Predictors of poor visual outcome in patients with Idiopathic Intracranial Hypertension (IIH): An ambispective cohort study

Highlights

• In patients of IIH, diminution of vision at presentation is the sole predictor of poor visual outcome at six months.

• MRI brain may of diagnostic but not of prognostic value in IIH.

• Female sex and obesity are less prevalent in patients of IIH in North India.

• History of any visual deficit in patients of IIH warrants aggressive management.

Abstract

Objective

Idiopathic intracranial hypertension (IIH) is a disease of young with threat to vision if not diagnosed timely. This study looked at the putative predictors of poor visual outcome in patients with IIH at six months after presentation via a cohort study.

Patients and methods

All patients diagnosed with IIH from January 2011 to May 2015 were enrolled. The study design was ambispective cohort study. The baseline clinical and radiological characteristics assessed were age, sex, body mass index (BMI), duration of symptoms, transient visual obscuration, cranial nerve palsy, diminution of vision, Cerebrospinal fluid (CSF) opening pressure, empty sella, optic nerve dilatation, global configuration and transverse sinus stenosis. Follow up of visual outcome at six months was done to know the predictors of poor visual outcome.

Results

Eighty nine (89) patients were enrolled and 56 patients had follow-up of six months at the time of analysis. Majority of the patients were females (73/89 (82%)). The mean age was 29.9 ± 11.0 years. Mean body mass index (BMI) was 27.1 ± 5.4 kg/m². Diminution of vision at presentation was seen in 54 (62%) patients. 64 eyes (36%) had visual acuity less than 6/18. Poor visual outcome at six months was seen in 23(41%) patients. Diminution of vision at presentation was found to be a poor predictor.

Conclusion

We found female sex and obesity to be less prevalent in our setting. Diminution of vision at presentation was a predictor of poor visual outcome at six months.

Introduction

Idiopathic Intracranial Hypertension (IIH) is characterized by features of raised intracranial pressure (ICP), causing headache, papilledema and potential visual loss in the absence of a space-occupying lesion or other identifiable cause. Initially described as serous meningitis by Quincke in 1893 [1], IIH still remains a disorder of uncertain pathogenesis. The clinical course is very variable with headache causing long term disability and visual loss being a potential threat. Prompt diagnosis and treatment are important because permanent visual field loss is common and blindness occurs in 10% of affected individuals [2], [3].

There are several clinical predictors of poor visual outcome like male sex [4], early onset reduced vision [5], high grade papilledema [6], [7], optic disc haemorrhages [8] and high body mass index (BMI) [9], [10]. High BMI has been implicated in both pathogenesis and poor prognosis of the disease. Predictors of good outcome are early age of onset and high diagnostic ICP, since they are brought to earlier medical attention [11]. The radiological characteristics in IIH also help in diagnosis of the disease and exclusion of alternative diagnosis but their role in prognostication is not clear. The predictors of visual loss may be most suitably reflected in a prospective study. The knowledge of predictors of visual loss may aid in more aggressive management when the vision is still salvageable.

We conducted an ambispective cohort study to identify the predictors of poor visual outcome in patients of IIH at six months after presentation to our center.