Benign intracranial hypertension: correlation of cerebral blood flow with disease severity

Benign intracranial hypertension (BIH) is characterized by symptoms and signs of raised intracranial pressure in the absence of an intracranial mass lesion, infection or hydrocephalus. The purpose of this study was to evaluate the effect of disease severity on cerebral blood flow in patients with BIH on acetazolamide therapy.

11 patients (nine females, two males; mean age 30.5 years; range 22-29 years) with BIH were studied. All patients underwent CT and MRI scanning which were normal. The CSF pressure of all patients was above 200 mm H2O. All patients were under treatment with acetazolamide (1 g/day). Disease severity was determined by visual field examination and by clinical symptoms. Five patients were categorized into mild to moderate BIH (group I) and six patients had severe BIH (group II). All patients underwent perfusion brain SPECT with 740 MBq of Tc-99m-HMPAO.

Brain perfusion abnormalities were observed in six of the 11 patients. One out of five patients in group I (20%) and five out of six patients (83%) in group II, had abnormal SPECT findings (P<0.04). In four patients of group II the left parietal lobe was involved and another patient had a right occipital abnormality. The single patient from group I with SPECT abnormalities demonstrated focal decreased perfusion in the left temporal area and decreased perfusion in the left caudate nucleus.

Patients with severe degree of BIH have a higher incidence of cerebral perfusion abnormalities. This group may have an increased risk of cerebrovascular complications. The continuous administration of acetazolamide which affects the vascular autoreactivity may contribute to the regional hypoperfusion. Further studies are recommended to evaluate the natural course of disease versus iatrogenic treatment effects.