<unk>  <unk> , sometimes called benign<unk><unk>  (BIH) or pseudotumor cerebri (PTC) is a neurological disorder that is characterized by increased<unk>  pressure (ICP), in the absence of a tumor or other diseases affecting the brain or its lining. The main symptoms are headache and visual problems. Diagnosis requires brain scans and lumbar puncture. There are various medical and surgical treatments.
The terms "benign" and "pseudotumor" derive from the fact that increased<unk>  pressure was, especially in the era before computed tomography (CT), associated by brain tumors. Those patients in whom no tumour was found were therefore diagnosed with "pseudotumor cerebri" (a disease mimicking a brain tumor). The disease was renamed "benign<unk><unk> " to distinguish it from<unk><unk>  due to malignancy (i.e. cancer); this was also felt to be misleading, and the name was therefore revised to<unk>  (of no identifiable cause)<unk><unk> ".
Raised ICP due to another cause (e.g. meningitis, tumor) can be classified as "secondary<unk><unk> ". The term<unk><unk> " is sometimes used (see IHRF) as a blanket term to describe<unk><unk>  of all aetiologies.
Idiopathic intracranial hypertension
Arachnoiditis
Subarachnoid hemorrhage
Neoplastic meningitis
Viral meningitis
Cavernous sinus thrombosis
Cerebral venous sinus thrombosis
Gliomatosis cerebri