SAEM Clinical Images Series: Seeing Double

ophthalmoplegia

A 53-year-old woman with no significant past medical history presented to the emergency department with a 3-day history of double vision on leftward gaze. She initially presented to urgent care with a chief complaint of chest heaviness and concern that her blood pressure was too high, but was sent to the emergency department for further cardiac and neurological evaluation after her urgent care provider noticed abnormal eye movement. She endorsed mild, intermittent headaches associated with diplopia when looking to the left. However, she denied any blurry vision when looking forward. She denied any trauma or falls.

Physical Exam

Vitals: Temp 36.7°C; Heart rate 86 beats/min; Respirations 18 breaths/min; BP 150/82 mmHg; O2 Saturation: 100%

General: No acute distress and appears comfortable. She is alert and oriented.

Eyes: Equal, round and reactive pupils and severely limited adduction of the right eye, all other extraocular movements are normal.

Neuro: All other cranial nerves are intact, normal tone in bilateral upper and lower extremities, normal sensation bilaterally to light touch and pinprick except for mildly decreased sensation to pinprick over right ulnar distribution.

Laboratory Data

CBC, CMP, EKG, and Troponins were normal.

Lipid panel: Cholesterol 241 (H)

CSF: No oligoclonal bands, Protein 197 (H), Albumin 57 (H), IgG 16.3 (H)

Case Question: What are some possible causes of this patient's right-sided internuclear ophthalmoplegia?

Internuclear ophthalmoplegia (INO) is defined as the inability to adduct the eye due to a lesion in the medial longitudinal fasciculus (MLF) and can be accompanied by nystagmus in the same eye. The two main causes of internuclear ophthalmoplegia are demyelination of the medial longitudinal fasciculus (MLF) from multiple sclerosis (MS) and ischemic cranial nerve damage from stroke. However, a comprehensive list of causes of INO includes: infarction (ischemic stroke), demyelination (MS), tumor, encephalitis, hemorrhage, hydrocephalus, Chiari malformation, infection (Lyme Disease), and trauma. Usually, MS is seen in younger patients where both eyes are affected whereas strokes occur more often in older patients and only one eye is affected.

Case Question: What labs and imaging can aid in the diagnosis of this patient?

The therapeutic approach focuses on treating the underlying cause and hence determining the etiology is of immense importance. A brain MRI should be ordered to evaluate for ischemia and demyelination. Proton density imaging is beneficial in identifying MLF lesions in multiple sclerosis. A lumbar puncture can also help rule out infections. A kappa-free light chain antibody test is a faster and less expensive way to test for multiple sclerosis than looking for oligoclonal bands in the CSF.

Given this patient’s relatively young age and vascular risk factors, stroke is highest on the differential. Her brain MRI showed areas of restricted diffusion in the right dorsal medial pons correlating with her exam. It also showed periventricular and subcortical white matter changes which is a non-specific finding in chronic small vessel ischemic changes vs underlying demyelinating disease. This was followed up with an MRI of her spine that demonstrated C5-6 stenosis with associated cord edema and an additional enhancing C3-4 lesion concerning for demyelinating disease. Her lumbar puncture revealed 3 nucleated cells and a protein of 197 but was deemed a traumatic tap. There were no oligoclonal bands. The initial brain MRI findings favored stroke for which she underwent a stroke work-up and was ultimately discharged on aspirin and atorvastatin for secondary prevention. However, due to concern for demyelinating disease, she was also treated with a 3-day course of IV methylprednisolone. Ultimately, she was discharged and asked to come back for a follow-up for repeat brain imaging and evaluation. A recent study showed that patients with unilateral or bilateral INO who experienced symptomatic diplopia were commonly managed by uniocular occlusion. Another case report showed that a young man who presented with acute INO responded rapidly to treatment with IV alteplase when administered within 2 hours of the onset of symptoms and resolution within 15 minutes. A case series revealed that 1 in 5 patients failed to recover from an INO. Hence, it is critical that a definitive workup is carried out to determine the etiology of the INO.

Case Discussion

Take-Home Points

Brain MRI including DWI is a useful diagnostic tool for INO.
Unilateral INO is more frequently related to ischemic/vascular causes whereas bilateral INO is associated with MS.

References

Kim SS, Lee MH, Ji C. Unilateral Internuclear Ophthalmoplegia Following Minor Head Injury. Korean J Neurotrauma. 2022 Oct 24;18(2):329-334. doi: 10.13004/kjnt.2022.18.e64. PMID: 36381451; PMCID: PMC9634317.
Mahawish KM, Aravind A. Acute onset internuclear ophthalmoplegia responsive to treatment with intravenous alteplase. N Z Med J. 2020 May 22;133(1515):119-121. PMID: 32438384.
Simmons J, Rhodes M. Conservative and Surgical Management of Unilateral and Bilateral Internuclear Ophthalmoplegia (INO)-A Retrospective Analysis. Br Ir Orthopt J. 2022 Nov 7;18(1):152-158. doi: 10.22599/bioj.280. PMID: 36420121; PMCID: PMC9650975.

Copyright

Images and cases from the Society of Academic Emergency Medicine (SAEM) Clinical Images Exhibit at the 2023 SAEM Annual Meeting | Copyrighted by SAEM 2023 – all rights reserved. View other cases from this Clinical Image Series on ALiEM.