Ans- D Phenoxybenzamine Ref - Practice Essentials A pheochromocytoma (see the image below) is a rare, catecholamine-secreting tumor that may precipitate life-threatening hypertension. The tumor is malignant in 10% of cases but may be cured completely by surgical removal. Although pheochromocytoma has classically been associated with 3 syndromes--von Hippel-Lindau (VHL) syndrome, multiple endocrine neoplasia type 2 (MEN 2), and neurofibromatosis type 1 (NF1)--there are now 10 genes that have been identified as sites of mutations leading to pheochromocytoma. Axial, T2-weighted magnetic resonance imaging (MRI) scan showing large left suprarenal mass of high signal intensity on a T2-weighted image. The mass is a pheochromocytoma. View Media Gallery Signs and symptoms Classically, pheochromocytoma manifests as spells with the following 4 characteristics: Headaches Palpitations Diaphoresis Severe hypertension Typical patterns of the spells are as follows: Frequency may vary from monthly to several times per day Duration may vary from seconds to hours Over time, spells tend to occur more frequently and become more severe as the tumor grows The following may also occur during spells: Tremor Nausea Weakness Anxiety, sense of doom Epigastric pain Flank pain Constipation Clinical signs associated with pheochromocytomas include the following: Hypertension: Paroxysmal in 50% of cases Postural hypotension: From volume contraction Hypertensive retinopathy Weight loss Pallor Fever Tremor Neurofibromas Tachyarrhythmias Pulmonary edema Cardiomyopathy Ileus Cafe au lait spots See Clinical Presentation for more detail. Diagnosis Diagnostic tests for pheochromocytoma include the following: Plasma metanephrine testing: 96% sensitivity, 85% specificity 24-hour urinary collection for catecholamines and metanephrines: 87.5% sensitivity, 99.7% specificity Test selection criteria include the following: Use plasma metanephrine testing in patients at high risk (ie, those with predisposing genetic syndromes or a family or personal history of pheochromocytoma) Use 24-hour urinary collection for catecholamines and metanephrines in patients at lower risk Imaging studies should be performed only after biochemical studies have confirmed the diagnosis of pheochromocytoma. Studies are as follows: Abdominal CT scanning: Has accuracy of 85-95% for detecting adrenal masses with a spatial resolution of 1 cm or greater MRI: Preferred over CT scanning in children and pregnant or lactating women; has reported sensitivity of up to 100% in detecting adrenal pheochromocytomas Scintigraphy: Reserved for biochemically confirmed cases in which CT scanning or MRI does not show a tumor PET scanning: A promising technique for detection and localization of pheochromocytomas Additional studies to rule out a familial syndrome in patients with confirmed pheochromocytoma include the following: Serum intact parathyroid hormone level and a simultaneous serum calcium level to rule out primary hyperparathyroidism (which occurs in MEN 2A) Screening for mutations in the ret proto-oncogene (which give rise to MEN 2A and 2B) Genetic testing for mutations causing the MEN 2A and 2B syndromes Consultation with an ophthalmologist to rule out retinal angiomas (VHL disease) See Workup for more detail. Management Surgical resection of the tumor is the treatment of choice and usually cures the hypertension. Careful preoperative treatment with alpha and beta blockers is required to control blood pressure and prevent intraoperative hypertensive crises. Preoperative medical stabilization is provided as follows: Start alpha blockade with phenoxybenzamine 7-10 days preoperatively Provide volume expansion with isotonic sodium chloride solution Encourage liberal salt intake Initiate a beta blocker only after adequate alpha blockade, to avoid precipitating a hypertensive crisis from unopposed alpha stimulation Administer the last doses of oral alpha and beta blockers on the morning of surgery See Treatment and Medication for more detail.