Phaeochromocytoma and Adrenal Disorders in Pregnancy
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Direct answer
Phaeochromocytoma is a catecholamine-secreting tumour of the adrenal medulla that can mimic severe pre-eclampsia in pregnancy. Its classic features are episodic hypertension with headache, sweating and palpitations, and the diagnosis rests on plasma or urinary metanephrines. Management is alpha blockade first, then beta blockade, with adrenalectomy usually planned in the second trimester once the patient is controlled.
What you must remember
- Classic triad: headache, sweating and palpitations, often with paroxysmal hypertension, pallor and tremor, which help separate it from pre-eclampsia.
- Biochemical diagnosis: plasma free metanephrines, or 24-hour urinary fractionated metanephrines and catecholamines; a normal result makes the tumour very unlikely.
- Localisation: ultrasound as a first look, with non-contrast MRI preferred in pregnancy to limit fetal exposure.
- Alpha blockade first: phenoxybenzamine controls pressure and restores volume before any other agent is used.
- Beta blockade second: added only after adequate alpha blockade, since unopposed alpha stimulation can precipitate a hypertensive crisis.
- Cushing syndrome: excess cortisol from an adrenal adenoma causes hypertension, glucose intolerance and central obesity, and surgery is definitive.
- Addison disease: adrenal insufficiency needs glucocorticoid replacement and stress-dose steroids during labour, surgery and illness.
A graded pathway from suspicion to adrenalectomy
A pregnant woman with paroxysmal hypertension and palpitations has not got pre-eclampsia until a catecholamine tumour is excluded. The steps below protect the mother while the diagnosis is confirmed and the drugs are sequenced correctly.
- Suspect and confirm: episodic hypertension with headache, sweating and tachycardia prompts plasma or urinary metanephrine testing.
- Localise the lesion: ultrasound first, then non-contrast MRI, to find the tumour and check for bilateral or extra-adrenal disease.
- Block alpha receptors: start phenoxybenzamine and continue until pressure and volume are stable, with salt and fluids as needed.
- Add beta blockade: introduce a beta blocker only after adequate alpha blockade, because unopposed alpha stimulation is the dangerous pathway.
- Plan surgery in the second trimester: laparoscopic adrenalectomy is generally best performed in the second trimester, when fetal risk is lower.
- Monitor the fetus: serial growth scans and fetal surveillance follow, because maternal catecholamine surges can compromise the fetus.
Where the exam tries to catch you
Vignettes lean on the paroxysmal pattern and on the reflex to start an antihypertensive, so the sequence of blockade is the point most often tested.
- Trap: Diagnosing pre-eclampsia because the blood pressure is high and proteinuria is present. Correct: Phaeochromocytoma produces spikes with pallor and tremor, and proteinuria points to pre-eclampsia, which can coexist.
- Trap: Giving a beta blocker first for the tachycardia. Correct: Alpha blockade comes first, because unopposed alpha stimulation can cause a severe hypertensive crisis.
- Trap: Delaying surgery until term. Correct: Adrenalectomy is best in the second trimester, since untreated disease carries a high maternal risk through labour.
Frequently asked questions
What is the first step in managing phaeochromocytoma in pregnancy?
Alpha blockade is started first, usually with phenoxybenzamine, to control blood pressure and restore circulating volume. Beta blockade is added only after adequate alpha blockade. Surgery follows once the patient is stable.
Which investigation confirms phaeochromocytoma in pregnancy?
Plasma free metanephrines or 24-hour urinary fractionated metanephrines and catecholamines confirm the diagnosis. The tumour is then localised with ultrasound and non-contrast MRI, which avoids ionising radiation to the fetus.
When is adrenalectomy performed in a pregnant woman with phaeochromocytoma?
Adrenalectomy is generally performed in the second trimester, after the patient is controlled with alpha and beta blockade. Laparoscopic surgery is preferred where expertise is available. Timing is individualised to the patient.
How does Cushing syndrome present in pregnancy?
Cushing syndrome presents with hypertension, glucose intolerance, central obesity and striae, which can mimic gestational diabetes or pre-eclampsia. An adrenal adenoma is the usual cause in pregnancy. Surgical removal is the definitive treatment.
What is the main risk in untreated Addison disease during labour?
Untreated adrenal insufficiency during labour, surgery or illness can cause an adrenal crisis with refractory hypotension. Women on glucocorticoid replacement need stress-dose hydrocortisone at delivery. This is why the steroid plan is made ahead of time.