May 04, 2021
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Man experiences acute unilateral loss of vision

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A 68-year-old man was referred to the New England Eye Center neuro-ophthalmology clinic for evaluation of acute loss of vision in the left eye.

The patient reported that he first noted the loss of vision upon waking up in the morning 6 weeks before this visit. Since that time, there was some progressive worsening of vision. It felt like lace was covering his left eye.

Christine Benador-Shen
Christine Benador-Shen
Malgorzata Dymerska Peterson
Malgorzata Dymerska Peterson

The patient denied any trauma preceding the vision change. He did not have any eye pain, headache, temporal tenderness, jaw claudication, weight loss, joint pain, unexplained fever or chills. His ocular history was notable only for myopia. His medical history included type 2 diabetes, hypertension, hyperlipidemia, gastroesophageal reflux disease and gout. He was previously obese, but his weight normalized after undergoing bariatric surgery 5 years before presentation. His medications included allopurinol, atorvastatin, metformin, liraglutide, insulin glargine, pantoprazole, valsartan, aspirin and calcitriol. He had no known medication allergies. He was a retired rabbi. He last smoked cigarettes more than 50 years ago. He drank alcohol only socially and did not use any drugs. His family history was significant for laryngeal cancer in his mother and kidney cancer in his brother.

Examination

The patient’s corrected visual acuity was 20/20 in the right eye and hand motions only in the left eye. The right pupil was round and reactive to light. The left pupil was round and did not react directly to light, with a relative afferent pupillary defect noted. IOP was 15 mm Hg in the right eye and 16 mm Hg in the left eye. Extraocular motility was full bilaterally. Confrontation visual field was full in the right eye and diffusely limited in the left eye. On external exam, there was no proptosis. Anterior segment exam was notable only for nuclear sclerotic cataracts bilaterally. Posterior segment exam in the right eye was unremarkable, with a pink and healthy optic nerve with a cup-to-disc ratio of 0.5 and no evidence of diabetic retinopathy. The left optic nerve exhibited subtle blurring of the borders, suggestive of mild optic nerve edema, and the cup-to-disc ratio was 0.3 (Figure 1). The vitreous was clear, and the vessels, macula and retinal periphery were within normal limits, with no evidence of diabetic retinopathy.

optic nerve
Figure 1. The right optic nerve was pink and healthy, with no edema. The left optic nerve exhibited slight blurring of the borders, suggestive of mild optic nerve edema.

Source: Malgorzata Dymerska Peterson, MD, and Thomas R. Hedges III, MD

Humphrey visual fields (HVF) 30-2 showed nonspecific defects in the right eye and diffuse depression in the left eye (Figure 2). OCT of the retinal nerve fiber layer (RNFL) of the right eye showed average thickness of 86 µm, whereas the RNFL thickness in the left eye was 127 µm (Figure 3), confirming mild edema of the left optic nerve. OCT of the ganglion cell complex (GCC) of the right eye was within normal limits, whereas the left eye exhibited thinning, worst in the superotemporal region (Figure 4).

HVF 30-2
Figure 2. HVF 30-2 showed nonspecific defects in the right eye and diffuse depression in the left eye.
OCT of the RNFL
Figure 3. OCT of the RNFL of the right eye showed average thickness of 86 µm, whereas the RNFL thickness in the left eye was 127 µm, confirming mild edema of the left optic nerve.
OCT of the GCC
Figure 4. OCT of the GCC of the right eye was within normal limits, whereas the left eye exhibited thinning, worst in the superotemporal region.

What is your diagnosis?

See answer below.

Acute loss of vision

This 68-year-old patient described acute painless loss of vision in the left eye upon waking up in the morning 6 weeks before presentation, with some progression since then. Exam of the left eye at the time of our assessment showed vision of hand motions only, a relative afferent pupillary defect and mild optic nerve edema. Given the patient’s age and comorbidities, including diabetes, hypertension and hyperlipidemia, ischemic optic neuropathy was high on the differential.

