Pseudotumor cerebri, or idiopathic intracranial hypertension, is a condition caused by pressure around the brain that mimics a tumor when there is no tumor. It occurs most often in overweight women of childbearing age. It is thought to be caused by an excess buildup of cerebrospinal fluid (CSF) in the brain.

Symptoms may include headaches — usually behind the eyes, ringing in the ears (tinnitus), nausea and vomiting, and neck, back, or shoulder pain.

Several vision problems may also occur, including blurred or double vision, tunnel vision, light flashes, or even brief periods of blindness.

The condition is diagnosed using a CT or MRI to scan the brain (to rule out actual tumors or other abnormalities), along with an examination by an eye doctor (ophthalmologist). A lumbar puncture may also be performed. The lumbar puncture — inserting a fine needle between the vertebra in the lower back to remove some CSF for testing — may also provide temporary and sometimes permanent relief from the symptoms.

A key treatment for relief of symptoms is weight loss. After that, some glaucoma medications and other drugs may be given. Surgery to maintain sight and relieve intracranial pressure is a final, last-resort option.