Hypertensive Crisis
Hypertensive crisis is an umbrella term for severe hypertension, usually BP >180/120 mmHg, with or without acute end-organ damage.
| Term | Definition |
|---|---|
| Acute severe hypertension | BP >180/120 mmHg with NO life-threatening end-organ damage |
| Hypertensive emergency | Severe hypertension (>180/120 mmHg) PLUS life-threatening end-organ damage
Severe hypertension alone does NOT constitute a hypertensive emergency; there must be evidence of acute and/or life-threatening end-organ damage Severe pre-eclampsia and eclampsia are major multisystem hypertensive emergencies specific to pregnant patients, covered separately in the Hypertension in Pregnancy article. Phaeochromocytoma can also result in a hypertensive emergency, covered separately in the Phaeochromocytoma article. |
| Malignant hypertension / accelerated hypertension | Severe hypertension (>180/120 mmHg) PLUS retinal haemorrhage and/or papilloedema
Malignant hypertension (MHT) can be sub-classified into:
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Hypertensive Emergency
Recognising Hypertensive Emergency
As mentioned, a hypertensive emergency is defined by the presence of severe hypertension (>180/120 mmHg) PLUS evidence of life-threatening end-organ damage:
| Organ system | Specific condition / end-organ damage | Red flag features |
|---|---|---|
| Brain (neurological) |
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New onset:
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| Heart (cardiovascular) |
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| Lungs (pulmonary) |
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| Kidneys (renal) |
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Management
Suspected hypertensive emergency requires immediate hospital admission (typically level 2 or 3 care, like HDU or ITU)
Primary approach: IV therapy
- Most cases: labetalol (often 1st line) or nicardipine
- Drug choices in a specific scenario
- Subarachnoid haemorrhage → oral nimodipine is recommended to prevent cerebral vasospasm
- Acute coronary syndrome → IV GTN or labetalol
- Hypertensive heart failure / acute pulmonary oedema → IV GTN or nitroprusside + IV loop diuretics (beta blockers like labetalol are contraindicated)
Note: The above management focuses on BP reduction in hypertensive emergency. Patients also require cause-specific and organ-specific management depending on the target-organ damage present.
A “golden rule” of BP reduction is that a rapid or excessive drop in blood pressure can be more dangerous than no change at all. Because a rapid or excessive drop in blood pressure can severely restrict blood flow to vital organs and cause complications like strokes, blindness, or myocardial infarction.
Universal target for the first 6-24 hours:
- Reduce the mean arterial pressure by NO MORE than 20-25%
- Aiming to reduce the diastolic blood pressure to ~110 mmHg
The guidelines strongly emphasise personalising the blood pressure targets and pharmacological choices based on the specific failing organ system.
Malignant Hypertension (Accelerated Hypertension)
If the patient has complicated malignant hypertension (i.e. presence of another life-threatening end-organ damage, apart from the eye) → manage as hypertensive emergency with IV therapy (see above).
For uncomplicated malignant hypertension (i.e. no other end-organ damage apart from the eye):
- Generally, outpatient care is appropriate
- Oral medications are the standard of care
- 1st line: CCBs (e.g. amlodipine, long-acting nifedipine), or low-dose beta blocker (e.g. atenolol)
- 2nd line:
- Alpha blockers (e.g. doxazosin)
- Thiazide-like diuretics alongside CCBs in selected patients (e.g. Afro-Caribbean ethnicity)
- Gradual reduction of BP over days to weeks is important (a rapid or excessive drop in blood pressure can severely restrict blood flow to vital organs and cause complications like strokes, blindness, or myocardial infarction)
- Within 24 hours: lower BP to <200/120 mmHg
- Within 1 week: lower BP to <160/100 mmHg
- Within 6-12 weeks: aim for <140/90 mmHg
RAAS inhibitors (i.e. ACE inhibitors / ARBs) should be avoided in acute phase of malignant hypertension, as they often result in a dangerous, rapid drop in blood pressure.
References
Related Articles
Hypertension in Pregnancy (Gestational Hypertension, Pre-Eclampsia, and Eclampsia)