michigan hypertension core curriculum - State of Michigan

an indication for careful and modest additional lowering to SBP 160/90 mm Hg (MAP 110 mm Hg).
However, if there is suspicion of increased intracranial pressure, simultaneous intracranial pressure
monitoring may be required to maintain cerebral perfusion pressure 60 - 80 mm Hg.
Subarachnoid Hemorrhage (SAH)
The management of BP in patients with subarachnoid hemorrhage can be divided into 2 distinct
phases. Prior to definitive therapy of the bleeding source, immediate blood BP control (MAP < 100 mm
Hg or SBP < 160 mm Hg) is considered a key aspect of preventing additional bleeding. Following surgical
clipping or occlusion by endovascular coils of the ruptured aneurysm, cerebral vasospasm (which occurs
in approximately 30% of patients following SAH) becomes the primary threat to the patient’s recovery.
Traditional management during the period of risk for vasospasm (approximately 3 weeks) consists of 21
days of nimodipine plus “triple H” therapy (hypertension, hypervolemia, and hemodilution) as needed. 16
Hypertensive Encephalopathy
Hyperperfusion of the cerebral cortex during hypertensive emergencies can lead to headache,
nausea, vomiting, and visual disturbances. In more severe cases seizures, confusion or decreased
level of consciousness may result. The underlying pathology is a spectrum consisting of cerebral
edema, posterior reversible leukoencephalopathy, small hemorrhages, and fibrinoid necrosis and
fibrin thrombi with microinfarctions. Symptoms typically develop over 24 – 48 hours, and start to
resolve within 12 hours of controlling the BP. Although a CT of the head is usually indicated initially
to rule out intracerebral hemorrhage, other etiologies must be ruled out if there is no improvement
noted with 12 hours. MRI is more sensitive than CT for detecting ischemic changes and the posterior
leukoencephalopathy, brain stem pathology, and microhemorrhages. The latter are seen on gradient
echo pulse sequences.
242 Hypertension Core Curriculum