38. Bilateral internuclear ophthalmoplegia and third nerve palsy in giant cell arteritis
Authors: El-Ghazali Shawki , Hogarth Maxine 
Published: September 2019

Abstract

Introduction
We present a case of a gentleman with atypical headache symptoms clinically diagnosed as giant cell arteritis (GCA) and initiated on high dose oral steroids. He subsequently developed progressive neurological deficit including bilateral internuclear ophthalmoplegia (INO), as well as third cranial nerve involvement despite above treatment. He received IV methylprednisolone and demonstrated clinical response, temporal artery biopsy confirmed histological evidence of GCA. The nature of his presentation was atypical of cranial giant cell arteritis. Few reported cases describe INO in the context of GCA, with bilateral manifestation being rarer, especially with additional third cranial nerve involvement.

Case description
A 66-year-old gentleman presented with a 7-day history of bilateral temporal headaches. He noted prominence of both temporal arteries with mild tenderness during this period. He denied any visual changes, PMR symptoms, and jaw claudication or weight loss. He had been experiencing generalised fatigue and myalgia for the preceding 4 months.
He was noted to have raised inflammatory markers (CRP 194, ESR 74) and due to the non-specific nature of headache, concern was for possible meningitis. CT head scan was unremarkable and lumbar puncture and CT-CAP did not demonstrate any abnormality including evidence of infection.
He was assessed by the rheumatology team and a clinical diagnosis of GCA was made. He was initiated on prednisolone 60mg daily, and described clinical improvement of headaches over the subsequent day. Inflammatory markers also initially responded to treatment.
After 2 days of oral therapy, he developed double vision as well as intermittent headache. CRP remained static at 40. He was seen with the neurology team and was found to have divergent gaze of the left eye with ptosis. Eye movements demonstrated bilateral internuclear opthalmoplegia with involvement of the left third cranial nerve. MRI head scan demonstrated small vessel ischaemic changes but no obvious focal pathology. Due to new visual involvement despite prednisolone 60mg, IV methylprednisolone was administered for a period of 3 days. Ophthalmological symptoms did not progress and CRP reduced to 8. Temporal artery biopsy reported findings consistent with GCA.
He was re-established on prednisolone 60mg however intermittent headache recurred and CRP gradually increased. Decision was made to increase prednisolone to 80mg (1mg/kg). At this dose headache resolved and CRP decreased to normal range. Methotrexate was introduced at 20mg weekly in order to facilitate with prednisolone weaning.
Within 3 weeks of initial IV methylprednisolone administration, ophthalmological symptoms slowly improved to complete resolution.

Discussion
Typical manifestion of cranial GCA consists of unilateral temporal headache. Patients can however exhibit other symptoms including bilateral involvement and features of systemic inflammation which may be non-specific.
Cases of neurological involvement have also been described, with diplopia and cranial nerve involvement being widely reported. Few case reports have described bilateral internuclear ophthalmoplegia which is syndrome involving the medial longitudinal fasciculus of the brainstem. This is usually associated with multiple sclerosis however any pathology of this anatomical region can result in this clinical picture. This gentleman additionally demonstrated features of third nerve palsy of the left eye which would be in keeping with a more typical cranial nerve involvement in GCA. The hypothesis for his clinical picture would be of reversible localised ischaemia to the brain stem secondary to active inflammation of the supplying vessel. MRI imaging did not identify any focal pathology and as mentioned previously, following treatment, his clinical findings fully resolved in a gradual manner over a period of weeks.
In regards to the management of his case, following exclusion of infection and in the absence of visual findings on presentation, he was started on prednisolone 60mg daily (40-60mg dose suggested within current BSR guidelines). He described improvement of his headache and CRP was seen to improve initially. Despite this treatment, he developed features of INO and third nerve palsy as described. Implementation of IV methylprednisolone therapy prevented further progression of his symptoms and subsequent resolution of raised CRP. However restarting prednisolone at 60mg after this appeared to demonstrate incomplete control of his condition, thus it was increased to 80mg. Decision to introduce methotrexate at an early stage was made in anticipation of likely difficulties in weaning prednisolone.
He remains under close follow-up to monitor prednisolone weaning. He currently has not had any recurrence of his symptoms.

Key learning points
GCA can present in an atypical manner and should remain a differential in cases of unexplained headache with associated inflammation. A combination of INO and third nerve palsy is an atypical manifestation of this condition.
Due to the nature of his presentation, our gentleman was seen by various specialties including the acute-medical team, rheumatologists and neurologists. Fortunately, a probable diagnosis of GCA was made early and appropriate treatment was initiated. However as this case demonstrates, response to treatment can vary and such adjustments were made to accommodate for this, potentially preventing long term disability.

Conflicts of interest
The authors have declared no conflicts of interest.