The three major critical conditions of hypertension: malignant hypertension, crisis, and encephalopathy.

Acute and critical conditions of hypertension include malignant hypertension, hypertensive crisis, and hypertensive encephalopathy. Among these emergencies, the life-threatening complications are mainly left ventricular failure, coronary heart disease, cerebral hemorrhage, cerebral infarction, and renal failure, among other cardiac, cerebrovascular, and renal complications. Therefore, rapid yet cautious antihypertensive treatment is necessary. Emergency blood pressure reduction is generally required, aiming to control blood pressure within one day of symptom onset. If there are no complications, blood pressure can usually be lowered to 160/110 mmHg within 24 hours. ① Malignant hypertension: Malignant hypertension, also known as "malignant hypertension," refers to hypertension that progresses rapidly from the outset or suddenly and rapidly develops after years of slow progression. It is characterized by a significantly elevated blood pressure, usually with diastolic pressure consistently ≥130 mmHg. Pathologically, it is characterized by fibrotic necrosis of the renal arterioles. The onset is sudden and more common in young and middle-aged adults. Significant retinopathy is common, such as retinal hemorrhage, exudates, and papilledema. Without timely treatment, the prognosis is extremely poor, often resulting in death from uremia, stroke, or heart failure. ② Hypertensive crisis: A hypertensive crisis refers to a temporary and severe spasm of small arteries throughout the body in hypertensive patients under strong mental stimulation, emotional excitement, or overexertion, leading to increased peripheral vascular resistance and a rapid rise in blood pressure. Blood pressure changes are primarily characterized by a sudden and significant increase in systolic pressure, but diastolic pressure may also rise, heart rate increases, and symptoms may include headache, dizziness, palpitations, and vomiting. In severe cases, angina pectoris, pulmonary edema, renal insufficiency, and hypertensive encephalopathy may occur. Attacks are generally brief, and the condition improves rapidly after blood pressure is controlled. ③ Hypertensive encephalopathy: Hypertensive encephalopathy occurs during the course of hypertension, when a patient experiences a strong and persistent spasm of small arteries in the brain, causing a rapid rise in blood pressure. The excessively high blood pressure exceeds the brain's self-regulating capacity, leading to passive dilation of cerebral blood vessels, impaired cerebral blood circulation, and excessive cerebral perfusion, resulting in cerebral edema and increased intracranial pressure. Symptoms may include severe headache, dizziness, projectile vomiting, and confusion; in severe cases, generalized convulsions or coma may occur. If this occurs, immediate emergency treatment at a hospital is necessary. Hypertensive crisis often occurs in patients with rapidly progressing malignant hypertension. Hypertensive encephalopathy can also occur in patients with preeclampsia, glomerulonephritis, renovascular hypertension, and pheochromocytoma. Treatment of acute cerebral hemorrhage: When blood pressure is ≥200/110 mmHg, antihypertensive treatment should be initiated to maintain blood pressure slightly above pre-illness levels; when blood pressure is <180/105 mmHg, antihypertensive drugs may be temporarily withheld. Close monitoring of blood pressure is necessary when systolic blood pressure is between 180 and 200 mmHg or diastolic blood pressure is between 100 and 110 mmHg. The goal of acute subarachnoid hemorrhage treatment is to prevent rebleeding and reduce intracranial pressure. Absolute bed rest for 4–6 weeks is required, and all factors that could raise blood pressure should be avoided. Controlling blood pressure levels can delay or even prevent the onset and progression of diabetic nephropathy. Antihypertensive treatment should begin when blood pressure is above 145/(90–95) mmHg. In the risk stratification of hypertensive patients, the very high-risk group refers to stage 3 hypertension with one or more risk factors or target organ damage.