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Kumar and Srikala/ J. Adv. Vet. Anim. Res., 2(2): 221-224, June 2015 221
Hypothyroid associated megaesophagus in dogs: four years (2009-
2013) study in Hyderabad, India
Karlapudi Satish Kumar* and Devarakonda Srikala
Veterinary Medicine, College of Veterinary Science, Sri Venkateswara Veterinary University, Tirupati, India.
*Corresponding author’s e-mail: drsatish.ksk@gmail.com
ABSTRACT
Megaoesophagus is uncommon but an important
consideration for chronic regurgitation in dogs. Five
dogs of various breeds were presented to the
Teaching Veterinary Clinical Complex (TVCC) at
College of Veterinary Science, Hyderabad with signs
of chronic regurgitation, loss of weight, lethargy,
weakness, dehydration and abnormalities of skin,
and hair coat were diagnosed for megaesophagus on
barium meal contrast radiography. At the TVCC,
radiography and gastroscopy were performed, and
the condition was confirmed as megaesophagus.
Ancillary hemato-biochemical evaluations revealed
normocytic normochromic anemia and mild
leukocytosis with normal enzymatic activity in liver
and kidneys. The thyroid profile in 80% (n=4/5) dogs
showed decreased T3 and T4, and elevated thyroid
stimulating hormone (TSH) levels confirming
hypothyroidism. Ultrasonography of abdomen
eliminated obstructions in the gastro-intestinal tract
and other systemic conditions. Echocardiographic
observations were normal in all the dogs. Treatment
with metoclopramide (dosed at 5 mg/kg bwt) and
levothyroxine (dosed at 20 μg/kg bwt) and modified
management practices involving feeding and diets
were successful in controlling the regurgitation in
dogs and resulted in good clinical recovery within 20-
30 days of post-treatment.
Keywords
Dogs, Megaesophagus, Regurgitation, Hypothyroidism
ARTICLE HISTORY
Received : 31 August 2014, Revised: 28 October 2014,
Accepted : 10 November 2015, Published online: 7 February 2015.
INTRODUCTION
Megaesophagus is a condition in which the muscles of
the esophagus lose their tone and are no longer able to
propel food into the stomach. As a result, the
esophagus becomes dilated leading to esophageal
paralysis and dysfunction. The majority of cases in
canine, megaesophagus have no apparent cause and
hence the condition may be termed as idiopathic
megaesophagus. The disease can be either secondary to
underyling disease, such as, hypothyroidism or
mysthenia gravis or a congenital disease associated
with vascular ring anomaly in very young puppies.
Clinical signs of megaesophagus vary depending on
severity and may include: regurgitation that may begin
minutes to several hours after eating or drinking,
excessive salivation, mild to moderate weight loss,
coughing or wheezes (German, 2005).
MATERIALS AND METHODS
Five dogs of various breed, age and sex were presented
during 2009 to 2013 to the Teaching Veterinary Clinical
Complex (TVCC), Bhoiguda, College of Veterinary
Science, Hyderabad with the history and clinical signs
of chronic recurrent regurgitation of undigested food
following food intake, loss of weight, lethargy,
weakness, dehydration and abnormalities of skin, and
hair coat. After thorough clinical examination, blood
and serum were collected for hemato–biochemical
evaluations viz. total erythrocyte count (TEC),
hemoglobin, liver and kidney specific enzymes, and
thyroid profile. Later, imaging studies like thoracic and
abdomen radiography (plane and contrast) were
undertaken, followed by gastroscopy and abdomen
ultrasonography were done to evaluate the cause of
chronic vomiting.
J. Adv. Vet. Anim. Res., 2(2): 221-224.
Available at- http://bdvets.org/JAVAR
CASE REPORT
OPEN ACCESS
DOI: 10.5455/javar.2015.b69
Volume 2 Issue 2 (June 2015)
eISSN 2311-7710
Kumar and Srikala/ J. Adv. Vet. Anim. Res., 2(2): 221-224, June 2015 222
Based on radiographic, gastroscopic and thyroid profile
findings, the dogs were diagnosed for megaesophagus
associated with hypothyroidism. The dogs were
managed with administration of parenteral
administration of metoclopramide dosed at 5 mg/kg
bwt, and oral levothyroxine dosed at 20 μg/kg bwt,
along with other supportive drugs and managemental
practices.
