What Is Viral Hemorrhagic Fever?

Viral hemorrhagic fever is a group of natural epidemic diseases caused by arboviruses, characterized by fever, hemorrhage, and shock. Such diseases are widely distributed in the world, with more severe clinical manifestations and high mortality rates. At present, more than ten types have been found in the world. Their pathogens, parasitic hosts, and routes of transmission are different, and there are some differences in their clinical manifestations, and they are often endemic in certain areas.

Basic Information

English name: viral hemorrhagic fever
Visiting department: Infectious Diseases
Common causes: Viral infection

Common symptoms: Fever, bleeding, and shock
Contagious: Have
way for spreading: Mosquito vector, tick vector, animal origin

Causes of viral hemorrhagic fever

Since the 1960s, more than a dozen species of hemorrhagic fever caused by the virus have been found around the world. The pathogens belong to 4 families, namely, the mantle virus family, the bunya virus family, the sand virus family, and the Filo (linear) family . There are four types of transmission, namely mosquito-borne, tick-borne, animal-derived and transmission routes are unknown. Among them, epidemic hemorrhagic fever (renal syndrome hemorrhagic fever) and Xinjiang hemorrhagic fever (Crimea-Congo hemorrhagic fever) are widespread in China.

Clinical manifestations of viral hemorrhagic fever

Although the clinical manifestations of various viral hemorrhagic fevers are different, they have the following basic manifestations.

Fever

This is the most basic symptom of this group of diseases. Different hemorrhagic fevers have different durations and heat patterns. The mosquito-mediated hemorrhagic fever is mostly bimodal fever, and various symptoms are exacerbated by the second fever, and the epidemic hemorrhagic fever is mostly persistent fever.

2. Bleeding and rash

All kinds of hemorrhagic fever have bleeding and rash, but the location, time and degree of bleeding and rash are different. There are only a few bleeding points and skin rash in the mild, and the gastrointestinal tract, respiratory tract or urogenital system can occur in severe cases. Major bleeding.

(1) Epidemic hemorrhagic fever has an acute appearance during the fever period of 1 to 5 days after onset. The face, cheeks, and upper chest are congested and flushed, and the conjunctiva is congested. Such as drunken appearance, small bleeding spots can be seen on the skin and mucous membranes, often distributed in the palate, eye conjunctiva, underarms, and before and after axillary, in a clustered distribution or stripe; some patients can see bruising at the puncture and compression sites, pharynx Hyperemia, conjunctival sac significantly edema, more than 95% of patients with positive beam test. In the hypotensive period of 5 to 8 days after the onset of symptoms, the symptoms of congestion subsided, and the bleeding phenomenon increased, the skin and mucosal bleeding points increased, which could be merged into stasis, and it could be accompanied by gastrointestinal bleeding and pulmonary bleeding. When entering the oliguria phase (mostly on the 8th to 12th days after the illness), the bleeding phenomenon is more significant, and large patches of skin can be seen on the skin of the compression part, and major cavity bleeding can occur, such as hemoptysis, vomiting blood, blood in the stool, and nosebleed.

(2) Dengue hemorrhagic fever Dengue virus can cause dengue fever without bleeding tendency. However, in the past 20 years, dengue fever in Southeast Asia has often been accompanied by severe bleeding and severe epidemics of shock, which is called "dengue hemorrhagic fever". Dengue hemorrhagic fever is a clinical syndrome. The main symptoms are high fever, hepatosplenomegaly, shock, and bleeding. Most patients see scattered silt spots on the limbs, face, armpits, and soft palate, and sometimes merge into stasis. In addition, erythema, maculopapular rash, and wind-like rash can still occur, and some patients can develop nosebleeds, gum bleeding, gastrointestinal bleeding, and hematuria.

(3) Hemorrhagic fever in Xinjiang is accompanied by congestion and flushing of the skin of the face and neck and upper chest, and there are stasis spots and stains on the chest, back, underarms, face, neck and extremities, and they are mostly arranged in a cord-like pattern under the armpit ; The bleeding point is more upper body, less lower body, stasis of the eyes, soft palate and gums, hematoma and ecchymosis can be seen at the injection site, and conjunctiva of the eye has edema.

(4) Far East hemorrhagic fever is caused by arboviruses, and its transmission vector is rodents, which are mainly prevalent in the Americas and North Korea, and they suddenly occur. From the beginning, there are systemic symptoms such as fever, headache, and low back pain, and silt spots appear on the conjunctiva and skin (especially the armpit).

(5) Hemorrhagic fever in Argentina The disease is caused by the arbovirus Junin virus. Its transmission vector is mites, including fever, headache, low back pain, gums and nosebleeds.

(6) Bolivian hemorrhagic fever is caused by the arbovirus Machup virus. Its transmission vector is rodents. It initially has fever, headache, arthralgia, and muscle pain. Some patients feel allergic to the skin, even after being exposed to light. It causes pain in the skin, obvious conjunctivitis, and edema around the orbit, but the skin mucosa has no petechiae, gastrointestinal bleeding may occur, and diffuse hair loss may occur during the recovery period.

