0071643192.pdf

Stroke syndromes are often considered a form of hypertensive emergency,

though the extreme elevations of BP may be a response to the stroke and not an

immediate cause.

Accelerated hypertension (malignant hypertension)is a term that reflects

progressive end-organ damage.

PATHOPHYSIOLOGY

■ In the heart, an abrupt, severe elevation of BP →acute left ventricular failure

or increase myocardial O 2 demand→ischemia and pulmonary edema.

■ In the brain, an abrupt rise in BP that exceeds the upper limits of cerebral

autoregulation (typically MAP >160, see Figure 2.20) →hypertensive

encephalopathy.

■ Chronic hypertension shifts the cerebral autoregulation curve to the right,

which has important implications during treatment.

■ In the kidney a sustained elevation of blood pressure →↓renal perfusion,

ischemia, and renal impairment.

■ Other presentations include uncontrolled bleeding, eclampsia, aortic

dissection.

SYMPTOMS

■ Chest pain, dyspnea, nausea if myocardial ischemia

■ Dyspnea, cough, pink-tinged sputum if pulmonary edema

■ Tearing pain in chest or upper back if aortic dissection

■ Severe headache, nausea, vomiting, confusion, visual changes if hyperten-

sive encephalopathy

EXAM

■ Blood pressure is often markedly elevated, exceptions being eclampsia and

aortic dissection with tamponade.

■ Evidence of end-organ damage may include:

■ S3, new murmur, unequal pulses

■ Rales, wheezing, hypoxia, respiratory distress

■ Decreased mental status, seizures, focal deficits

■ Papilledema, retinal hemorrhages

CARDIOVASCULAR EMERGENCIES

Hypertensive emergency =

HTN with acute end-organ

dysfunction.

MAP =Pdiastolic+1/3(Psystolic–

Pdiastolic)

Cerebral autoregulation is

effective between a MAP of

60—160 mmHg.

FIGURE 2.20. The normal cerebral autoregulation curve.

(Reproduced, with permission, from Morgan GE, Mikhail MS, Murray MJ, Clinical

Anesthesiology, 4th ed. New York: McGraw-Hill, 2006:616.)