RESULTS AND DISCUSSION
Detailed and thorough anamnesis revealed that the
dogs were expelling the undigested food within few
minutes of consumption. Further, almost all the dogs
were showing similar manifestations viz., vomiting,
cough, dull, dehydrated and weight loss with increased
appetite, and most of them were (n=4/5) lethargic with
exercise intolerance, bilateral alopecia, pigmentation
with rat tail (Figure 1 to 3). Thorough clinical
examination revealed normal clinical parameters viz.,
temperature (101.20F), pulse (68/min) and respiration
rates (23/min), but with moderately pale visible
mucous membranes. Hematologically, moderately low
TEC (5.14X106/L) and hemoglobin (7.64 g/dL), along
with mild leukocytosis (9.36X103/L) with neutrophilia
(82%) were recorded. Similarly, no abnormality was
detected with liver specific and kidney enzymatic
activity. In dogs with megaesophagus, the esophagus
dilates, or enlarges due to the lack of muscle tone, as a
result of which, the food gets lodged in the esophagus,
and unable to move to the stomach. Megaesophagus is
seen more often in dogs as compared to cats. Some
breeds like, German shepherds, Dachshunds, Great
Dane, Labrador retriever and Pug are reported to be
predisposed to this condition (Suryavamshi et al.,
2001). Regurgitation is considered the hallmark sign of
megaesophagus. Also, aspiration pneumonia may
develop due to the entrance of food or liquid into the
lungs. Vomiting, cough, nasal discharge, respiratory
noises, weight loss with increased hunger, halitosis and
poor growth were the significant signs associated with
megaesophagus (Guilford, 2005). In the present study,
the condition was similar diagnosed in Labrador
retreiver (n=3), Pomeranian (n=1) and German
shepherd (n=1) with support of the findings of
Suryavamshi et al. (2001) and Guilford (2005). Whereas,
Suryavamshi et al. (2001) opined that emaciation,
hidebound condition, shrunken abdomen, prominent
ribcage and slight to moderate pain and discomfort at
cervical and abdominal area on palpation were the
prominent clinical signs in megaesophagus dogs.
Figure 1. Depressed, dehydrated and weakened
megaesophagus dog.
Figure 2. Bilateral alopecia and rat tail appearance-
hypothyroidism.
Figure 3. Patchy alopecia - hypothyroidism.
Kumar and Srikala/ J. Adv. Vet. Anim. Res., 2(2): 221-224, June 2015 223
Figure 4. Dilated esophagus – contrast Xray.
Figure 5. Barium meal contrast radiograph – dilated
esophagus.
Figure 6. Endoscopic image – dilated esophagus with
flaccid walls.
The authors further reported that no significant serum
chemistry alterations could be commonly seen in
megaesophagus cases. Plain radiographic examination
of thorax and abdomen of all the cases did not reveal
any foreign body. Similarly, ultrasonographic
evaluation of abdomen did not reveal any abnormality
in echogenic texture of gastric wall and small intestine.
Further, echocardiographic evaluation was found as
negative for any persistent aortic arch (Umarani, 2007).
Whereas, barium meal contrast radiography of all the 5
dogs revealed dilatation of cervical and thoracic
esophagus (Figure 4 and 5). Guilford (2005) reported
that plain radiography might not help to diagnose
megaesophagus. However, Jain and Tayal (2008) could
diagnose the condition by using contrast radiography
with barium meal.In our study, gastroscopy was
performed under ketamine (dosed at 10 mg/kg bwt)
and xylazine (dosed at 1 mg/kg bwt) anesthesia.
Endoscopic examination of all the 5 dogs revealed
severely dilated esophagus (Figure 6) from cervical
portion to gastro-esophageal sphincter, giving a
cavernous appearance and the flaccid redundant walls
that were draped against trachea, with pooling of
gastric fluid into the esophageal lumen (Tams, 1996).
Gualtiere (2001) and Guilford (2005) strongly suggested
that endoscopic evaluation had no comparison in
diagnosing megaesophagus, and differentially
diagnosing regurgitation in dogs.
