sickle cell crisis


crisis

 [kri´sis] (pl. cri´ses) (L.) 1. the turning point of a disease for better or worse; especially a sudden change, usually for the better, in the course of an acute disease.2. a sudden paroxysmal intensification of symptoms in the course of a disease.3. crisis" >life crisis.addisonian crisis (adrenal crisis) the symptoms accompanying an acute onset or worsening of addison's disease: anorexia, vomiting, abdominal pain, apathy, confusion, extreme weakness, and hypotension; if untreated these progress to shock and then death.aplastic crisis a sickle cell crisis in which there is temporary bone marrow aplasia.blast crisis a sudden, severe change in the course of leukemia" >chronic granulocytic leukemia, characterized by an increased number of blasts, i.e., myeloblasts or lymphoblasts.catathymic crisis an isolated, nonrepetitive act of violence that develops as a result of intolerable tension.celiac crisis an attack of severe watery diarrhea and vomiting producing dehydration and acidosis, sometimes occurring in infants with celiac disease.developmental crisis maturational crisis.hemolytic crisis an uncommon sickle cell crisis in which there is acute red blood cell destruction with jaundice.hypertensive crisis dangerously high blood pressure of acute onset.identity crisis a period in the psychosocial development of an individual, usually occurring during adolescence, manifested by a loss of the sense of the sameness and historical continuity of one's self, confusion over values, or an inability to accept the role the individual perceives as being expected by society.life crisis a period of disorganization that occurs when a person meets an obstacle to an important life goal, such as the sudden death of a family member, a difficult family conflict, an incident of domestic violence (spouse or child abuse), a serious accident, loss of a limb, loss of a job, or rape or attempted rape.maturational crisis a crisis" >life crisis in which usual coping mechanisms are inadequate in dealing with a stress common to a particular stage in the life cycle or with stress caused by a transition from one stage to another. Called also developmental crisis.myasthenic crisis the sudden development of dyspnea requiring respiratory support in myasthenia gravis; the crisis is usually transient, lasting several days, and accompanied by fever.oculogyric crisis a symptom of an acute dystonic reaction in which the person demonstrates a fixed gaze, usually upward; also, the uncontrollable rolling upwards of the eye. It can be a result of encephalitis or a reaction to antipsychotic medications.salt-losing crisis see salt-losing crisis.sickle cell crisis see sickle cell crisis.tabetic crisis a painful paroxysm occurring in tabes dorsalis.thyroid crisis (thyrotoxic crisis) see thyroid crisis.vaso-occlusive crisis a sickle cell crisis in which there is severe pain due to infarctions in the bones, joints, lungs, liver, spleen, kidney, eye, or central nervous system.

sickle cell

 a crescentic or sickle-shaped erythrocyte, the abnormal shape caused by the presence of varying proportions of hemoglobin S. See illustration at cell.sickle cell anemia an autosomal dominant, chronic form of hemolytic anemia in which large numbers of sickle cells circulate in the blood; it is most common among persons of African and Mediterranean descent. Persons genetically homozygous have 85 to 95 per cent sickle cells and have the full-blown condition; see sickle cell disease. Those who are heterozygous are usually asymptomatic.sickle cell crisis a broad term describing several different acute conditions occurring as part of sickle cell disease, such as crisis" >aplastic crisis, crisis" >hemolytic crisis, and crisis" >vaso-occlusive crisis.sickle cell disease any of the diseases associated with the presence of hemoglobin" >hemoglobin S, including sickle cell anemia" >sickle cell anemia, thalassemia" >sickle cell–thalassemia, and the conditions called sickle cell–hemoglobin C and D disease. They are found most often in those of black African descent, but they also occur in persons of Mediterranean (Southern European and North African), Middle Eastern, or Asian Indian ancestry. About 8 to 10 per cent of all African Americans carry the sickle cell gene. About 90 per cent of persons with the gene are heterozygous for it, simply carriers of the sickle cell trait and usually without symptoms. The remainder, or about 1 in 500 of an ethnic group where the gene occurs, are homozygous for hemoglobin S, actually having sickle cell disease and suffering from the effects of hemolysis.
Sickle cell disease is a serious, hereditary, chronic disease in which the red blood cells have reduced life span and are rigid, with a crescent or sickle shape. The shape is the result of an abnormality in the hemoglobin, which alters the deformability of the cells under conditions of low oxygen tension. Because of their distorted shape the cells have difficulty passing through the small arterioles and capillaries and have a tendency to clump together and occlude the blood vessel. Some scientists believe that sickle cell disease developed as a defense against malaria. Malarial parasites do not grow in erythrocytes containing hemoglobin S. Therefore, carriers (heterozygotes) have an advantage in areas where malaria is prevalent (called the heterozygote advantage). (See accompanying figure.)Symptoms. There are many symptoms of sickle cell disease, all of them related to the defective hemoglobin and its effect on red blood cells. Some persons with the condition suffer from only a few symptoms, while others are severely affected and have a short life span. Better understanding and management of the disease in recent decades has improved the prognoses for patients with it.

