Adrenal Disorders II

1. Adrenal Disorders II Khalid Al-Shali MBBS, MSc, FRCP(C), FACP Assistant Professor, Department of Medicine

2. Topics to be Covered Pheochromocytoma Primary Hyperaldosteronism (Conn’s syndrome)

3. Pheochromocytoma Pheochromocytomas are tumours arisng from chromaffin cells in the sympathetic nervous system They release epinephrine or norepinephrine (or both)—and in some cases dopamine—into the circulation, causing HTN and other signs & symptoms Pheos have been reported to produce other peptides: CRH, ACTH, vasopressin, somatostatin, VIP, PTH-RP etc. Atypical clinical presentations can occur as a result In 10% of pts the tumor is found incidentally during CT or MRI of the abdomen for unrelated symptoms Found at all ages and in both sexes, but commonly diagnosed in the 4th or 5th decades. Incidence in Sweden: 2 per million Important to diagnose because undiagnosed it may be fatal in pregnant women during delivery or in patients undergoing surgery for other disorders

4. Pheochromocytoma Pathology and Familial Syndromes: Over 95% of pheos are found in the abdomen, and 85% of these are intraadrenal 5 to 10% are multiple 10% are malignant Most pheos are sporadic, a few have the disease as part of a familial disorder, in these pts the pheos are likey bilateral: MEN2A: AD, pheo+thyroid medullary ca+hyperparathyroidism MEN2B: AD, pheo+medullary thyroid ca+mucosal neuromas von Hipple-Lindau: pheo (15%)+retinal angiomas+renal and pancreatic cysts, cerebellar hemangioblastoma, renal cell ca Neurofibromatosis type 1: 6% of patients develop pheos

5. Pheochromocytoma Clinical features: Most patients experience episodic symptoms: “Classic triad”: Headache, Sweating, Palpitation—Sensitivity 91%, Specificity 94% for pheo Attacks usually occur several times a week and last for 15 min or less Frequently ppt by activities that compress the tumour (eg exercise, lifting, defecation, or eating) and by emotional distress and anxiety Anxiety or fear of impending death Tremor Fatigue or exhaustion Nausea and vomiting Abdominal or chest pain Visual disturbances Chronic symptoms : sweat, cold hands & ft, wt loss, DM, constipat HTN occurs during an attack and may be present between attacks A few patients are free of symptoms & HTN between attacks

6. Pheochromocytoma Clinical features: Physical exam: Hypertension with postural hypotension Explanation: HTN is due to B1 receptor-mediated increase in COP and a receptor-mediated peripheral vasoconstriction. Chronic constriction of the arterial and venous beds leads to a reduction in plasma volume so that when the patient arises there is an inability to further constrict these vessels leading to postural hypotension Patient usually thin Forceful heartbeat that is often visible and easily palpable Patient may have pallor, cool and moist hands and feet A mass may be palpable in the abdomen or neck and deep palpation of the abdomen may produce a typical paroxysm

7. Pheochromocytoma Disorders mimicking pheochromocytoma: Apnea due to coronary vasospasm Severe anxiety and panic states Hypertension Hypertensive crisis associated with: Surgery, CVA, acute pulmonary edema, paraplegia, etc Menopausal hot flushes Autonomic epilepsy Thyrotoxicosis Migraine and cluster headache Sympathomimetic drug ingestion Hyperdynamic beta-adrenergic states

8. Pheochromocytoma Diagnosis: Urinary catecholamine excretion: Nearly all pheochromocytoma patients have increased urinary excretion of catecholamine metabolites (vanillylmandelic acid and metanephrines) and free catecholamines 24hr urinary metanephrines is the most sensitive test. A level >6.5 µmol/day is highly suggestive of a pheochromocytoma False positive results can occur with certain drugs or foods Plasma catecholamines: A plasma total catecholamine (norepinephrine+epinephrine) >11.8 nmol/L in a supine patient with an indwelling cannula who has been at rest for at least 30 minutes is diagnostic of pheo However, false +ve results are frequent (15% at Mayo Clinic)