Concern about poor weight gain is one of the commonest anxieties that parents have, and this is a practical and helpful article for professionals to be able to reassure the vast majority of these families who have healthy children.

I would like to suggest a simple additional examination test and suggest some other indications for referal.

It is very important to include measurement of head circumference in the clinical examination of any baby where there are concerns about growth. This is inexpensive, reproducible, reliable and easy to perform in all settings. If head circumference is at a higher centile than weight and particularly if it is increasing from the centile recorded at birth, early paediatric assessment should take place in either a community or a hospital setting to review neurodevelopment and consider other diagnoses such as hydrocephalus or tumour. It should be repeated during follow up visits.

A second indication for referal is persistent parental concern. If parents remain worried about their child and return more than twice to primary care with the same anxieties and worries, serious underlying conditions such as malignancy are more likely. As is elegantly described for neglect in the article, most of these infants will not have underlying organic pathology, but there is a significantly higher incidence in this group that does justify referal to secondary care.

Finally it is important that any assessment is holistic and considers any additional problems that the child may have. Although extremely rare, the diencephalic syndrome which is characterised by growth failure in association with compression of the third ventricle by tumour (usually from a glioma arising from the optic chiasm or hypothalamus) can be diagnosed later than normal because the significance of poor weight gain and signs of visual disturbance such as nystagmus are not connected by clinical teams caring for the child. Paediatric ophthalmologists, general paediatricians and general practitioners should all be familiar with the HEADSMART guidance for when to refer children for suspected brain tumours www.headsmart.org.uk . They should also be aware that failure to thrive may be one presenting feature. Delayed diagnosis may compromise future vision.

Competing interests: None declared