Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 58, Num. 5, 2010, pp. 818-819

Neurology India, Vol. 58, No. 5, September-October, 2010, pp. 818-819

Letter to Editor

Idiopathic intracranial hypertension presenting as unilateral papilledema

Pandurang R Wattamwar, Neeraj N Baheti, Ashalatha Radhakrishnan

Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India

Correspondence Address:
Ashalatha Radhakrishnan
Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala
India
drashalatha@sctimst.ac.in

Date of Acceptance: 22-Jul-2010

Code Number: ni10238

PMID: 21045536

DOI: 10.4103/0028-3886.72208

Sir,

Idiopathic intracranial hypertension (IIH) is a common cause of bilateral papilledema without any other focal deficits. Although classically bilateral, unilateral and highly asymmetrical papilledema is rarely described in IIH. ^[1] This atypical presentation can pose a diagnostic challenge if the treating physician is unaware of such association.

A 32-year-old obese woman presented with a 4-month history of transient visual obscurations in the right eye without headache or raised intracranial pressure symptoms. Her past medical history was unremarkable. Examination showed normal visual acuity in both eyes. Optic fundi showed absent venous pulsations with papilledema in the right eye [Figure - 1]a; left optic fundus was normal. The remainder of the neurological examination was unremarkable. Magnetic resonance imaging [Figure - 2] showed empty sella, buckling of optic nerves and prominent perioptic cerebrospinal fluid (CSF) spaces bilaterally. Orbital and retro-orbital structures were normal, and no other structural lesion or ventriculomegaly was noted. MR venogram was normal.

The possibility of an atypical presentation of IIH with unilateral papilledema was considered. Cerebrospinal fluid opening pressure was 290 mm of water with normal composition. She was initiated on acetazolamide, her symptoms improved, reinforcing the diagnosis of IIH. At 3-month follow-up, she remained asymptomatic with partial resolution of papilledema [Figure - 1]b.

Unilateral papilledema usually results from orbital or retro-orbital mass lesions; however, it is also reported with IIH. The exact cause(s) is unknown; however, various mechanisms have been proposed, like anomalous optic nerve sheath, variations of the trabecular meshwork of fibrous adhesions in the subarachnoid space surrounding the optic nerve and anatomical difference in lamina cribrosa. ^[2],[3],[4] A recent study suggests compartmentation of the subarachnoid space of the optic nerve as a cause of asymmetric papilledema in IIH. ^[5]

Lepore ^[1] noted that patients with unilateral papilledema are significantly older than those with bilateral papilledema; however, there was no difference between the groups with respect to disease duration, symptoms, severity, visual performance measures, CSF opening pressure and clinical course. Prompt evaluation and early diagnosis and management can prevent complications like permanent visual loss. ^[5] A treating physician/ ophthalmologist should be aware of such an atypical albeit rare presentation of IIH, and a lumbar puncture along with monitoring of CSF opening pressure should be considered in cases of unilateral optic disc edema if there is no obvious cause determined by neuroimaging.

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