Pallor as a clinical sign of severe anaemia in children: an investigation in the Gambia

Abstract

Anaemia associated with malaria is a major public health problem in African countries. Since most primary health facilities have to rely on physical signs and not laboratory tests to detect anaemic patients who need referral for blood transfusion, we have assessed the reliability of simple clinical signs to predict severe anaemia. A trained field assistant examined 368 children admitted to a tertiary care hospital, assessing the pallor of their eyelids (conjunctiva), palms and nailbeds, counting the respiratory rate, and looking for signs of respiratory distress. After the children's admission, their packed cell volume (PCV) was measured, and the need for transfusion and the outcomes were noted. A second observer examined 173 of these children so that interobserver variability in the detection of clinical signs could be assessed. A total of 27% of the 368 children had a PCV of < 15%. In a multiple regression analysis, definite pallor of the conjunctiva, definite pallor of the palms, and a "sick" appearance of the child were identified as independent significant predictors of a PCV of < 15%. The best predictor was a combination of definite pallor of the conjunctiva and pallor of the palms, with a sensitivity of 80% and a specificity of 85%. Inclusion of signs of respiratory distress did not improve the prediction. Pallor was a reproducible sign (weighted kappa statistic for the comparison between two observers: kappa = 0.6 for conjunctival pallor). We conclude that pallor can be used as a sign for referring children who may require blood transfusion.

PIP: Most primary health care facilities in Africa, must rely on physical signs, rather than expensive laboratory tests, to detect anemic patients in need of referral for blood transfusion. This study assessed the reliability of simple clinical signs to predict severe anemia in 368 children, admitted to a tertiary care hospital (Royal Victoria) in the Gambia, primarily with malaria. A trained field assistant examined each child, assessing pallor of the conjunctiva, palms, and nailbeds, on a scale of 0 (no pallor) to 3 (definite severe pallor), and looked for signs of respiratory distress. Examination of 173 of these children by a second observer confirmed inter-observer consistency in the detection of pallor. After the children's admission, their packed cell volume (PCV) was measured. 27% of the children had a PCV under 15%, indicative of severe anemia. Multiple regression analysis identified definite pallor of the conjunctiva, definite pallor of the palms, and a "sick" appearance as significant independent predictors of a PCV under 15%. The best predictor, a combination of definite pallor of the conjunctiva and definite pallor of the palms, had a positive predictive value of 67%, a sensitivity of 80%, and a specificity of 85%. Inclusion of signs of respiratory distress did not improve the prediction. These findings indicate that definite pallor of the conjunctiva, alone or in combination with definite pallor of the palms, can be used in primary health care centers to predict severe anemia with high precision.