There are two things. Hypertensive Urgency and Hypertensive emergency. In hypertensive urgency we don’t see any target organ damage while in emergency we see target organ damage along with high blood pressure greater than systolic >220. Now depending upon target organ damage you will decide whether you have hypertensive emergency or urgency. It is essential to bring down high blood pressure in hypertensive emergency immediately, while in urgency, bring down blood pressure very rapidly is not required.
Pathogenesis of malignant hypertension is fibrinoid necrosis of arterioles and small arteries. Red blood cells are damaged as they flow through vessels obstructed by fibrin deposition, resulting in microangiopathic hemolytic anemia. Another pathologic process is the dilatation of cerebral arteries resulting in increased blood flow to brain which leads to clinical manifestations of hypertensive encephalopathy. Common age is above 40 years and it is more frequent in man rather than women. Black people are at higher risk of developing hypertensive emergencies than the general population.
Target organs are mainly Kidney, CNS and Heart. So symptoms of Malignant hypertension are oligurea, Headache, vomiting, nausea, chest pain, breathlessness, paralysis, blurred vision. Most commonly heart and CNS are involved in malignant hypertension. The pathogenesis is not fully understood. Up to 1% of patients with essential hypertension develop malignant hypertension, and the reason some patients develop malignant hypertension while others do not is unknown. Other causes include any form of secondary hypertension; use of cocaine, MAOIs, or oral contraceptives; , beta-blockers, or alpha-stimulants. Renal artery stenosis, withdrawal of alcohol, pheochromocytoma {most pheochromocytomas can be localized using CT scan of the adrenals}, aortic coarctation, complications of pregnancy and hyperaldosteronism are secondary causes of hypertension. Main Investigations to access target organ damage are complete renal profile, BSR, Chest Xray, ECG, Echocardiography, CBC, Thyroid function tests.
Management:
Patient is admitted in Intensive Care Unit. An intravenous line is taken for fluids and medications. The initial goal of therapy is to reduce the mean arterial pressure by approximately 25% over the first 24-48 hours. However Hypertensive urgencies do not mandate admission to a hospital. The goal of therapy is to reduce blood pressure within 24 hours, which can be achieved as an outpatient department. Initially, patients treated for malignant hypertension are instructed to fast untill stable. Once stable, all patients with malignant hypertension should take low salt diet, and should focus on weight lowering diet. Activity is limited to bed rest until the patient is stable. Patients should be able to resume normal activity as outpatients once their blood pressure has been controlled.
Hospitalization is essential until the severe high blood pressure is under control. Medications delivered through an IV line, such as nitroglycerin, nitroprusside, or others, may reduce your blood pressure. An alternative for patients with renal insufficiency is IV fenoldopam. Beta-blockade can be accomplished intravenously with esmolol or metoprolol. Labetalol is another common alternative, providing easy transition from IV to oral (PO) dosing. Also available parenterally are enalapril, diltiazem, verapamil, Hydralazine is reserved for use in pregnant patients as it also increases uterine profusion, while phentolamine is the drug of choice for a pheochromocytoma crisis. After the severe high blood pressure is brought under control, regular anti-hypertensive medications taken by mouth can control your blood pressure. The medication may need to be adjusted occasionally.
Remember, It is very necessary to control malignant hypertension, otherwise it can lead to life threatening conditions like Heart Failure, Infarction, Kidney failure and even blindness.
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