DENGUE FEVER IN ONE PAGE
1. Dengue is a mosquito-borne disease caused by the dengue virus. The mosquito species responsible is Aedes aegypti. The incubation period is 2-7 days.
2. Fever of dengue is high grade at onset (like malarial fever) and is fairly continuous (like typhoid fever). Rigors may or may not be present.
3. Associated symptoms:
- Severe myalgias are almost always present. This feature is unusual in typhoid or malaria.
- Arthralgias are fairly common too.
- Nausea, vomiting and diarrhoea may be present.
- Redness of eyes is common.
- Retro-orbital pain is fairly typical.
- Macular rash or significant pruritus without any rash may be present.
- Marked weakness and prostration is common.
4. Clinical findings:
- Hepatosplenomegaly occurs less than in malaria and enteric fever.
- Extravasation of fluid can present as pedal oedema, facial puffiness, ascites and pleural effusion.
- Pleural effusion is usually mild and hence non-detectable on chest examination. It is either asymptomatic or presents as dyspnoea and cough. One must clinically suspect pleural effusion if a patient of dengue has tachypnoea.
- Ascites too is mild and can present as rebound tenderness in the lower abdomen.
5. Laboratory findings:
- Increased Hb and reduced serum albumin are due to extravasation.
- SGOT elevation > SGPT elevation.
- Leucopenia appears before fall in platelets or a rise in haemoglobin.
- Dengue NS1 antigen is positive during first 4 to 5 days of fever.
- Dengue IgM becomes positive around the 5th day and will stay positive for several weeks.
- In children, both dengue IgG and Dengue IgM are often done. If both are positive then it indicates that they are prone to complications like Dengue Shock Syndrome (DSS).
- Thrombocytopenia: Platelets typically start falling further as fever disappears and may continue to fall for 48 hours thereafter.
6. Treatment: There is no specific treatment for Dengue. Antibiotics should not be used. The treatment is mainly symptomatic.