Hypertensive emergency
Encyclopedia
Malignant hypertension or hypertensive emergency is severe hypertension
(high blood pressure) with acute impairment of an organ system (especially the central nervous system
, cardiovascular system and/or the renal system) and the possibility of irreversible
organ-damage. In case of a hypertensive emergency, the blood pressure
should be substantially lowered over minutes to hours with an antihypertensive
agent.
. A diagnosis of malignant hypertension must show papilledema
.
The brain shows manifestations of increased intracranial pressure, such as headache, vomiting, subarachnoid, and cerebral hemorrhage.
Patients will usually suffer from left ventricular dysfunction.
The kidneys will be affected, resulting in hematuria
, proteinuria
, and acute renal failure
.
It differs from other complications of hypertension in that it is accompanied by papilledema
. This can be associated with hypertensive retinopathy
.
The former requires immediate lowering of blood pressure such as with sodium nitroprusside infusions while urgencies can be treated with oral agents, with the goal of lowering the mean arterial pressure (MAP) by 20% in 1–2 days with further reduction to "normal" levels in weeks or months. The former use of oral nifedipine
, a calcium channel blocker, has been strongly discouraged because it is not absorbed in a controlled and reproducible fashion and has led to serious and fatal hypotensive problems.
Sometimes, the term hypertensive emergency is also used as a generic term, comprising both hypertensive emergency as a specific term for a serious and urgent condition of elevated blood pressure and hypertensive urgency as a specific term of a less serious and less urgent condition (the terminology hypertensive crisis is usually used in this sense).
| Terminology >
Systolic Pressure (mm Hg)
Diastolic Pressure (mm Hg)
>-
| Normal
< 120
| Pre-hypertension 120-139
| Hypertension stage 1 140-159
| Hypertension stage 2 ≥ 160
| Hypertensive crisis ≥ 180
| Hypertensive emergency ≥ 180
The term hypertensive emergency is primarily used as a specific term for a hypertensive crisis with a diastolic blood pressure greater than or equal to 120 mmHg and/or systolic blood pressure greater than or equal to 180mmHg. Hypertensive emergency differs from hypertensive crisis due to the evidence of acute organ damage.
Hypertensive emergency pathophysiology includes:
If the process is not stopped, a vicious cycle of homeostatic failure begins, leading to loss of cerebral and local autoregulation, organ system ischemia and dysfunction and myocardial infarction
.
It is estimated that in up to 83% of hypertensive emergency patients a single-organ involvement is found and two-organ involvement in nearly 14% of patients. Almost 3% of the patients are found with multi-organ failure which means failure of at least 3 organ systems.
The most common clinical presentations of hypertensive emergencies are cerebral infarction
(24.5%), pulmonary edema
(22.5%), hypertensive encephalopathy
(16.3%), and congestive heart failure
(12%). Less common presentations include. intracranial hemorrhage
, aortic dissection
, and eclampsia
Cerebral autoregulation is the ability of the blood vessels in the brain to maintain a constant blood flow
. It has been shown that people who suffer from chronic hypertension can tolerate higher arterial pressure before their autoregulation system is disrupted and that they have an increased cerebrovascular resistance which makes them more at risk of developing cerebral ischemia if the blood flow decreases into normotensive ranges. On the other hand, sudden or rapid rises in blood pressure may cause hyperperfusion and increased cerebral blood flow, causing increased intracranial pressure and cerebral edema. Hypertensive encephalopathy
is one of the clinical manifestations of cerebral edema and microhemorrhages seen with dysfunction of cerebral autoregulation and is characterized by hypertension, altered mentation, and papilledema
.
In what concerns heart damage, this seems to be caused by an increased arterial stiffness
, increased systolic blood pressure, and widened pulse pressures, all of these as results of chronic hypertension. The coronary perfusion pressures are decreased by these factors, which increase the myocardial oxygen consumption as well, leading to left ventricular hypertrophy
. As the left ventricle is unable to compensate for an acute rise in systemic vascular resistance, left ventricular failure and pulmonary edema
or myocardial ischemia may occur.
