Sudden-onset Blindness from a Spontaneous Carotid-cavernous Fistula with Secondary Central Retinal Artery Occlusion and Posterior Ischemic Optic Neuropathy

Unilateral Optic Nerve Diffusion Restriction After Sinus Surgery Secondary to Central Retinal Artery Occlusion: Case Report and Literature Review

INTRODUCTION

Permanent perioperative vision loss is caused by ischemic optic neuropathy (ION) or central retinal artery occlusion (CRAO). Whereas diffusion restriction of the optic nerve (ON) on brain magnetic resonance imaging has been previously reported in perioperative posterior ION (PION), there are no reports of ON diffusion restriction in patients diagnosed with acute perioperative CRAO. We present a case of perioperative CRAO to highlight this neuroimaging finding for neuroradiologists and neurologists.

CASE REPORT

A 71-year-old male without vascular risk factors underwent maxillary bilateral antrostomy and septoplasty for chronic sinusitis. Twenty to thirty minutes upon awakening, he complained of painless left eye vision loss. Ophthalmoscopic examination showed retinal whitening, segmented arterioles, and hyperemic disc. Brain MR-diffusion weighted imaging/apparent diffusion coefficient revealed ON diffusion restriction in the proximal segment. Despite attempted reperfusion, left eye remained with no light perception at 6 months. Patients undergoing nonocular surgeries who develop perioperative vision loss related to PION may exhibit ON diffusion restriction but usually have normal ophthalmoscopic findings. CRAO shows retinal whitening, edema, segmentation of arterioles, and cherry red spot on ophthalmoscopy. A recent study reported that ON diffusion restriction in nonperioperative CRAO cases has a sensitivity and specificity of 55% and 70% to 100%. Here, PION was initially considered based on imaging. However, given the neuro-ophthalmic findings, a proximal embolus in the central retinal artery, obstructing its entrance into the proximal ON was deemed more likely.

CONCLUSION

We highlight that proximal ON diffusion restriction on brain magnetic resonance imaging can be diagnostic of proximal thromboembolic CRAO. Future studies should evaluate the diagnostic utility and accuracy of MR-diffusion weighted imaging/apparent diffusion coefficient in perioperative visual loss.

Optic neuropathy associated with acute pancreatitis: A case report

The present article describes a case of a 24-year-old patient who suffered from acute pancreatitis. The patient simultaneously developed visual acuity loss and changes in the visual field. When examined, the finding was physiological, including the fundoscopy. Neither fluorescein angiography or optical coherence tomography demonstrated any retinal abnormalities; electroretinography was physiological as well. The visual evoked potentials (VEP) showed abnormalities in amplitudes. Patient's visual field was reduced to 40˚. The follow-up examination 13 months after the first symptoms proved a progression of changes in the visual field and prolonged latency of P100 peak in VEP. The retinal nerve fibre layer stayed unchanged, but the vessel density on the optic nerve head decreased. Magnetic resonance brain imaging showed non-specific subcortical and paraventricular focuses in the white matter of both hemispheres. There were no other abnormalities detected by magnetic resonance imaging. Neurological examination was normal. In conclusion, the present study verified this decrease of visual functions as a lesion in the visual pathway using VEP, which was also confirmed by magnetic resonance brain imaging.

Spontaneous direct carotid-cavernous fistula with acute visual loss in an elderly patient: case report and review of the literature

Carotid-cavernous fistulas are acquired vascular lesions, representing abnormal connections caused by a direct shunt or dural branches of the internal carotid artery and/or the external carotid artery connected to the cavernous sinus. We present an interesting, rare case of a spontaneous fistula with acute vision loss in an older patient. The patient was diagnosed with a direct carotid-cavernous fistula based on the clinical and radiological findings. We concluded that early diagnosis and etiological treatment could improve the prognosis of this type of carotid-cavernous fistula.

Diagnosis of ischemic optic neuropathy caused by dissection of the internal carotid artery: A case report

RATIONALE

Ischemic optic neuropathy (ION), due to diseases of the arteries supplying the optic nerve, is an ischemic damage of the optic nerve. This report highlights a case with monocular decreasing visual acuity caused by dissection of the internal carotid artery (ICA), which is a relatively rare cause for ION.

PATIENT CONCERNS

A 44-year-old woman presented with a decreasing visual acuity and defected visual field in the right eye for 1 week. The best corrected visual acuity (BCVA) was 20/400 in the right eye, and 20/20 in the left eye. In the right eye, the pupil showed little reaction to light with a relative afferent pupillary defect. The visual field test disclosed a defect in the inferior field connecting to the blind spot. Electroretinogram recording showed no obviously declined retinal function. No recognizable waveforms were presented in pattern visual-evoked potential (PVEP) examination, whereas the flash visual-evoked potential result revealed a delayed peak time and a reduced amplitude of P2-wave.

DIAGNOSIS

The patient was diagnosed as ION with the aid of computed tomographic angiography of the brain and neck, which revealed a stenosis in the right ICA and an occlusion in the right cerebral middle artery. The stenosis was verified as dissection of the ICA by digital subtraction angiography.

INTERVENTIONS

Based on the clinical findings, stent implantation inside the right ICA was performed.

OUTCOMES

The ICA was recanalized soon and the BCVA of the right eye was improved to be 20/25 five months later. A second PVEP examination revealed a recognizable waveform in the right eye, although the peak time and amplitude of the P100-wave was a bit abnormal compared to that of the left eye.

LESSONS

ION with the sign of decreasing monocular visual acuity could occur due to dissection of the ICA, with no obvious neurologic symptom at the beginning. The present case emphasizes the importance of suspicion of ICA problems as the underlying cause for ION, which could help to take in-time measure to save the vision and avoid further complications.