Week 11 Endocrine Pancreatic Diseases w Addison's/Cushings woDM PDF

Hypothyr Thyroid hormone deficiency oid Leads to decreased Disease metabolic rate Hypothyroidism common disease of dogs...

Hypothyr Thyroid hormone deficiency oid Leads to decreased Disease metabolic rate Hypothyroidism common disease of dogs 6-10 years of age, females more prone Genetic disposition Golden Retrievers, Labs Dobermans Irish Setters Miniature Schnauzers Spaniels Dachshunds Hypothyroidism in Animals - Endocri ne System - Merck Veterinary Manu Cocker Spaniel al Airedale Terriers  Hypothyroid Disease Etiology  Dysfunction anywhere in the hypothalamic- pituitary-thyroid axis may result in thyroid hormone deficiency > 95% of cases are dogs and is from destruction of gland itself termed “primary hypothyroidism” or thyroid atrophy  Causes: lymphocytic thyroiditis (autoimmune disease) and idiopathic atrophy of the thyroid gland  Secondary is uncommon but may be from a tumor, or congenital. Hypothyroid Disease Clinical Signs Metabolic & Dermatological Signs Lethargy Weight gain Altered skin/coat: alopecia, excessive shedding, dry skin coat Loss of hair on tail common, “rat tail” Sun seeking Recurrent skin infections, UTI’s Reproductive problems (anestrus)  Hypothyroidism is probably one of the most Hypothyroid Disease overdiagnosed diseases in dogs *can easily mimic Diagnosis other diseases Clinical Signs *careful attention to +/- Hypercholesterolemia Low T3, free T4 Serum thyroid hormone testing: “Thyroid Stimulating Hormone” (TSH) = high Hypothyroid Disease Treatment Lifelong supplement with thyroid hormone replacement Human options make treatment fairly inexpensive Orally BID, good success Monitor dosage frequently Too high a dosage = hyperthyroid Once stabilized recheck 1-2 times Thyrotoxicosis is rare in dogs and can result in polyuria and per year polydipsia, weight loss, Indication of tx success = clinical panting, nervousness, or improvement tachycardia. Hyperthyroid Diseases Hyperthyroidism in Animals - Endocrine System - M erck Veterinary Manual Hyperthyroidism common disease of cats Middle aged – older cats most common Excess of T3 & T4 due to thyroid adenoma, thyroid carcinoma possibly Screening & early detection: T4 Blood tests, esp in senior cats Can sometimes palpate enlarged gland without other clinical signs and T4 concentration normal, recheck T4 in 6 months or if clinical signs develop  Hyperthyroid Diseases Clinical Signs Weight loss Polyphagia Occasional vomiting Increased appetite Tachycardia +/- murmur Hypertension Blindness + retinal detachment Increased vocalization, especially at night Hyperthyroid Diseases Diagnosis Increased T4 in serum chemistry is diagnostic if clinical signs present If high and no CS, recheck in 2 weeks Palpate enlarged thyroid glands DI  Hyperthyroid Diseases Treatment 1. Radioactive Iodine-131 Curative treatment of choice Simple & effective Diseased tissue absorb radioactive 131 = destruction of cells Hospitalization until radioactive material becomes absent from body Specialized procedure Hyperthyroid Diseases …Treatment 2.Antithyroid drug therapy Palliative approach Daily, life-long Block thyroid hormone synthesis Oral, transdermal, caution when touching Routine blood, BP, physical exam monitoring E.g. methimazole, carbimazole Hyperthyroid Diseases …Treatment 3. Diet o Lifelong o Iodine-deficient diet o Without iodine the thyroid can’t produce hormones o Indicated if not a candidate for radioiodine/thyroidectomy o Most effective if only moderate increases in T4 o Can’t eat any other food than this! (no treats, prey, scraps…)  Hyperthyroid Diseases Treatment 4. Surgery - Thyroidectomy Potentially curative but with anesthetic risks Removal of thyroid glands = removal of thyroid hormone = cure One (unilateral) or both (bilateral) tyroid gland removal Requires competent surgeon who will spare parathyroid glands Supplement with thyroid hormone orally  Hyperthyroidism Complications Secondary disorder that can arise: Thyrotoxic hypertrophic cardiomyopathy Systemic hypertension Chronic kidney disease (CKD)