Chronic hypertension has a great impact on the renal vasculature as well as it may cause pathologic changes to the small arteries of the kidney
. The arteries develop endothelial dysfunction and impaired vasodilation
, which alter renal autoregulation. When the renal autoregulatory system is disrupted, the intraglomerular pressure starts to vary directly with the systemic arterial pressure, thus offering no protection to the kidney during blood pressure fluctuations. During a hypertensive crisis, this can lead to acute renal ischemia.
Endothelial injury occurs due to severe elevations of blood pressure and fibrinoid necrosis
of the arterioles follow. The vascular injury leads to deposition of platelets and fibrin
, and a breakdown of the normal autoregulatory function. Ischemia
occurs as a result which prompts further release of vasoactive substances. This process completes the vicious cycle.
Many factors and causes contribute in hypertension crises. One main cause is the discontinuation
of antihypertensive medications. Other common causes of hypertensive crises are autonomic hyperactivity, collagen-vascular diseases, drug use including cocaine
and amphetamines, glomerulonephritis
, head trauma, neoplasias, preeclampsia and eclampsia
, renovascular hypertension.
During a hypertensive emergency uncontrolled BPs lead to progressive or impending end-organ dysfunction; therefore, it is important to lower the BP aggressively. Acute end-organ damage may occur including neurological, cardiovascular and other. Some examples of neurological damage include hypertensive encephalopathy
, cerebral vascular accident/cerebral infarction
, subarachnoid hemorrhage
, and intracranial hemorrhage
. Cardiovascular damages include myocardial ischemia
/infarction, acute left ventricular dysfunction, acute pulmonary edema, and aortic dissection. Other end-organ damage include acute renal failure
or insufficiency, retinopathy
, eclampsia
, and microangiopathic hemolytic anemia
. Also, severe blood pressure leads to problems in the eye such as retinopathy or damage to the blood vessels in the eye.
injection
which has an almost immediate antihypertensive
effect is suitable but in many cases not readily available. In less urgent cases, oral agents like captopril
, clonidine
, labetalol
, prazosin
, which all have a delayed onset of action by several minutes compared to sodium nitroprusside, can also be used.
It is also important that the blood pressure is lowered not too abruptly, but smoothly. The initial goal in hypertensive emergencies is to reduce the pressure by no more than 25% (within minutes to 1 or 2 hours) and then toward a level of 160/100 mm Hg within 2–6 hours. Excessive reductions in pressure may precipitate coronary, cerebral, or renal ischemia
.
The diagnosis of a hypertensive emergency is not only based on the absolute level of blood pressure, but also on the individual regular level of blood pressure before the hypertensive crisis. Individuals with a history of chronic
hypertension may not tolerate a "normal" blood pressure.
According to a research published in 2006, hypertension prevalence is again on the rise with 28.6% of the U.S. population suffering it in 1999-2002. According to the study, incidence rates of hypertension range between 3% and 18%. These numbers depend on the age
, gender
, ethnicity, and body size.
According to Whelton, the incidence and prevalence of hypertension is about 50% higher in African-American adults than in white or Mexican-American populations. Also, Whelton adds that prevalence of hypertension has increased progressively in children and adolescents between 1988-2000. According to the study recent estimates indicate that approximately 1 billion adults have hypertension. The highest prevalence of hypertension is in Eastern Europe
and the Latin American/Caribbean region.
As a result of the use of antihypertensives, the incidence of hypertensive emergencies has declined from 7% to 1% of patients with hypertension. The 1 – year survival rate has also increased. Before 1950, this survival rate was only 20%, and it is now more than 90% with the proper medical treatment. Hypertensive crises affect less than 1% of hypertensive adults in the United States
.
Hypertensive crises more commonly occur among African-Americans and the elderly. Most patients who experience hypertensive crises have previously been diagnosed as hypertensive. Many of such patients have been prescribed antihypertensive therapy , but have inadequate blood pressure control.
Estimates indicate that approximately 1% to 2% of patients with hypertension develop hypertensive crisis at some point in their lifetime. Men are usually more affected by hypertensive crises than women.
The incidence of hypertensive crises has increased and hospital admissions tripled between 1983 and 1990, from 23,000 to 73,000 per year in the United States. The incidence of postoperative hypertensive crisis varies and such variation depends on the population examined. Most studies report and incidence of between 4% to 35%.
