Hemorrhagic fever are viral infections with a natural focal spread, occurring with hemorrhagic and acute febrile syndrome. The symptoms of hemorrhagic fever include severe intoxication, high body temperature, hemorrhagic rash, bleeding of various localization, multiple organ disorders. The form of hemorrhagic fever is determined taking into account clinical, epidemiological and laboratory data (PCR, ELISA, RIF). In hemorrhagic fever, detoxification, antiviral, hemostatic therapy, the introduction of specific immunoglobulins, and the fight against complications are carried out.
Hemorrhagic fever are a group of infectious diseases of a viral nature that cause toxic damage to the vascular walls, contributing to the development of hemorrhagic syndrome. They occur against the background of general intoxication, provoke multiple organ pathologies. Hemorrhagic fever are common in certain regions of the planet, in the habitats of carriers of the disease. Hemorrhagic fever are caused by viruses of the following families: Togaviridae, Bunyaviridae, Arenaviridae and Filoviridae. A characteristic feature that unites these viruses is the affinity for human vascular endothelial cells.
The reservoir and source of these viruses are humans and animals (various types of rodents, monkeys, squirrels, bats, etc.), the carrier is mosquitoes and ticks. Some hemorrhagic fever can be transmitted by contact, household, food, water and other ways. According to the method of infection, these infections are divided into groups: tick-borne infections (Omsk, Crimean-Congo and Kyasanur forest fever), mosquito-borne (yellow, dengue fever, Chukungunya, Rift Valley) and contagious (Laos, Argentine, Bolivian, Ebola, Marburg, etc.).
The susceptibility to hemorrhagic fever in humans is quite high, mainly people whose professional activities are related to wildlife get sick. The incidence in cities is more common among citizens who do not have a permanent place of residence and employees of household services who come into contact with rodents.
Hemorrhagic fever in most cases combine a characteristic course with a sequential change of periods: incubation (usually 1-3 weeks), initial (2-7 days), peak (1-2 weeks) and convalescence (several weeks). The initial period is manifested by general intoxication symptoms, usually very intense. Fever in severe cases can reach critical figures, intoxication can contribute to a disorder of consciousness, delirium, hallucinations.
Against the background of general intoxication, toxic hemorrhage (capillarotoxicosis) is already noted in the initial period: the face and neck, conjunctiva of patients are usually hyperemic, sclera are injected, elements of hemorrhagic rash on the mucous membrane of the soft palate can be detected, endothelial symptoms (“tourniquet” and “pinch”) are positive. There are toxic cardiac arrhythmias (tachycardia, turning into bradycardia), a decrease in blood pressure. During this period, a general blood test shows leukopenia (persists for 3-4 days) and increasing thrombocytopenia. In the blood formula, neutrophilosis with a shift to the left.
Before the onset of the peak period, there is often a short-term normalization of temperature and improvement of the general condition, after which toxicosis increases, the intensity of the general clinic increases, multiple organ pathologies develop, hemodynamic disorders. During the period of convalescence, there is a gradual regression of clinical manifestations and restoration of the functional state of organs and systems.
Hemorrhagic Far Eastern nephrosonephritis is often called hemorrhagic fever with renal syndrome, since this disease is characterized by a predominant lesion of the renal vessels. Incubation of hemorrhagic Far Eastern nephrosonephritis is 2 weeks, but can be reduced to 11 and lengthened to 23 days. For the first time in the days of the disease, prodromal phenomena (weakness, malaise) are possible. Then severe intoxication develops, the body temperature rises to 39.5 degrees or more and persists for 2-6 days. 2-4 days after the onset of fever, hemorrhagic symptoms appear against the background of progressive intoxication. Sometimes there may be meningeal symptoms (Kernig, Brudzinsky, rigidity of the occipital muscles). Due to toxic brain damage, consciousness is often confused, hallucinations and delusions appear.
The general hemorrhagic syndrome is accompanied by symptoms from the kidneys: lower back pain, a positive symptom of Pasternatsky, erythrocytes, cylinders, protein are detected in the general urine analysis. With the progression of the disease, the renal syndrome worsens, as well as hemorrhagic. At the height of the disease, bleeding from the nose, gums, hemorrhagic rash on the trunk (mainly in the shoulder girdle and lateral surfaces of the chest) are noted. When examining the mucous membrane of the mouth and oropharynx, spot hemorrhages on the palate and lower lip are detected, oliguria develops (in severe cases up to complete anuria). Macrohematuria is noted (urine acquires the color of “meat slops”).
