What Causes Hemorrhagic Fever?

Hemorrhagic fever, or epidemic hemorrhagic fever, is also known as renal syndrome hemorrhagic fever. It is an important infectious disease that is harmful to human health. It is caused by the epidemic hemorrhagic fever virus (Hantan virus). Sexually transmitted diseases. The main clinical manifestations were fever, bleeding, congestion, hypotension shock, and kidney damage.

Basic Information

nickname: Epidemic hemorrhagic fever, hemorrhagic fever with renal syndrome
English name: hemorrhagic fever
Visiting department: Infectious Diseases
Multiple groups: Young people
Common causes: Caused by epidemic hemorrhagic fever virus (Hantavirus)

Common symptoms: Fever, headache, low back pain, orbital pain, nausea and vomiting, chest tightness
Contagious: Have
way for spreading: It is mainly of animal origin. The virus can be excreted through the blood and saliva, urine, and stool of the host animal. Direct transmission from mice to humans is an important way for human infection.

Causes of hemorrhagic fever

Caused by the epidemic hemorrhagic fever virus (Hantavirus).

Host animal and source of infection

Mainly small rodents, including wild rats and house rats.

2. Ways of transmission

It is mainly of animal origin. The virus can be excreted through the blood and saliva, urine, and stool of the host animal. Direct transmission from mice to humans is an important way for human infection.

3. Population susceptibility

It is generally believed that the population is generally susceptible, the rate of recessive infection is low, the general incidence of young adults is high, and there is lasting immunity after illness.

Clinical manifestations of hemorrhagic fever

The incubation period of hemorrhagic fever is generally 2 to 3 weeks. The typical clinical process is divided into five phases: fever, hypotension shock, oliguria, polyuria, and recovery.

Fever period

The main symptoms are infectious viremia and systemic capillary damage.

Sudden onset of symptoms, fever (38 ° C ~ 40 ° C), three pains (headache, low back pain, orbital pain), and nausea, vomiting, chest tightness, abdominal pain, diarrhea, general joint pain, etc. The upper chest is red), the conjunctiva is congested, and the severe person looks drunk. Bleeding spots or plaques of various sizes appear in the oral mucosa, chest back, and underarms, or there are cord-like, scratch-like bleeding spots.

2. Hypotension shock period

Most of the time, fever is 4-6 days, when the body temperature begins to drop or shortly after fever, it is mainly the performance of hypovolemic shock. The patient developed hypotension, and severe cases developed shock.

3. oliguria

The 24-hour urine output is less than 400ml, and there is often no clear boundary between the oliguria phase and the hypotension phase.

4. Polyuria

Renal tissue damage is gradually repaired, but because the renal tubular reabsorption function has not been completely restored, the urine output has increased significantly. It is more common on the 8th to 12th days, lasting 7 to 14 days, and the urine output is about 4000 to 6000ml per day, which can easily cause dehydration and electrolyte disturbance.

5. Recovery period

With the gradual recovery of renal function, when the urine output drops below 3000ml, it enters the recovery period. Urine volume and symptoms gradually returned to normal, and recovery took months.

Hemorrhagic fever examination

Routine inspection

(1) Blood routine The total number of white blood cells in the early stage is normal or low, and it increases significantly after 3 to 4 days, mostly at (15 to 30) × 10 ⁹ / L. Atypical lymphocytes can appear within 1 to 2 disease days, and increase daily , Generally 10% to 20%, some of which reach more than 30%; platelets are significantly reduced, hypotension and oliguria are the lowest, and abnormal, meganuclear platelets appear, and polyuria recovers later. Red blood cells and hemoglobin begin to rise during the fever phase, gradually increase during the period of hypotension, and patients in shock phase rise significantly, at least during the urinary phase. The dynamic changes can be used as an important indicator to judge blood concentration and blood dilution.

(2) Urine routine Significant urinary protein is an important feature of the disease and the earliest manifestation of kidney damage. There can also be red blood cells, casts, or membranes in the urine (a mixture of clots, proteins, and necrotic epithelial cells).

2. Blood biochemical examination

(1) Urea nitrogen and creatinine The hypotension shock period is mild and moderately elevated. The oliguria to polyuria peaked, and then gradually decreased. The degree and extent of the increase were directly proportional to the condition.

(2) Electrolyte Serum potassium may be reduced during the fever phase, but still low during shock, increased to hyperkalemia during oliguria, and decreased during polyuria. However, there are those with hypokalemia during oliguria. Blood sodium and chlorine were reduced throughout the course of the disease, with shock and oliguria most significant. Blood calcium is also reduced throughout the course of the disease.

(3) Carbon dioxide binding power is decreased in the later stage of fever, the hypotension shock period is obvious, and the oliguria period is also decreased.

3. Blood coagulation test

A large amount of coagulation factors are consumed, platelets are decreased, prothrombin and partial thromboplastin time are prolonged, and fibrinogen is reduced. Secondary hyperfibrinolysis is characterized by prolonged thrombin coagulation time, increased fibrin degradation products, and shortened euglobulin dissolution time. The plasma protamine paracoagulation test (3P test) was positive.

4. Specific antigen, antibody and pathogenic examination

Early use of immunofluorescence test, enzyme-linked immunosorbent assay (ELISA, colloidal gold method can detect specific antigens in serum, urine sediment cells. Detection of serum specific antibodies IgM1: 20 or more and IgG antibodies 1:40, positive serum, recovery period serum Specific IgG antibodies that are more than four times higher than the acute phase can also be diagnosed. RT-PCR method for detecting viral RNA in serum can be used for early diagnosis.

Hemorrhagic fever diagnosis

Generally based on clinical characteristics and laboratory inspections, combined with epidemiological data, and comprehensive diagnosis on the basis of excluding other diseases, diagnosis of typical cases is not difficult, but in non-endemic areas, non-epidemic seasons, and atypical It is difficult to diagnose the case, and it must be confirmed by specific serological diagnosis. Divided into suspected cases, clinically diagnosed cases, confirmed cases.

Hemorrhagic fever treatment

General principle

Early detection, early rest, early treatment and in-situ isolation. According to the report of class B infectious diseases, observe the vital signs closely, and carry out corresponding comprehensive treatment according to the clinical situation of stage 5.

Fever can be used for physical cooling or adrenal corticosteroids. When hypotension shock occurs, blood volume should be replenished. Low molecular dextran, fluid replacement, plasma, and protein are commonly used. If there is oliguria, diuretics (such as furosemide, etc.) can be injected intravenously. Sufficient fluids and electrolytes (potassium salts) should be added when polyuria, mainly oral. After entering the recovery period, pay attention to prevent complications, strengthen nutrition, and gradually resume activities.

2. Symptoms and complications

Patients with significant bleeding should be transfused with fresh blood to provide a large number of normal functioning platelets and coagulation factors; those with significantly reduced platelet counts should be transfused with platelets; those with disseminated intravascular coagulation can be treated with anticoagulants such as heparin. Cardiac dysfunction should be used in patients with cardiac insufficiency; patients with renal oliguria can be treated as acute renal failure: limit fluid intake, use diuretics, maintain electrolyte and acid-base balance, and take dialysis therapy if necessary; patients with impaired liver function can Give liver protection treatment. Severe patients may use antibiotics as appropriate to prevent infection.

Prognosis of hemorrhagic fever

The case fatality rate is as high as 20% to 90%. Those with high body virus and severe damage to liver and kidney organs have a poor prognosis.

Hemorrhagic fever prevention

Rodent control is the key to eliminating the disease. Do a good job of food, environment, and personal hygiene. If necessary, vaccination with hemorrhagic fever vaccine is available.