The morbidity and mortality of hypertensive emergencies depend on the extent of end-organ dysfunction on presentation and the degree to which blood pressure is controlled subsequently. With blood pressure control and medication compliance, the 10-year survival rate of patients with hypertensive crises approaches 70%.
The risks of developing a life-threatening disease affecting the heart or brain increase as the blood flow increase. Commonly, ischemic heart attack and stroke are the causes that lead to death in patients with severe hypertension. It is estimated that for every 20 mm Hg systolic or 10 mm Hg diastolic increase in blood pressures above 115/75 mm Hg, the mortality rate for both ischemic heart disease and stroke doubles.
Several studies have concluded that African Americans have a greater incidence of hypertension and a greater morbidity and mortality from hypertensive disease than non-Hispanic whites
. It appears that hypertensive crisis is also more common in African Americans compared with other races.
Although severe hypertension is more common in the elderly, it may occur in children though very rarely. Also, women have slightly increased risks of developing hypertension crisis. The lifetime risk for hypertension is 86-90% in females and 81-83% in men.
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure) with acute impairment of an organ system (especially the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, cardiovascular system and/or the renal system) and the possibility of irreversible
Irreversible
Irreversible may refer to:*Irreversible process, in thermodynamics, a process that is not reversible*Irréversible, a 2002 film*Irréversible , soundtrack to the film Irréversible...
organ-damage. In case of a hypertensive emergency, the blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
should be substantially lowered over minutes to hours with an antihypertensive
Antihypertensive
The antihypertensives are a class of drugs that are used to treat hypertension . Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from...
agent.
Signs and symptoms
The eyes may show retinal hemorrhage, or exudateExudate
An exudate is any fluid that filters from the circulatory system into lesions or areas of inflammation. It can apply to plants as well as animals. Its composition varies but generally includes water and the dissolved solutes of the main circulatory fluid such as sap or blood...
. A diagnosis of malignant hypertension must show papilledema
Papilledema
Papilledema is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare....
.
The brain shows manifestations of increased intracranial pressure, such as headache, vomiting, subarachnoid, and cerebral hemorrhage.
Patients will usually suffer from left ventricular dysfunction.
The kidneys will be affected, resulting in hematuria
Hematuria
In medicine, hematuria, or haematuria, is the presence of red blood cells in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract , ranging from trivial to lethal...
, proteinuria
Proteinuria
Proteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes...
, and acute renal failure
Acute renal failure
Acute kidney injury , previously called acute renal failure , is a rapid loss of kidney function. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract...
.
It differs from other complications of hypertension in that it is accompanied by papilledema
Papilledema
Papilledema is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare....
. This can be associated with hypertensive retinopathy
Hypertensive retinopathy
Hypertensive retinopathy is damage to the retina due to high blood pressure .-Pathophysiology:The retina is one of the "target organs" that are damaged by sustained hypertension....
.
- Chest pain
- Arrhythmias
- Headache
- Epistaxis
- Dyspnea
- Faintness or vertigo
- Severe anxiety
- Agitation
- Altered mental status
- Paresthesias
- Vomiting
The former requires immediate lowering of blood pressure such as with sodium nitroprusside infusions while urgencies can be treated with oral agents, with the goal of lowering the mean arterial pressure (MAP) by 20% in 1–2 days with further reduction to "normal" levels in weeks or months. The former use of oral nifedipine
Nifedipine
Nifedipine is a dihydropyridine calcium channel blocker...
, a calcium channel blocker, has been strongly discouraged because it is not absorbed in a controlled and reproducible fashion and has led to serious and fatal hypotensive problems.
Sometimes, the term hypertensive emergency is also used as a generic term, comprising both hypertensive emergency as a specific term for a serious and urgent condition of elevated blood pressure and hypertensive urgency as a specific term of a less serious and less urgent condition (the terminology hypertensive crisis is usually used in this sense).
