Feline Hyperthyroidism Flashcards Preview

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Flashcards in Feline Hyperthyroidism Deck (13):
1

Hyperthyroidism

Clinical Signs

  • Weight loss despite polyphagia
  • hyperdefecation +/- steatorrhea
  • vx/dx
  • PU/PD
  • Restlessness, nervousness
  • Unkempt hair coat

2

Hyperthyroidism

Physical Findings

  • Weight loss (even 1 kg in a 19 kg cat)
  • Tachycardia +/- murmur
  • Tachypnea
  • Palpable Goiters
  • +/- hypertension
  • +/- Retinal hemorrhage (Start on 11/23)

3

Hyperthyroid DX test

  • total T4
    • One aside: Cats with chronic renal disease can have an elevated T4

4

Thyrotoxicosis

Apathetic Hyperthyroidism

  • extreme hyperthyroidism
  • Lacks usual featers of hyperthyroidism, cardiac dz dominates
  • cardiac pathologies
    • myocardial thickening

5

Apathetic hyperthyroidism signs

  • Tachycardia
  • Dyspnea
  • Abnormal lung sounds
  • +/- palpably enlarged thyroid glands
  • Rarely seen because of earlier dx

6

Non surgical Tx of hyperthyroidism

  • Beta blockers to slow down the heart
    • Propranolo
    • atenolol
  • If hypertensive
    • Amlodipine
  • Methimazole/tapazole: anti thyroid drug
  • I131
  • Hills diet y/d: devoid of iodine

7

Tapazole/Methimazole action

  • Prevents organification of iodide to iodine =>
    • prevents syntheses of thyroid hormone

8

Methimazole/Tapazole Toxic Effects

  • Anorexia
  • Vomiting
  • Lethargy
  • Facial pruritus => stop the drug
  • Bleeding diathesis
  • Icterus (hepatotoxicity)

9

Methimazole: Hematologic side effects

  • Eosinophilia
  • Lymphocytosis
  • Leukopenia
  • agranulocytosis => stop drug
  • Thrombocytopenia
  • Positive ANA

10

Surgery - Pre-OP

  • Restore euthyroidism pre-op
  • Assess KIDNEY function pre-op
  • Propranolol or atenolol for tachycardia
  • Anesthesia
    • avoid atropine
    • acepromazine and ketamine ok

11

Post op

  • Monitor for hypocalcemia with bilateral removal
  • Treat with Ca gluconate if indicated
  • Thyroxine if indicated

12

Renal function after hyperthyroid treatment

  • Chronic Kidney disease can benefit from the inc blood flow to kidneys during hyperthyroid states. 
    • treating the hyperthyroidism can toast the kidneys

13

Hyperthyroidism

Take home message

  • Usually older cats
  • common signs: weight loss, polyphagia
  • Assess cardiac status
  • treat with methimazole, and beta blockers
  • Do tapazole test before I 131
  • Watch out for renal disease
  • monitor for hypocalcemia after bilateral thyroidectomy