Year : 2021 Month : February Volume : 10 Issue : 8 Page : 555-557

Rare Case of Unilateral Disc Oedema Secondary to Idiopathic Intracranial Hypertension

Praveena Kiran Kher1, Jigna Mukesh Motwani2, Sachin Vishwanath Daigavane3

1, 2, 3 Department of Ophthalmology, Jawaharlal Nehru Medical College, DMIMS, Sawangi, Maharashtra, India.

CORRESPONDING AUTHOR

Dr. Jigna Mukesh Motwani, Department of Ophthalmology, Jawaharlal Nehru Medical College, DMIMS, Sawangi Maharashtra, India.
Email : jignamotwani04@gmail.com

INTRODUCTION

Majority of idiopathic intracranial hypertension (IIH) cases present with bilateral papilloedema. Unilateral papilloedema is a rare condition in IIH. This is a report of one such unusual case. Papilloedema is clinically defined as swelling of the optic nerve head secondary to raised intracranial pressure.1 Disc oedema is a non-specific term that includes papilloedema but also refers to a disc swollen from other causes. Classically, presence of papilloedema is most commonly due to an intracranial space occupying lesion leading to raised intracranial pressure; however, it may be caused due to other aetiologies such as hydrocephalus, shunt failures, idiopathic intracranial hypertension and drugs.2 Idiopathic intracranial hypertension, also known as pseudotumour cerebri, is a disorder characterised by increased intracranial pressure of unclear pathogenesis in the absence of other structural and obstructive lesions. This is a case of acute established unilateral disc oedema secondary to idiopathic intracranial hypertension.

PRESENTATION OF CASE

A 40-year-old female presented with headache along with acute onset of pain, swelling and redness in the left eye of 15 days duration. This was associated with diminution of vision and photophobia in the same eye with no history of diplopia, tinnitus, trauma, insect bite or foreign body fall in that eye. She had complaints of severe headache which was worse in the morning. The diminution of vision was insidious in onset and gradually progressive in nature. There was no history of fever or recent weight gain. She gave history of similar episode of pain and redness in left eye which was associated with nausea and vomiting. She gave past history of hypertension, and was on treatment, taking tab amlodipine 5 mg once a day, for 5 years. There was no significant family history.

 

Clinical Examination

On initial evaluation she was hemodynamically stable and afebrile. General examination was within normal limits. Her body mass index was normal. Her blood pressure was within normal limits. On neurological examination, she was fully alert and oriented and had fluent speech and comprehensive abilities. There were no signs of meningeal irritation. All cranial nerve examination was normal.

 

Ophthalmologic Examination

The best corrected visual acuity in right eye was 6 / 6 and in left eye was 6 / 18. Colour vision was normal in both eyes and there were no visual field defects. Extraocular movements were full, free and painless in all directions and there was slight pain in left eye movement to the lateral gaze. Anterior segment examination of right eye was within normal limits. In the left eye, lid oedema was present. Conjunctival congestion was seen. Rest of the anterior segment was normal with brisk pupillary reflexes. Fundus examination of right eye was within normal limits. Fundus examination of left eye revealed clear media, hyperaemic disc with blurred and elevated margins, obliterated cup, tortuous vessels around optic nerve head and peripapillary haemorrhages, suggestive of established disc oedema in the left eye. The patient had raised cerebrospinal fluid (CSF) opening pressures on lumbar puncture.

 

 

Radiological evaluation: Magnetic resonance imaging of brain and orbit was advised to the patient to rule out any space occupying lesions or inflammatory diseases of optic nerve. The findings were widened peri optic CSF spaces, kinking of bilateral optic nerve and mild concavity of optic disc bilaterally suggestive of idiopathic intracranial hypertension.

DISCUSSION OF MANAGEMENT

On clinical examination, patient was suspected to be a case of optic neuritis of left eye and started on maximum dose of intravenous injection of methylprednisolone 1 gm for 3 days. Blood sugar levels and blood pressure was monitored during steroid administration.3 This was followed by oral prednisolone in tapering dose of 1 mg / kg body weight over 7 days. The patient did not show any improvement on follow up. On higher investigations, the diagnosis was confirmed. A course of oral acetazolamide 250 mg twice a day was given on radiological evidence of idiopathic intracranial hypertension. The patient showed improvement of visual symptoms on further follow up.