Definition
>-
| Normal
| Pre-hypertension
| Hypertension stage 1
| Hypertension stage 2
| Hypertensive crisis
| Hypertensive emergency
The term hypertensive emergency is primarily used as a specific term for a hypertensive crisis with a diastolic blood pressure greater than or equal to 120 mmHg and/or systolic blood pressure greater than or equal to 180mmHg. Hypertensive emergency differs from hypertensive crisis due to the evidence of acute organ damage.
Pathophysiology
The pathophysiology of hypertensive emergencies is not well understood. Failure of normal autoregulation and an abrupt rise in systemic vascular resistance are typically initial steps in the disease process.Hypertensive emergency pathophysiology includes:
- Abrupt increases in systemic vascular resistance likely related to humoral. vasoconstrictors
- Endothelial injury
- Fibrinoid necrosisFibrinoid necrosisFibrinoid necrosis is a form of necrosis, or tissue death, in which there is accumulation of amorphous, basic, proteinaceous material in the tissue matrix with a staining pattern reminiscent of fibrin. It is associated with conditions such as immune vasculitis Fibrinoid necrosis is a form of...
of the arterioles - Deposition of platelets and fibrinFibrinFibrin is a fibrous, non-globular protein involved in the clotting of blood. It is a fibrillar protein that is polymerised to form a "mesh" that forms a hemostatic plug or clot over a wound site....
- Breakdown of the normal autoregulatory function.
- The resulting ischemiaIschemiaIn medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
prompts further release of vasoactive substances completing a vicious cycle.
If the process is not stopped, a vicious cycle of homeostatic failure begins, leading to loss of cerebral and local autoregulation, organ system ischemia and dysfunction and myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
.
It is estimated that in up to 83% of hypertensive emergency patients a single-organ involvement is found and two-organ involvement in nearly 14% of patients. Almost 3% of the patients are found with multi-organ failure which means failure of at least 3 organ systems.
The most common clinical presentations of hypertensive emergencies are cerebral infarction
Cerebral infarction
A cerebral infarction is the ischemic kind of stroke due to a disturbance in the blood vessels supplying blood to the brain. It can be atherothrombotic or embolic. Stroke caused by cerebral infarction should be distinguished from two other kinds of stroke: cerebral hemorrhage and subarachnoid...
(24.5%), pulmonary edema
Pulmonary edema
Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...
(22.5%), hypertensive encephalopathy
Hypertensive encephalopathy
Hypertensive encephalopathy is a neurological dysfunction induced by malignant hypertension. The term "hypertensive encephalopathy" was introduced to describe this type of encephalopathy by Oppenheimer and Fishberg in 1928. It describes cerebral conditions, typically reversible, caused by sudden...
(16.3%), and congestive heart failure
Congestive heart failure
Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
(12%). Less common presentations include. intracranial hemorrhage
Intracranial hemorrhage
An intracranial hemorrhage is a hemorrhage, or bleeding, within the skull.-Causes:Intracranial bleeding occurs when a blood vessel within the skull is ruptured or leaks. It can result from physical trauma or nontraumatic causes such as a ruptured aneurysm...
, aortic dissection
Aortic dissection
Aortic dissection occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta and force the layers apart. The dissection typically extends anterograde, but can extend retrograde from the site of the intimal tear. Aortic dissection is a medical...
, and eclampsia
Eclampsia
Eclampsia , an acute and life-threatening complication of pregnancy, is characterized by the appearance of tonic-clonic seizures, usually in a patient who had developed pre-eclampsia...
Cerebral autoregulation is the ability of the blood vessels in the brain to maintain a constant blood flow
Blood flow
Blood flow is the continuous running of blood in the cardiovascular system.The human body is made up of several processes all carrying out various functions. We have the gastrointestinal system which aids the digestion and the absorption of food...
. It has been shown that people who suffer from chronic hypertension can tolerate higher arterial pressure before their autoregulation system is disrupted and that they have an increased cerebrovascular resistance which makes them more at risk of developing cerebral ischemia if the blood flow decreases into normotensive ranges. On the other hand, sudden or rapid rises in blood pressure may cause hyperperfusion and increased cerebral blood flow, causing increased intracranial pressure and cerebral edema. Hypertensive encephalopathy
Hypertensive encephalopathy
Hypertensive encephalopathy is a neurological dysfunction induced by malignant hypertension. The term "hypertensive encephalopathy" was introduced to describe this type of encephalopathy by Oppenheimer and Fishberg in 1928. It describes cerebral conditions, typically reversible, caused by sudden...
is one of the clinical manifestations of cerebral edema and microhemorrhages seen with dysfunction of cerebral autoregulation and is characterized by hypertension, altered mentation, and papilledema
Papilledema
Papilledema is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare....