In the present study, 4 out of 5 dogs were shown
altered levels of thyroid profile viz., decreased T4 (1.26
μg/dL), T3 (29.54 ng/dL) and increased thyroid
stimulating hormone (TSH) (7.58 ng/mL) against
normal levels (3.44, 72.18 and 2.12), respectively. One of
the probable causes for megaesophagus was
hypothyroidism, which could be attributed to general
metabolic derangements that occurred in impaired
thyroid function or might be an indication of a
neuropathy or myopathy (Fors, 2008). The findings
were supported by Jaggy et al. (1994), who stated that,
in hypothyroidism, nerves did not conduct electrical
impulses normally. This might account for some of the
general weakness, exercise intolerance, lethargy and
listlessness observed in hypothyroidism.
From the present findings, the presented 5 dogs were
diagnosed for megaesophagus, of which 4 were
associated with hypothyroidism and 1 was of
idiopathic origin. All these dogs were treated with
antiemetic (metachlopromode dosed at 0.5 mg/kg, IM),
for three days along with levothyroxine (n=4/5 dogs)
dosed at 20 μg/kg, orally once for 30 days. Further, the
owners were advised to feed small amount of liquid or
semi solid food that was easily digestible. All the 5
dogs gradually improved physically with alleviation of
clinical signs and became normal with normal
hydration status and skin and coat condition (n=4/5
cases) by 20-30 days. However, levothyroxine was
continued for hypothyroid cases.
Kumar and Srikala/ J. Adv. Vet. Anim. Res., 2(2): 221-224, June 2015 224
Megaesophagus could be associated with certain
neuromuscular diseases like myasthenia gravis. But
most of the causes, the condition might be of idiopathic
in origin. However, other known causes of megaeso-
phagus were hypothyroidism, hypoadrenocorticism,
esophagitis, autoimmune diseases and heavy metal
poisoning (Scott-Moncrieff, 2007). In the dogs having
paralysis of esophagus, the food, water and
medications might be placed in a vertical or elevated
position to allow gravitational fall into the stomach.
German (2005) and Jain and Tayal (2008) documented
that, offering food, water and treats with the placement
of pet in a vertical position (i.e., sitting up in a begging
pose) were important aspects in management of
megaesophagus. Feeding from a height made use of
gravity and optimized passive transport of food from
oro-pharynx into stomach. The affected dogs could also
be fed over shoulder and held in a vertical position to
allow passage of food into stomach. German (2005)
reported that feeding of dogs by gravity might lead to
complications like aspiration pneumonia and
malnutrition. Further, it was suggested that the amount
of food offered at each feeding; the number of meals
per day and the format (liquefied food, blended to a
smooth consistency in a blender, or food compressed
into meatball form) played a major role in management
of megaesophagus. Jain and Tayal (2008) on evaluating
feeding practices in dogs with megaesophagus
reported that high fat, raw, processed and rice diets
were leading to frequent regurgitation, aspiration
pneumonia, bacterial infections and poor tolerance,
respectively. However, it was suggested to feed low fat
diets, as it was well tolerated by dog. The findings in
the present study revealed that the 80% dogs (n=4/5)
were associated with hypothyroidism and 20% (n=1/5)
with an idiopathic origin. Whereas, all the affected
cases were effectively managed with an antiemetic viz.
metachlopromide dosed at 0.5 mg/kg, IM, for three
days, and to those hypothyroidic dogs with
levothyroxine dosed at 20 μg/kg, PO, S.I.D for 1
month. Further, the owners were advised to feed soft
and easily digestible liquid diets and/or semi-solid
foods in small quantities but at frequent intervals from
an elevated platform. However, by the end of
treatment schedule (20–30 days), all the 5 dogs showed
complete clinical recovery.
CONCLUSION
Dogs presented with signs of chronic regurgitation,
loss of weight, lethargy, weakness, dehydration and
abnormalities of skin and hair coat are suggested for
megaesophagus. In most cases, megaesophagus in dogs
is found to be associated with hypothyroidism.
Treatment with metoclopramide and levothyroxine
and modified management practices involving feeding
and diet can be used in controlling the regurgitation in
the dogs.
ACKNOWLEDGEMENT
The authors are thankful to Sri Venkateswara
Veterinary University, Tirupati for providing the
facilities to carry out this work.
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