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Other symptoms include:
* Fever
* Chills
* Constant headaches
* Bleeding from nose, mouth or gums
* Severe dizziness
* Loss of appetite
Some cases develop much milder symptoms which can be misdiagnosed as influenza or other viral infection when no rash is present. Thus travelers from tropical areas may pass on dengue in their home countries inadvertently, having not been properly diagnosed at the height of their illness. Patients with dengue can pass on the infection only through mosquitoes or blood products and only while they are still febrile.
The classic dengue fever lasts about six to seven days, with a smaller peak of fever at the trailing end of the disease (the so-called "biphasic pattern"). Clinically, the platelet count will drop until the patient's temperature is normal.
Cases of DHF also show higher fever, haemorrhagic phenomena, thrombocytopenia, and haemoconcentration. A small proportion of cases lead to dengue shock syndrome (DSS) which has a high mortality rate.
Diagnosis
The WHO definition of dengue haemorrhagic fever has been in use since 1975; all four criteria must be fulfilled:[3]
2. Hemorrhagic tendency (positive tourniquet test, spontaneous bruising, bleeding from mucosa, gingiva, injection sites, etc.; vomiting blood, or bloody diarrhea)
3. Thrombocytopenia (<100,000 platelets per mm³ or estimated as less than 3 platelets per high power field)
Dengue shock syndrome is defined as dengue hemorrhagic fever plus:
- Weak rapid pulse,
- Narrow pulse pressure (less than 20 mm Hg)
- Cold, clammy skin and restlessness.
Treatment
The presence of melena may indicate internal gastrointestinal bleeding requiring platelet and/or red blood cell transfusion.
Aspirin and non-steroidal anti-inflammatory drugs should be avoided as these drugs may worsen the bleeding tendency associated with some of these infections. Patients may receive paracetamol preparations to deal with these symptoms if dengue is suspected.[4]
Emerging treatments
Emerging evidence suggests that mycophenolic acid and ribavirin inhibit dengue replication. Initial experiments showed a fivefold increase in defective viral RNA production by cells treated with each drug.[5] In vivo studies, however, have not yet been done.