.
In what concerns heart damage, this seems to be caused by an increased arterial stiffness
Arterial stiffness
Arteries stiffen as a consequence of age and arteriosclerosis. Age related stiffness occurs when the elastic fibres within the arterial wall begin to fray due to mechanical stress. The two leading causes of death in the developed world, myocardial infarction and stroke, are both a direct...
, increased systolic blood pressure, and widened pulse pressures, all of these as results of chronic hypertension. The coronary perfusion pressures are decreased by these factors, which increase the myocardial oxygen consumption as well, leading to left ventricular hypertrophy
Ventricular hypertrophy
Ventricular hypertrophy is the enlargement of ventricles in the heart. Although left ventricular hypertrophy is more common, enlargement can also occur in the right ventricle, or both ventricles.- Physiology :...
. As the left ventricle is unable to compensate for an acute rise in systemic vascular resistance, left ventricular failure and pulmonary edema
Pulmonary edema
Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...
or myocardial ischemia may occur.
Chronic hypertension has a great impact on the renal vasculature as well as it may cause pathologic changes to the small arteries of the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
. The arteries develop endothelial dysfunction and impaired vasodilation
Vasodilation
Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
, which alter renal autoregulation. When the renal autoregulatory system is disrupted, the intraglomerular pressure starts to vary directly with the systemic arterial pressure, thus offering no protection to the kidney during blood pressure fluctuations. During a hypertensive crisis, this can lead to acute renal ischemia.
Endothelial injury occurs due to severe elevations of blood pressure and fibrinoid necrosis
Fibrinoid necrosis
Fibrinoid necrosis is a form of necrosis, or tissue death, in which there is accumulation of amorphous, basic, proteinaceous material in the tissue matrix with a staining pattern reminiscent of fibrin. It is associated with conditions such as immune vasculitis Fibrinoid necrosis is a form of...
of the arterioles follow. The vascular injury leads to deposition of platelets and fibrin
Fibrin
Fibrin is a fibrous, non-globular protein involved in the clotting of blood. It is a fibrillar protein that is polymerised to form a "mesh" that forms a hemostatic plug or clot over a wound site....
, and a breakdown of the normal autoregulatory function. Ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
occurs as a result which prompts further release of vasoactive substances. This process completes the vicious cycle.
Many factors and causes contribute in hypertension crises. One main cause is the discontinuation
Discontinuation
Discontinuation is the process of quitting a procedure, such as, the course of treatment with a drug or a consumer product line.*Discontinuation of a treatment is to stop taking a drug...
of antihypertensive medications. Other common causes of hypertensive crises are autonomic hyperactivity, collagen-vascular diseases, drug use including cocaine
Cocaine
Cocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
and amphetamines, glomerulonephritis
Glomerulonephritis
Glomerulonephritis, also known as glomerular nephritis, abbreviated GN, is a renal disease characterized by inflammation of the glomeruli, or small blood vessels in the kidneys...
, head trauma, neoplasias, preeclampsia and eclampsia
Eclampsia
Eclampsia , an acute and life-threatening complication of pregnancy, is characterized by the appearance of tonic-clonic seizures, usually in a patient who had developed pre-eclampsia...
, renovascular hypertension.
During a hypertensive emergency uncontrolled BPs lead to progressive or impending end-organ dysfunction; therefore, it is important to lower the BP aggressively. Acute end-organ damage may occur including neurological, cardiovascular and other. Some examples of neurological damage include hypertensive encephalopathy
Hypertensive encephalopathy
Hypertensive encephalopathy is a neurological dysfunction induced by malignant hypertension. The term "hypertensive encephalopathy" was introduced to describe this type of encephalopathy by Oppenheimer and Fishberg in 1928. It describes cerebral conditions, typically reversible, caused by sudden...