3. Hypotension shock

Shock can occur with a variety of hemorrhagic fevers, but the frequency and degree of occurrence vary widely. Epidemic hemorrhagic heat shock occurs most frequently and is severe.

4. Renal failure

Epidemic hemorrhagic fever has the most severe renal damage. Other hemorrhagic fevers may also have varying degrees of renal damage, but most of them are mild, showing only mild to moderate proteinuria.

Viral hemorrhagic fever

1. The number of white blood cells is low or normal in the early stage. After 3 to 4 days, the number of leukocytes increases significantly.

2. The coagulation time of some patients was slightly prolonged.

3. Early-stage patients can develop proteinuria to varying degrees, with individual casts and elevated blood urea nitrogen and creatinine.

4. Mild liver dysfunction can occur early in the onset of disease, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are elevated, and some patients have elevated serum bilirubin.

5. Specific antigen and antibody detection: ELISA double antibody sandwich method, reverse hemagglutination test can detect circulating antigens in serum, and antibody capture ELISA method can be used to detect specific IgM antibodies for early diagnosis. Patients with suspicious results or new epidemic areas need to further apply the complement binding test or neutralization test to confirm the diagnosis. Serum-specific IgG antibodies were more than 4 times higher than in the acute phase.

6. Other: Examination of Hantan virus (or EHF) antigen or viral RNA from patients' white blood cells or urine sediment cells.

Viral hemorrhagic fever diagnosis

Clinical diagnosis can be comprehensively analyzed based on epidemiological data, clinical manifestations, and laboratory test results. The diagnosis must be confirmed by serological or virological evidence.

Differential diagnosis of viral hemorrhagic fever

Fever period should be distinguished from upper respiratory tract infection, sepsis, acute gastroenteritis, and bacillary dysentery. The shock phase should be distinguished from other septic shocks. The oliguria phase is distinguished from acute renal failure caused by acute nephritis and other causes. Patients with significant bleeding need to be distinguished from peptic ulcer bleeding, thrombocytopenic purpura, and other causes of DIC. People with ARDS as their main manifestation should be distinguished from those with other causes. Patients with abdominal pain as the main sign should be identified from surgical abdomen.

Viral hemorrhagic fever treatment

There is currently no effective treatment for various viral hemorrhagic fevers. For most patients with hemorrhagic fever, early treatment with corticosteroids can achieve better results. Should be actively and reasonably symptomatic treatment, when there is indeed a diffuse intravascular coagulation (DIC), anticoagulant treatment should be strived for as early as possible. In addition, active prevention and treatment of shock, major hemorrhage, renal failure, pulmonary edema, and heart failure should be actively performed.

General treatment

Early in bed should rest, reduce moving, give sufficient calories and vitamins. In the early stages of the disease, dexamethasone can be applied to patients with severe poisoning symptoms to reduce the symptoms of systemic poisoning, improve the body's stress ability and supplement the reduction of adrenal corticosteroid secretion caused by adrenal and pituitary bleeding, but it should not be applied in advanced patients. Patients with high fever can use physical cooling, such as warm water rubbing, ice, etc. can reduce symptoms, but avoid using antipyretic agents. Pay attention to water-electrolyte balance. Those with high fever and vomiting who cannot eat can be given intravenous injection of glucose injection and balanced salt injection.

2. Antiviral treatment

Early use of ribavirin, intravenous infusion for 3 to 5 days or intramuscular injection of high-priced immune serum (sheep), allergy test before injection. If necessary, inject another 12 to 24 hours later. Given that a small number of people with negative skin tests can also develop anaphylactic shock, a small amount of subcutaneous injection can be given first, followed by a full injection after 30 minutes of no response. Desensitization injection can also be used. Those with a history of allergy or a positive allergy test should reduce the first injection and subsequent increments appropriately and inject several times to avoid violent reactions. At present, human specific immunoglobulin injection has been used in foreign countries to obtain significant curative effects, and some believe that the combined effect with ribavirin is better.

Prognosis of viral hemorrhagic fever

Severe patients often have a poor prognosis, and the main causes of death are bleeding and shock. The case fatality rate is 30% to 50%.

Viral hemorrhagic fever prevention

Comprehensive measures should be taken to prevent viral hemorrhagic fever, rodents should be killed regularly, and ticks should be regularly killed in vitro to reduce tick density. When entering the desert, the workers in the pasture or forest area must take personal protection, prevent tick bites, contact the blood of sick animals or patients, wear gloves and avoid drinking raw milk. Vaccination is the main measure to prevent this disease. Domestic inactivated suckling rat brain refined vaccine can be used. After three trials of injection in the population, the positive rate of antibody conversion can reach more than 70%.