Main

Sir,

The coexistence of optic disc drusen (ODD) and idiopathic intracranial hypertension (IIH) was first described in an adult in 1979.1 To date there have been eight cases reported in the literature,1, 2, 3, 4 but to our knowledge this is the first report in a child.

Case Report

An 11-year-old girl was referred with possible papilloedema. She admitted to a 2-week history of headaches, but was otherwise well. There was no relevant past medical history.

Her visual function was normal with enlarged blind spots present bilaterally. Fundoscopy revealed anomalous discs, suggestive of papilloedema. An urgent paediatric referral was made. Following a normal CT brain, lumbar puncture revealed an elevated cerebral spinal fluid (CSF) pressure of 40 cm of water. CSF analysis was normal. A diagnosis of IIH was made and treatment with acetazolamide commenced (500 mg mane, 750 mg lunch, and nocte), which controlled the CSF pressure at 10 cm of water. The headaches resolved.

On follow up at the Eye Unit, ODD were identified (Figure 1) and confirmed by B-scan ultrasonography. The diagnosis of IIH was therefore questioned, although the neurological opinion was that the CSF pressure measurements were accurate and that the two conditions must be in coexistence.

Figure 1
figure 1

On follow-up optic disc drusen were identified.

Full size image

The patient's visual acuities have remained 6/4 and there has been no deterioration in the visual fields to date. She continues under neurological and ophthalmological follow up.

Comment

ODD are hyaline-containing bodies that begin ‘buried’ in the substance of the optic nerve, migrate forward with age and become visible around the second decade. 4, 5 They occur in 3.4–24 per 1000 population and are bilateral in approximately 75% of cases.4 Impairment of visual acuity is rare, but visual field defects may occur in up to 50%,6 although generally are not significant, and patients remain asymptomatic. Follow-up is not required.

IIH is characterized by increased intracranial pressure in the presence of normal imaging. It is relatively uncommon in childhood, presenting once or twice a year to a large referral centre.8 The headache is often frontal and severe and occasionally associated with vomiting. Transient visual obscurations may occur, although may be described by children as ‘blurring or mistiness’. The papilloedema is typically bilateral and symmetrical.9

Disregarding ODD, the diagnosis of IIH in children may be challenging. Apart from the difficulties in examination, accurate imaging, and lumbar puncture assessment may require separate anaesthetics. Also, the normal range for CSF pressure in children has not been established and general anaesthesia may artificially increase measurements.8

This case emphasizes the importance of detailed clinical history taking in children with presumed pseudopapilloedema. In the setting of IIH, the finding of ODD may lead to diagnostic confusion causing delay in appropriate management. Enquires must be made with regard to neurological symptoms prior to accepting the diagnosis of pseudopapilloedema.