High blood pressure usually is asymptomatic for many years or even decades before the complications develop. High blood pressure causes damage to multiple organs of the body and most commonly; kidney, heart, peripheral arteries, brain and eyes are affected. Some of the complications like heart attack, stroke, etc. can be fatal. The table given below describes the various complications occurring in the most commonly affected organs.

Table 1: Organ Damage in Long Standing Hypertension

Organs	Damage
Kidney	Loss of protein in urine, Progressive Renal Failure
Heart	Congestive Heart Failure, Ischemic Heart Disease, Cardiac Arrhythmia, Left Ventricular Hypertrophy, Congestive Heart Failure, Acute Left Ventricular Failure, Aortic Dissection
Peripheral Arteries	Peripheral Arterial Disease
Brain	Cognitive Decline, Stroke, Transient Ischemic Attacks, Subarachanoid Hemorrhage, Hypertensive Encephalopathy, Malignant Hypertension,
Eyes	Retinal Damage due to Hypertensive Retinopathy, Optic Neuropathy

Kidney

High blood pressure frequently damages the kidneys. Also, kidney diseases can result in high blood pressure. One of the earliest manifestations of kidney damage in hypertension is the presence of proteins in the urine. Kidney damage in hypertension can progress to renal failure.

Heart

Heart is also commonly affected by high blood pressure. Raised blood pressure means that heart has to do extra work and the heart muscles hypertrophies as an adaptation to the increased load. Hypertrophy of heart muscle and hypertension by itself increases the risk of ischemic heart disease. Heart failure occurs when heart can no longer pump the blood against such high pressure. Heart failure may occur suddenly, resulting in acute left ventricular failure, or it may occur slowly, resulting in congestive heart failure. It could also occur after a heart attack, whose risk increases in people with high blood pressure. These various heart conditions can result in disturbances in normal rhythm of the heart (cardiac arrhythmias).

Peripheral Arteries

Hypertension and in presence of other risk factors causes increased risk of developing peripheral arterial disease. Hallmark of this condition is pain in lower limbs on walking some distance that subsides with rest (known as intermittent claudication)

Brain

Complications of hypertension that involves brain are stroke and transient ischemic attacks. Hypertension can also result in faster age related cognitive decline. Malignant hypertension, hypertensive encephalopathy and major stroke are the most important hypertensive emergencies that can involve brain. Transient ischemic attacks are mini strokes caused by temporary disruption of blood supply to brain or its part. In contrast to stroke, symptoms of TIA resolve within 24 hours (sometimes in minutes). Strokes are also caused by disruption of blood supply to the brain. However, in stroke, there is permanent damage due to death of the tissues. Symptoms of TIA and strokes are highly variable depending upon on the part of the brain that is affected.

Eyes

Hypertension damages the retina resulting in hypertensive retinopathy. Retinopathy can result in visual field defects and may even progress to blindness. Eyes may also be involved in various hypertensive emergencies like malignant hypertension, hypertensive encephalopathy, etc. Blurring of vision is a common symptom in such conditions. Hypertension can also cause damage to the optic nerve, resulting in optic neuropathy.

HYPERTENSIVE EMERGENCIES

Hypertension can result in some life-threatening emergencies that warrant immediate medical care. The most commonly encountered ones are described in the table given below. Generally the hypertensive emergencies are due to the involvement of heart or the brain.

Table 2: Hypertensive Emergencies

Emergencies	Description
Malignant Hypertension	Extremely high blood pressure. Often Systolic >180, Diastolic >130 (mm of Hg). Risk of heart attack, brain damage, permanent blindness and kidney failure.
Hypertensive Encephalopathy	Very high blood pressure associated with neurological deficits. Neurological abnormalities reversible if treatment started immediately.
Myocardial Infarction	Heart attack or Myocardial Infarction is characterized by death of heart muscle fibers.
Stroke	Stroke is caused by loss of blood supply to a part of brain. Some strokes can even cause death.
Acute Left Ventricular Failure	Acute heart failure can occur due to hypertension. Sudden onset sever shortness of breath is most important feature.
Aortic Dissection	High blood pressure can cause tear in the aorta (the main blood vessel that carries blood from the heart to other organs)
Subarachnoid hemorrhage	Bleeding between the layers of the meninges (the outer covering of the brain). Very severe headache is typical.
Sudden Death	Can occurs due to cardiac arrhythmias or strokes

Brain

Malignant Hypertension occurs because of a quick rise of blood pressure to very high levels. Diastolic blood pressure is often above 130 mm of Hg, and systolic blood pressure is above 180 mm of Hg. People with high blood pressure secondary to a cause in kidneys are particularly at higher risk. Malignant hypertension commonly presents with headache, dizziness, confusion, blurring of vision and vomiting. Malignant hypertension can result in heart attack, brain damage, permanent blindness and renal failure.

Hypertensive encephalopathy is characterized by high blood pressure and presence of numerous neurological deficits like speech disturbances, visual disturbances, seizures, altered sensation, disorientation and loss of consciousness. These deficits are usually fully reversible with adequate control of high blood pressure.

Hypertension can also cause stroke, and the presentation and future outlook is highly variable depending on location and size of stroke. Severe hemorrhagic stroke can even cause sudden death. Stroke may result in variety of symptoms like altered mental state, hearing or vision changes, weakness or paralysis of arm/leg/face, etc.

Subarachanoid hemorrhage is another serious complication of hypertension. In this condition, bleeding occurs between the layers of the outer coverings of the brain (called meninges). Person often experiences a very severe headache. There may be other symptoms like nausea, vomiting, neck stiffness, eye discomfort on exposure to bright light, personality and mood changes, altered mental state, etc.

Heart

Myocardial infarction or heart attack is one of the most common hypertensive emergencies. Heart attack can occur due to sudden rise in blood pressure that places increased load on heart or due to long standing coronary artery disease and hypertrophy of heart muscles.

Hypertension can also result in acute left ventricular failure without a heart attack. It is characterized by severe shortness of breath of sudden onset, which keeps on increasing in severity. It occurs due to failure of left side of the heart which causes accumulation of fluids in the lungs (acute pulmonary edema).

Aortic dissection can occur due to hypertension. In this condition, there is a tear in the aorta which results in severe, sharp, stabbing chest pain. Other symptoms depend on the location of tear and a tear near the origin of the aorta can even result in sudden death.