HPT-CPG

Definition of severe hypertension:
Severe hypertension is defined as BP >180/110 mmHg.

These patients may present in the following manner:

• incidental finding in an asymptomatic patient

• non-specific symptoms like headache, dizziness, lethargy

• symptoms and signs of acute target organ damage. These
include acute heart failure, acute coronary syndromes, acute
renal failure, dissecting aneurysm, hypertensive encephalopathy
and stroke

Patients are then categorised as having:
a) asymptomatic severe hypertension,
b) hypertensive urgencies, or
c) hypertensive emergencies
(b) and (c) are also referred to as hypertensive crises.58

1 Specific management
The aim of drug therapy in patients with severe hypertension is to
reduce BP in a controlled, predictable and safe manner in order to
avoid acute coronary, cerebral or renal ischaemia; or if ischaemia is
already present, to avoid aggravating the situation.

1.1 Asymptomatic severe hypertension
Admission may be necessary in the newly diagnosed, or where
compliance may be a problem. Patients already on treatment need
to have their drug regime reviewed.59 (Level III)

1.2 Hypertensive urgencies
These include patients with grade III or IV retinal changes (also
known as accelerated and malignant hypertension respectively), but
no overt organ failure. These patients may need admission. BP
measurement should be repeated after 30 minutes of bed rest. Initial
treatment should aim for about 25% reduction in BP over 24 hours
but not lower than 160/90 mmHg.60-61 (Level III) Oral drugs proven to be
effective are outlined in Table 10. Combination therapy is often
necessary.



1.3 Hypertensive emergencies
These include patients with complications of severe hypertension
such as acute heart failure, dissecting aneurysm, acute coronary
syndromes, hypertensive encephalopathy, subarachnoid
haemorrhage and acute renal failure. These may occur in patients
with BP <180/110 mmHg, particularly if the BP has risen rapidly.
All these patients should be admitted. The BP needs to be reduced
rapidly. It is suggested that the BP be reduced by 25% depending on
clinical scenario over 3 to 12 hours but not lower than 160/90
mmHg.62-64 (Level III)
This is best achieved with parenteral drugs. (Table 11)

Dangers of rapid reduction in blood pressure
Rapid reduction of BP (within minutes to hours) in asymptomatic
severe hypertension or hypertensive urgencies is best avoided as
it may precipitate ischaemic events.65
Oral or sublingual drugs with rapid onset of action can result in an
uncontrolled BP reduction. Several serious side effects have been
reported with the administration of sublingual fast-acting nifedipine
and therefore this is no longer recommended.66 (Level II-2),67
Following stabilization of patient's BP, subsequent management is
tailored towards achieving optimal control.For management of patients with severe hypertension and stroke, refer to section on Hypertension and Stroke