
 
Minimally invasive surgery of the abdomen constitutes an increasingly common and developed set of surgical options in small animal veterinary patients. In addition to established procedures, such as laparoscopic gonadectomy and biopsies, more advanced procedures, such as adrenalectomy, cholecystectomy, cisterna chyli ablation, and lymph node extirpation, are described. Some laparoscopic procedures have been reported using different techniques or approaches, reflecting the field's progression beyond its infancy. Advances in equipment and experience among an ever-growing group of veterinary surgeons are expected to result in progressively more widespread adoption of minimally invasive procedures. Copyright © 2015 Elsevier Inc. All rights reserved.
 
Pharmacologic agents may have a significant effect on the outcome of radiographic interpretation in small animal imaging. Alterations in the abdomen and thorax may represent artifactual or transient changes or changes reflecting cytotoxicity. Examples of agents that may influence the appearance of radiographs include anticonvulsants, sedatives, anesthetics, analgesics, antiinflammatories, gastrointestinal prokinetic drugs, antineoplastics, and hormones such as megestrol acetate. Radiographic studies may be part of a disease-monitoring process. It is important to understand how pharmaceuticals (e.g., chemotherapeutics or therapy for an underlying medical condition) affect the radiographic appearance. Caution should be exercised in the interpretation of radiographic studies because the findings may relate to the drug therapy rather than the underlying condition.
 
Invasive cytology of the thoracic and abdominal cavities can provide diagnostic information in a timely manner for the practitioner. The information depends on obtaining a quality sample followed by thorough cytologic evaluation. Diagnostic imaging can enhance the sampling process and minimize the risk. As an adjunct to the historic and clinical information, cytology is valuable in establishing a diagnosis or list of differentials and directing future diagnostics or therapy. The application of cytology of internal organs opens a new window for the differential diagnosis of disease.
 
Acute abdomen patients present a diagnostic and therapeutic challenge to emergency clinicians. The decision to perform surgery or to treat medically is often difficult to make and requires assimilating patient information, laboratory findings, radiological studies, and DPL. The importance of careful and repetitive PE cannot be overemphasized when managing these patients. If all diagnostics performed are not definitive and the patient continues to exhibit signs of abdominal pain, it is advisable to explore the abdominal cavity while administering supportive measures. Abdominal ultrasonography is emerging as a valuable diagnostic tool for the acute abdomen patient. Laparoscopy, CT, and CAD may also prove useful in certain cases.
 
Both radiography and ultrasound provide noninvasive imaging of suspected abdominal masses with minimal discomfort or risk for the geriatric patient. Radiography is more readily available and less expensive than ultrasonography, but contrast resolution is poor. Displacement of adjacent structures and addition of special contrast studies will provide clues to the possible organ of origin and extent of suspected abdominal masses. Cystic lesions can be differentiated from solid masses with ultrasound, but the appearance of focal abnormalities is not specific for any one disease process. Abdominal ultrasonography often provides the best diagnostic yield when used in combination with radiography and image-guided biopsy techniques.
 
The techniques of and general interpretive principles of gray-scale, two-dimensional abdominal ultrasonography in small animals are described. Using case examples, commonly encountered imaging artifacts and categories of disease are integrated with a description of what was obtained by radiography. Tissue echogenicity as a basis for general assessment of organ abnormalities as well as the expectations (interpretive and prognostic) one should have of abdominal ultrasonography are presented.
 
The laboratory evaluation of abdominal, thoracic, and pericardial effusions is a useful diagnostic tool for the assessment of disease states that result in fluid accumulation. Although the numeric values pertaining to cell count and protein content are important, the microscopic evaluation is a critical aspect of the diagnostic procedure; not only does it allow complete classification of the fluid but it allows identification of specific cell types or microorganisms that might be responsible for the fluid accumulation. These findings should always be interpreted in conjunction with the history, signalment, physical findings, and other diagnostic aids in making a definitive diagnosis.
 
Pediatric patients are commonly presented to the veterinarian because of signs referable to the abdominal cavity caused by congenital anomalies,dietary indiscretion, parasitic infestation, and infectious disease. Abdominal ultrasound provides valuable clinical information about the peritoneal cavity, great vessels, abdominal viscera, and lymph nodes,which is obtained in a noninvasive fashion and usually does not necessitate sedation or anesthesia. Ultrasonography thus greatly facilitates diagnostic evaluation of the pediatric patient. Ultrasound equipment already in place in many small animal veterinary clinics is appropriate for most pediatric cases.
 
This is an introductory article on abdominal vascular ultrasound in dogs. An overview of the hemodynamics of venous and arterial blood flow and Doppler principles, spectral analysis, and velocity waveforms is given. The anatomic and Doppler features of major abdominal vessels that can be examined routinely with ultrasonography are discussed. Select cases of vascular pathology affecting various abdominal vessels in the dog and cat are described.
 
