Dengue fever is an acute infectious disease caused by mosquito-borne transmission of dengue virus. Clinical manifestations include high fever, headache, muscle and bone and joint aches, rash, bleeding tendency, swollen lymph nodes, reduced white blood cell count, and thrombocytopenia. It is one of the leading causes of death among children in Southeast Asia.
It has been compared to “dengue fever”, which is lighter than the common cold, but if it develops into “heavy dengue fever” or “dengue hemorrhagic fever”, it is not as bad as Ebola, but it is still an extremely critical clinical condition. It needs early treatment, early recognition and treatment, otherwise it will be life-threatening. Although in China, dengue fever is prevalent in Hainan Island, South China, Hong Kong, Macao and Taiwan, it is necessary to know about this disease.
I. Epidemiological characteristics
1.Infectious source
Patients and latently infected persons are the main source of infection. Patients are most infectious from 1 day before to 3-5 days after the onset of the disease.
2, the vector of transmission
Aedes aegypti is the main vector of this disease, including Aedes aegypti and Aedes albopictus.
Second, the clinical manifestation
The incubation period is from 1 to 15 days, the average is about 6 days.
1.Typical dengue fever
(1) Fever: Most of the cases have sudden onset, body temperature reaches 39℃ or above rapidly, generally lasts for 2-7 days, body temperature is irregular, some cases drop to normal on the 3rd to 5th day, and then rise again after 1 day, showing bimodal fever or saddle fever. In children, the onset of the disease is slower and the fever level is lower.
(2) Accompanying symptoms: headache, back pain, muscle and joint pain, orbital pain, pain behind the eyes, etc. Gastrointestinal symptoms such as sensory allergy, nausea, vomiting, abdominal pain, poor appetite, diarrhea and constipation may be present. The face and conjunctiva of the eyes are congested, and the skin of the neck and upper chest is flushed.
(3) Rash: It appears 2 to 5 days after the onset of the disease, initially on the trunk and abdomen, gradually extending to the neck and extremities, and in some patients on the face. The rash is diverse and can be maculopapular, measles-like rash, scarlet fever-like rash, erythematous rash, slightly itchy, and visible skin islands. There are also small bruises on the back of the feet, legs, ankles, back of the wrists, and axillae during the last day of fever or after the fever subsides, which fade within 1 to 3 days, leaving brown spots briefly. The rash usually subsides at the same time as the body temperature.
(4) Bleeding: 5 to 8 days after the onset of the disease, some cases may have bleeding at different sites and to different degrees, such as epistaxis, skin bruises, gastrointestinal bleeding, hemoptysis, hematuria and vaginal bleeding.
(5) Lymph node enlargement: There may be mild enlargement of lymph nodes throughout the body with mild tenderness.
(6) Other: hepatomegaly may be present.
Patients often feel weak after the disease and full recovery often takes several weeks. Emphasis on one point: during the observation of typical dengue fever treatment, it is necessary to pay attention to the changes of the disease during 3~5 days of the course of the disease, and to deal with the severe manifestation in time.
2.Heavy dengue fever
It is the severe type of typical dengue fever. On the 3rd to 5th day of the course of the disease, there is an aggravation of the disease. It is divided into two types: one is meningoencephalitis type, which is characterized by aggravation of headache, accompanied by nausea, vomiting and impaired consciousness. The second is the hemorrhagic shock type, which is characterized by gastrointestinal hemorrhage and hemorrhagic shock. Severe dengue fever often dies due to central respiratory failure and hemorrhagic shock because of the rapid development of the disease.
3.Dengue hemorrhagic fever
(1) Shock: It usually occurs on the 2nd to 5th day of the disease, the patient is irritable, the limbs are cold, the face is pale, the skin has floral patterns, the body temperature drops, the breathing is fast and irregular, the pulse is weak, the pulse pressure is progressively reduced, the blood pressure drops or even cannot be measured, and the brain edema may appear during the course of the disease, occasionally coma. If not rescued in time, most of them die within 24 hours.
(2) Hemorrhage: serious bleeding tendency, including nasal bleeding, blood bruises on the skin, vomiting blood, blood in stool, hemoptysis, hematuria, vaginal bleeding and even intracranial bleeding.
III. Treatment
At present, there is no exact and effective pathogenic treatment for this disease, mainly taking supportive and symptomatic treatment measures.
1.Lowering body temperature
Patients with high fever should first use physical cooling, such as ice, alcohol swab may aggravate the rash to be used with caution, antipyretic and analgesic drugs should also be used with caution. For patients with high fever and severe systemic symptoms, small doses of adrenocorticotropic hormone can be applied for a short period of time.
2. Rehydration
For those who sweat a lot and have diarrhea, take oral rehydration first and pay attention to water, electrolytes and acid-base balance. If necessary, intravenous rehydration should be used to correct dehydration, hypokalemia and metabolic acidosis.
3.Lower intracranial pressure
In cases of severe headache and intracranial hypertension, dehydration treatment should be applied promptly. Adrenocorticosteroids can be used at the same time. Patients whose respiratory center is suppressed should be treated with artificial ventilator in time.
IV. Prognosis
Dengue fever is a self-limiting disease and usually has a good prognosis, with a duration of about 10 days without complications. Most of the fatal cases are heavy patients.