Amongst the many medical problems that can accompany obesity, one that may fly under the radar (due to lack of awareness in the health care community) is pseudotumor cerebri, or idiopathic intracranial hypertension (IIH).
IIH is a condition where the pressures in the brain are elevated. Symptoms include headache, blurry vision or transient defects in vision; pulsatile ringing in the ears (tinnitus); and double vision. Symptoms often wax and wane for weeks or months, though a more aggressive course with rapid vision loss can also occur.
Although the exact mechanism/cause of IIH is unclear, obesity may lead to IIH because of impaired drainage of venous blood out of the brain, due to higher pressures in the abdomen caused by excess fat in the abdominal cavity. Fortunately, IIH is fairly rare in the general population at 2-3 per 100,000 people per year, but the incidence is rising along with the rise in obesity. For reasons unclear, women in their childbearing years with obesity seem to be at the highest risk of developing IIH, with estimates as high as 12-18 new cases per 100,000 per year.
For health care professionals to make the diagnosis of IIH, the following criteria must be fulfilled:
- Symptoms and signs of increased intracranial pressure (eg, headache, transient visual obscurations, pulse synchronous tinnitus, papilledema, visual loss)
- Normal neurological exam aside from the above
- A brain imaging study that shows no cause for intracranial hypertension
- Elevated intracranial pressure with normal cerebrospinal fluid (CSF) composition
- No other cause of intracranial hypertension is apparent.
Untreated, IIH can cause permanent visual damage. The main treatment of IIH in people with obesity is weight loss. Medications such as acetazolamide are also often used. If there is progressive vision loss, a CSF shunt to keep intracranial pressures down may be necessary.
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