|Year : 2015 | Volume
| Issue : 2 | Page : 285-287
Uncommon presentation of idiopathic intracranial hypertension
Vignesh Kumar Chandiraesharan1, Ajay Kumar Mishra1, Maria Koshy1, Sunithi Elizabeth Mani2
1 Department of General Medicine, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
2 Department of Radiology, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
|Date of Web Publication||16-Dec-2015|
Ajay Kumar Mishra
Christian Medical College and Hospital, Vellore, Tamil Nadu
Source of Support: None, Conflict of Interest: None
A 51-year-old gentleman, a known hypertensive on medications presented with transient visual disturbance in his left eye. Examination revealed the presence of unilateral optic disc edema. A lumbar puncture revealed elevated opening pressure with normal cerebrospinal fluid biochemical parameters. Neuroimaging showed no evidence for an alternative cause for intracranial hypertension thus confirming the diagnosis of idiopathic intracranial hypertension (IIH). IIH can rarely present with a unilateral papilledema. This emphasizes the need to meticulously examine both optic fundi in all patients with suspected intracranial hypertension. Early diagnosis of this condition can help in the prevention of permanent visual loss. We hereby report the second case of IIH presenting with a unilateral papilledema in Indian literature.
Keywords: Imaging, intracranial hypertension, modified dandy criteria, unilateral papilledema
|How to cite this article:|
Chandiraesharan VK, Mishra AK, Koshy M, Mani SE. Uncommon presentation of idiopathic intracranial hypertension. Arch Med Health Sci 2015;3:285-7
| Introduction|| |
Idiopathic intracranial hypertension (IIH) is an uncommon disorder which can result in permanent visual loss if left untreated. A high index of suspicion along with meticulous clinical examination is required to identify this condition. This case highlights the rare occurrence of a unilateral papilledema in IIH, which emphasizes the need to consider this diagnosis as a differential of unilateral disc abnormality in addition to orbital and retro-orbital diseases. Demonstration of elevated cerebrospinal fluid (CSF) opening pressures and ruling out alternate causes for raised intracranial hypertension by neuroimaging and CSF analysis is the cornerstone for diagnosing this condition.
| Case Report|| |
A 51-year-old gentleman presented with a 15 days history of intermittent, transient and painless visual disturbance involving his left eye. He did not have associated the photophobia, diplopia, headache or vomiting. He was a known hypertensive for 20 years on appropriate medications. On examination, he was obese (body mass index -32), and his vital parameters were stable. He was found to have normal visual acuity, a normal visual field and normal blind spot charting; however a fundus examination revealed papilledema involving the left eye; the right optic fundus being normal. The rest of his neurological examination was unremarkable. A magnetic resonance imaging (MRI) done [Figure 1] and [Figure 2] showed a prominence of the subarachnoid space around the retina and orbital segments of left optic nerve, posterior scleral buckling and partially empty sella. The right optic nerve, bilateral orbits, the rest of the brain parenchyma and the vasculature were normal. A lumbar puncture in the lateral decubitus position revealed an elevated opening pressure of 35 cm of water with a normal cell count and biochemical parameters [Table 1]. Secondary causes of intracranial hypertension such as space occupying lesion, hydrocephalus, central nervous system infections, and vascular abnormalities, were ruled out with the help of MRI with a post-contrast imaging and CSF analysis. Thus, he fulfilled the criteria for IIH by Friedman and Jacobson and the modified Dandy criteria for definite IIH. Risk factors for IIH such as endocrine abnormalities, exposure to drugs, lupus, polycythemia were also ruled out with the help of appropriate investigations. He was initiated on acetazolamide and was advised weight reduction and a salt restricted diet. On follow-up, he was symptomatically better and had clinical improvement in vision.
|Figure 1: T2-weight axial section through the orbits showing dilated perineural fluid space around the left optic nerve (short arrows) as compared with normal on the right (arrowheads) and posterior scleral buckling (long arrow|
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| Discussion|| |
Idiopathic intracranial hypertension also known as benign intracranial hypertension or pseudotumor cerebri can cause intractable and disabling headaches with a risk of severe, permanent vision loss. The risk factors for the condition include female gender, pregnancy, obesity, anemia, uremia, sleep apnea, certain drugs, Systemic Lupus Erythematosus, Behcet's syndrome, Addison disease and hypoparathyroidism. The pathological mechanisms causing IIH are intracranial venous hypertension, increased CSF outflow resistance, altered sodium and water retention mechanisms and abnormalities of Vitamin A metabolism.
IIH most commonly presents with headache. The other associated symptoms in the order of their frequency are transient visual disturbances, intracranial noises (pulsatile tinnitus), diplopia, retrobulbar pain and sustained visual loss. Although, the hallmark of IIH is bilateral papilledema, atypical presentations which a clinician should be aware of are, asymmetrical, or even unilateral papilledema; and rarely IIH can also occur in the absence of papilledema (IIH without papilledema).The other features which have been recorded in literature include : v0 isual field loss and cranial nerve palsies, in particular affecting the sixth cranial nerve. 
Unilateral optic disc abnormalities are commonly seen in orbital and retro-orbital lesions. There are a few case reports of a unilateral papilledema in IIH.  The hypotheses which have been postulated for the occurrence of a unilateral papilledema in raised intracranial tension are optic nerve sheath anomalies and differences in the lamina cribrosa. Presence of high CSF opening pressures along with neuroimaging to rule out intracranial lesions, documentation of normal CSF biochemical parameters and complete ophthalmological evaluation to rule out alternate diagnoses are prerequisites to diagnose IIH. Several characteristic MRI finding are known and are described in [Table 2].  Of the various imaging findings present in IIH, flattened posterior sclera, slit like ventricle and intraocular protrusion of optic nerve head have 100% specificity in clinching the diagnosis. However of these flattened posterior sclera has been found to have the highest sensitivity of 80% in the literature. 
Prompt evaluation and early diagnosis and management can prevent complications like permanent visual loss. Medical management includes weight reduction, elimination of risk factors, and pharmacological agents such as acetazolamide, loop diuretics and corticosteroids. Among the drugs, acetazolamide is the most commonly used agent with a good clinical response.  Surgical modalities, including lumboperitoneal or ventriculoperitoneal shunt surgery, subtemporal decompression, endovascular venous sinus stenting, optic nerve decompression (OND), and the recently described endoscopic OND have been used in the management of refractory cases with impending permanent visual loss. ,
| Conclusion|| |
A treating physician should be aware of atypical presentations of IIH [Table 3]. A lumbar puncture along with a determination of CSF opening pressure should be made in cases of unilateral optic disc edema where there are no obvious causes determined by neuroimaging. This case serves to remind us to consider the possibility of papilledema in cases of unilateral swollen disks. To the best of our knowledge, this is the second case report of IIH presenting with unilateral papilledema  from India.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]