The role of raised intracranial pressure in the progression and refractoriness of migraine. A pilot study.

To assess the prevalence and possible pathogenetic involvement of raised intracranial pressure in patients presenting with unresponsive chronic migraine (CM), the intracranial opening pressure (OP) and the clinical outcome of a single cerebrospinal fluid withdrawal by lumbar puncture (LP) has been evaluated in 44 consecutive patients, diagnosed with unresponsive CM and evidence of sinus stenosis at magnetic resonance venography. The large majority of patients complained of daily or near-daily headache. Thirty-eight (86.4%) had an OP >200 mmH2O. Normalization of intracranial pressure by LP resulted in prompt remission of chronic pain in 34/44 patients (77.3%) and an episodic pattern of headache was maintained for 2, 3 and 4 months in 24 (54.6%), 20 (45.4%) and 17 (38.6%) patients, respectively. The medians of overall headache days/month and of disabling headache days/month significantly decreased (p<0.0001) at each follow-up versus baseline. Despite the absence of papilledema, 31/44 (70.5%) patients fulfilled diagnostic criteria for "Headache attributed to Intracranial Hypertension". Our findings indicate that most patients diagnosed with unresponsive CM in specialized headache clinics may present an increased intracranial pressure involved in the progression and refractoriness of pain. Moreover, a single LP with cerebrospinal fluid withdrawal results in sustained remission of chronic pain in many cases. Prospective controlled studies are needed before this procedure can be translated into clinical practice.