Phaeochromocytoma: Clinical Presentation

Phaeochromocytoma: Clinical Presentation, Diagnostic Evaluation, and Management Clinical Presentation Phaeochromocytoma is a rare neuroendocrine tumor arising from chromaffin cells in the adrenal medulla or sympathetic ganglia. It produces catecholamines (epinephrine, norepinephrine), leading to episodic or sustained hypertension and a range of other symptoms: 1. Hypertension: o Paroxysmal: Sudden and severe episodes of hypertension, often with palpitations and sweating. o Persistent: Continuous hypertension, less common but can lead to complications. 2. Symptoms During Hypertensive Episodes: o Palpitations and Tachycardia: Due to increased catecholamines. o Headaches: Severe and pounding headaches. o Diaphoresis: Profuse sweating. o Pallor and Tremors: Due to sympathetic nervous system activation. 3. Other Symptoms: o Anxiety and Panic Attacks: Mimicking symptoms of anxiety disorders. o Abdominal Pain: Often localized to the epigastric or flank regions. o Weight Loss: Unintentional, due to increased metabolic rate. o Heat Intolerance: Due to increased metabolic activity. Diagnostic Evaluation Diagnosis of phaeochromocytoma involves a combination of clinical suspicion, biochemical testing, and imaging studies: 1. Biochemical Testing: o Plasma and Urinary Metanephrines: Highly sensitive for detecting elevated levels of metanephrines (breakdown products of catecholamines). o Plasma Catecholamines: Direct measurement of epinephrine and norepinephrine levels. o 24-hour Urinary Catecholamines: To assess catecholamine excretion over time. 2. Imaging Studies: o CT Scan or MRI: Localizes adrenal or extra-adrenal tumors. Typically, phaeochromocytomas are well-circumscribed and enhance with contrast. o Metaiodobenzylguanidine (MIBG) Scan: Useful for detecting extra-adrenal or metastatic lesions. 3. Genetic Testing: o Multiple Endocrine Neoplasia (MEN) Syndromes: Phaeochromocytomas can be associated with MEN syndromes, particularly MEN type 2A and 2B (RET mutations) and MEN type 1 (MEN1 mutations). Association with Multiple Endocrine Neoplasia (MEN) Syndromes 1. MEN Type 2A (Sipple Syndrome): o Components: Phaeochromocytoma, medullary thyroid carcinoma, and hyperparathyroidism. o Genetic Mutation: Activating mutations in the RET proto-oncogene (chromosome 10q11.2). 2. MEN Type 2B: o Components: Phaeochromocytoma, medullary thyroid carcinoma, and mucosal neuromas. o Genetic Mutation: Also involves mutations in the RET proto-oncogene, but different from MEN 2A. 3. MEN Type 1 (Wermer Syndrome): o Components: Often associated with parathyroid adenomas, pituitary adenomas, and pancreatic tumors (e.g., gastrinomas, insulinomas). o Genetic Mutation: Inactivating mutations in the MEN1 gene (chromosome 11q13). Management Management of phaeochromocytoma includes medical stabilization, surgical resection of the tumor, and genetic counseling for familial syndromes: 1. Medical Stabilization: o Alpha-adrenergic Blockers: Phenoxybenzamine or doxazosin to control hypertension and prevent hypertensive crises. o Beta-adrenergic Blockers: Used cautiously after alpha-blockade to control tachycardia. 2. Surgical Resection: o Laparoscopic Adrenalectomy: Preferred for localized tumors. o Preoperative Alpha-Blockade: Ensures adequate alpha-blockade before surgery to prevent intraoperative hypertensive crises. 3. Follow-up: o Postoperative Monitoring: Assess for recurrence and monitor blood pressure regularly. o Genetic Screening: Family members should undergo genetic testing if MEN syndrome is suspected.