Cavitary parenchymal lesions are composed of varying amounts of soft tissue, fluid, and/or gas. These cavitary lesions are focal or multifocal and therefore readily detected ultrasonographically. The ultrasonographic appearance of cystic and noncystic cavitary lesions are described. Differential diagnoses for these cavitary lesions in abdominal organs are listed.
 
Total ear canal ablation combined with bulla osteotomy is a salvage procedure recommended primarily for end-stage inflammatory ear canal disease but also for neoplasia and severe traumatic injuries. Due to the complexity of the procedure and the poor exposure associated with the surgical approach, there is significant risk for a variety of complications. This review discusses intraoperative, early postoperative, and late postoperative complications reported in large retrospective studies, the causes for these complications, and recommendations about how to prevent them.
 
No single technique allows one to diagnose all causes of urinary incontinence and abnormal increased frequency of urination. Cystography is indicated for cases of abnormal urinary bladder position, size, or shape. Ultrasonography is best for mass effects, calculi, and extrinsic nonskeletal abnormalities. The combined cystography and excretory urography technique is recommended for diagnosing ectopic ureteral insertions. Computerized tomography and MR imaging are indicated when the techniques described previously fail to elucidate the problem sufficiently, but these methods are usually not selected as primary diagnostic techniques.
 
Abnormal repetitive behaviors (ARBs) represent a diverse group of behaviors whose underlying mechanism is poorly understood. Their neurobiology likely involves several different neurotransmitter systems. These behaviors have been referred to as compulsive disorders, obsessive compulsive disorders and stereotypies. Underlying medical conditions and pain can often cause changes in behavior that are mistaken for ARBs. A complete medical work-up is always indicated prior to reaching a presumptive diagnosis. The frequency of ARBs can be reduced but not always eliminated with the use of selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs) in conjunction with behavior modification and environmental enrichment.
 
Animals with disorders of hemostasis are often presented as emergency patients and, as such, offer a challenge to the attending clinician. This article reviews the basic physiology of hemostasis and laboratory tests used for diagnosis. Guidelines for the evaluation and treatment of patients with bleeding disorders are provided.
 
Ultrasonographic imaging is widely used in small animal practice for the diagnosis of pregnancy and the determination of fetal number. Ultrasonography can also be used to monitor abnormal pregnancies, for example, conceptuses that are poorly developed for their gestational age (and therefore are likely to fail), and pregnancies in which there is embryonic resorption or fetal abortion. An ultrasound examination may reveal fetal abnormalities and therefore alter the management of the pregnant bitch or queen prior to parturition. There are, however, a number of ultrasonographic features of normal pregnancies that may mimic disease, and these must be recognized.
 
Static analysis of the canine hip has given some insight to the nature and trend of the force and subsequent stress that is normally applied to the joint. Using the static model, the magnitude and direction of force and stress worsens in the hip with the anatomic and stability changes associated with CHD. More sophisticated dynamic models that take into account unbalanced forces and moments with the resultant motion are needed to better understand the mechanics of the hip joint.
 
Subclinical abnormalities in hemostasis occur commonly in small animal patients with cancer, but the incidence of clinical thrombosis or hemorrhage is unknown. Malignancy can lead to abnormalities in both primary and secondary hemostasis, which in turn can lead to either thrombotic or hemorrhagic tendencies. These coagulation abnormalities can be associated with the tumor itself, with anticancer chemotherapy, or with secondary organ dysfunction. Thrombocytopenia and DIC are probably the most common defects associated with clinical bleeding in small animal patients.
 
Ascites and renal dysfunction are often associated with decreased liver function and reflect the complex abnormalities of water, protein, electrolyte, and acid-base metabolism that may complicate severe liver disease. This article discusses the pathophysiology and management of ascites, polydipsia and polyuria, decreased renal function, and acid-base and electrolyte alterations that can complicate liver disease.
 
With ever-increasing sophistication of veterinary cardiology, minimally invasive per-catheter occlusion and dilation procedures for the treatment of various congenital cardiovascular abnormalities in dogs have become not only available, but mainstream. Much new information about minimally invasive per-catheter patent ductus arteriosus occlusion has been published and presented during the past few years. Consequently, patent ductus arteriosus occlusion is the primary focus of this article. Occlusion of other less common congenital cardiac defects is also briefly reviewed. Balloon dilation of pulmonic stenosis, as well as other congenital obstructive cardiovascular abnormalities is discussed in the latter part of the article.
 
