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Original Research
8.
Hypothyroidism - A cause for dilated cardiomyopathy
in dogs; four year study (2008-2011) -
Satish Kumar Karlapudi, Devarakonda Srikala , D S
Tirumala Rao
Vet World. 2012; 5(12): 742-747
doi:
10.5455/vetworld.2012.7
42-747
Abstract
Aim:
The study was carried out to understand the thyroid
dysfunction and its association with dilated
cardiomyopathy in dogs.
Materials and Methods:
The study was done at Teaching Veterinary Hospital,
Bhoiguda, College of Veterinary Science, Hyderabad
for four years, i.e., from 2008 to 2011. A total of
256 dogs of various breed, age and sex were
presented with typical skin and coat abnormalities.
Few were also exhibiting signs of low metabolic
rate. Skin sample analysis was done to rule out the
causes of dermatitis. Thyroid profile was estimated
to diagnose hypothyroidism. Selected cases were also
subjected for echocardiography to study the
association of cardiomyopathy. Based on thyroid
profile, hypothyroid dogs were treated with
levothyroxine @20mcg/kg wt, once daily, orally on
empty stomach and dilated cardiomyopathy (DCM)
associated patients were additionally supplemented
with enalapril @0.5 mg/kg, twice daily, orally for 6
months. The hemato biochemical and echocardiographic
aspects are discussed.
Results: The classical
signs that were recorded in almost all the thyroid
dysfunction dogs (231) were bilateral alopecia, rat
tail and pigmentation and whereas, dyspnoea at rest,
exercise intolerance, obesity, pale mucosae and
corneal lipidosis were the significant low metabolic
rate signs noticed in 42 dogs. However, syncope and
seizures were also recorded in 31 of these
hypothyroid dogs. Echocardiographic evaluation
revealed significantly (P<0.01) increased LVEDd and
LVEDs along with decreased IVS and LVPW both at
systole and diastole among 33 dogs. Normocytic,
normochromic and non-regenerative anemia and
significantly (P<0.05) low T3, fT4, tT4 along with
elevated serum cholesterol, triglycerides, TSH, CKMB,
LDH and ALP were the hemato – biochemical findings
among these dogs. After the initiation of therapy,
improvement in clinical signs was noticed from day 7
and complete clinical recovery by the end of
therapy. However, a non significant improvement was
recorded with respect to left ventricle dimensions.
Conclusions: From the present study it may be
concluded that thyroid dysfunction is presented by
manifestations of two different systems, i.e., skin
and coat and metabolic abnormalities.
Echocardiography is the more sensitive diagnostic
aid to ascertain the involvement of cardiovascular
system and to assess the therapeutic response.
Further, supplementation of ACE inhibitors along
with the specific thyroid supplements helps to
resolve the disorder.
Keywords: dilated
cardiomyopathy, dogs, enalapril, hypothyroidism,
levothyroxine