Fever usually lasts 8-9 days, after which a decrease in body temperature occurs within 2-3 days, but after its normalization, the condition of patients does not improve, vomiting may occur, and renal syndrome progresses. Improvement of the condition and regression of clinical symptoms occurs on 4-5 days after the fever subsides. The disease goes into a phase of convalescence. Polyuria is characteristic at this time.
Crimean hemorrhagic fever is characterized by an acute onset: vomiting, abdominal pain on an empty stomach, chills are noted. Body temperature rises sharply. The appearance of patients is characteristic of hemorrhagic fever: hyperemic edematous face and injected conjunctiva, eyelids, sclera. Hemorrhagic symptoms are expressed: petechial rashes, bleeding gums, nosebleeds, admixture of blood in feces and vomit, uterine bleeding in women. The spleen often remains of normal size, some patients may have an increase in it. The severe course of the disease is manifested by intense abdominal pain, frequent vomiting, melena. The pulse is labile, blood pressure is lowered, heart tones are deaf.
Omsk hemorrhagic fever proceeds more easily and benign, hemorrhagic syndrome is less pronounced (although lethality also occurs with this infection). In the first days, the fever reaches a little over 39 degrees, in half of the cases, the fever period proceeds in waves, with periods of increase and normalization of body temperature. The duration of fever is 3-10 days.
Hemorrhagic dengue fever is characterized by an incubation period of 5 to 15 days, a benign course, symptoms of general intoxication, increasing by 3-4 days and a spotty-papular rash of hemorrhagic origin, passing 2-3 days after the appearance (usually occurs at the height of the disease) and leaving no pigmentation or peeling. The temperature curve can be two-wave: fever is interrupted by a 2-3-day period of normal temperature, after which a second wave occurs. This form is typical for Europeans, residents of Southeast Asia have Dengue fever develops according to the hemorrhagic variant and has a more severe course.
Hemorrhagic fever can contribute to the development of severe, life-threatening conditions: infectious and toxic shock, acute renal failure, coma.
Diagnosis of hemorrhagic fever is performed on the basis of the clinical picture and epidemiological history data, confirming the preliminary diagnosis in the laboratory. Specific diagnostics is performed using serological studies (RSC, RNIF, etc.), enzyme immunoassay (ELISA), detection of viral antigens (PCR), virological method.
Hemorrhagic fever are usually characterized by thrombocytopenia in the general blood test, the detection of red blood cells in urine and feces. With severe hemorrhage, symptoms of anemia appear. A positive stool test for latent blood indicates bleeding along the gastrointestinal tract.
Fever with renal syndrome also manifests itself in laboratory diagnostics in the form of leukopenia, aneosinophilia, an increase in the number of rod-shaped neutrophils. Significant pathological changes in the general analysis of urine – the specific gravity is reduced, protein is noted (often the increase reaches 20-40%), cylinders. Residual nitrogen is elevated in the blood. Crimean fever is characterized by lymphocytosis against the background of general normocytosis, a shift of the leukoformula to the left and normal ESR.
Patients with any hemorrhagic fever are subject to hospitalization. Prescribed bed rest, semi-liquid calorie easily digestible diet, maximally saturated with vitamins (especially C and B) – vegetable broths, fruit and berry juices, rosehip infusion, fruit drinks). In addition, vitamin therapy is prescribed: vitamins C, R. Vikasol (vitamin K) is taken daily for four days.
Intravenously, a glucose solution is prescribed, during the fever period, blood transfusions in small portions can be performed, as well as the administration of iron preparations, preparations based on an aqueous extract from the liver of cattle. The complex therapy includes antihistamines. Discharge from the hospital is made after a complete clinical recovery. Upon discharge, patients are observed on an outpatient basis for some time.
Prognosis and prevention
The prognosis depends on the severity of the disease. Hemorrhagic fever can vary over a very wide range, in some cases causing the development of terminal conditions and ending fatally, but in most cases, with timely medical care, the prognosis is favorable – the infection ends in recovery.
Prevention of hemorrhagic fever primarily involves measures aimed at destroying vectors of infection and preventing bites. In the area of the spread of infection, thorough cleaning of places prepared for settlement is carried out from blood-sucking insects (mosquitoes, ticks), in epidemiologically dangerous regions it is recommended to wear thick clothing, boots, gloves, special mosquito-resistant overalls and masks, use repellents in forests. For Omsk hemorrhagic fever, there is a method of specific prevention, planned vaccination of the population with the help of a killed virus vaccine.