The major symptoms are anemia, periodic joint and limb pain and sometimes edema of the joints, chronic ulceration about the ankles, episodes of severe abdominal pain with vomiting, and abdominal distention. The spleen becomes infarcted so that it is essentially absent and predisposes the patient to infection with encapsulated organisms. Bone changes often can be seen on x-ray and are due to bone infarcts. Headache, paralysis, and convulsions may result from cerebral thrombosis, which can cause stroke, blindness, and other neurological disturbances. There is a tendency toward progressive renal disease and renal failure.Sickle cell crisis is a broad term that describes several different conditions, particularly aplastic crisis, which is temporary bone marrow aplasia; hemolytic crisis, which is acute red cell destruction, leading to jaundice; and vaso-occlusive crisis, which is severe pain due to infarctions located in the bones, joints, lungs, liver, spleen, kidney, eye, or central nervous system. Factors that precipitate a crisis include infection, dehydration, trauma, strenuous physical exertion, emotional stress, and extremes of heat and cold.Treatment and Care. There is no cure for sickle cell disease. Treatment is symptomatic; preventive measures are employed to reduce the incidence of crises and to avoid infections. It is also important that the patient receive all available immunizing agents. Nutritional deficiencies should be corrected when present (folate supplementation is especially important), and then a well-balanced dietary intake should be maintained. hydroxyurea and prophylactic penicillin are administered according to therapeutic guidelines. Social service programs are required to facilitate adjustment to the disease and its sequelae. Control of pain associated with this condition should be a priority.
Patient Care. Sickle cell disease is a chronic condition with acute episodes related to vaso-occlusion. Virtually every system of the body can be affected by the ischemia resulting from obstruction of the blood vessels by clumps of deformed erythrocytes. Among the more common acute complications are inflammation of fingers and toes, aplastic anemia, splenic sequestration, and stroke. Chronic disorders include leg ulcers, renal complications, aseptic necrosis, and retinopathy. Bacterial infection is one of the major causes of morbidity and mortality in patients with sickle cell disease.
Because of the potential for serious complications due to occlusion of blood vessels, patients with sickle cell disease should have regular physical examinations to detect early changes. Periodic eye examinations are necessary to monitor retinal changes due to vaso-occlusion of retinal vessels.
Measures to improve or maintain the general well-being of patients include preventing dehydration, maintaining adequate nutrition to optimize the patient's resistance to infection and resources for healing, and managing the anemia that is characteristic of sickle cell disease. Education of patients and their parents and family members is an essential component of care. Patient support groups can be an effective mechanism to diffuse fear. Guidelines for the management of acute and chronic pain are available from the American Pain Society. A comprehensive biopsychosocial clinical assessment should be performed at least yearly.
The National Heart, Lung, and Blood Institute of NIH has published a guide called NIH Management and Therapy of Sickle Cell Disease. A printed copy is available as NIH publication number 95-2117. The guidelines are available online at http://www.emory.edu/peds/sickle/nih1/htm.Clinicopathologic findings in sickle cell anemia. The findings are a consequence of infarctions, anemia, hemolysis, and recurrent infection. From Damjanov, 2000.Statistical probabilities of inheriting sickle cell anemia.sickle cell disorders any blood disorders associated with the presence of hemoglobin S, including the sickle cell diseases and sickle cell trait.

sick·le cell a·ne·mi·a

[MIM*603903] an autosomal recessive anemia characterized by crescent- or sickle-shaped erythrocytes and accelerated hemolysis, due to substitution of a single amino acid (valine for glutamic acid) in the sixth position of the β-chain of hemoglobin, the gene of which is on chromosome 11; affected homozygotes have 85-95% hemoglobin (Hb) S and severe anemia, whereas heterozygotes (said to have sickle cell trait) have 40-45% Hb S, the rest being normal Hb A; low oxygen tension causes polymerization of the abnormal β-chains, thus distorting the shape of the red blood cells to the sickle form. Homozygotes develop "crisis" episodes of severe pain due to microvascular occlusions, bone infarcts, leg ulcers, and atrophy of the spleen associated with increased susceptibility to bacterial infections, especially streptococcal pneumonia. Occurs most commonly in people of African descent. Synonym(s): drepanocytic anemia, sickle cell disease

sick·le cell a·ne·mi·a

(sik'ĕl sel ă-nē'mē-ă) An autosomal dominant anemia characterized by crescentic or sickle-shaped erythrocytes and by accelerated hemolysis, due to substitution of a single amino acid (valine for glutamic acid) in the sixth position of the beta chain of hemoglobin (Hb); affected homozygotes have 85-95% Hb S and severe anemia, whereas heterozygotes (said to have sickle cell trait) have 40-45% Hb S, the rest being normal Hb A; low oxygen tension causes polymerization of the abnormal beta chains, thus distorting the shape of the red blood cells to the sickle form. Homozygotes develop "crises": episodes of severe pain due to microvascular occlusions, bone infarcts, leg ulcers, and atrophy of the spleen associated with increased susceptibility to bacterial infections, especially streptococcal pneumonia. Occurs almost exclusively in blacks.
Synonym(s): crescent cell anemia, drepanocytic anemia, sickle cell disease.