, cerebral vascular accident/cerebral infarction
Cerebral infarction
A cerebral infarction is the ischemic kind of stroke due to a disturbance in the blood vessels supplying blood to the brain. It can be atherothrombotic or embolic. Stroke caused by cerebral infarction should be distinguished from two other kinds of stroke: cerebral hemorrhage and subarachnoid...
, subarachnoid hemorrhage
Subarachnoid hemorrhage
A subarachnoid hemorrhage , or subarachnoid haemorrhage in British English, is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain...
, and intracranial hemorrhage
Intracranial hemorrhage
An intracranial hemorrhage is a hemorrhage, or bleeding, within the skull.-Causes:Intracranial bleeding occurs when a blood vessel within the skull is ruptured or leaks. It can result from physical trauma or nontraumatic causes such as a ruptured aneurysm...
. Cardiovascular damages include myocardial ischemia
Myocardial ischemia
Myocardial ischemia is an imbalance between myocardial oxygen supply and demand. Left untreated, it results in angina pectoris, myocardial stunning, myocardial hibernation, ischemic preconditioning, postconditioning, or under the most severe instances, acute coronary syndrome and myocardial...
/infarction, acute left ventricular dysfunction, acute pulmonary edema, and aortic dissection. Other end-organ damage include acute renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
or insufficiency, retinopathy
Retinopathy
Retinopathy is a general term that refers to some form of non-inflammatory damage to the retina of the eye. Frequently, retinopathy is an ocular manifestation of systemic disease.-Pathophysiology:Causes of retinopathy are varied:...
, eclampsia
Eclampsia
Eclampsia , an acute and life-threatening complication of pregnancy, is characterized by the appearance of tonic-clonic seizures, usually in a patient who had developed pre-eclampsia...
, and microangiopathic hemolytic anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
. Also, severe blood pressure leads to problems in the eye such as retinopathy or damage to the blood vessels in the eye.
Treatment
Several classes of antihypertensive agents are recommended and the choice for the antihypertensive agent depends on the cause for the hypertensive crisis, the severity of elevated blood pressure and the patient's usual blood pressure before the hypertensive crisis. In most cases, the administration of an intravenous sodium nitroprussideSodium nitroprusside
Sodium nitroprusside is the inorganic compound with the formula Na2[Fe5NO]·2H2O. This red-coloured salt, which is often abbreviated SNP, is a potent vasodilator...
injection
Injection (medicine)
An injection is an infusion method of putting fluid into the body, usually with a hollow needle and a syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body...
which has an almost immediate antihypertensive
Antihypertensive
The antihypertensives are a class of drugs that are used to treat hypertension . Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from...
effect is suitable but in many cases not readily available. In less urgent cases, oral agents like captopril
Captopril
Captopril is an angiotensin-converting enzyme inhibitor used for the treatment of hypertension and some types of congestive heart failure. Captopril was the first ACE inhibitor developed and was considered a breakthrough both because of its novel mechanism of action and also because of the...
, clonidine
Clonidine
Clonidine is a sympatholytic medication used to treat medical conditions, such as high blood pressure, some pain conditions, ADHD and anxiety/panic disorder...
, labetalol
Labetalol
Labetalol is a mixed alpha/beta adrenergic antagonist, which is used to treat high blood pressure.-Indications:...
, prazosin
Prazosin
Prazosin, trade names Minipress, Vasoflex, Pressin and Hypovase, is a sympatholytic drug used to treat high blood pressure and Anxiety, PTSD and Panic Disorder. It belongs to the class of alpha-adrenergic blockers. Specifically, prazosin is selective for the alpha-1 receptors on vascular smooth...
, which all have a delayed onset of action by several minutes compared to sodium nitroprusside, can also be used.
It is also important that the blood pressure is lowered not too abruptly, but smoothly. The initial goal in hypertensive emergencies is to reduce the pressure by no more than 25% (within minutes to 1 or 2 hours) and then toward a level of 160/100 mm Hg within 2–6 hours. Excessive reductions in pressure may precipitate coronary, cerebral, or renal ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
.
