Makindo Medical Notes

Related Subjects: |Assessing Chest Pain |Hypertension |Hypertension in Pregnancy |Malignant Hypertension |Preeclampsia, Eclampsia and HELLP |Acute Heart Failure |Chronic Heart Failure

In many instances patients with Malignant hypertension may be salt and water deplete and will require fluid replacement with normal saline in addition to antihypertensive agents

About

• Symptoms complex associated with high BP
• Commonest in middle aged men
• Fairly uncommon now with screening and good treatment of BP

Diagnosis

• Systolic blood pressure > 220mmHg and Diastolic blood pressure>= 120mmHg.
• Severe or life-threatening end-organ damage e.g. retinopathy (haemorrhages, exudates or papilloedema) or AKI or ACS

Clinical

• Headache, anxiety, distress
• Acute Pulmonary oedema
• Microangiopathic haemolytic anaemia
• Renal failure, Retinal changes
• Stroke (ischaemic or haemorrhagic), Confusion, Delirium

Scale

Investigations

• FBC, U&E, LFTs, ECG, Urinalysis
• Echocardiogram for evidence of LVH
• Renal USS - asymmetry, polycystic, small and damaged
• Renal MRA - renal artery stenosis
• Screen for secondary causes - Cortisol collection , Urinary catecholamines/metanephrines
• Toxicology screen for cocaine if suspected

Red flags cases needing urgent treatment

• Aortic dissection
• Acute left ventricular failure and pulmonary oedema
• Acute renal failure or worsening of chronic renal failure
• Hypertensive encephalopathy
• Focal neurologic damage indicating thrombotic or haemorrhagic stroke
• Phaeochromocytoma, cocaine overdose, or other hyperadrenergic states
• Unstable angina or myocardial infarction
• Eclampsia

In those with severe hypertension an initial goal of therapy is to reduce mean arterial BP by no more than 25% acutely. There is no evidence base. Certainly a SBP < 200 mmHg is desirable or < 180/120 mmHg. It very much depends on context. Take expert advice.

Management

• Many older patients (over 80s) who have significant essential hypertension present with extremely high BPs but are otherwise well. The BP needs brought down slowly. A sudden drop may cause cerebral hypoperfusion and stroke. The HTN is often undiagnosed and treated or medication compliance is poor. The blood pressure should be slowly lowered over hours to a systolic of 160-180 mmHg. Too precipitous a drop can cause stroke or MI. Blood pressure may be elevated due to anxiety, chest pain, urinary retention or alcohol withdrawal and these issues need to be addressed first. True malignant hypertension is very rare. In these cases, rest, sedation, pain relief can help and always exclude acute urinary retention or a broken hip in the confused patient. Blood pressure should be lowered slowly and carefully. Oral medications such as Amlodipine 5 mg or an oral beta-blocker or a small dose of an ACEI can be trialled.
• A different approach is needed in those in the younger patients with aortic dissection, acute MI, pulmonary oedema or encephalopathy or eclampsia where a lower target is used. Drugs may be given IV. Can give oral amlodipine 5 mg and also start with Labetalol 20 mg slow IV is useful and can be repeated over an hour several more times up to 100-200 mg. If there is volume overload Furosemide may be given. If there is chest pain then IV nitrates can be considered and standard ACS beta-blockade. In dissection, once labetalol has been given then an infusion of Nitroprusside should be started to keep the BP around 120/80 or lower if needed and tolerated.
• True Isolated Malignant hypertension is rare and the drugs of choice are Labetalol IV which is easy to start first and/or Nitroprusside is used but it needs intraarterial BP monitoring and has risks of lactic acidosis due to cyanide toxicity. Can only be given on HDU. Take expert advice.
• Hypertension in pregnancy. Suspected eclampsia/preeclampsia. Take obstetric advice. Labetalol is safe.
• Hypertension in Haemorrhagic stroke. BP should be reduced gradually to 140-150/90 mmHg using beta-blockers (labetalol, esmolol), ACE inhibitor (enalapril), calcium channel blocker (nicardipine), or hydralazine. BP should be checked every 10-15 minutes

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