[Low-pressure] variant of idiopathic intracranial hypertension: a unique subtype of chronic daily headache

Headache, papilledema and elevated CSF pressure above 200 mm H2O [250 mm H2O in obese patients] in a patient with normal neurological examination and neuro-imaging meet the international headache society [IHS] diagnostic criteria for idiopathic intracranial hypertension [IIH]. However variants of the classic syndrome have been reported i.e apapilledimic [without papilledema] and pure ophthalmic [without headache]. The aim of this study was to investigate a series of patients with refractory chronic daily headache [CDH] without papilledema, and with borderline CSF pressure [160-200 mm H2O in non-obese patients; 160-250 mm H2O in obese patients] to highlight their clinical, and neuroimaging findings. Twenty five cases with refractory chronic daily headache [CDH] who presented at the neurosurgery and neurology outpatient clinics were included in the study. All patients were evaluated clinically and radiologically and CSF manometry was recorded. All patients had unclassified chronic daily headache, visual field defects, a partial empty sella on imaging studies and borderline CSF pressure [160-200 mm H20 in non-obese patients; 160-250 mm H2O in obese patients]-. The majority of patients showed headache improvement after treatment with medications that lower intracranial pressure in combination with their conventional headache therapy regimens. The constellation of chronic daily headache, field defects, a partial empty sella and borderline CSF pressure in a patient with normal neurologic examination may constitute a [low-pressure] variant of idiopathic intracranial hypertension