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
Thyroid tumor
Diagnostics
T4 and FT4
Radiographs, ultrasound, CT/MRI to check invasiveneness and metastasis
FNA/Biopsy with cytology/histopath
Thyroid tumor
Treatment
Surgery, radiation, and chemo
Thyroid tumor
Prognosis
Good to excellent with treatment
Client education: harness, reduced activity
