What is Hemorrhagic Fever with Renal Syndrome (HFRS) in Children?
Hemorrhagic fever with renal syndrome (HFRS) is known under many names – Ural, Tula, Yaroslavl fever, hemorrhagic nephrosonephritis. This is an acute infectious disease of viral origin, which is manifested by the following symptoms: fever, intoxication, hemorrhagic renal syndromes.
Hemorrhagic fever with renal syndrome is transmitted from animal to person. Natural foci of the disease are located in Kazakhstan, Eastern Siberia, Transbaikalia, the Far East, etc. Voles, rats, field and forest mice, and other mouse rodents are infected.
Between animals, the infection spreads with gamasid ticks and fleas. In mouse-like rodents, the infection rarely proceeds with severe symptoms, often they transfer the disease in a latent form. The virus is excreted in animals with feces and urine. A person becomes infected by breathing dust with mice, as well as in the case of contaminated material getting on damaged skin (even with microtrauma) or rubbing it into intact skin. There is a risk of infection when eating rodent-contaminated foods, such as vegetables, bread, etc.
Previously considered the main vector-borne transmission of the disease. But at present, researchers have doubts about this, discussions are ongoing. From person to person, infection is not transmitted (low probability of transmission).
Hemorrhagic fever with renal syndrome in children occurs in separate cases, but small outbreaks also occur.
Since children under 7 years of age have very limited contact with nature, they are ill in rare cases. Outbreaks of this disease occur in kindergartens, pioneer camps, sanatoriums for children (which are located in the vicinity of the forest).
The highest incidence rate is annually from May to November. In the Far East, the largest number of diseases occurs in May and July, and the second wave in October and December. It depends on the migration of rodents into residential and household premises and on agricultural work.
Hemorrhagic fever with renal syndrome (HFRS) is manifested in typical, erased and subclinical forms of the disease. There are mild, moderate and severe forms – according to the degree of intoxication, the severity of hemorrhagic syndrome, the degree of renal function impairment.
Causes of Hemorrhagic Fever with Renal Syndrome (HFRS) in Children
The causative agent of hemorrhagic fever with renal syndrome (HFRS) in children belongs to the Bunyavirtdae family. It contains two specific viral agents called Hantaan and Piumale. The virus is RNA-containing; its diameter is from 80 to 120 nm. HFRS virus is unstable. From 10 to 20 minutes it is stored at a temperature of 50 ° C.
Pathogenesis during Hemorrhagic Fever with Renal Syndrome (HFRS) in Children
Infection initially accumulates vascular endothelium and, presumably, in the epithelial cells of some organs. Further, the virus spreads through the bloodstream, provoking the onset of the disease and the manifestation of symptoms of general intoxication. The virus has a capillarotoxic effect. It damages the walls of blood vessels, negatively affects blood coagulation, which leads to thrombohemorrhagic syndrome. In various organs, especially in the kidneys, thrombi appear.
The violations described above in severe cases lead to hemorrhages in the internal organs and large cavity bleeding. The virus also has a toxic effect on the central nervous system.
Morphological changes are found mainly in the kidneys. They increase dramatically, the capsule is tense, sometimes tears and multiple hemorrhages form.
Microscopic analysis shows plethora, focal edematous and destructive changes in the vascular walls and other processes in the kidneys. The urinary tubules are dilated, their lumen is filled with hyaline and granular cylinders, the collecting tubes are glorified. Other organs of a sick child are characterized by plethora, dystrophic changes, edema, hemorrhage, etc.
Symptoms of Hemorrhagic Fever with Renal Syndrome (HFRS) in Children
10 to 45 days pass before the disease begins to manifest. On average, the incubation period for hemorrhagic fever lasts 20 days. The disease goes through four cycles. First, the febrile stage, then the oliguric, polyuric and final stage of convalescence.
In most cases, the disease is characterized by an acute onset, the temperature “jumps” to 39 – 41 ° C, general toxic symptoms appear, such as lethargy, nausea and vomiting, sleep disorders, lethargy, anorexia. On the first day of the disease, the child has headaches localized in the frontal and temporal regions, dizziness, fever, slight chills, pain in the knees and muscles, body aches are possible. Severe abdominal pain is likely, especially in the area of the kidneys, soreness when moving the eyeballs.
Symptoms are most pronounced on the second or third day. The patient’s condition is characterized as severe or very severe. Tremor of the tongue and fingers, hyperthermia are characteristic, there is a possibility of delirium, convulsions, hallucinations.
Older children may complain of a veil before their eyes or “flies.” Visual acuity decreases, objects can be seen in red shades.
Doctors during examination record puffiness and hyperemia of the face, hyperemia of the mucous membranes of the pharynx, injection of conjunctival vessels and sclera (overflow with their blood). The patient complains of thirst and sore throat.
