Dengue Haemorrhagic fever (DHF) is a severe and sometimes fatal form of dengue. Typical cases of DHF are characterized by four major clinical manifestations: high fever, haemorrhagic phenomena, hepatomegaly and circulatory failure. Moderate to marked thrombocytopenia with concurrent haemoconcentration is a distinctive clinical laboratory finding of DHF. The major pathophysiological change that determines severity of disease in DHF is leakage of plasma, as manifested by an elevated haematocrit (haemoconcentration), a serous effusion or hypoproteinaemia.

Children with DHF commonly present with a sudden rise in temperature accompanied by facial flush and other non-specific constitutional symptoms resembling dengue fever, such as anorexia, vomiting, headache, muscle, bone or joint pain.

Hepatomegaly - enlargement of liver.

Haemorrhagic – bleeding

Haematocrit – volume percentage of erythrocytes (red blood cells) in whole blood.

Hypoproteinaemia – deficiency of proteins in blood.