Initial neuro-ophthalmological manifestations in Churg-Strauss syndrome

Abstract

Churg-Strauss syndrome (CSS) is a systemic vasculitis with frequent respiratory tract involvement. It can also affect the nervous system, notably the optic tract. The present work reports the case of a 65-year-old man diagnosed as having CSS in the context of several acute onset neurological symptoms including muscle weakness and signs of temporal arteritis, including bilateral anterior ischaemic optic neuropathy (ON). Electroretinograms (ERGs) and visual evoked potentials (VEPs) were performed. Flash ERGs were normal whereas VEPs were highly abnormal, showing a dramatic voltage reduction, thus confirming the ON. The vision outcome was poor. Ophthalmological presentations of CSS have rarely been reported, but no previous case of sudden blindness documented by combined ERG and VEP investigations were found in the literature. The present case strongly suggests that the occurrence of visual loss in the context of systemic inflammation with hypereosinophilia should lead to considering the diagnosis of CSS.

Figure 1

Fluorescein angiography of the right eye (left) and left eye (right) before injection (upper left), and 1 min (upper right), 3 min (lower left) and 6 min (lower right) after injection of fluorescein. Retinal vessels are of normal calibre and aspect. A moderate bilateral papillary oedema (empty arrow) can be seen, with minor haemorrhage in the right eye (solid arrows).

Figure 2

Flash visual evoked potentials (VEPs) and electroretinogram (ERG): ERG responses recorded with an active electrode placed on the inferior eyelid of the stimulated eye and bilateral earlobe reference electrodes are shown in the top and bottom traces. VEPs recorded at the O1 (left) and O2 (right) occipital positions of the 10/20 international electroencephalography (EEG) system, recorded against a mediofrontal reference electrode (Fz) are shown in the two intermediate traces for each eye. ERG and VEPs were recorded simultaneously by averaging monocular responses to 100 full-field white flashes delivered at 1 Hz. Stimulation runs were repeated three times for each eye and responses to each of these runs are superimposed in all traces. Negativity at the active recording electrode is represented by upward deflection. The vertical dotted line represents the upper normal limit (134 ms) of peak III latency in our normative database. Left eye stimulations: the ERG is of normal latency and amplitude showing a and b waves (upper trace), but no reproducible cortical VEPs could be obtained. This is consistent with preserved retinal function and a severe conduction block in the left optical nerve. Right eye stimulations: the ERG is of normal latency and amplitude showing a and b waves (bottom trace). Delayed VEP peaks III and IV can be identified on superimposed traces with an amplitude that is slightly above noise level. Calibration: 2.5 µV for ERG, 5 µV for VEPs.