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Vetdle Archive

Archive Case #8: Feline Hyperthyroidism

Cat veterinary case - Easy - March 11, 2026

Clinical Clues

  1. A 13-year-old domestic shorthair cat is presented for weight loss.
  2. The owner reports the cat has been eating more than usual over the past several months.
  3. The cat has also become more active and vocal than normal.
  4. On examination the cat is thin, tachycardic, and a small thyroid nodule can be palpated in the neck.
  5. Blood testing reveals a markedly elevated total T4 concentration.
  6. This endocrine disorder results from excessive thyroid hormone production, leading to increased metabolic rate in older cats.

Diagnosis

Feline Hyperthyroidism

Feline hyperthyroidism is a common endocrine disease in older cats caused by hyperfunctional thyroid tissue, usually adenomatous hyperplasia.

Learning review

Review the case evidence

Use the paired clues to explain how the evidence in this cat case supports the provided diagnosis, Feline Hyperthyroidism, then compare your reasoning with the case explanation.

Evidence checkpoints

Clues 1-2

  1. Clue 1: A 13-year-old domestic shorthair cat is presented for weight loss.
  2. Clue 2: The owner reports the cat has been eating more than usual over the past several months.

Clues 3-4

  1. Clue 3: The cat has also become more active and vocal than normal.
  2. Clue 4: On examination the cat is thin, tachycardic, and a small thyroid nodule can be palpated in the neck.

Clues 5-6

  1. Clue 5: Blood testing reveals a markedly elevated total T4 concentration.
  2. Clue 6: This endocrine disorder results from excessive thyroid hormone production, leading to increased metabolic rate in older cats.

Self-review prompts

  1. After clues 1-2, what evidence from this cat case shaped your initial interpretation?
  2. When you compare clues 3-4 with clues 1-2, what changed in your reasoning about Feline Hyperthyroidism?
  3. How do clues 5-6 align with the case explanation for Feline Hyperthyroidism?

Educational Use

Vetdle archive cases are educational veterinary games for diagnostic reasoning practice. They do not provide veterinary advice, diagnosis, treatment, or professional medical guidance.