michael s
(Michael S)
#1
8 How do I manage the patient with malignant
hypertension?
Aroon Hingorani
Malignant hypertension was originally defined as hypertension
in association with grade IV retinopathy (papilloedema),
although it is now clear that hypertension associated with grade
III retinopathy (retinal haemorrhages without papilloedema)
shares the same poor prognosis. The identification of malignant
hypertension should prompt an urgent and active search for
secondary causes of hypertension, particularly renal disease
(acute renal failure must be excluded), renovascular disease and
phaeochromocytoma.
Management is based on the published experience from case
series rather than randomised controlled trials. In the absence of
hypertensive heart failure, aortic dissection or fits and confusion
(hypertensive encephalopathy), bed rest and oral antihyper-
tensive treatment are the mainstays of management, the aim being
to reduce the diastolic blood pressure gradually to 100mmHg in
the first few hours of presentation. Too rapid reduction in BP may
precipitate “watershed” cerebral infarction. Oral therapy with -
adrenoceptor blockers (e.g. atenolol 50–100mg) ± a thiazide
diuretic (e.g. bendrofluazide 2.5mg) will lower the blood pressure
smoothly in most patients. There is less experience with newer
antihypertensive agents. Nifedipine given via the sublingual route
may produce a rapid and unpredictable reduction in BP and
should be avoided. Similarly, angiotensin-converting enzyme
inhibitors should also be avoided because of the risk of first dose
hypotension. Older drugs such as hydralazine (25–50mg 8
hourly), or methyldopa (10–20mg 8 hourly) have been used
successfully and are an alternative in individuals in whom -
adrenoceptor blockers are contraindicated.
Hypertensive encephalopathy (headache, fits, confusion,
nausea and vomiting) demands intensive care, intra-arterial BP
monitoring and a more urgent, but nevertheless controlled, blood
pressure reduction with parenteral antihypertensive therapy.
Labetalol (initial dose 15mg/hr) or sodium nitroprusside (initial
dose 10 micrograms/min) are effective and readily titratable
agents. The aim is to titrate the dose upwards to produce a
controlled reduction in diastolic blood pressure to 100mmHg
