Clinical presentations of dengue hemorrhagic fever in infants compared to children

Dengue infections are endemic in Thailand. Infants are at risk of developing dengue fever (DF) and dengue hemorrhagic fever (DHF). Many infants have severe DHF with unusual manifestations and may suffer from complications and even death because of difficulties in early diagnosis and improper management.

To study the incidence of infants DHF and to compare clinical and laboratory findings of DHF between infants and children in order to improve diagnosis and management of infants with DHF.

A retrospective review of hospital charts of DHF patients who were admitted to the Children's Hospital between 1995-1999 was carried out. Only confirmed DHF cases, either by serologic or virologic studies were included. Clinical and laboratory findings were compared using the standard software package SPSS.

There were 4,595 confirmed dengue patients admitted to the Children's Hospital during this 5-year period and among these 245 infants were under one year old (5.3%). Unusual presentations of DHF including upper respiratory tract infection (URI) symptoms, diarrhea, convulsions and encephalopathy were found more in the infants (4.5%, 13.1%, 12.7% and 4.1%) than in the children (1.7%, 2.0%, 2.0% and 0.6%) but shock was found less in the infants (25%) than in the children (30.9%). The percentages of Tourniquet test positive and low WBC (< or = 5,000 cells/mm3) which help in the early diagnosis of dengue were less in the infants (50.2% and 26.8%) than in the children (92.2% and 71.9%). Liver involvement and/or dysfunction were found more in the infants as shown by mean aspartate aminotransferase/alanine aminotransferase (AST/ALT) elevation and prolonged prothrombin time. Duration of i.v. fluid was shorter in the infants than in the children (21.9 vs 38.2 hours). Complications of fluid overload were found more often in the infants than in the children (9% vs 3.6%). The case fatality rate was 1.2 in the infants and 0.3 in the children.

Management of infants with DHF is critical because early diagnosis is rather difficult and they sometimes present with unusual manifestations (convulsions, encephalopathy and associated infections). Complications such as hepatic dysfunction and fluid overload are more commonly found in infants than in children and adults and also the case fatality rate is higher. Judicious i.v. fluid resuscitation and replacement is critical to the outcome of infants with DHF. It seems that the degree of plasma leakage is less in infants and the duration of plasma leakage is shorter in infants than in children.