Acute macular neuroretinopathy in a patient with acute coronary syndrome

Abstract

A young man presented with bilateral diminution of vision after acute coronary syndrome. Fundus showed dark wedge-shaped perifoveal lesions in both eyes. Fundus fluorescein angiography and indocyanine angiography were normal. Optical coherence tomography showed characteristic findings of outer nuclear layer thinning and disruption of ellipsoid zone. Optical coherence tomography angiography showed flow voids in deep capillary plexus. A diagnosis of acute macular neuroretinopathy was made. The multimodal imaging findings and pathophysiology of such a scenario are presented.

Background

Acute macular neuroretinopathy (AMN) has been reported previously in the setting of systemic shock and is bilateral in 55% of such cases. However, AMN following acute coronary syndrome with ventricular tachycardia has not been reported.

Case presentation

A 22-year-old young man presented 6 weeks after diminution of vision in both eyes (Oculus Uterque (OU)) following acute coronary syndrome due to ventricular tachycardia. He had been stabilised acutely with direct current cardioversion and was managed medically after that. Best corrected visual acuity (BCVA) was 20/80 and anterior segment was unremarkable OU. Dilated fundus revealed OU dark wedge-shaped lesions (figure 1A, B), which were better visualised on blue and infrared reflectance (figure 1C–E).

Figure 1.

Colour fundus photograph of right (A) and left eye (B) showing dark wedge-shaped lesions surrounding the fovea. These are better appreciated on blue reflectance (C, D) and infrared reflectance (E, F).

Swept-source optical coherence tomography (SS-OCT) showed outer nuclear layer (ONL) thinning and disruption of ellipsoid zone (EZ) OU (arrows, figure 2A, B). SS-OCT angiography (SS-OCTA) revealed normal superficial plexus (figure 2C, D) and flow voids in deep capillary plexus (arrows, figure 2E, F). Fluorescein and indocyanine green angiography were normal (figure 3A–D). Microperimetry revealed dense scotomas in the affected areas (figure 3E, F). A diagnosis of resolved AMN was made and patient was apprised of the situation.

Figure 2.

Optical coherence tomography shows attenuation of ellipsoid zone in the right (arrows, A) and the left eye (arrows, B). Optical coherence tomography angiography (OCTA) of superficial plexus is normal (C, D). Flow void areas are seen on deep plexus on OCTA (arrows, E, F).

Figure 3.

Fundus fluorescein angiography (A, B) and indocyanine green angiography (C, D) are normal in both eyes. Microperimetry shows dense scotomas in the affected areas (black dots, E, F).

Investigations

SS-OCT showed ONL thinning and disruption of EZ OU (arrows, figure 2A, B). SS-OCTA revealed normal superficial plexus (figure 2C, D) and flow voids in deep capillary plexus (arrows, figure 2E, F). Fluorescein and indocyanine green angiography were normal (figure 3A–D). Microperimetry revealed dense scotomas in the affected areas (figure 3E, F).

Differential diagnosis

The condition can be easily mistaken as posterior ischaemic optic neuropathy.

Outcome and follow-up

BCVA in our patient improved spontaneously but did not recover completely. This could be due to large lesions that involved almost whole of macula.

AMN is a rare entity caused by insult to deep retinal capillary plexus and choriocapillaris.^{1 2} Diagnosis of AMN is confirmed by OCT, which shows hyper-reflective bands in outer plexiform layer and ONL in acute stages and attenuation of ONL and EZ after resolution.³ It is likely that our patient had prolonged hypotension due to cardiogenic shock, which may have lead to hypoperfusion of deep capillary plexus. BCVA in our patient improved spontaneously but did not recover completely. This could be due to large lesions that involved almost whole of macula.

AMN has been reported previously in the setting of systemic shock and is bilateral in 55% of such cases.^{3 4} However, AMN following acute coronary syndrome with ventricular tachycardia has not been reported.

To conclude, subtle changes of resolved AMN can be missed in the absence of high index of suspicion and multimodal imaging. The condition can be easily mistaken as posterior ischaemic optic neuropathy.

Patient’s perspective.

I was able to understand the underlying pathology better when explained with the help of multimodal imaging.

Learning points.

1. Acute macular neuroretinopathy (AMN) is a rare disease and can be missed easily in the absence of high index of suspicion and multimodal imaging comprising infrared imaging, optical coherence tomography (OCT) and OCT angiography.

2. A proper systemic history should be elicited in a suspected case of AMN causing hypotension/shock.

3. There is no specific treatment for this disease and proper counselling of the patient is required about the course of the disease. Usually, the symptoms resolve spontaneously with time.