P027. Idiopathic intracranial hypertension without papilledema in refractory chronic daily headache

Background

A diagnosis of idiopathic intracranial hypertension without papilledema (IIHWOP) should be considered in unresponsive chronic daily headache (CDH) patients[1]. A CSF opening pressure (OP) above 200 mm H2O has been detected in chronic migraine patients with conflicting result, ranging from 10% to 86% of patients[1, 2]. Moreover, controversies exist regarding the OP cut-off value greater than 200 or 250 mm H2O and the role of transverse sinus stenosis (TSS)[3, 4].

Aim

To investigate the frequency of IIHWOP and TSS in adult patients with refractory CDH.

Methods

In a prospective study, patients with refractory CDH underwent ophthalmologic evaluation and Optical Coherence Tomography to rule out the presence of papilledema; cerebral MR venography (MRV) to detect TSS; and a lumbar puncture to measure OP. In patients showing an OP < 200 mmH2O the procedure was stopped after a 6 mL CSF withdrawal for routine analysis. In subjects with an OP > 200 mm H2O, intracranial pressure measurements were repeated every 2 mL of extracted CSF, up to about 100 mm H2O. An MRV was repeated 1 month after LP in patients with OP > 200 mmH2O. TSS was identified using a combined conduit score (CCS).

Results

Thirty-six patients were enrolled. Five patients were excluded due to protocol violations. Analyses were conducted in 31 patients (24 F, 7 M; mean age 50.4±11; mean BMI 26.5±6.5). None of the patients had papilledema. All displayed an OP lower than 250 mm H2O (range 102-245). Six patients (19%) had an OP greater than 200 mm H2O: three of them achieved an improvement of headache frequency or intensity after 8-18 ml CSF withdrawal. Fifteen patients (48%) had MRV evidence of TSS: bilateral in 4 and unilateral in 11. Using a Pearson's correlation coefficient test, no significant correlation between CCS and OP was found. After CSF withdrawal, no changes of CCS were found in the six patients who repeated MRV.

Conclusions

In our series, all patients displayed normal OP values (< 250 mm H2O). Nineteen percent of patients had an OP greater than 200 mm H2O. Our results confirm a low prevalence of IIHWOP in chronic headache sufferers. Moreover, the prevalence of sinus venous stenosis (50%) was lower than previously described in unresponsive chronic headache patients (92.8%), but similar to a series of unselected chronic headache patients (50.6%)[1, 5]. Transverse sinus stenosis seems not to correlate with CSF opening pressure, putting its role into question.

Written informed consent to publication was obtained from the patient(s).