CLINICAL CHALLENGES
Headache Hell: Part Two
Sometimes it takes a lot of work to get a noncompliant patient into a safer situation.
By Eric Schmidt, O.D.

Last month we met Angie, whom I diagnosed with pseudotumor cerebri (PTC), or idiopathic intracranial hypertension (IIH). Many clinicians refer to this as benign IIH, but as you'll see with Angie's case, IIH is definitely not a benign disease.

The first tier of treatment

Angie's opening intracranial pressure (ICP) was more than 400 mm, which was most likely the cause of her headaches. I prescribed acetazolamide (Diamox) 500 mg b.i.d. after consulting with her neurologist. Acetazolamide is a hyperosmotic agent that decreases cerebro spinal fluid (CSF) by setting up an osmotic gradient. The acetazolamide effectively pulls the CSF from its area of highest concentration (intracranial tissue) to areas of lower concentration (the ventricles). The CSF leaves the brain from the ventricles, reducing the ICP.

Also important to Angie's initial therapy was to encourage weight loss. She was overweight by at least 70 pounds and this increased body mass precipitates the accumulation of excess CSF. Many times in these cases losing sufficient weight cures the disorder. I referred Angie to a weight loss clinic and scheduled her for a visual field analysis/follow-up appointment in three weeks.

Learning of Angie's progress

Angie called five days later complaining about the acetazolamide. She said that she was nauseous and had "tingliness" in her hands and feet. She also said that she had no energy and that she began feeling this way the day after she started the agent.

I instructed her to try just one 500-mg tablet of acetazolamide each day, but after four days she still felt terrible. Two days later, Angie returned to my office. She had stopped the acetazolamide completely and said that her headaches seemed worse. She'd also missed her appointment at the weight loss clinic. Angie's visual acuity (VA) measured 20/30 OD and 20/25-2 OS. The rest of her exam was unchanged.

My tech performed a central 24-2 visual field analysis on Angie, which revealed a dense, binasal hemianopia that was more complete OS than OD (Fig. 1). The increased ICP was cutting off enough axoplasmic flow to produce a visual field defect. I obviously needed to step up Angie's treatment rather aggressively.

The second tier

Angie's neurologist agreed to see her the next day. He concurred that more therapy was warranted and prescribed the anti-epileptic drug topiramate (Topamax) 200 mg b.i.d. Similar to acetazolamide, topiramate inhibits carbonic anhydrase formation in the brain but with less systemic side effects. Thus topiramate can effectively reduce ICP and restore comfort to patients who have IIH. Another fortuitous finding with topiramate is that it promotes weight loss.

Pursuing further treatment

Angie tolerated the topiramate well and took it for more than one year. During that time, I saw her regularly (every three months) and her papilledema would show signs of remissions and exacerbations. Likewise, her symptoms would improve for a period of time, but then her vision and headaches would worsen. Her visual fields (VFs) didn't improve (or worsen) over a 15-month period. Angie still refused to seek help for her weight.

Angie, her neurologist and I were all resolved to maintain this course for as long as possible, but eventually Angie began to experience episodes where her vision would "black out." She described these events as usually occurring in both eyes and lasting for hours at a time. Angie said that her vision returned to normal after these events, but that it definitely seemed worse than it was three years earlier.

Her clinical picture remained unchanged. Her VA hovered around 20/25 - 20/30 and the VF picture was the same. She showed consistent disk edema OU, but no worse than before. But because of the transient visual obscurations (TVO) she was experiencing, the neurologist performed another lumbar puncture (LP). Her ICP was 339 -- even on topiramate -- and was probably even higher during the episodes of TVO. Once again, the situation indicated further treatment.

Intervening surgically

Given Angie's intolerance to acetazolamide and her unwillingness to lose weight, surgical intervention was her only option. After a neurosurgery consult, the neurosurgeon decided to implant an intracranial shunt, which would alter the accumulation of CSF in the brain by directly transporting it through the shunt and out of the head.

Within days of the procedure Angie felt better. Her headaches had resolved and she felt that her vision was likewise improved. Over a three-year period, Angie remained stable and fairly asymptomatic. Her VA improved to 20/20 OU and the papilledema was significantly reduced and her VF showed improvement (Fig. 2).

Getting a scare

Angie returned to my office two months early for her six-month follow up in a bit of a panic. For the past three days she had severe headaches "like the ones that I used to have!" She also felt that her vision had gotten worse over the last few days.

Angie was still taking the topiramate as directed and had lost 20 pounds over the past year. But when I checked her VA it had decreased to 20/25-3 OD and 20/25 OS. Examination of the posterior poles once again revealed frank disk edema, which I graded at 2+ OU. I relayed my findings to the neurosurgeon, who saw Angie the next day.

A test revealed that her shunt had become blocked, causing an accumulation of CSF that once again elevated her ICP. The neurosurgeon pumped out the shunt obstruction and returned the normal flow through the shunt. Once again, Angie's symptoms were dramatically reduced.

Holding steady . . . for now

Since clearing her shunt, Angie has remained relatively stable. I examine her regularly and have seen no further disk edema. Angie understands that the shunt can become occluded again and she diligently monitors her symptoms and vision. I repeatedly stress the need for aggressive weight loss, but these pleas have not spurred Angie into taking that action.

Because Angie is fairly young, there is a possibility of complete shunt failure in the future. The neurosurgeon, Angie and I have all discussed the possibility that she may require more surgery such as an optic nerve sheath defenestration at some point down the road. But at this point, she's stable. Her VA remains 20/20 and her VF is stable as well. She continues to take topiramate. Hopefully this "benign" disease process will stay that way!

Contributing Editor Eric Schmidt, O.D., is director of the Bladen Eye Center in Elizabethtown, N.C. E-mail him at kenziekate@aol.com.