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The Case
• GP, 23 year old female, sought consultation at Fatima Medical Center due to intermittent attacks of severe headaches, palpitations and sweating.
• PE revealed an elevated BP = 180/100 and tachycardia (CR = 100/min).
• Attending physician requested for a 24 hour urine VMA determination which revealed an elevated result = 15 mg/24 hours.
Initial Differential Diagnosis
• Cocaine Abuse• Migraine – pain in the head (usually
unilateral), vertigo, nausea and vomiting, photophobia, and scintillating appearances of light.
• Possible CVA – “intermittent attacks” wrong presentation
• Brain Tumor – “intermittent attacks” wrong presentation
• Angina Pectoris• Anxiety Disorders• Hyperthyroidism
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The Case (cont’)
• Attending physician requested for a 24 hour urine VMA determination which revealed an elevated result = 15 mg/24 hours.
VMA?
• VMA – Vanillyl Mandelic Acid
• The major urinary metabolite of adrenal and sympathetic catecholamines; elevated in most patients with pheochromocytoma.
Pheochromocytoma• Considered an endocrinologic secondary cause of
hypertension • A functional chromaffinoma, usually benign, derived
from adrenal medullary tissue cells and characterized by the secretion of catecholamines, resulting in hypertension
• Hypertension may be paroxysmal and associated with attacks of palpitation, headache, nausea, dyspnea, anxiety, pallor, and profuse sweating.
• Pheochromocytomas are not innervated, and catecholamine release is not precipitated by neural stimulation
Incidence
• Race – can occur in any race
• Gender – occurs equally in males and females
• Age – can occur at any age, with peak between 30 – 50.
Biological Effects Of Catecholamines
• Stimulation of alpha-adrenergic receptors – elevated blood pressure– increased cardiac contractility– glycogenolysis– Gluconeogenesis– intestinal relaxation
• Stimulation of beta-adrenergic receptors – increase in heart rate – Increase in contractility.
Typical Clinical History
Spells characterized by: • Headaches• Palpitations• diaphoresis All in association with severe hypertension
(possibly paroxysmal). • Typical progressively worsen, increase in
frequencyWithout these symptoms and hypertension, can
rule out pheochromocytoma diagnosis.
Other Clinical Signs
• Hypertension (paroxysmal in 50% of cases)
• Postural hypotension: Hypertensive retinopathy
• Weight loss • Pallor
• Fever • Tremor • Neurofibromas Café
au lait spots• Tachyarrhythmias • Pulmonary edema • Cardiomyopathy • Ileus
Lab Diagnosis• Perform a 24-hour urine collection for creatinine,
total catecholamines, vanillyl mandelic acid, and metanephrines. – Measure creatinine in all collections of urine to
ensure adequacy of the collection. – Metanephrine levels are considered the most
sensitive and specific test for a pheochromocytoma, while vanillylmandelic acid is the least specific test and has a false-positive rate greater than 15%.
– The collection container should be dark and acidified and should be kept cold to avoid degradation of the catecholamines.
Imaging Studies
• Perform imaging studies after lab diagnosis of a pheochromocytoma.
• MRI is preferred over CT scanning. – sensitivity of up to 100% in detecting adrenal
pheochromocytomas, – does not require contrast, – does not expose the patient to ionizing radiation. – MRI is also superior to CT scanning for detecting extra-adrenal
pheochromocytomas.
• CT – an accuracy of 85-95% for detecting adrenal masses with a
spatial resolution of 1 cm or greater. – less accurate for lesions smaller than 1 cm.
Histologic Findings
• Pheochromocytomas vary from 2 g to 3 kg but, on average, weigh 100 g (normal: 4-6 g).
• These tumors are well encapsulated, highly vascular, and appear reddish brown on cut section.
• the tumor cells are arranged in balls and clusters separated by endothelial-lined spaces: zellballen.
• The cells vary in size and shape and have finely granular basophilic or eosinophilic cytoplasm.
• The nuclei are round or oval with prominent nucleoli. • Nuclear giantism and hyperchromasia are common.
Treatment• Surgical resection, but first need to medically stabilize.
– Preferable to remove only affected adrenal gland– If both are removed, patient requires lifetime glucocorticoid
and mineralocorticoid replacement therapy
• Use non-selective alpha-adrenergic antagonists to control hypertension– DOC: phenoxybenzamine– Phentolamine
• If significant tachycardia is experienced after alpha blockade, give non-selective beta-adrenergic blockers– DOC: Propranolol