💤 Apathetic thyrotoxicosis is an atypical presentation of hyperthyroidism, most often seen in older adults.
Instead of hyperactivity and restlessness, patients show a striking lack of energy, enthusiasm, and motivation.
They may appear withdrawn, flat, or depressed — hence the term "apathetic." This subtle picture contrasts with the
classic hyperkinetic presentation of thyrotoxicosis.
📖 About
- Apathetic thyrotoxicosis = atypical form of thyrotoxicosis in elderly patients.
- Classic adrenergic signs (tremor, restlessness, anxiety) may be absent ❌.
- Instead, patients present with apathy, lethargy, and features mimicking depression or frailty.
⚠️ Clinical Features
- Marked weight loss despite reduced appetite 🍽️⬇️.
- Lethargy, fatigue, reduced activity → may lead to falls in older adults.
- Apathy and low mood — often misdiagnosed as depression.
- Cognitive changes including delirium or pseudo-dementia 🧠.
- Atrial fibrillation and other arrhythmias are common, sometimes the first clue ❤️⚡.
🧪 Investigations
- Thyroid Function Tests (TFTs): ↑ Free T4 / T3, ↓ TSH → confirms thyrotoxicosis.
- ECG may reveal atrial fibrillation or tachyarrhythmias.
- Consider bone profile (osteoporosis risk) and glucose (thyrotoxicosis can worsen diabetes).
💊 Management
- Antithyroid drugs (Carbimazole, PTU) – first-line to suppress hormone synthesis.
- Radioactive iodine therapy ☢️ – effective in elderly, often preferred for definitive control.
- Beta-blockers (e.g., propranolol, atenolol) – relieve adrenergic symptoms and control AF.
- Surgery (thyroidectomy) – rarely required, reserved for refractory cases or where malignancy suspected.
🔑 Teaching Pearls
- Apathetic thyrotoxicosis is a classic “masquerader” in geriatrics – think of it in any older patient with unexplained weight loss, depression, or new AF.
- Arrhythmias, rather than hyperactivity, may be the most dangerous presenting feature.
- Always check TFTs in an older adult with new-onset “depression” or “failure to thrive.”
