FAVYZM (favismus, fabismus; lat. faba a bean) — one of forms of hereditary hemolitic anemia arising at persons with insufficiency of enzyme of a glyukozo-6-phosphate-dehydrogenase in connection with consumption or inhalation of flower pollen of horse beans — Vicia faba, or Vicia fava.
The first message on the hemolitic jaundice connected with the use of horse beans belongs to the Portuguese doctor Franco (M. of Franco, 1843). The name «favism» is offered the ital. doctor Montano. Zone of incidence F. matches a zone of distribution of bean cultures, and also the centers of malaria in the past and in a crust, time. T. the hl is widespread. obr. in the countries of the Mediterranean, Iraq, Iran. In the Soviet Union family diseases F. meet in the southern districts of the Azerbaijani SSR.
Etiology and pathogeny. T. there is only at persons with genetically caused insufficiency in erythrocytes of enzyme a glyukozo-6-phosphate — dehydrogenases (G6PD), hl. obr. its Mediterranean option B". Predisposition to F. it is inherited on the type linked to a floor. Children up to 15 years, preferential boys — gemizigota, carriers patol are ill generally. chromosomes of X. In areas where F is widespread., sick girls — homozygotes rather often meet. Experiences of in vitro of Bottini (E. Bottini,
1973) showed that the substances extracted from bean grains cause reduction of concentration of the recovered glutathione (GSH) and the sulphhydryl groups (SH) which are contained in a membrane in erythrocytes. In the conditions of deficit of G6FD catalyzing reaction of recovery of GSH permeability of membranes of erythrocytes for ions To, Na and 02 increases that finally leads to a lysis of erythrocytes. Consider that lysis G6FD-defitsitnykh of erythrocytes causes not carbohydrate component of a r-glycoside-devitsin close which is contained in beans on the structure to L-DOFA; on a nek-eye to data, hemolysis causes directly izoumarit (contained in horse beans derivative a pyrimidine), possessing action, synergistic with L-DOFA. Cases F are known. at the babies raised by milk of mother eating horse beans and also milk of the goat eating beans. Possibly, for manifestation of a favism one deficit of G6FD does not suffice. The combination of two fermental defects — deficit of G6FD and disturbance of neutralization of toxin of beans is required. Thereof not all persons with deficit of activity of G6FD can have a wedge, a picture of a favism.
Pathological anatomy. At F. find yellowness and dystrophic changes of internals. The liver is yellow-brown, it is increased. The spleen is red-brown, it is increased, full-blooded. Kidneys are increased, bulked up.
Microscopically capillaries of a liver and sine of a spleen are filled with the detritis formed at the expense of an erythrocytolysis. In hepatic cells, an endothelium of sine, macrophages of a spleen and marrow are postponed in a large amount of grain of a blood pigment like hematin and hemosiderin. In renal balls — exudate with fine-grained disintegration; in an epithelium of gyrose tubules — muddy swelling and a necrosis; in gleams of direct tubules — the gemoglobinovy and granular cylinders giving positive reaction to iron.
In marrow, according to an intravital trepanobiopsiya of an ileal bone, in the period of acute hemolitic crisis the hyperplasia of elements of a hemogenesis, reduction of amount of fat is found. Histologically against the background of the general hyperplasia of erythroidal elements peculiar centers of an erythroidal hypoplasia — an anerit-roblastoz in the form of so-called fields of devastation are found; the last disappear in a phase of the regeneration which is characterized by normoblastic reaction and an eosinophilia.
Clinic. Get sick with F. more often in spring months, in a blooming period bean (so-called. Baghdad spring fever). Expressiveness a wedge, manifestations is various — from slight symptoms of hemolysis to a picture of the hardest hemolitic crisis (see), Krom is often preceded by the prodromal phenomena in the form of a febricula, temperature increase, went. - kish. frustration. Usually initial symptoms of a disease arise during the first hours after reception of horse beans (rarely for the 2nd or 3rd day), and at inhalation of flower pollen symptoms of a disease can appear in a few minutes. Distinguish severe, moderately severe and easy forms F. The severe form proceeds with a picture of an acute intravascular hemolysis, jaundice (at the expense of not conjugated bilirubinemia), a haemoglobinaemia (see) and to hemoglobin a yard (see). The blood analysis reveals anemia with a high reticulocytosis, normoblastozy, emergence of little bodies of Heinz (see Gemogramm), a neutrophylic leukocytosis with shift to myelocytes, sometimes with an eosinophilia at normal number of thrombocytes to the left. In marrowy punctate — the expressed erythroblastic reaction, an eosinophilia. At a cytochemical research of erythrocytes total absence of granules the, specific to G6FD, found in normal erythrocytes is noted. The moderately severe form gives a picture of hemolitic jaundice (see) with moderate anemia and a haemoglobinaemia, but without hemoglobin of a riya. At an easy form F. the wedge, a picture is characterized by symptoms of food intoxication (nausea, vomiting, a diarrhea), short-term yellowness of scleras and mucous membranes is possible; in blood — the raised reticulocytosis, but anemia does not come to light.
The diagnosis is established on the basis of data of the anamnesis, typical by a wedge, pictures and definitions of insufficiency of G6FD of erythrocytes.
Treatment. Pathogenetic treatment is not developed. Use of xylitols, Riboflavinum, nicotinic to - you, ethylene diamine tetraacetic to - you for the purpose of increase in erythrocytes of the GSH level was inefficient. At emergence of the first symptoms of intoxication the gastric lavage and intestines is shown. Treatment of hemolitic crisis (see) comes down to a complex of the events held at an acute intravascular hemolysis, first of all — hemotransfusions (from donors with the normal maintenance of erythrocyte G6FD). At an acute renal failure (see) the hemodialysis is shown (see).
The forecast is defined by weight of a current and age of the diseased. The lethality at children's age reaches 8 — 12%, at adults it is lower. Death comes from the acute renal failure which is followed by an anury (see) and uraemia (see) or owing to thrombosis of vessels of a brain the breaking-up erythrocytes with development of a coma (see).
Prevention consists in caution of children from consumption of horse beans and inhalation of their flower pollen, a dignity. - a gleam. to work among the population and withdrawal of cultures bean in local on F. areas. Holding similar actions allowed to achieve almost complete elimination of a favism in the Azerbaijani SSR.
See also Enzimopenichesky anemia.
Bibliography: D R. B. Fa's zhavad -
a vizm, Baku, 1975; Idelson L. I., D and d to about in with to and y N. A. and E r m and l of ý-h e N to about G. V. Hemolitic anemias, M., 1975; In about t t i n i E. Favism, current problems arid investigations, J. med. Genet., v. 10, p. 154, 1973. G. A. Alekseev.