Aetiological investigations in early developmental impairment: are they worth it?

Abstract

Objective To study the frequency a diagnosis is made in children with early developmental impairment (EDI), and the contribution made to diagnosis by specific investigations. Design Retrospective case note review. setting Community, neurodisability and neurology department at a UK tertiary centre. Participants Children referred to determine the aetiology of EDI where a cause was not evident on history and examination. Participants were divided into two groups: EDI and no additional features (EDI−) and EDI with additional features (EDI+). Main outcome measures The frequency a cause was found for the child's EDI and which tests contributed to a diagnosis. results 699 participants, 68.8% boys, median age at investigation 2 years 8 months (range 3 months to 11 years 5 months). 61 (8.7%) of participants had no investigations, and children with EDI− were less likely to be investigated (χ 2 =12.5, p<0.05). A diagnosis was made in 166 children (23.7%) and was more frequent in EDI+ (EDI− 9.9%, EDI+ 27.3%, χ 2 =19.0; p<0.05). Full blood count, zinc protoporphyrin, renal or liver function, bone profile, biotinidase, creatine kinase or lead level revealed no diagnoses. The following investigations found causes for EDI: MRI (23.1%), microarray (11.5%), Fragile X (0.9%), plasma amino acids (1.2%), urine organic acids (0.9%) and thyroid function tests (0.5%). Conclusions The majority of 'screening' investigations for EDI do not contribute to a diagnosis, highlighting an area of cost saving for the NHS and reduced burden for patients and families. We propose a streamlined guideline for the investigation of EDI based on our data.

Investigation of developmental delay

“…We cannot agree with the very limited metabolic screen proposed by Hart et al 1 for children with developmental delay without additional features. We agree that investigations can be more targeted after a thorough clinical assessment.…”

“…The investigations performed are very variable across the UK and this is a key area where the clinical and cost-effectiveness of every laboratory investigation needs to be further evaluated. Hart et al 1 suggest a very limited metabolic screen for children with developmental delay without additional features, whereas Mithyantha et al 2 suggest more extensive metabolic screening.…”

Investigating early developmental impairment: what’s the cost?

“…These figures are for first-line investigations and do not include MRI. Our local experience is 55% of children receive MRI,5 and the cost charged by our centre to a district general hospital for MRI under general anaesthetic as a day case is £932 per patient.…”

“…Our recent paper data recommended only microarray, CK and thyroid function as first-line investigations in children with EDI, which would find an aetiology in approximately 12%–14.2% 5. The cost of these first-line investigations would be £309.35/patient.…”

The wisdom of investigating early developmental impairment

“…It seems straightforward on the face of it but complex in practice. Attempts to standardise such assessments are not new1 2 and the efforts of three teams, Hart et al ,3 Best et al 4 and Ghosh et al 5 explore various aspects of this challenge, and help us take another step forward in making sensible investigative decisions.…”