RESUMO
Background. Global developmental delay is a common reason for referral to a paediatrician. We examined the aetiological yield of an extensive diagnostic work-up in young children with developmental delay in a tertiary referral centre. Methods. To assess the diagnostic possibilities, we systematically examined 100 consecutive children with global developmental delay (<5 years of age) who visited the paediatric outpatient department over a period of 18 months. An association between the presence of features at initial contact and aetiology was analysed by the 2-tailed Fisher exact test and chi-square test. Results. Of the 100 children, 65 were <2 years of age (mean age 23.6 months) at presentation. The presence of birth asphyxia, sepsis, seizures, abnormal neurological findings, and dysmorphism were significant predictors of aetiology. Four diagnostic categories—chromosomal disorders including Down syndrome, hypoxic–ischaemic encephalopathy, multiple malformation syndromes and cerebral dysgenesis—were the most common causes of global development delay in 20%, 15%, 14% and 11%, respectively. Moderate delay was seen in 42%, severe in 33% and mild in 25% of the patients. The aetiological yield did not differ with the severity of global developmental delay. Additional investigations such as neuroimaging, cytogenetic analysis, metabolic tests and specific molecular tests contributed to a diagnosis in 73% of the children, while in 23% these were the sole means of arriving at a diagnosis. Neuroimaging for a specific indication was almost twice more likely to yield an aetiology when compared with neuroimaging performed as a screening tool (65% v. 35%; p=0.003). Conclusion. The aetiological yield in this selected cohort with global developmental delay was 73%. A step-wise investigational approach is justified in all children with developmental delay, regardless of the severity of delay or the absence of findings on history and physical examination. This study is an attempt to formulate an investigative approach in a child with global developmental delay, especially in developing countries where advanced molecular and cytogenetic studies are not routinely available.