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Neuro-Ophthalmology

Case 30

 

Patient Presentation: A 36-year-old woman presented to a tertiary neuro-ophthalmology clinic with progressive vision loss in the right eye, headaches, and pulsatile tinnitus for 6 months. Her past medical history was significant for iron deficiency anemia, obesity (BMI = 37.6 kg/m2), and migraine. Additionally, she gained 18 kg of weight over two years. She did not smoke or drink alcohol. Her mother had a history of glaucoma. On initial examination, her visual acuity was 20/400 OD and 20/20 OS. There was no RAPD. Humphrey visual field testing (24-2) was performed and is shown below:

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Question 1: What visual field defect(s) is/are present in this patient?

Dilated fundus examination was performed and is shown below:

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Question 2: Based on the patient’s presentation, history, and fundus findings, what is the differential diagnosis?

Magnetic resonance imaging (MRI) and venography (MRV) was performed and revealed signs consistent with IIH. Moreover, lumbar puncture was performed and there were normal CSF contents and an opening pressure of 47 cm H­2O.

Question 3: What treatment should be initiated for patients with IIH?

Acetazolamide was initiated in this patient to a maximal dose of 4 g daily; however, her symptoms continued to persist, and there was no improvement in visual function. Subsequently, she underwent bilateral transverse-sigmoid venous sinus stenting which resulted in resolution of her headaches and pulsatile tinnitus; however, there was sustained deterioration of her visual function.

At 1-month follow-up, there was complete resolution of papilledema and optic disc pallor, but her visual acuity was counting fingers (CF) OD and 20/40 OS.

OCT RNFL and ganglion cell analysis was performed at 1-month follow-up and is shown below:

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Humphrey visual field testing (24-2) demonstrated persistent central scotomas OU at 1-month follow-up:

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Question 4: What are the key findings in the OCT RNFL and ganglion cell analysis?

An additional optic neuropathy was suspected as culprit for her worsening visual function. A complete blood count (CBC) was performed and B12 and folate levels were checked and within normal limits.

Question 5: What is the next best step in the management for this patient?

This patient underwent mitochondrial genetic testing which unveiled a m.8623A>G, p.(Thr33Ala) mutation in the ATP6 gene and a diagnosis of LHON was made.

Question 6: Which of the following has/have been implicated as a risk factor(s) for triggering vision loss in LHON?

At 12-month follow-up, her VA remained at CF OD and improved to 20/30 OS. Moreover, her central scotomas continued to persist.

References:

  1. Araya, Javiera MD; Araya, Claudio MD; Conrads, Tomas MD; Sadun, Alfredo MD, PhD;
    Seleme, Nicolas MD. Leber hereditary optic neuropathy conversion in a patient with idiopathic
    intracranial hypertension. J Neuroophthalmol. 2022.

  2. Lamirel C, Cassereau J, Cochereau I, Vignal-Clermont C, Pajot O, Tanguy J, Zanlonghi X,
    Reynier P, Amati-Bonneau P, Dubas F, Bonneau D, Verny C. Papilloedema and MRI enhancement of the prechiasmal optic nerve at the acute stage of Leber hereditary optic neuropathy. J Neurol Neurosurg Psychiatry. 2010;81(5):578-580. doi:10.1136/jnnp.2009.174953

 

Learning Objectives:

  1. To understand the history, exam findings, and management of IIH

  2. To understand the role of elevated ICP/IIH as a trigger for vision loss in LHON

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