People who experience severe, rapidly progressing loss of vision should seek immediate medical attention, because this may signal elevated pressure in the brain that could lead to permanent blindness, neurologists warn.

In the journal Neurology this month, Dr. Madhav Thambisetty of Emory University in Atlanta and colleagues report on 16 patients with this condition, known as fulminant idiopathic intracranial hypertension (IIH).

IIH typically worsens fairly slowly, and rapid progression is usually due to a secondary cause such as a blood clot in the brain or meningitis, the researchers explain. But in the 16 patients they describe, no secondary causes were identified.

“Although fulminant IIH is rare, it affects young, otherwise healthy women, who often become legally blind over the course of a few days,” Thambisetty and his team write.

All of the patients in the current report were women, and their average age was about 24. All of them were obese and all had experienced headaches before seeking treatment, while nine had nausea and vomiting. Nine had ringing in their ears, eight had temporary blurry vision, and five had double vision.

Eleven of the patients underwent a shunting procedure to relieve pressure on the brain, while optical nerve sheath fenestration - in which “windows” are cut into the tissue surrounding the nerve - was performed in five. While 14 of the patients had some visual improvement after treatment, eight remained legally blind.

The researchers warn that emergency physicians and neurologists will often overlook fulminant IIH as a potential cause of headaches, nausea and visual disturbances, but they say aggressive treatment is essential to prevent permanent vision loss.

All of the patients in the current report who experienced significant improvement received surgery within four days, Thambisetty and colleagues note, while the three patients who delayed surgery - for 10, 12 and 37 days after evaluation - remain legally blind.

SOURCE: Neurology, January 2007.