In the midst of the onset of symptoms, sometimes there is a hemorrhagic enanthema on the mucous membranes of the soft palate and a petechial rash on the skin of the chest, in the armpits, in the neck, etc. It looks like a trace from a whip. In some cases, there are gastric, uterine, and nosebleeds.
In the early days of the disease, the pulse is frequent, then bradycardia develops, blood pressure decreases, even collapse or shock can occur. Palpation of the abdomen often causes pain (in the upper part). In 50 cases out of 100, the liver is enlarged. The stool is most often difficult, but there is a possibility of diarrhea, periods with blood.
The oliguric period in patients with hemorrhagic fever of children occurs on the 3-4th day of the disease, maximum – on the 6-8th. The body temperature suddenly “drops”, diuresis also drops (the child goes to the toilet a little), lumbar pain intensifies. Symptoms of intoxication are increasing, kidney damage is becoming larger, which leads to a deterioration in the general condition of the patient.
Urinalysis shows proteinuria, hematuria, cilruria. Renal epithelium is constantly detected. The relative density of urine is reduced.
The onset of recovery is noted in the polyuritic period, which occurs on 8-12 days from the onset of the disease. The general condition of the sick child is getting better, lower back pain is reduced, there is no vomiting. In this period, sleep and appetite return to normal. Diuresis increases, a patient may develop 3-5 liters of urine per day.
The reconvalescence period lasts 3-6 months. The patient recovers slowly, general weakness persists, diuresis is also restored at a slow pace. The relative density of urine is gradually returning to normal. Within six months or even a year, the state of post-infectious asthenia may persist.
During the febrile period, short-term leukopenia is observed in the blood, which is replaced by leukocytosis with a shift of the formula to the left to stab forms and young forms. There may also be a decrease in platelet count and the appearance of plasma cells, as well as aneosinophilia. Soe is normal or elevated. In acute renal failure, the level of residual nitrogen increases in the blood, and potassium grows, while the content of chloride and sodium decreases.
The course of hemorrhagic fever is always acute. The prognosis is favorable for mild and moderate forms of hemorrhagic fever in children. Severe cases are fatal, leading to hemorrhage in the brain and adrenal cortex, tearing of the cortical substance of the kidneys, hemorrhagic pulmonary edema, azotemic uremia or acute cardiovascular failure.
Diagnosis of Hemorrhagic Fever with Renal Syndrome (HFRS) in Children
The diagnosis of hemorrhagic fever with renal syndrome is based on the symptoms: hyperemia of the face and neck, fever, kidney damage, hemorrhagic rashes on the shoulder girdle (looking like a trace of a lash), the appearance of plasma cells and leukocytosis with a shift to the left.
Doctors find out for diagnosis whether there would be a patient in the outbreak zone, whether there are rodents in his house / apartment, whether the sick child used vegetables or fruits with traces of rodent bites.
To diagnose hemorrhagic fever with renal syndrome in children, laboratory methods are used: RIF, ELISA, hemolysis reaction of chicken red blood cells, etc.
Differential diagnostics are carried out with hemorrhagic fevers of another etiology, influenza, leptospirosis, acute nephritis, typhus, typhus, sepsis and other similar diseases.
Treatment of Hemorrhagic Fever with Renal Syndrome (HFRS) in Children
Treatment of hemorrhagic fever with renal syndrome in children is carried out in a hospital. A sick child should observe bed rest, a diet is prescribed with a restriction of meat, but with a normal amount of table salt. At the peak of the disease, intravenous infusions of 10% glucose solution, Ringer’s solution, albumin, 5% ascorbic acid solution are prescribed.
Doctors prescribe corticosteroids for 5-7 days in severe cases. In case of cardiovascular insufficiency, it is obligatory to take cordiamine, mesatone, and in case of hypertension – aminophylline and papaverine. In the oliguric period, the introduction of mannitol, polyglucin, gastric lavage with 2% sodium bicarbonate solution is necessary.
With increasing azotemia and anuria, doctors can prescribe extracorporeal hemodialysis with an “artificial kidney” apparatus. With massive bleeding, blood transfusions and blood substitutes are necessary. To prevent thrombohemorrhagic syndrome, heparin is administered. When there is a threat of bacterial complications, doctors usually prescribe antibiotics.
Prevention of Hemorrhagic Fever with Renal Syndrome (HFRS) in Children
Preventive measures include the destruction of mouse-like rodents on the territory of natural foci of hemorrhagic fever with renal syndrome. It is also necessary to prevent contamination of food and water sources with rodent excrement, strict observance of the sanitary-anti-epidemic regime in and around houses / apartments / summer cottages.