If you have a fever, how do you know if I have dengue fever?

Today I have collected some knowledge about dengue fever. Everyone should pay attention to precautions.

Dengue fever is an acute infectious disease caused by the dengue virus and is mainly spread through the bites of Aedes aegypti or Aedes albopictus. Summer and autumn are the peak seasons for dengue fever.

If you suspect that you have been bitten by a mosquito and you develop symptoms such as fever, headache, joint pain, etc., please go to the hospital in time for early diagnosis and treatment to avoid serious illness.

How do I know it’s dengue fever?

The fever caused by dengue fever is usually high, and the body temperature can often reach 39°C or even 40°C. In addition to fever, dengue fever patients are often accompanied by bone pain, headache, muscle pain, rash, and bleeding spots. A decrease in white blood cells and platelets can be found in routine examinations. Some patients may also experience gastrointestinal symptoms such as diarrhea and stomach pain.

What are the main symptoms of dengue fever?

Sudden high fever: The body temperature can rise to 39°C to 40°C within a day or two, and the body temperature often persists for a week;

“Body pain”: feeling headache, orbital pain, muscle joint and bone pain, and the whole person feels very tired;

“Redness”: The skin of the face, neck, chest and limbs becomes red, seemingly “drunk”, and even conjunctival congestion, superficial lymph node enlargement, gum bleeding, etc. may occur.

“Skin rash”: mainly measles-like and hemorrhagic rash, not higher than the skin.

What are the clinical manifestations of dengue fever?

The incubation period of dengue fever is generally 3 to 15 days, most often 5 to 8 days.

Dengue virus infection can manifest as asymptomatic latent infection, non-severe infection, and severe infection. Dengue fever is a systemic disease with complex and diverse clinical manifestations. The typical course of dengue fever is divided into three stages, namely the acute febrile stage, the extreme stage and the recovery stage. According to the severity of the disease, dengue infection can be divided into two clinical types: common dengue fever and severe dengue fever.

Acute febrile stage: 

Patients usually have an acute onset of illness, with the first symptom being fever, which may be accompanied by chills, and the body temperature can reach 40°C within 24 hours. In some cases, the body temperature drops to normal after 3 to 5 days of fever, and then rises again after 1 to 3 days, which is called bimodal fever. Fever can be accompanied by headache, body muscle, bone and joint pain, obvious fatigue, and gastrointestinal symptoms such as nausea, vomiting, abdominal pain, diarrhea, etc.

The acute fever period usually lasts 2 to 7 days. Congestive rash or punctate hemorrhagic rash appears on the face and limbs on the 3rd to 6th day of the disease. Typical rashes include pinpoint bleeding spots and “island”-like manifestations found on the limbs. Bleeding phenomena of varying degrees may occur, such as subcutaneous bleeding, petechiae at the injection site, gum bleeding, epistaxis, and positive arm band test, etc.

Extreme stage: 

In some patients, high fever persists without relief, or the condition worsens after the fever subsides. Increased capillary permeability may lead to significant plasma leakage. In severe cases, shock and other important organ damage may occur. The peak stage usually occurs on the 3rd to 8th day of the disease. Severe abdominal pain, persistent vomiting and other severe warning signs often indicate the beginning of the extreme period.

Recovery period: 

After 2 to 3 days the extreme period, the patient’s condition improves, gastrointestinal symptoms are relieved, and the patient enters the recovery period. Some patients may see pinpoint bleeding spots, most common on the lower limbs, and may experience skin itching. The white blood cell count begins to rise and the platelet count gradually recovers.

Most patients present with ordinary dengue fever, while a few patients develop severe dengue fever, and some patients only have a fever period and a recovery period.

How is dengue fever diagnosed?

The diagnosis of dengue fever can be made based on the epidemiological history, clinical manifestations and laboratory test results. In cases where the epidemiological history is unknown, diagnosis is made based on clinical manifestations, auxiliary examinations and laboratory test results.

1. Suspected cases: those who are consistent with the clinical manifestations of dengue fever, have an epidemiological history (have traveled to dengue fever endemic areas within 15 days before the onset of illness, or have dengue fever cases in their place of residence), or have leukopenia and thrombocytopenia.

2. Clinically diagnosed cases: consistent with the clinical manifestations of dengue fever, with a history of epidemiology, simultaneous reduction of white blood cells and platelets, and a single serum dengue virus-specific IgM antibody positive.

3. Confirmed cases: Suspected or clinically diagnosed cases, NS1 antigen or viral nucleic acid is detected in the acute phase serum, or dengue virus is isolated or the specific IgG antibody in the convalescent phase serum is positive or the titer is increased by more than 4 times.

What are the laboratory diagnostic standards?

1. Blood routine: 

The total number of white blood cells decreases. In most cases, it starts to decrease in the early stage and reaches the lowest point on the 4th to 5th day. The differential count of white blood cells mainly decreases in neutrophils. Most cases have thrombocytopenia, which can be as low as 10 x 109/L.

2. Urine routine: 

A small amount of protein, red blood cells, etc. can be seen, and casts may appear.

3. Blood biochemical tests: 

More than half of the patients have elevated transaminase and lactate dehydrogenase, and some patients have elevated cardiac enzymes, urea nitrogen, and creatinine. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were mildly or moderately elevated, total bilirubin was elevated, and serum albumin was reduced in a few patients. Some patients may develop electrolyte disorders such as hypokalemia; coagulation function tests show reduced fibrinogen, prolonged prothrombin time and partial thromboplastin time, and reduced coagulation factors II, V, VII, IX and X in severe cases. .

