Cardiovascular · Year 1 · from Cardiovascular
Case 1: Pheochromocytoma - Paroxysmal Hypertension
Patient Presentation
Demographics: 38-year-old female
Chief Complaint: Episodic severe headaches with palpitations and sweating
History of Present Illness: A 38-year-old female presents with a 6-month history of episodic severe headaches, palpitations, and profuse sweating. Episodes occur 2-3 times weekly, lasting 20-30 minutes, and are accompanied by a sense of impending doom. During episodes, she has measured her blood pressure at home as high as 220/130 mmHg. Between episodes, her BP is 145/92 mmHg. She also reports unintentional 15-pound weight loss and anxiety.
Physical Examination (during episode):
- Vital Signs: BP 235/140 mmHg, HR 130 bpm, RR 22/min, SpO2 99%, Temp 37.8°C
- General: Diaphoretic, anxious, tremulous, pale
- Cardiovascular: Tachycardic, regular rhythm, S4 gallop
- Pupils: Dilated
- Skin: Cool, pale, diaphoretic (not flushed)
Workup
- Labs (24-hour urine collection):
- Metanephrines: 2,850 μg/24h (markedly elevated, normal <400)
- Normetanephrines: 3,200 μg/24h (markedly elevated)
- VMA (vanillylmandelic acid): 18 mg/24h (elevated)
- Plasma metanephrines: 4.2 nmol/L (elevated)
- CT Abdomen: 4.5 cm right adrenal mass with heterogeneous enhancement
- MIBG scan: Intense uptake in right adrenal gland confirming pheochromocytoma
- Echocardiogram: Concentric LVH, EF 60%
- Genetic testing: RET mutation negative, VHL negative
Diagnosis
Pheochromocytoma with episodic catecholamine-mediated hypertensive crises
Blood Pressure Regulation Correlation:
Classic triad: Headache, palpitations, diaphoresis (present in 50% of cases)
Catecholamine effects on BP:
- Norepinephrine (α1): Vasoconstriction → ↑ SVR → ↑ BP
- Epinephrine (β1): ↑ HR, ↑ contractility → ↑ CO
- Net effect: Severe hypertension from both ↑CO and ↑SVR
Why episodic?
- Tumor releases catecholamines in bursts
- Triggers: Physical activity, tumor manipulation, certain foods (tyramine), anesthesia, medications
Baroreceptor response:
- Normally high BP activates baroreceptors → ↓ sympathetic tone
- In pheochromocytoma, the catecholamine surge overwhelms this reflex
- Chronic exposure may reset baroreceptor sensitivity
Pale (not flushed): Due to α1-mediated cutaneous vasoconstriction
Treatment
- Alpha-blockade first: Phenoxybenzamine (irreversible) or doxazosin (selective α1)
- Must block alpha before beta to prevent unopposed α-mediated vasoconstriction
- Beta-blockade second: Add after adequate alpha-blockade (propranolol or metoprolol)
- Preoperative preparation: 10-14 days of alpha-blockade, high-salt diet, IV fluids
- Surgical resection: Laparoscopic adrenalectomy (definitive treatment)
- Intraoperative management: Have nitroprusside and phentolamine ready for hypertensive surges
Clinical Image
Image Description: CT scan of the abdomen showing a right adrenal mass (pheochromocytoma) appearing as a heterogeneous, well-circumscribed mass superior to the kidney with areas of necrosis or hemorrhage.
Source: Radiopaedia - Pheochromocytoma License: CC BY-NC-SA 3.0 URL: https://radiopaedia.org/cases/phaeochromocytoma-3