Purpose
Prior studies have failed to consistently demonstrate abnormalities of cerebrospinal fluid (CSF) protein level in adults with idiopathic intracranial hypertension (IIH). Here we seek to evaluate a clinical observation that prepubertal children with IIH have low CSF protein levels compared to healthy children and pubertal children with IIH.
Methods
The study is a retrospective chart review of patients between ages 0 and 21 diagnosed with IIH in the Neuro-ophthalmology clinic using revised modified Dandy criteria. Charts were analyzed with attention to patients’ demographic characteristics, clinical presentation, clinical course, ancillary studies (visual fields and OCT) and lumbar puncture results. Control group consisted of children who underwent similar evaluation as above because of suspicion for IIH (because of headaches or anomalous-looking optic nerves) who turned out not to have the disease.
Results
We identified 23 prepubertal children with IIH (age range 0.75 to 13 years), 16 pubertal children with IIH (age range 13-21 years), and 12 controls (age range 3-14 years). CSF analysis revealed that prepubertal children with IIH had significantly lower CSF protein levels (17.3 +/- 5.7 mg/dL) when compared to pubertal children with IIH (23.4 +/- 8.4 mg/dL; p<0.05) or healthy controls (23.5 +/- 6.4 mg/dL; p<0.05). Furthermore, 9 out of 23 (39%) of prepubertal IIH patients had abnormally low CSF proteins (< 15 mg/dL), compared to zero pubertal IIH patients and zero controls (p<0.05). Acetazolamide use increased CSF protein level in 100% of patients who underwent repeat lumbar puncture after starting the medication (average increase 10.3 mg/dL).
Conclusions
Prior studies have suggested that prepubertal pediatric IIH may be a different clinical entity from pubertal IIH or adult IIH based on clinical features of the disease. Our work demonstrates that CSF protein levels are lower in prepubertal children with IIH compared to pubertal children with IIH and controls. We speculate that low CSF protein levels are caused by CSF overproduction leading to increased flow rate across the arachnoid villi, resulting in greater protein resorption from CSF. Suppression of CSF production with acetazolamide conversely leads to an increase in CSF protein levels. Thus, CSF overproduction may be one of the underlying pathophysiological mechanisms of prepubertal IIH.
Keywords: 612 neuro-ophthalmology: diagnosis •
613 neuro-ophthalmology: optic nerve