Many patients presented to the emergency veterinarian are suffering from global or local tissue hypoperfusion. Global or systemic hypoperfusion can occur secondary to a reduction in the effective circulating intravascular volume (hypovolemic shock) or reduced ability of the heart to pump blood around the body secondary to reduced cardiac function (cardiogenic shock),obstruction to blood flow (obstructive shock), or maldistribution of the circulating intravascular volume (distributive shock). Initial assessment involving physical examination supplemented by measurement of hemodynamic and metabolic parameters allows the clinician to recognize and treat patients with severe global hypoperfusion. Use of techniques like sublingual capnometry and measurement of central venous oxygen saturation may aid recognition and evaluation of early hypoperfusion. Treatment decisions are made based on an assessment of the severity of the hypoperfusion and its probable underlying cause. Early effective treatment of hypoperfusion is likely to lead to a better outcome for the patient.
 
Veterinarians will encounter hematologic abnormalities routinely while treating small animal cancer patients. Some of these abnormalities, such as monoclonal gammopathy, are relatively rare and highly associated with specific neoplasms. Thus, their detection should compel a search for underlying cancer. Other hematologic abnormalities, such as anemia or thrombocytopenia, are very common in cancer patients, and their identification should prompt clinicians to consider the different mechanisms by which they may have arisen and whether further diagnostic tests are needed to fully characterize their etiology. Although cancer-related hematologic abnormalities are frequently described in the veterinary literature, the incidence, prevalence, and clinical significance of these abnormalities are less well-defined. Anemia and coagulopathies are major causes of morbidity and mortality in human cancer patients, and may have a tremendous impact on disease progression and tumor response to antineoplastic therapy. It is plausible that the same is true for veterinary cancer patients, given the pathological and biological similarity between human and small animal tumors. Future studies should address the epidemiology and clinical significance of these, and perhaps other, hematologic abnormalities in order to determine whether therapeutic intervention to correct them may improve patient outcomes.
 
Disease of or injury to the central nervous system is a common rea-son for hospital admission on an emergency basis in veterinary medicine. Head injuries, seizures, and diseases that lead to intra-cranial hypertension frequently result in significant alteration of neurologic function. A thorough understanding of the pathophysiologic disturbances that occur during these conditions is para-mount for providing stabilizing emergent care. A detailed approach that focuses on meticulous physical evaluation, provision of timely and optimal stabilizing treatment, and continued monitoring can aid in improving outcomes in animals with signs and symptoms of neurologic disease or injury.
 
In this problem-oriented review of abnormalities associated with cancer, we have emphasized distinctive diagnostic points related to pathogenesis for each condition and outlined how the approach to management is determined by pathogenesis. For abnormalities of the complete blood count, it is important to distinguish between abnormalities directly related to marrow malignancy and abnormalities associated with extramarrow malignancy. Hemopoietic tumors consist of developmentally deficient blood cells produced by a clonal population of malignant stem cells. Tumors infiltrating marrow cause overcrowding in the limited marrow microenviroment. Extramarrow malignancies cause blood abnormalities, but the potential for normal marrow function is present. Abnormalities of blood cells secondary to therapy are usually clearly identified by consideration of clinical history. The initial differential diagnosis for hypercalcemia is malignancy. An aggressive diagnostic approach may be needed to identify the neoplasm, and therapy should incorporate measures to prevent renal failure. Hypoproteinemia and hyperproteinemia may be caused by neoplasia. Monoclonal gammopathies should be identified and may be associated with hyperviscosity syndrome. Hypoglycemia in the adult animal is most frequently caused by insulin-secreting tumors, but it has also been associated with hepatic and other tumors. Increased blood urea nitrogen, creatinine, lipase, amylase, and liver enzyme activities may also be caused by malignancy. Inadequate urine concentrating ability may be caused by hypercalcemia or malignancy-associated renal insufficiency. Hematuria in older animals is suggestive of urinary tract neoplasia. Exfoliated tumor cells may be identified in the urine sediment of these patients.
 
Nephrotic syndrome is often associated with a hypercoagulable state and thrombotic complications. Thrombosis may be due to a number of abnormalities in blood, including AT III deficiency, increased concentrations of fibrinogen, factors V and VIII, and platelet hyperaggregability. The therapeutic approach to thrombosis in nephrotic syndrome is the use of anticoagulants as a preventive measure or an attempt at thrombolysis with streptokinase, urokinase, or stanozolol.
 
Top-cited authors
Carl A Osborne
  • University of Minnesota Twin Cities
Jody P Lulich
  • University of Minnesota Twin Cities
Lisa K Ulrich
  • University of Minnesota Twin Cities
John Kruger
  • Michigan State University
Lori A Koehler
  • University of Minnesota Twin Cities