Usefulness of clinical case-definitions in guiding therapy for African children with malaria or pneumonia

Abstract

The World Health Organisation has developed disease-specific clinical case-definitions to guide management of children with fever or cough, the cardinal signs of malaria and pneumonia. To assess the usefulness of the case-definitions and to investigate their interaction, we studied children with fever or cough brought to a hospital in Lilongwe, Malawi. For all children, a thick blood smear was examined for Plasmodium falciparum parasites. Chest radiography was done only for children with parasitaemia and those who satisfied the clinical case-definition for pneumonia; others were assumed to have normal chest radiographs. Of 1599 enrolled children, 566 (35%) had parasitaemia and 116 had radiographic evidence of pneumonia; 43 had both pneumonia and parasitaemia. Of the 471 children who met the clinical definition for pneumonia, 449 (95%) also met the malaria clinical definition. Among children with radiographic evidence of pneumonia, the clinical definition for malaria was not predictive of parasitaemia (sensitivity 93%, specificity 5%). Whether malaria parasitaemia was present or absent, the pneumonia clinical definition distinguished children with and without radiographic evidence of pneumonia (sensitivity and specificity > 60%). Children who satisfied the pneumonia clinical definition were more likely to have radiographic evidence of pneumonia (odds ratio 10.4, 95% confidence interval 5.2-20.7), parasitaemia (1.6, 1.2-2.2), or both at the same time (4.2, 2.1-8.4) than were children who did not meet the definition. Children who satisfy the malaria and pneumonia clinical definitions need treatment for both disorders. Scarce diagnostic methods, especially microscopy, are needed for more specific treatment of children with fever and cough.

PIP: The WHO has developed disease-specific clinical case definitions to guide the management of children with fever and cough, the cardinal signs of malaria and pneumonia. To assess the usefulness of these case definitions and to investigate their interaction, the authors studied children with fever or cough who were brought to Lilongwe, Malawi. For all children, a thick blood smear was examined for Plasmodium falciparum parasites. Chest radiography was done only for children with parasitemia and those who satisfied the clinical case definition for pneumonia; others were assumed to have normal chest radiographs. Of 1599 enrolled children, 566 (35%) had parasitemia; 43 had both parasitemia and pneumonia. Of the 471 children who met the clinical definition for pneumonia, 449 (95%) also met the clinical definition for malaria. Among children with radiographic evidence of pneumonia, the clinical definition for malaria was not predictive of parasitemia (sensitivity 93%, specificity 5%. Whether malaria parasitemia was present or not, the pneumonia clinical definition distinguished children with and without radiographic evidence of pneumonia (sensitivity and specificity 60%). Children who satisfied the pneumonia clinical definition were more likely to have radiographic evidence of pneumonia (odds ration 10.4, 95% confidence interval 5.2-20.7), parasitemia (1.6, 1.2-2.2), or both at the same time (4.2, 2.1-8.4) than were children who did not meet the definition. Children who satisfy both clinical definitions need treatment for both disorders. Scarce diagnostic methods, especially microscopy, are necessary for more specific treatment of children with fever and cough.