A 35-year-old male patient came to the emergency department with a severe bifrontoparietal headache lasting 8 hours, which did not change with Valsalva manoeuvres or posture, and partially subsided with analgesics.

The patient's personal history included an episode of ICH treated with oral acetazolamide and naproxen, with clinical recovery and disappearance of papilledema.

The general and neurological examination was normal, with a body mass index of 22 kg/m2. Ophthalmological examination showed a corrected visual acuity of 0.7 in both eyes. Intrinsic ocular motility, anterior segment examination and intraocular pressure (IOP) were normal.

Funduscopic examination showed bilateral papilledema. Fluorescein angiography showed early bilateral peripapillary leakage. Nerve fibre layer study (fast RNFL strategy) by optical coherence tomography (Stratus OCT; Carl Zeiss Meditec, Dublin, CA) showed thickening of the fibre layer in the right eye (OD) and thickness at high limits of normal in the left eye (OI).

Orbital ultrasound, computerised axial tomography and automatic perimetry were normal.

Lumbar puncture was performed, showing an opening pressure of 30 cm of water, with normal CSF composition and serology.

The analytical and coagulation studies and the determination of ANCAs, ANAs, PCR, RF, ASLO, thyroid hormones and antithyroid antibodies were negative.

Magnetic resonance imaging (MRI) and phleboresonance imaging ruled out the presence of cranial sinus thrombosis, finding a segmental stenosis of the right lateral sinus.

The patient was treated with acetazolamide and naproxen and clinical improvement was observed. After venography and cranial sinus manometry, a long stenosis of the right transverse sinus was observed with a pressure gradient of 7 mmHg, of a small amount and similar to that of the contralateral sinus. For this reason, and in view of the clinical improvement, dilatation by angioplasty and stenting was discarded.