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Acetazolamide and a low-sodium, weight-reduction diet might benefit patients with IIH and mild vision loss.

The annual incidence of idiopathic intracranial hypertension (IIH) — also called pseudotumor cerebri — has been estimated in several countries as 0.9/100,000 in the general population, rising to 3.5/100,000 in women 15 to 44 years old and 19.3/100,000 in women 20 to 44 years old who are 20% or more above their ideal body weight. Patients may experience subjective visual loss as the initial symptom of IIH. They may report blurred vision, a dark spot temporally that correlates with enlargement of the physiologic blind spot, or tunnel vision.

In this multicenter, randomized, double-blind, placebo-controlled study, 165 patients with IIH and mild vision loss received a low-sodium, weight-reduction diet in addition to randomly assigned placebo or acetazolamide (up to 4 g/day) for 6 months. The primary outcome variable was the change in perimetric mean deviation (PMD) from baseline in the most affected eye. Secondary outcomes included changes in papilledema grade, quality of life, headache disability, and weight.

The mean improvement in PMD was significantly greater with acetazolamide than with placebo (1.43 dB increase vs. 0.71 dB increase). Improvements in papilledema grade and vision-related quality of life (but not headache disability or visual acuity) were also significantly greater with acetazolamide.

COMMENT

This study provides evidence that patients with mild idiopathic intracranial hypertension can be treated effectively by weight loss plus acetazolamide. The combination provides a modest improvement in visual field function for these patients. The clinical importance of this improvement remains to be determined. IIH is best managed using a team approach, and a low-sodium, weight-reduction diet is usually advocated for obese patients. If vision is failing despite medical treatment, rapid surgical intervention (usually with lumboperitoneal shunt or optic nerve sheath fenestration) is necessary (Neurol Clin N Am 2004; 22:99).

Jaime Toro, MD reviewing The NORDIC Idiopathic Intracranial Hypertension Study Group Writing Committee. JAMA 2014 Apr 23/30.

CITATION(S):

The NORDIC Idiopathic Intracranial Hypertension Study Group Writing Committee. Effect of acetazolamide on visual function in patients with idiopathic intracranial hypertension and mild visual loss: The Idiopathic Intracranial Hypertension Treatment Trial. JAMA 2014 Apr 23/30; 311:1641.
[PubMed® abstract]