Hypertension Emergencies

As human bodies age, there is a natural “tendency” for increased levels: blood cholesterol levels, triglyceride levels, sugar levels…etc. Blood pressure is no exception, and hypertension is very common. One of my favorite medical facts is this: the most common etiology of essential hypertension is UNKNOWN! What makes it an emergency then? When the blood pressure is so high that there is life-threatening damage to end-artery organs. This is called hypertensive crisis or malignant hypertension and usually takes place when the blood pressure is at 180/115 or above. (Where there is no life threatening organ damage it is called hypertensive urgency.)

As the pressure starts damaging end-artery organs, symptoms will start to manifest:

·      Brain-related

o   Dizziness

o   Headache

o   Fatigue

o   Epistaxis

o   Flushed-face

o   Nervousness

·      Heart-related

o   Fourth heart sound and broad, notched P-waves on ECG

o   Echocardiographic evidence of left ventricular hypertrophy may appear later

o   Aortic dissection or leaking aneurysm may show up on CXR

·      Kidney-related

o   Polyuria/nocturia

o   Proteinuria

o   Microhematuria

o   Diminished renal concentrating ability

o   Nitrogen retention

·      Eye-related

o   Retinal hemorrhages/exudates

o   Papilledema

History and physical examination should be performed. Usually the blood pressure should be measured on two separate occasions, at least 3~5 minutes apart. But a very high reading (greater than or equal to 180/120) along with papilledema on examination constitutes as hypertensive emergency. Basic tests such as CBC, urinalysis, electrolytes and kidney function, and ECG should be ordered as well as more focused tests looking for specific causes of hypertension such as CXR and screening for pheochromocytoma.

Although most of essential hypertension is of unknown cause, there are a handful of diseases that will cause life-threatening hypertension:

o   Drugs! The use of sympathomimetic drugs such as cocaine and amphetamines can bring on severe hypertension. MAOI use with ingestion of tyramine-containing food (red wine and cheese—who knew my favorite combo can be deadly?) can also cause it.

o   Pheochromocytoma is a tumor made of chromaffin cells that secretes catecholamines—causing high blood pressure. Symptoms will include various combinations of headache, palpitations, tachycardia, excessive perspiration, tremor, and pallor.

o   Pre-eclampsia (140/100 or above PLUS proteinuria) and eclampsia during pregnancy (pre-eclampsia plus seizures). This can be life threatening for both mother and fetus, and deliver of the fetus is the definitive treatment.

Sometimes a disease does not lead to malignant hypertension but is so often associated with it that it really pays to check for these when a patient presents with severe hypertension:

o   Hypertensive encephalopathy—essentially, the blood pressure gets so high that cerebral autoregulation is lost, leading to vasospasms, which ultimately leads to ischemia.

o   Pulmonary edema—hypertension is often accompanied by left heart trouble (sometimes it may even be the cause of the trouble). Symptoms and signs of myocardial ischemia may be present.

o   Catastrophic intracranial event—anything from severe head trauma, ischemic stroke, SAH, or ICH can present with hypertension. This is the only setting where bringing down the blood pressure too quickly can be harmful, causing cerebral perfusion to drop. So a balance of sedation, analgesia, and antihypertensive care must be considered (maintain 150/100 for 5 days).

o   Thoracic aortic dissection—chronic hypertension is the underlying cause in 90% of cases. Patients can present with cardiac symptoms, and the telltale sign is DIFFERENTIAL ARM BP readings! CXR can show widened mediastinum. This is the only circumstance where rapid lowering of blood pressure to 110~120 systolic is done!

The general goal is to lower the blood pressure gradually over 24~48 hours (except for ischemic stroke), the 25% lowered in the first hour. The most common treatment is nitroprusside and labetalol. Glyceryl trinitrate is good if the patient also has myocardial ischemic symptoms. Hydralazine is used in pregnant women. Other anti-hypertensives such as ACE inhibitors are reserved for long-term blood pressure control.

This information is available in podcast form! Look for me at www.medonthego.podbean.com and stay tuned for more episodes!