adrenal medulla disorders Flashcards
adrenal medulla
-Composed of chromaffin cells
-Synthesize & secrete catecholamines (epinephrine & norepinephrine)
-Sympathetic nervous system
-“flight or fight”
-Chronotropic & inotropic effects on the heart
-Bronchodilation
-Peripheral and splanchnic vasoconstriction
-Skeletal muscular vasodilation
-Glycogenolysis, lipolysis, and renin release
disorders of the adrenal medulla
-Pheochromocytoma- Tumor of chromaffin cells, which secrete catecholamines
-Hormones of the adrenal medulla: Epinephrine, Norepinephrine
-Clinical features result from excessive catecholamine levels
-Classic Triad- Paroxysmal headaches, tachycardia, and sweating
pheochromocytoma
-rare
-cause of 2ndary HTN
-HTN- moderate to severe
-most cases dx at autopsy
-Excessive levels of norepinephrine or neuropeptide
-Tumor in either or both adrenal or along sympathetic nervous chain
“Paragangliomas” - primary extra-adrenal pheos.
-Aberrant locations – sympathetic chain, thorax, bladder, brain
types of pheochromocytoma
-Hereditary forms of pheochromocytoma include
-Multiple endocrine neoplasia type 2 (MEN 2)
-von Hippel-Lindau syndrome
-Neurofibromatosis type 1
-Familial paragangliomas
-Medullary thyroid carcinoma - screen for pheochromocytoma prior to surgery
pheochromocytoma- symptoms
-‘Attacks’ of severe headaches
-Perspiration
-Palpitations
-Anxiety
-Sense of impending doom
-Tremor
-Mottled cyanosis
-Facial pallor / flushing – vasoconstriction / vasodilatation
-Tachycardia
-Prechordial / abdominal pain
-Vomiting
-Increased nervousness and irritability
-Increased appetite and weight loss
-Angina (EKG changes)
-increase body temp
-Psychosis/confusion
-Seizures
-Hyperglycemia
-paresthesias
-reynaud’s phonmenon
-can be asymptomatic
pheochromocytoma: cardiac
-Hypertension (90% of pts) -> Sustained
-Sustained with paroxysms
-Paroxysmal only
-Cardiomegaly → heart failure, pulmonary edema
-Cardiomyopathy
-Postural tachycardia ( change of > 20 beats)
-Postural hypotension
-Basal body temperature ↑
-IV contrast dye, glucagon injection, needle biopsy of the mass, anesthesia & surgical procedures could trigger off:
-Catastrophic hypertensive crisis
-Fatal cardiac arrhythmias
-bradycardia
-hypotension
pheochromocytoma tests
-Hypermetabolic state present
-Thyroid function tests – normal
-Hyperglycemia + - mild
-ESR ↑ ±
-Leukocytosis – common
-Plasma renin ↑
-Plasma fractionated free metanephrine
-Most sensitive; false positives – common
-Assay of urinary catecholamines and metanephrines - Detect most pheochromocytomas
-24-hour / overnight urine specimen
-Metanephrine > 2.2 mcg/ mg creatinine
-> 135mcg total catecholamines per gram creatinine
-Urinary assay for vanillylmandelic acid (VMA) - 89% sensitive but not often necessary
factors interfering with pheochromocytoma tests
-Medications, foods and stress can affect test of catecholamine levels
-Drugs
-Acetaminophen
-Anti-hypertensive meds (captopril, aldomet)
-Antihistamines
-Foods
-Bananas, caffeine, peppers
-Conditions
-Severe emotion
-Vigorous exercise hypoglycemia
-Severe pain renal failure
other tests for pheochromocytoma
-Genetic testing
-Imaging
-CT; MRI
-Nuclear imaging
diff dx for pheochromocytoma
-Thyrotoxicosis
-Essential hypertension
-Myocarditis
-Glomerulonephritis
-Renal lesions
-Toxemia of pregnancy
-Eclampsia
-Anxiety attack
complications
-All complications of severe hypertension
-Hypertensive crises – sudden blindness, CVA
-Sudden death
-Acute respiratory distress syndrome
-After removal of tumor -> Severe hypotension, shock (resistant to epi Rx)
Renal failure, MI
-Seeding of tumor during surgery
pheochromocytoma- tx
-Treatment of choice- Laparoscopic surgery
-Other
-Open laparotomy
-Selective resection- Recurrence
-Pre-op
-α-adrenergic blocking drugs
-Calcium channel blockers
-Propranolol – tachycardia
-Nicardapine – hypertensive crisis
-Post-op hypotension – blood transfusion; volume replacement
-Follow up
-Recheck urinary catecholamine levels
-Whole body scan
-Inoperable/metastatic tumors – metyrosine; competitive blocker of catecholamine
-Metastatic pheochromocytoma
-Combination chemotherapy
-Irradiation
pheochromocytoma prognosis
-Early diagnosis
-Smaller benign tumors
-Surgical mortality -< 3%
-Malignancy - metastases
-Large tumors (>7cm in diameter)
-Paragangliomas
-5 year survival rate – 44% after surgery
-Combined with radiotherapy – 75% survival rate
-Tumors limited to abdomen – better prognosis
neurofibromatosis type 1
-first described pheochromocytoma- assoc syndrome
-classic features:
-multiple neurofibromas
-cafe au lait spots
-axillary freckling on the skin
-lisch nodules of the iris
-pheochromocytomas occur in only about 1% of these pts -> located predominantly in adrenals
