Brain tumours in paediatrics: when should they be suspected?

The paper by Chu et al presents retrospective case note review data on a large number of patients with brain tumours. The authors used a large-scale number crunching exercise to show brain tumour diagnosis can be delayed and that these children often present with non-specific symptoms making diagnosis more difficult. The data for this study is relatively old as cohorts examined were between 1989 and 1997 to 2006. The patients had symptoms up to 2 years before diagnosis and presented to primary and secondary care with increasing frequency until the diagnosis was reached. What is to be done? The tabloid press regularly complains that UK doctors are slow to see patients and slow to do diagnostic tests. In the UK the general practitioner (GP) has traditionally been a gatekeeper, trying to prevent the unnecessary overinvestigation of patients. Most GPs and paediatricians recognise that resources are limited but are themselves usually very concerned when a diagnosis is missed. Subtle symptoms in preschool children are particularly difficult. Headache is a very common symptom at all ages, with up to 20% of children complaining of this symptom at some time. Trying to decide who should be referred for a scan can be a challenge. History and examination remains the cornerstone of diagnosis in medicine including paediatrics, but with nonspecific symptoms and limited signs, or examination proving difficult, a brain tumour may not be suspected. Delays in diagnosing a brain tumour have long been recognised with a fifth of patients initially misdiagnosed with primary headache. 4 Diagnostic delay may in turn have a deleterious effect on the acute management and the ultimate prognosis for the child. This paper noted that in children 0–4 years old, the predominant symptoms at diagnosis were visual disturbance including disturbance of cranial nerves II, III, IV and VI. In this cohort, non-localising symptoms of raised intracranial pressure (ICP) such as nausea, vomiting, papilloedema and increasing head circumference were also more commonly noted alongside behavioural/cognitive changes and nonspecific presentations such as irritability, drowsiness, failure to thrive and delayed milestones. Focal neurological deficits, convulsions, growth and endocrine problems and headache were less common. Beyond this age, presentation with headache was by far the most common symptom, with increasing presentation rate with age. Visual disturbance was also a common symptom, which again increased in presentation rate with age. Convulsions were most common in young adults. All symptoms increased in presentation rate over time to diagnosis. A history of persistence and an increase in frequency and severity of initial symptoms can therefore point to intracranial pathology. Persistent headache is a common symptom in clinical practice. Most of us will have patients with chronic daily headache resistant to all treatment interventions. These patients rarely have a tumour but when arising as a new and escalating symptom in a previously well child, brain tumour does need to be excluded particularly if there are other symptoms such as behavioural or cognitive changes. Symptoms more specific of raised ICP only become prominent in the month prior to diagnosis, with alterations in general mood and cognition also occurring more commonly from 3 months to 6 months prior to diagnosis. Focal neurological deficits may not be obvious even at time points close to eventual diagnosis. Efforts have been made to try and improve diagnostic accuracy. The study by Berlaer et al, looked at 117 children under 16 years presenting to the emergency department with headache. None of 33 children imaged due to concomitant ‘red flag’ symptoms had an intracranial tumour. This would suggest that imaging for all children presenting with headache would be costly and give a low diagnostic yield. The predictive power of this and other individual symptoms may be improved by a history of other red flag symptoms such as diurnal variation of headache, other raised ICP symptoms, squints, faltering growth, behavioural and developmental regression as well as clinical signs, such as increasing head circumference. The size of the problem is well described by Wilne et al with 10 new tumours diagnosed in the UK every week. New (2015) National Institute of Health and Care Excellence (NICE) guidelines recommend ‘very urgent’ referral (within 48 h) for suspected brain tumour in children with newly abnormal cerebellar function or other central neurological function. The guidelines recognise that delineating very specific symptoms and signs would be too narrow and would potentially miss cases amenable to early management. Chu et al, and others have shown that localising signs occur late in the disease process and early non-specific symptoms may not trigger early suspicion of brain tumour. Waiting for specific localising signs or symptoms of raised ICP will delay time to diagnosis. Children with brain tumours will present with increasing number and persistence of symptoms. This pattern over time Department of Paediatric Neurology, Children’s Hospital Oxford, Oxford, UK; Childrens Hospital Oxford, John Radcliffe Hospital, Oxford, UK