Feline Hyperthyroidism Flashcards
Thyroid Gland
Synthesis
Synthesizes hormones that incorporate iodine
* thyroxine (T4)
* triiodothyronine (T3)
Thyroid Gland
Hormone Effects
Physiologic
Increase
* metabolic rate
* HR
* oxygen consumption
* erythropoiesis
* catecholamine response
Thyroid Gland
Hormone Effects
Tissue
Catabolic effects on tissues
* muscle
* adipose
Hyperthyroidism
C/S
- Weight loss with polyphagia
- Thyroid nodule (slip)
- Hyperactivity
- Vomiting
- Increased vocalization
- Tachycardia / murmur or gallop
- Thyrotoxic cardiomyopathy
Hyperthyroidism
Diagnosis
Preferred Screening Test: Serum Total T4
* some may be a “gray zone” - slighly above normal
* retest should be done
Hyperthyroidism
Treatment Options
- Medical
- Surgical
- Radioactive Iodine
- Dietary Therapy
Thyroid and Renal Function
Regardless of treatment, renal function should be monitored
* renal insufficiency common comorbid condition
* severity / presence can be masked by hyperthyroidism
Hyperthyroidism
Medical Treatment
Oral or TDG Methimazole
* treatment for initial therapy
* possible side effects - facial excoriations (skin picking)
Hyperthyroidism
Surgical Treatment
Thyroidectomy
* bilateral disease = bilateral removal
Hyperthyroidism
Radioactive Iodine Treatment
I-131
* single dose administration
* required hospitalization for several days to weeks
Hyperthyroidism
Dietary Treatment
Iodine
* restricted diet reduces T3 and T4 production
* controversial - reserved when other options not available
