Thyroid Gland Flashcards
Hyperthyroidism
Signalment
Older cats
Hyperthyroidism
Pathophysiology
Excessive production of T4 and T3
Benign adenomas
1-3% are malignant thyroid carcinomas
Hyperthyroidism
Clinical signs/Physical exam
Wt loss, polyphagia, palpable thyroid, tachycardia
Hyperthyroidism
Diagnostics
Elevated T4 and FT4
TSH - low
Increased ALT and ALP
Scintigraphy
Hyperthyroidism
Treatment
Methimazole
Thyroidectomy
Radioiodine therapy
Iodine-restricted diet
Hyperthyroidism
Prognosis
Depends on age, concurrent diseases, and method of treatment
Hypothyroidism
Pathophysiology
Inadequate production of Triiodothyronine and thyroxine
Primary: 95% of cases Lymphocytic thyroiditis (immune-mediated process destroys normal tissue and replaces it with fibrous connective tissue)
Secondary:
Malformation or neoplasia of the PG
Hypothyroidism
Signalment
Dogs
Hypothyroidism
Clinical signs/Physical exam
Lethargy, wt gain, and alopecia
Hypothyroidism
Diagnostics
T4 - low
FT4 - more specific
TSH - increased
Euthyroid sick syndrome - when it looks like hypothyroid, because of other diseases. T4 low, FT4 normal.
Diseases that affect thyroid concentrations: Cushing’s, renal disease, hepatic disease, heart failure, severe infection, DKA.
Drugs that affect thyroid concentrations: glucocorticoids, phenobarbital, NSAIDS, sulfa antibiotics, clomipramine, contrast agents
Hypothyroidism
Treatment
Levothyroxine
Monitor q 4-8 weeks until appropriate dose and then 6-12 months.
Hypothyroidism
Prognosis
Life expectancy normal with treatment
Thyroid Tumor
Pathophysiology
70-100% are malignant
30-60% have metastasis at time of diagnosis
Thyroid tumor
Signalment
Dogs
Middle aged - older
Boxers, beagles, and golden retrievers
Thyroid Tumor
Clinical signs/Physical exam
Palpable mass on ventral neck
Trouble swallowing, regurg, tachypnea, dyspnea, loud breathing, coughing, bark change
Lethargy, wt loss, decreased appetite
Signs of hyperthyroidism is the tumor is functional
