Idiopathic Intracranial Hypertension Associated With Transverse Sinus Giant Arachnoid Granulation Successfully Treated by Endovascular Stenting

The incidence of Idiopathic intracranial hypertension (IIH), defined as increased intracranial pressure of unknown origin, has been reported to be very low in Japan. A 42‐year‐old Japanese woman was admitted to our hospital with headache, blurred vision, and tinnitus. She had experienced episodic occipital headaches a year before admission which became persistent eight months later. The pain worsened upon forward bending and defecation. She consulted an ophthalmologist for blurred vision and was immediately referred to our hospital. On admission, fundoscopic examination revealed papilledema and venous distension. The opening cerebrospinal fluid pressure was > 35 cmH 2 O. Computed tomography angiography revealed hypoplasia of the left transverse sinus and stenosis of the right transverse sinus with giant arachnoid granulation. She was subsequently diagnosed with IIH and successfully treated with endovascular stenting which eliminated the pressure gradient and resolved her headache completely. As a treatable condition, transverse sinus arachnoid granulation should not be overlooked.