Wednesday, August 1, 2012

Secondary Causes of Hypertension & Hypertensive Emergencies

When to consider a secondary cause of hypertension:
1. sudden onset or worsening of hypertension at any age
2. onset of hypertension in those less than 30 years old (with no family history or obesity)
3. hypertension resistant to 3 drugs

Secondary causes of hypertension and their clues:
-Renovascular disease: abdominal bruit, rise in creat>30% upon ACE inhibitor or ARB initiation, atherosclerosis elsewhere, history of flash pulmonary edema with hypertensive episodes

-Pheochromocytoma: paroxysmal hypertension, typical spells (headache, palpitations, sweating, panic attacks, pallor), hypertension triggered by beta-blockers, MAO inhibitors or changes in abdominal pressure (ie. intraoperatively),adrenal mass

-Hyperaldosteronism (often missed!): hypokalemia  less than 3 .5 without diuretics or less than 3.0 on diuretics, adrenal incidentaloma on imaging

-Cushing's syndrome: typical appearance, history of exogenous steroids

-Sleep apnea: body habitus (including neck circumference more than 16 inches in women and more than 17 inches men), history of snoring/apneic spells/morning headache/daytime somnolence

-Medications: OCP, HRT, some NSAIDS, some antidepressants (eg Venlafaxine), sympathomimetics including decongestants

-Coarctation of the aorta: don't forget to check for brachiofemoral delay in this patients... has been detected for the first time in adulthood



Hypertensive Emergencies
"Urgency": SBP over ~180 or DBP over ~110 without end-organ damage- needs correction over days with oral agents
"Emergency": Above, but with acute end-organ damage, needing urgent lowering, usually with IV medications in a monitored setting.

End organ complications and specific treatments:
1) Aorta- dissection (B-blockade, nitroprusside after B-bl. No pure vasodilators)
2) Brain- encephalopathy (note that headache without neuro deficits does not count!)- sz, cerebral hemorrhage/infarction, raised ICP
3) Heart- MI, CHF (acute diastolic dysfunction leading to pulmonary edema)- careful with B-bl. May use nitro infusion
4) Kidney- renal failure- careful diuresis, calcium antagonists useful
5) Placenta (pre-eclampsia)- hydralazine, labetalol, delivery
6) Hemolysis (can look just like TTP with MAHA, fragments)
7) Eyes: papilledema, hemorrhages

Treatment Targets: 
-         emergency: lower BP by no more than 25% in minutes to 2 h using IV medications (exception: aortic dissection, where it must be lowered more rapidly)
-         urgency: lower BP over hours to days with PO
-         meds PO: amlodipine, captopril, hydralazine, clonidine
-         meds IV: labetalol, nitroprusside, nitroglycerin, hydralazine

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