4. Etiological and serological testing: 

Blood samples in the acute phase and convalescent phase can be collected and submitted for testing. Medical institutions that have the conditions for pathogenic testing should test as soon as possible, and medical institutions that do not have the conditions for pathogenic testing should collect specimens and send them to designated institutions for testing.

During the acute fever period, dengue fever antigen (NS1) detection and viral nucleic acid detection can be used for early diagnosis, and virus isolation can be carried out if conditions permit.

In patients with the first infection, IgM antibodies can be detected 3 to 5 days after the onset of illness, reaching the peak 2 weeks after the onset of illness, and can last for 2 to 3 months; IgG antibodies can be detected 1 week after the onset of illness, and IgG antibodies can last for several years or even lifetime; Within 1 week, the detection of high-level specific IgG antibodies in the patient’s serum indicates secondary infection. It can also be combined with the IgM/IgG antibody ratio detected by the capture method to make a comprehensive judgment.

What are the warning signs for severe dengue fever?

(1) High-risk groups

1. Patients with secondary infection;

2. Those with underlying diseases such as diabetes, hypertension, coronary heart disease, liver cirrhosis, peptic ulcer, asthma, COPD, chronic renal insufficiency;

3. The elderly or infants;

4. People who are obese or severely malnourished;

5. Pregnant women.

(2) Clinical indications

1. The condition worsens after the fever subsides;

2. Severe abdominal pain;

3. Continuous vomiting;

4. Symptoms of plasma leakage;

5. Drowsiness and irritability;

6. Obvious bleeding tendency;

7. Hepatomegaly > 2 cm;

8. Oliguria.

(3) Laboratory indications

1. Rapid decrease in platelets;

2.HCT is elevated.

7How to diagnose severe dengue fever?

Those who have one of the following circumstances:

1. Severe bleeding includes subcutaneous hematoma, hematemesis, melena, vaginal bleeding, gross hematuria, intracranial hemorrhage, etc.;

2.Shock;

3. Important organ dysfunction or failure: liver damage (ALT and/or AST > 1000 IU/L), ARDS, acute heart failure, acute renal failure, encephalopathy (encephalitis, meningoencephalitis), etc.

I heard that there is no specific medicine for dengue fever, so how should it be treated?

Currently, there are no specific antiviral treatment drugs, and supportive and symptomatic treatment measures are mainly adopted. The treatment principles are early detection, early treatment, and early mosquito prevention and isolation. Early identification and timely treatment of severe cases are the key to reducing the mortality rate.

(1) General treatment:

1. Rest in bed and eat light food;

2. Anti-mosquito isolation until fever subsides and symptoms are relieved;

3. Monitor consciousness, vital signs, urine output, platelets, HCT, etc.

(2) Symptomatic treatment:

1. Reduce fever: mainly physical cooling;

2. Rehydration: Oral rehydration is the main method;

3. Sedation and analgesia: Symptomatic treatment such as diazepam and cranialin can be give.

(3) Treatment of severe dengue fever

In addition to the monitoring indicators mentioned in general treatment, severe dengue fever cases should also undergo dynamic monitoring of electrolytes. Patients with severe plasma leakage, shock, ARDS, severe bleeding or other important organ dysfunction should be actively treat accordingly.

1. Principle of fluid rehydration: 

The principle of fluid rehydration for severe dengue fever is to maintain good tissue and organ perfusion. Crystalloids such as balance salts can be give, and colloids such as albumin should be supplement in time for patients with severe exudation. The type and amount of rehydration should be adjust at any time according to the patient’s HCT, platelet, and electrolyte conditions. On the premise that the urine output reaches about 0.5 ml/kg/h, the amount of intravenous rehydration should be minimize.

2. Anti-shock treatment: 

Fluid resuscitation treatment should be carry out as soon as possible when shock occurs. The type and amount of infusion are as shown in the principles of rehydration. At the same time, the acid-base imbalance should be actively correct. When fluid resuscitation therapy cannot maintain blood pressure, vasoactive drugs should be use; for shock cause by severe bleeding, red blood cells or whole blood should be transfuse in a timely manner. Hemodynamic monitoring can be perform and treatment can be guid if conditions permit.

3. Treatment of bleeding:

(1) If the bleeding site is clear, local hemostasis will be provided, such as severe epistaxis. Patients with gastrointestinal bleeding should be give antacids. Try to avoid invasive diagnosis and treatment such as gastric tube and urinary catheter insertion;

(2) For severe bleeding, red blood cells should be transfuse in a timely manner according to the condition;

（3）Severe bleeding accompanied by significant thrombocytopenia requires platelet transfusion.

4. Other treatments: 

While circulatory support treatment and bleeding treatment, attention should be pay to the monitoring and treatment of the functional status of other organs; prevention and timely treatment of various complications.

Do I need to be quarantin if I am diagnose with dengue fever?

If you are diagnose with dengue fever, you need to be treat in mosquito-proof isolation in the hospital to avoid transmitting the virus to your family or other people through mosquito bites. The isolation time is usually about 5 days.

The illness lasts for more than 5 days and the isolation can be release if the fever subsides for more than 24 hours.

Dengue fever patients can be discharge if their fever subsides for more than 24 hours and their clinical symptoms are relieve.

What is the prognosis of dengue fever?

Dengue fever is a self-limiting disease with generally good prognosis and low case fatality rate.

Factors affecting prognosis include the patient’s previous history of dengue virus infection, age, underlying diseases, complications, etc. A small number of severe dengue fever cases can cause death due to failure of important organs.

If you find these symptoms, you must take measures for treatment as soon as possible~