Clinical diagnosis

00000000Dengue virus infections may be asymptomatic or may lead to undifferentiated fever, dengue fever (DF) or dengue haemorrhagic fever (DHF) with plasma leakage that may lead to hypovolaemic shock (dengue shock syndrome, DSS) (Figure 2.1).

Dengue fever

00000000 The clinical features of DF frequently depend on the age of the patient. Infants and young children may have an undifferentiated febrile disease, often with a maculopapular rash. Older children and adults may have either a mild febrile syndrome or the classic incapacitating disease with high fever of abrupt onset, sometimes with 2 peaks (saddle-backed), severe headache, pain behind the eyes, muscle and bone or joint pains, nausea and vomiting, and rash. Skin haemorrhages (petechiae) are not uncommon. Leukopenia is usually seen and thrombocytopenia may be observed. Recovery may be associated with prolonged fatigue and depression, especially in adults.

00000000 In some epidemics, DF may be accompanied by bleeding complications, such as epistaxis, gingival bleeding, gastrointestinal bleeding, haematuria, and

Table 2.1 Observed frequency of findings in classical dengue fever in adults and chikungunya and dengue virus infections in Thai children diagnosed as having haemorrhagic fever

a + = 1-25 %; ++ = 26-50%; +++ = 51-75%; ++++ = 76-100%.
b Modified from Halstead SB et as. American journal of tropical medicine and hygiene, 1969, 18: 984-996, and refers mainly to Caucasian adults.