Hyperthyroidism vs Pheochromocytoma
How to tell Hyperthyroidism and Pheochromocytoma apart when a board question makes them look alike.
Thyroid excess is sustained metabolic overdrive; pheochromocytoma is episodic catecholamine storm.
Side by side
Weight loss, heat intolerance, tremor, goiter, hyperdefecation, low TSH, and high thyroid hormone.
Episodic headache, sweating, palpitations, and severe paroxysmal hypertension.
Excess thyroid hormone increases basal metabolic and adrenergic tone.
Catecholamine-secreting tumor releases norepinephrine and epinephrine surges.
Low TSH with elevated free T4 supports primary hyperthyroidism.
Elevated plasma free metanephrines support pheochromocytoma.
The trap
Sweating, tachycardia, anxiety, and weight loss all occur in both, so adrenergic symptoms alone do not pick the diagnosis. The deciding feature is the temporal pattern. Hyperthyroidism is sustained continuous overdrive with heat intolerance, fine tremor, brisk reflexes, and Graves features (diffuse goiter with bruit, exophthalmos, pretibial myxedema). Pheochromocytoma is episodic catecholamine paroxysms with the classic 5 P's (Pressure spike, Pounding headache, Palpitations, Perspiration, Pallor) and normal labs between attacks. Confirm pheochromocytoma with plasma free metanephrines, then localize with abdominal CT or MRI. Before any surgery, start alpha-blockade with phenoxybenzamine first; never give beta-blockade alone because unopposed alpha-mediated vasoconstriction can precipitate hypertensive crisis.
Watch it explained
The repair move
When adrenergic symptoms appear, ask whether the story is constant metabolic excess or episodic pressure surges.
Try a free question
CoreA patient has weight loss, heat intolerance, tremor, goiter, hyperdefecation, low TSH, and elevated free T4. Which diagnosis best explains the presentation?
Show answer and explanation
Answer: A. Hyperthyroidism. Sustained thyroid hormone excess causes metabolic overdrive with low TSH and high free T4.
Why the other choices are tempting
- B. Pheochromocytoma causes episodic catecholamine spells and severe hypertension.
- C. Panic disorder does not cause elevated thyroid hormone.
- D. Carcinoid syndrome causes flushing, diarrhea, and bronchospasm.
- E. Cushing syndrome causes cortisol excess with catabolic signs.
Flashcards
Tap a card to flip it.
What time course favors pheochromocytoma over hyperthyroidism?
Paroxysmal spells of headache, sweating, palpitations, and severe hypertension favor catecholamine surges.
What lab pattern confirms primary hyperthyroidism?
Suppressed TSH with elevated free thyroid hormone supports primary thyroid overproduction.
Quick answers
What is the fastest way to tell Hyperthyroidism from Pheochromocytoma?
Thyroid excess is sustained metabolic overdrive; pheochromocytoma is episodic catecholamine storm.
What is the key clue for Hyperthyroidism?
Weight loss, heat intolerance, tremor, goiter, hyperdefecation, low TSH, and high thyroid hormone.
What is the key clue for Pheochromocytoma?
Episodic headache, sweating, palpitations, and severe paroxysmal hypertension.
What is the common trap with Hyperthyroidism vs Pheochromocytoma?
Sweating, tachycardia, anxiety, and weight loss all occur in both, so adrenergic symptoms alone do not pick the diagnosis. The deciding feature is the temporal pattern. Hyperthyroidism is sustained continuous overdrive with heat intolerance, fine tremor, brisk reflexes, and Graves features (diffuse goiter with bruit, exophthalmos, pretibial myxedema). Pheochromocytoma is episodic catecholamine paroxysms with the classic 5 P's (Pressure spike, Pounding headache, Palpitations, Perspiration, Pallor) and normal labs between attacks. Confirm pheochromocytoma with plasma free metanephrines, then localize with abdominal CT or MRI. Before any surgery, start alpha-blockade with phenoxybenzamine first; never give beta-blockade alone because unopposed alpha-mediated vasoconstriction can precipitate hypertensive crisis.