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Drepanocytic anemia

Drepanocytic anemia — the disease connected with hereditary disturbance of synthesis of hemoglobin a form of erythrocytes is a consequence of the lowered solubility of the hemoglobin which gave oxygen.

Epidemiology
Abnormal hemoglobin S generally occurs at residents of the countries of the Central and East Africa, the coast of the Mediterranean Sea (Italy, Greece, Cyprus, Turkey, etc.). Middle East, and also India. In a tropical zone of Africa prevalence of HbS vvryirut from 15 to 45%, the number of heterozygous carriers of this hemoglobin reaches 40 000 people. Among the population Severnoy and South Africa this anomaly of hemoglobin occurs sporadic. Drepanocytic anemia meets at children more often; at teenagers and at adults it is observed less often.

Etiology and pathogeny
The changed sequence of the amino-acid remains in hemoglobin at drepanocytic anemia leads to delay of its electrophoretic mobility, low solubility (is 50 times lower, than at NYA) that is the cornerstone of one of important signs of availability of hemoglobin S — crescent forms of erythrocytes.

Formation of crescent erythrocytes leads to increase of viscosity of blood, delay of a blood-groove and a staz of blood in capillaries. Staz of blood in turn promotes development of a hypoxia in the struck zone that also strengthens crescent change of erythrocytes. Disturbances of processes of glycolysis, decrease in the ATP level and other shifts in exchange processes of the changed erythrocytes raise them autogemoliz.

Crescent form of erythrocytes appears when lowering partial pressure of oxygen (60 mm of mercury. below) first of all in erythrocytes with concentration of HbS of 90 — 100%; at concentration of HbS of 25 — 50% crescent form of erythrocytes arises with a partial pressure of oxygen of 10 mm of mercury.
When lowering partial pressure of oxygen or at effect of the recovering substances at persons with a hemoglobinosis S hemoglobin, passing into a gel state, forms hemicrystalline an oval form the tactoids changing a form of erythrocytes.

Classification
The hemoglobinosis of S has the homozygous and heterozygous forms, meets also in the form of a double geterozigotizm. At seprovidnokletochny anemia of HbS makes 80 — 100% of hemoglobin of a cell.

Approximate formulation of the diagnosis:
Drepanocytic anemia with hemolitic crises, a haemoglobinuria, ikterichnost of visible mucous membranes and integuments, increase of free fraction bilirubin of blood serum, urobilin in urine; tower type of a skull, salty and a hepatomegalia with development of heart attacks; pigmental stones in a gall bladder, an osteosclerosis, trophic shin ulcers, normokhromny anemia, a leukocytosis with shift to myelocytes, activation of an erythro-normoblastic sprout of marrow, among erythrocytes — targetoid and crescent forms.

Clinic
The drepanocytic illness proceeds very hard. Usually to five-months age the child inheriting HbS genes from the parents has first hemolitic crises, a painful swelling of feet, brushes, shins, joints. These crises, arising quite often against infections, proceed very hard. At the beginning the fever, fervescence, a haemoglobinuria are noted, the progressing anemia, then develops an ikterichnost of visible mucous membranes and integuments, the free fraction of bilirubin of blood serum, urobilin in urine and stercobilin in Calais raises.

The swelling of extremities has inflammatory character and is caused by fibrinferments of vessels. The aseptic necroses of heads of femoral and humeral bones which are shown painful pains and a swelling of soft tissues around the place of defeat meet. Heart attacks of lungs, spleens, a liver, kidneys, a brain and other bodies, fibrinferment of vessels of a liver and capillaries of a mesentery, a retinal apoplexy are observed. The asthenic constitution, decrease in body weight, trophic shin and upper extremities ulcers, pigmental stones in a gall bladder are noted. The tower type of a skull, gepato-and a splenomegaly with increase in volume of a stomach is characteristic, the kyphosis of chest department of a backbone or a lordosis of lumbar department are possible. Radiological osteoporosis, at late stages of an illness — an osteosclerosis with a thickening of a cortical layer comes to light.

Blood picture: normokhromny, is more rare hypochromia anemia, a reticulocytosis, a leukocytosis with shift to myelocytes, anizopoykilotsitoz, the anizokhromiya and basphilic stippling of erythrocytes, quite often meet targetoid erythrocytes and normoblasts. Crescent erythrocytes in blood smears come to light seldom. The term of circulation marked 51Cr erythrocytes happens shortened. In punctate of marrow the erythronormoblastic sprout is expanded. Aplastic crises meet.

Drepanocytic anemia at children's and youthful age can proceed benign. At the women having this disease are noted the late beginning of periods, frequent misbirths and premature births, pregnancy can be complicated by disturbance of cerebral circulation, development of heart failure etc.

Verification of the diagnosis
The diagnosis of drepanocytic anemia is established on the basis of the given characteristic clinical symptoms and hematologic disturbances. Also the simplest and available test on crescent form of erythrocytes using artificially caused local hypoxia (on the basis of a finger the plait is imposed) is used. Crescent form is revealed better by test with metabisulphite. At homozygous options of a disease crescent change of erythrocytes is found within 1 hour, and at heterozygous — in a day. Also the test for opacification (based on bad solubility of HbS) which is applied to a dress or instead of test on crescent form of erythrocytes is applied. The final diagnosis of drepanocytic anemia is established on the basis of identification on a hemoglobin elektroforegramma only of HbS or its combinations to HBF.

Treatment
In treatment of drepanocytic anemia transfusions of the washed or defrozen erythrocytes, according to indications — anticoagulants, a slepnektomiya, etc. are used.

 
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