The sudden nature of the vision loss, which seemed to occur overnight, was consistent with nonarteritic anterior ischemic optic neuropathy (NAION). Although the classic presentation is an altitudinal field defect, any pattern of visual field loss can be seen. However, NAION typically occurs in patients who have a “disc at risk,” an optic nerve with a small cup-to-disc ratio, which was not evident in our patient. Given the severity of vision loss and the report of some progression after the initial event, arteritic anterior ischemic optic neuropathy (AAION) also had to be considered, even though the patient did not report any systemic symptoms of giant cell arteritis (GCA). Posterior ischemic optic neuropathy was also possible, but it typically occurs in the setting of surgery, hypotension and anemia. Compressive optic neuropathy from an intraorbital or intracranial mass or an optic nerve meningioma was also on the differential, although patients typically note more subacute vision loss with those conditions. Demyelinating optic neuritis was a possibility; however, it typically presents in younger patients and causes pain with extraocular movements. Lastly, infiltrative optic neuropathy, caused by leukemia, metastasis, tuberculosis and sarcoidosis, could also present with findings seen in our patient.

Further workup

The erythrocyte sedimentation rate and C-reactive protein were checked urgently and were both found to be within normal limits. However, given the severe vision loss, the patient was referred for an urgent temporal artery biopsy to exclude GCA as the etiology. This was negative. An MRI of the brain and orbits with and without contrast was arranged concurrently. It showed abnormal enhancement in the left sphenoid sinus and posterior ethmoid air cells, with disruption of the posterior aspect of the left lamina papyracea and extension of the abnormal enhancement into the extraconal space of the medial and superior aspect of the left orbit, directly adjacent to the left optic nerve (Figure 5). An endoscopic biopsy of the mass showed findings consistent with adenocarcinoma of the left ethmoid and sphenoid sinus involving mucosa, fibrous tissue and bone. A PET scan did not show any metastases. The final diagnosis was ethmoid sinus adenocarcinoma locally invasive into the sphenoid sinus, left orbit, skull base and anterior cranial fossa, stage T4bN0M0. Of note, the patient denied any sinusitis symptoms but did have a single episode of infectious sinusitis 40 years ago.

MRI of the orbits
Figure 5. The MRI of the orbits with contrast showed abnormal enhancement in the left sphenoid sinus and posterior ethmoid air cells, with disruption of the posterior aspect of the left lamina papyracea and extension of the abnormal enhancement into the extraconal space of the medial and superior aspect of the left orbit, directly adjacent to the left optic nerve. Axial image of the T1 sequence with fat suppression (a) and coronal image of the T1 sequence with fat suppression (b).

Discussion

Sinonasal cancer is a rare cancer, accounting for approximately 5% of all head and neck malignancies. Most paranasal sinus cancers arise in the maxillary sinus, with the remainder originating mainly in the ethmoid sinus. These cancers are generally more common in men than women. Occupational exposure to substances such as wood and leather dust, glues, formaldehyde, chrome, nickel and compounds used in the textile industry have been shown to be risk factors for development of sinonasal cancer. While cigarette smoking is not as strong a risk factor as in other head and neck cancers, it has been shown to increase the risk as well. Additionally, HPV types 16 and 18 are known risk factors for tumorigenesis of sinonasal cancer.

Patients with sinonasal cancer tend to be asymptomatic or have nonspecific sinonasal symptoms that mimic benign disease. Once the sinus wall is breached, proptosis, diplopia and vision loss can occur. Harbison and colleagues reviewed 42 cases of sphenoid sinus cancer and found that 10 patients had loss of vision on presentation, and four patients had involvement of the optic nerve or the chiasm.

Ischemic optic neuropathy was high on the differential for our patient, given his cardiovascular comorbidities and the self-reported acute nature of his vision loss. With vision loss to the level of hand motions only and diffuse visual field loss, AAION and more specifically GCA have to be expeditiously ruled out in any patient older than 50 years, and corticosteroid treatment should be initiated right away if there is any clinical suspicion for GCA. As this case illustrates, early brain and orbit imaging should also be considered in presentations atypical for NAION.

Course continued

Given extensive local invasion of our patient’s tumor, the option of surgical resection of the tumor was considered too morbid. The patient was instead treated with proton beam radiation therapy and systemic chemotherapy. His most recent restaging scans showed interval decrease in the size of the tumor. His vision has remained stable.