Neurofilament light chain as biomarker in idiopathic intracranial hypertension

Background Damage of the optic nerve is the major complication of idiopathic intracranial hypertension. A biomarker indicative for optic nerve damage would help identifying high-risk patients requiring surgical procedures. Here, we studied the potential of cerebrospinal fluid neurofilament to predict idiopathic intracranial hypertension-induced optic nerve damage. Methods In two centers, serum and cerebrospinal fluid of 61 patients with clinically suspected idiopathic intracranial hypertension were prospectively collected. Neurofilament concentrations were measured and related to ophthalmological assessment. Results The average cerebrospinal fluid neurofilament concentration in patients with moderate and severe papilledema was increased compared to patients with minor and no papilledema (1755 +/- 3507 pg/ml vs. 244 +/- 102 pg/ml;p < 0.001). Cerebrospinal fluid neurofilament concentrations correlated with the maximal lumbar puncture opening pressure (r = 0.67,p < 0.001). In patients fulfilling the Friedman criteria for idiopathic intracranial hypertension with or without papilledema (n = 35), development of bilateral visual field defects and bilateral atrophy of the optic nerve were associated with increased average age-adjusted cerebrospinal fluid neurofilament concentrations. At last follow-up (n = 30), 8/13 of patients with increased, but only 3/17 with normal, cerebrospinal fluid neurofilament had developed bilateral visual field defects and/or bilateral optic nerve atrophy resulting in a sensitivity of 72.7% and a specificity of 73.7% of cerebrospinal fluid neurofilament to detect permanent optic nerve damage. Conclusions Cerebrospinal fluid neurofilament is a putative biomarker for optical nerve damage in idiopathic intracranial hypertension.