CANINE AUTOIMMUNE THYROID DISEASE: COMMON PROBLEM OF PUREBRED DOGS
“Most of the confusion about the diagnosis and treatment of thyroid disease in purebred or mixed breed dogs today stems from the expectation that affected animals must show clinical signs of inadequate thyroid hormonal production (i.e. hypothyroidism) in order to have the disease….The most common cause of canine thyroid disease is autoimmune thyroiditis (estimated 90% of cases).
please refer to complete article by Dr Jean Dodds DVM at http://www.canine-epilepsy-guardian-angels.com/ThyroidDisease.htm
highlights of the article presented here
Thyroiditis is an immune-mediated process that develops in genetically susceptible individuals and is characterized by the presence of antithyroid antibodies in the blood or tissues. Thyroiditis is believed to start in most cases around puberty, and gradually progress through mid-life and old age to become clinically expressed hypothyroidism once thyroid glandular reserve has been depleted. During this process, the animal or person becomes more susceptible to immune-mediated or other diseases affecting various target tissues and organs.” :
“CLINICAL SIGNS OF CANINE HYPOTHYROIDISM
Alterations in Cellular Metabolism
weakness / stiffness / laryngeal paralysis / facial paralysis / tragic expression / knuckling or dragging feet / muscle wasting / megaesophagus / head tilt / drooping eyelids
Neuromuscular Problems
seizures / mental dullness / exercise intolerance / neurologic signs polyneuropathy / lethargy / weight gain / cold intolerance / mood swings hyperexcitability / stunted growth / chronic infections
Dermatologic Diseases
dry, scaly skin and dandruff / coarse, dull coat / bilateral symmetrical hair loss / rat tail, puppy coat / hyperpigmentation / seborrhea or greasy skin pyoderma or skin infections / myxedema / chronic offensive skin odor
Reproductive Disorders
infertility of either sex / lack of libido / testicular atrophy / hypospermia aspermia / prolonged interestrus interval / absence of heat cycles / silent heats / pseudopregnancy / weak, dying or stillborn pups
Cardiac Abnormalities
slow heart rate (bradycardia) / cardiac arrhythmias / cardiomyopathys
Gastrointestinal Disorders
constipation / diarrhea / vomiting
Hematological Disorders
bleeding / bone marrow failure / low red blood cells / low white blood cells / low platelets
Ocular Diseases
corneal lipid deposits / corneal ulceration / uveitis Keratococonjunctivitis / sicca or dry eye / infections of eyelid glands (Meibomian gland)
Other Associated Disorders
lgA deficiency / loss of smell (dysosmia) / loss of taste / glycosuria / chronic active hepatitis / other endocrinopathies adrenal, pancreatic, parathyroid”
Thyroid panels and antibody test should be used for genetic screening of animals considered for breeding. This should be done after puberty. All dogs should have baseline thyroid levels drawn annually for health evaluation and comparison to allow for early treatment. Healthy young dogs should have thyroid levels in the upper 1/2 to 1/3 of the normal adult levels.(Intact females should have health screenings drawn in the anestrus period12-16 weeks from the onset of the previous heat for more reliable results)
Treatment recommended by Dr Dodds
The new information summarized here has changed our approach to treatment and control of thyroid disease. In addition to providing thyroid supplementation for dogs showing the typical signs of thyroid disease, we now know that treatment of dogs showing the early stages of thyroiditis (based on the testing described above) is necessary and important to correct the underlying thyroid imbalance, reduce the risk of developing other related immune-mediated disorders, and to control or prevent the process of thyroiditis from progressing to depletion and exhaustion of the thyroid gland.
Treatment of choice is T4 hormone.(levothyroxine) every 12 hours. With followup testing after 4 or 8 weeks, sample taken 4-6 hours after morning dose. Dogs on long term therapy should be monitored with complete panels every 6-12 months.
See orig article for more information.http://www.canine-epilepsy-guardian-angels.com/ThyroidDisease.htm<