Special Categories of Hypertension

Hypertensive emergencies are one of the important categories of hypertension and characterized by severe elevations in BP that are complicated by evidence of progressive target organ dysfunction and require immediate BP reduction (not necessarily to normal ranges) to prevent or limit target organ damage. Examples include hypertensive encephalopathy, intracranial hemorrhage, unstable angina pectoris, or acute myocardial infarction, acute left ventricular failure with pulmonary edema, dissecting aneurysm, or eclampsia. Hypertensive urgencies are severe elevations of BP but without evidence of progressive target organ dysfunction and that may benefit from BP reduction within a few hours. Examples include upper levels of stage 3 hypertension, papilledema, headache, shortness of breath, or pedal edema. Although hypertensive emergencies will require immediate admission to an intensive care unit (ICU) with continuous BP monitoring and parenteral antihypertensive therapy, most hypertensive urgencies can be managed in the emergency department (ED) with oral agents and appropriate follow-up within 24 hours to several days, depending on the individual characteristics of the patient.

a)Hypertensive Emergencies
Hypertensive emergencies should be treated within one hour. Hypertensive urgencies may be treated more slowly. The term accelerated malignant hypertension is used when retinal haemorrhages, exudates and pailloedema are found. Hypertensive encephalopathy denotes
cerebral involvement with headache, irritability, altered consciousness and seizures.As a general rule patients with a diastolic BP >130 should be treated fast. Urgent treatment also should be given to those in whom the rise in BP is found to be rapid.

1) Sodium nitroprusside infusion is the initial drug of choice (0.5 to 0.8 microgm, kg/min).May not be available in many centres. The dose should be very carefully titrated because of the possibility of hypotension and shock.

2) Nitroglycerin infusion: 0.25-5.0 microgm/kg/min

3) Labetalol: Bolus 2-10 mg or infusion: 2.5-30 microgram/kg/min

4) Captopril: Sublingual 12.5-25 mg

5) Hydralazine: IV 5-10 mg boluses

6) Enalapril: IV 0.5-5 mg bolus

7) IV diazoxide can be used as an alternative at a dose of 150 mg in 30-60 seconds as bolus.

If there is no evidence of volume depletion, IV frusemide should be added.List of Conditions Requiring Rapid Treatment of Hypertension

1)Cardiac:
• Acute aortic dissection

• Acute left ventricular failure

• Acute or evolving myocardial infarction

2)Cerebrovascular:
• Hypertensive encephalopathy

• Brain infarction

• Intracerebral haemorrhage

• Subarachnoid haemorrhage

3)Renal:

• Acute glomerulonephritis

4) Pheochromocytoma crisis

5) Eclampsia

6) Epistaxis

b) Elderly
Is the treatment of hypertension different in elderly?Generally, the target for treatment should be at lower levels in the elderly. This is because, the elderly have greater risk factors and thus would benefit from therapy, and eventually would result in lower incidence of myocardial infarction and heart failure.

c)Diabetics

One of the areas where treatment of hypertension has shown immense benefit is in diabetics.Aggressive treatment of hypertension especially with ACE Inhibitors and AR Blockers is found to retard or even prevent the renal complications of diabetes.

d)Gestational
A few points must be kept in mind while managing hypertension in pregnancy. Since plasma volume is decreased in pre eclampsia, diuretics must be avoided. The use of ACE inhibitors are associated with fetal death, and so they are avoided. The commonly used drugs are methyldopa and beta blockers.

e)Renovascular
The unique factor about hypertension due to renal artery stenosis is that it may be totally correctable by performing a corrective procedure such as angioplasty or surgery. But this has to be only after determining whether correction will be beneficial by specific investigations like isotopic scanning and differential renal studies.