The idiopathic intracranial hypertension treatment trial: clinical profile at baseline

Abstract

Importance: To our knowledge, there are no large prospective cohorts of untreated patients with idiopathic intracranial hypertension (IIH) to characterize the disease.

Objective: To report the baseline clinical and laboratory features of patients enrolled in the Idiopathic Intracranial Hypertension Treatment Trial.

Design, setting, and participants: We collected data at baseline from questionnaires, examinations, automated perimetry, and fundus photography grading. Patients (n = 165) were enrolled from March 17, 2010, to November 27, 2012, at 38 academic and private practice sites in North America. All participants met the modified Dandy criteria for IIH and had a perimetric mean deviation between -2 dB and -7 dB. All but 4 participants were women.

Main outcomes and measures: Baseline and laboratory characteristics.

Results: The mean (SD) age of our patients was 29.0 (7.4) years and 4 (2.4%) were men. The average (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) was 39.9 (8.3). Headache was the most common symptom (84%). Transient visual obscurations occurred in 68% of patients, back pain in 53%, and pulse synchronous tinnitus in 52%. Only 32% reported visual loss. The average (SD) perimetric mean deviation in the worst eye was -3.5 (1.1) dB, (range, -2.0 to -6.4 dB) and in the best eye was -2.3 (1.1) dB (range, -5.2 to 0.8 dB). A partial arcuate visual field defect with an enlarged blind spot was the most common perimetric finding. Visual acuity was 85 letters or better (20/20) in 71% of the worst eyes and 77% of the best eyes. Quality of life measures, including the National Eye Institute Visual Function Questionnaire-25 and the Short Form-36 physical and mental health summary scales, were lower compared with population norms.

Conclusions and relevance: The Idiopathic Intracranial Hypertension Treatment Trial represents the largest prospectively analyzed cohort of untreated patients with IIH. Our data show that IIH is almost exclusively a disease of obese young women. Patients with IIH with mild visual loss have typical symptoms, may have mild acuity loss, and have visual field defects, with predominantly arcuate loss and enlarged blind spots that require formal perimetry for detection.

Trial registration: clinicaltrials.gov Identifier: NCT01003639.

Figure 1. Symptoms

A, Graph shows initial symptoms reported at study entry. Other initial symptoms were floaters, dizziness, and nonpulse synchronous tinnitus. B, Graph shows the frequency of all symptoms reported at study entry.

Figure 2. Histogram of Mean Deviation Values of Idiopathic Intracranial Hypertension Treatment Trial Patients at Baseline

perimetric mean deviation of −2 to −7 dB was required for entry.

Figure 3. A Typical Example of the Most Common Visual Field Defect

Images show an enlarged blind spot with a partial inferior arcuate nerve fiber bundle defect.

Figure 4. Early Treatment Diabetic Retinopathy Study Score of the Worst Eye Plotted Against That for the Best Eye at Study Entry

Dark shaded areas indicate vision of 20/15 or better. The light shading indicates 20/40 vision or worse. The bold grid lines at the score of 85 are equivalent to 20/20; at 80 are 20/25; and at 75 are 20/32.

Figure 5. Frisén Papilledema Grading

Grade 1 by the Photographic Reading Center was required for study entry.