The diagnosis of a hypertensive emergency is not only based on the absolute level of blood pressure, but also on the individual regular level of blood pressure before the hypertensive crisis. Individuals with a history of chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
hypertension may not tolerate a "normal" blood pressure.
Epidemiology
Hypertensive crisis affects upward of 500,000 Americans each year. Although the incidence of hypertensive crisis is low, affecting fewer than 1% of hypertensive adults, more than 50 million adult Americans suffer from hypertension.According to a research published in 2006, hypertension prevalence is again on the rise with 28.6% of the U.S. population suffering it in 1999-2002. According to the study, incidence rates of hypertension range between 3% and 18%. These numbers depend on the age
Age
Age may refer to:* Age , an aspect of mathematical model theory* Age , an international peer-reviewed journal operated by Springer.* The Age, a daily newspaper published in Melbourne, Australia* Agé, a god* Åge, a given name...
, gender
Gender
Gender is a range of characteristics used to distinguish between males and females, particularly in the cases of men and women and the masculine and feminine attributes assigned to them. Depending on the context, the discriminating characteristics vary from sex to social role to gender identity...
, ethnicity, and body size.
According to Whelton, the incidence and prevalence of hypertension is about 50% higher in African-American adults than in white or Mexican-American populations. Also, Whelton adds that prevalence of hypertension has increased progressively in children and adolescents between 1988-2000. According to the study recent estimates indicate that approximately 1 billion adults have hypertension. The highest prevalence of hypertension is in Eastern Europe
Eastern Europe
Eastern Europe is the eastern part of Europe. The term has widely disparate geopolitical, geographical, cultural and socioeconomic readings, which makes it highly context-dependent and even volatile, and there are "almost as many definitions of Eastern Europe as there are scholars of the region"...
and the Latin American/Caribbean region.
As a result of the use of antihypertensives, the incidence of hypertensive emergencies has declined from 7% to 1% of patients with hypertension. The 1 – year survival rate has also increased. Before 1950, this survival rate was only 20%, and it is now more than 90% with the proper medical treatment. Hypertensive crises affect less than 1% of hypertensive adults in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Hypertensive crises more commonly occur among African-Americans and the elderly. Most patients who experience hypertensive crises have previously been diagnosed as hypertensive. Many of such patients have been prescribed antihypertensive therapy , but have inadequate blood pressure control.
Estimates indicate that approximately 1% to 2% of patients with hypertension develop hypertensive crisis at some point in their lifetime. Men are usually more affected by hypertensive crises than women.
The incidence of hypertensive crises has increased and hospital admissions tripled between 1983 and 1990, from 23,000 to 73,000 per year in the United States. The incidence of postoperative hypertensive crisis varies and such variation depends on the population examined. Most studies report and incidence of between 4% to 35%.
Prognosis
Severe hypertension is a serious medical condition with a general poor prognosis as it is estimated that people who do not receive appropriate treatment live up to three years after the diagnosis has been established.The morbidity and mortality of hypertensive emergencies depend on the extent of end-organ dysfunction on presentation and the degree to which blood pressure is controlled subsequently. With blood pressure control and medication compliance, the 10-year survival rate of patients with hypertensive crises approaches 70%.
The risks of developing a life-threatening disease affecting the heart or brain increase as the blood flow increase. Commonly, ischemic heart attack and stroke are the causes that lead to death in patients with severe hypertension. It is estimated that for every 20 mm Hg systolic or 10 mm Hg diastolic increase in blood pressures above 115/75 mm Hg, the mortality rate for both ischemic heart disease and stroke doubles.
Several studies have concluded that African Americans have a greater incidence of hypertension and a greater morbidity and mortality from hypertensive disease than non-Hispanic whites
Non-Hispanic Whites
Non-Hispanic Whites or White, Not Hispanic or Latino are people in the United States, as defined by the Census Bureau, who are of the White race and are not of Hispanic or Latino origin/ethnicity. Hence the designation is exclusive in the sense that it defines who is not included as opposed to who is...
. It appears that hypertensive crisis is also more common in African Americans compared with other races.
Although severe hypertension is more common in the elderly, it may occur in children though very rarely. Also, women have slightly increased risks of developing hypertension crisis. The lifetime risk for hypertension is 86-90% in females and 81-83% in men.