 

DISCUSSION

Unilateral disc oedema is a rare finding. As an association with an intracranial pathology or idiopathic intracranial hypertension, it is still an unusual entity.4 Idiopathic intracranial hypertension is an idiopathic condition with raised intracranial pressure in the absence of any structural abnormalities of central nervous system or venous flow abnormalities. The disease has a higher women predisposition, especially obese, in the second to fourth decade.3 The disease is almost always associated with bilateral papilloedema. Atypical patients include men, slim women, prepubescent children, and patients older than age 44 years. The diagnosis of idiopathic intracranial hypertension is made using the modified Dandy’s criteria, i.e. if the following criteria are met: 1) symptoms and signs attributable to increased intracranial pressure (ICP) or papilloedema; 2) elevated ICP recorded during lumbar puncture in the lateral decubitus position; 3) normal CSF composition; 4) no imaging evidence of ventriculomegaly or a structural cause for increased ICP, such as a brain parenchymal, ventricular, meningeal, or venous sinus abnormality; and 5) no other cause of intracranial hypertension identified, such as, use of certain medications.

One of the key early diagnostic features of IIH is papilloedema associated with visual loss. A study of 50 patients with IIH found 96 % patients presenting with visual field defects in at least one eye when assessed with Goldmann perimeter and 92 % patients by the Humphrey perimeter.5 Visual field testing is a sensitive diagnostic modality to detect early optic nerve damage producing visual loss.

Elevated ICP is a constant finding in patients with idiopathic intracranial hypertension, which may remain asymptomatic. In a study, over long-term follow-up, on lumbar puncture, persistent elevated intracranial pressure in the range of 220 to 550 mm H2O were noted in 83 % of the patients. Recurrent symptoms and chronic papilloedema are common features.6 Studies have proven that a CSF pressure of more than 250 mm H2O is diagnostic of IIH, from 201 to 249 is non-diagnostic, and less than 200 is normal.7 Papilloedema occurs when raised intracranial pressures cause mechanical compression resulting in stasis of axoplasmic transport followed by secondary vascular changes of venous dilation and haemorrhage. However, the mechanism of asymmetric papilloedema remains under reported. The differential diagnosis of unilateral disc swelling is extensive. Most commonly, local inflammatory, demyelinating, or vascular disorders are implicated. Compressive lesions that involve orbits and tumours of the optic nerve meninges or the nerve itself must also be excluded. Some cases of cerebral venous sinus thrombosis, gliomatosis cerebri, leptomeningeal infiltration by a chronic neoplastic or infectious process may not be detected by radiological investigations or CSF analysis in early stages.

Asymmetric papilloedema is rare in cases of idiopathic intracranial hypertension, as low as 4 %.8 The asymmetry in optic disc changes has been attributed to structural changes in the lamina cribrosa of the two sides, optic nerve sheaths or bony optic canal diameter. Sensitive techniques, such as standardised echography for measuring the size of the optic nerve sheath may be helpful in determining whether there is a correlation between differences in optic nerve sheath size and unilateral disc oedema in pseudotumour cerebri.

Treatment is not required for asymptomatic individuals with normal vision and minimal papilloedema, they can be monitored for development of symptoms or any diminution of vision. Therapy is initiated in presence of decline in vision or visual field defect, moderate to severe papilloedema or persistent headache. The idiopathic intracranial hypertension treatment trial (IIHTT) has proven the effective use of acetazolamide and additional weight loss to have significant improvement in mild vision loss, reduced papilloedema and intracranial pressure along with quality of life.9 Management protocol of cases with IIH include weight reduction, oral carbonic anhydrase inhibitors, oral diuretics, cerebrospinal fluid shunting, optic nerve sheath fenestration and venous sinus stenting. A low energy diet goes a long way in reducing the intracranial pressure along with improvement of symptoms as proven by studies.10 Diet with low vitamin A consumption is advised, since some studies have shown correlation between high serum retinol concentrations in patients with IIH.11 Acetazolamide is the first line medication for lowering intracranial hypertension in cases of IIH. Its carbonic anhydrase inhibition property reduces the secretion of CSF. Headaches should be managed with conventional prophylaxis. Surgical procedures like optic nerve sheath decompression and CSF diversion procedures are recommended in cases of progressive visual loss after maximal doses in medical therapy, severe papilloedema causing macular oedema or exudates, and severe or rapid visual loss.

It is essential to monitor the recurring visual disturbances with strict follow up for diagnosed cases of idiopathic intracranial hypertension. We managed to stabilise the symptoms of the patient within 14 days from onset as per protocol and the patient showed recovery. Early and adequate treatment delayed worsening of symptoms and progression of the disease in this case. The patient was managed well and is on regular follow ups for any recurrence of similar complaints.

Although rare, unilateral disc oedema should be diagnosed early, evaluated extensively and treated on a prompt basis. This case was particularly unusual due to its presentation in a nonobese female with classic symptoms of IIH presenting as unilateral disc oedema.

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DISCLOSURE AND FUNDING

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Financial or other competing interests: None.

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How to cite this article

Kher PK, Motwani JM, Daigavane SV. Rare case of unilateral disc oedema secondary to idiopathic intracranial hypertension. J Evolution Med Dent Sci 2021;10(08):555-557, DOI: 10.14260/jemds/2021/120

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