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Hemorrhagic fevers

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Hemorrhagic fevers

Hemorrhagic fevers — viral diseases in which clinical picture the hyperthermia and a hemorrhagic syndrome prevail. Typical manifestations of this group of infections — increase of permeability of vessels, a universal capillary toxicosis, prostration, infectious and toxic shock.

Etiology. Activators are very various. They belong to the category of the viruses differing on an antigenic structure and other properties. The group of hemorrhagic fevers includes more than ten viral diseases of the person. On etiological signs and factors of a transmission of infection these fevers are distributed as follows: tick-borne — Crimean, Omsk, kyasanursky, mosquito — yellow, the dengue, chikungunye; at contact with the infected animals — a hemorrhagic nephrosonephritis or hemorrhagic fever with a renal syndrome, the Argentina and Bolivian fevers, Lass's illness and others.

Epidemiology. In our country only 3 nosological forms meet: hemorrhagic fever with a renal syndrome; the Crimean and its version — the Central Asian fever; Omsk hemorrhagic fever. In recent years identical diseases in various geographical zones of the world — in Argentina, Bolivia, India, Thailand, on Philippines and in other countries are found. The majority of hemorrhagic fevers belong to natural and focal diseases. They meet in the form of sporadic diseases less often in the form of the epidemic flashes arising in the conditions of a certain landscape (the woody or steppe district, a taiga). Hemorrhagic fever with a renal syndrome which natural centers are revealed in Russia - the Tula, Yaroslavl, Vladimir, Kostroma areas, is most widespread in Cisural area and in the Urals, in Ukraine - in the Zakarpatye, Ivano-Frankivsk, Kharkiv, Rostov regions, and also in many countries of Europe where this illness is long since known under the name of an epidemic nephropathy. Flashes of a hemorrhagic nephrosonephritis were observed in South Korea, Manchuria. The reservoir of a virus are various rodents, mainly voles. Infection occurs at contact of people with the rodents or objects contaminated by their allocations. The laboratory flashes which resulted from aspiration infection are described. In transfer of Omsk and Crimean fevers the main role belongs to mites. Some fevers, in particular Central Asian, are transmitted from the person to the person. Incidence is defined by seasonality of distribution.

Pathogeny. The virus gets into a human body and causes profound changes of internals. Defeat of blood vessels is the most typical that leads to emergence of the hemorrhagic manifestations acting into the forefront in a clinical picture of an illness. In an origin of a hemorrhagic syndrome not only defeat of a vascular wall, but also disturbance of coagulant system of blood is of great importance. Damage of kidneys — bilateral intersticial serous and hemorrhagic nephrite and a segmented hydronephrosis destructive obturatsionnogo origins is characteristic of a number of fevers. On this soil azotemic uraemia, hemorrhages develops in pyramids of kidneys. The pathoanatomical picture which is characterized by the strengthened krovenapolneniye of bodies is typical.

Clinic. Each hemorrhagic fever has the distinctive features and at the same time all of them have similar signs. Incubation interval duration — from 1 to 3 weeks. These approximate terms can widely vary. The acute, sudden beginning with a fever, the Hyperthermia, weakness, the accruing intoxication is inherent in all fevers. Temperature usually sharply increases and soon decreases as crisis or the accelerated lysis. On the basis of nature of feverish reaction it is usually difficult to stop on any diagnosis. In cases of critical decrease it is quite often mistakenly considered as influenzal, sometimes she reminds tifo-paratyphoid, septic. In an initial stage quite often there is a headache amplifying at the height of an illness at the level of high temperature and abating in process of its decrease. From other complaints of an initial stage it is possible to note the general weakness, muscle and stomach pain, appetite loss, nausea and vomiting, dryness in a mouth, I am eager. Complaints are diverse, dynamic, changeable on an extent not only day, but also several hours. They reflect recurrence of an illness, natural change of separate symptoms.

Noticeable face reddening is characteristic. The hyperemia extends to a neck and upper part of a trunk. Eyelids slightly bulk up, from it the person gains some puffiness. Clearly the injection of vessels of scleras is expressed. The pharynx is hyperemic, the enantema of a soft palate is noted. The positive symptom of a pinch, hemorrhage on places of injections speak about the increased fragility of vessels. One of typical manifestations is the hemorrhagic syndrome: petekhialny rash, nasal, gastroduodenal, uterine bleedings.

In development of an illness the typical symptoms and signs allowing to differentiate hemorrhagic fevers on an etiological sign more and more clearly are shown. At an infectious nephrosonephritis in a clinical picture signs of deep damage of kidneys accrue. There is a back pain. Pasternatsky's symptom sharply positive. Even the light touch to a waist causes the sharp pain reaction which is so expressed that some patients evade from repeated survey under the pretext of strong morbidity. With approach of pain the oliguria is usually noted. Emergence in urine of protein, erythrocytes, degenerative cells of an epithelium of renal tubules and peculiar fibrinny cylinders, the exfoliating cells of a renal epithelium is characteristic. Protein appears in urine at the end of the 1st week of an illness, quickly accrues in process of strengthening of a back pain, reaching high rates. At addition in a test tube of sulphosalicylic acid urine turns into a continuous curdled deposit at once. In the subsequent the oliguria is replaced by a polyuria, the specific weight of urine is lost to 1002 — 1003.

The complaints connected with a visual disturbance are typical. Patients complain that at them as if the grid before eyes, fog, flickers before eyes, objects merge in the distance that it is possible to explain with accommodation paresis. The leukopenia arising in the beginning is replaced by a leukocytosis, SOE raises, activity of aminotransferases increases, the level of residual nitrogen in blood increases.

Frequent display of the Crimean fever are hemorrhages, widespread mialgiya, an abdominal pain, bradycardia, arterial hypotension, a moderate hepatolienal syndrome, is sometimes purulent - septic complications. The temperature curve has two-humped character. Pathology from kidneys is a little expressed. Blood picture: leukopenia, neutrocytosis, thrombocytopenia, increase in SOE. The Central Asian fever as clinical option of Crimean, is followed by plentiful hemorrhages, proceeds hard with a high lethality, differs in high contageousness. Omsk fever is characterized by a two-wave temperature curve, poorly expressed hemorrhages, quite often is complicated by pneumonia, bronchitis, the central nervous system is involved in pathological process. One of characteristics is bradycardia, decrease in the ABP. The abdominal pain arising sometimes can be explained with increase in retroperitoneal lymph nodes. Sometimes there is a back pain, rather myogenetic character.

At an assessment of a clinical course of hemorrhagic fevers it is necessary to consider prirodnoochagovy character of these diseases. The symptomatology of the same illness, especially weight of a clinical current, significantly changes depending on conditions of environment, a geographical landscape, meteorological factors in the conditions of the same local center. For example, in the Far East, in South Korea, Hungary, Bulgaria fever with a renal syndrome quite often proceeds in a severe form, and in the Scandinavian countries it is much more slight. Variability of a clinical current in the conditions of various geographical zones gets great value in recognition of prirodnoochagovy infections. This feature needs to be considered at statement of the final diagnosis.

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