Rare case of Bilateral Disc Edema Masquerade reported in JAMA

Case:

A 58-year-old man with a history of hypertensive retinopathy presented with acute onset, painless vision loss in his right eye accompanied by tinnitus and severe intermittent headaches. His extraocular movements were full, and he had no other neurologic deficits.

His visual acuity was 20/400 OD and 20/30 OS, respectively, and his fundi were notable for bilateral optic nerve edema. Results of recent computed tomography and angiography of the head and neck and magnetic resonance imaging of the brain and orbits were reportedly normal, and lumbar puncture revealed an opening pressure of 26 cmH2O (normal range, 6 to 25 cm H2O) with elevated protein.

The patient was given acetazolamide and referred to neuro-ophthalmology. On examination by neuro-ophthalmology 4 months later, his visual acuity was 20/50 OD and 20/20 OS. He had an afferent pupillary defect in the righteye, and Humphrey visual fields (24-2) showed binasal inferior defects with a superior defect in the right eye that was considered an artifact of testing.

According to the Ishihara color plates test, color vision was full in both eyes. Fundus examination was remarkable for pallor of both optic nerves, more notably in the right eye, without edema. Findings of screening for antinuclear antibodies, antineutrophil cytoplasmic antibodies, angiotensin-converting enzyme, Bartonella, HIV, tuberculosis (Quantiferon), Treponema pallidum, erythrocyte sedimentation rate, C-reactive protein, and a complete blood cell count were normal.

Patient was diagnosed as Primary angiitis of the central nervous system by repeated lumbar puncture with serologies.

Bilateral disc edema, transient vision loss, and elevated opening pressure on lumbar puncture are suggestive of intracranial hypertension, which may be idiopathic intracranial hypertension or secondary to a mass-occupying lesion, dural venous sinus thrombosis, or another underlying disease, including anemia, Addison disease, or systemic lupus erythematosus.

While tighter blood pressure control would be helpful in hypertensive retinopathy, elevated blood pressure medications do not mitigate elevated intracranial pressure. With negative laboratory findings for autoimmune or inflammatory disease, there was no indication to start high-dose corticosteroids.

The patient had persistent visual field deficits despite acetazolamide use, which requires further investigation beyond monitoring with serial testing. A repeated lumbar puncture revealed an opening pressure of 18 cm H2O, an IgG level of 6.6 mg/dL, and 4 oligoclonal bands (normal range, 0 to 1). Throughout this workup, the patient began to develop new neurological symptoms, including persistent left cranial nerve V numbness, paresthesia, fatigue, cold intolerance, throbbing headache, and bradyphrenia (ie, slowing of cognition).

A repeated brain magnetic resonance imaging and magnetic resonance venogram of the head showed no evidence of venous sinus thrombosis but identified multifocal enhancing and nonenhancing signal abnormalities of the brain at the calloso septal interface, juxtacortical regions, basal ganglia, and brainstem. In light of these findings and given the cerebrospinal fluid serology results, the patient was urgently referred for neuroinflammatory evaluation. A few weeks later, the patient was hospitalized after developing sudden onset confusion. During his hospitalization, an extensive workup of serum and cerebrospinal fluid studies for infectious, autoimmune, and demyelinating diseases was performed. Within the context of this patient's clinical course, a brain biopsy that showed histopathologic features suspicious for vasculitis helped determine the diagnosis. Primary angiitis of the central nervous system (PACNS) is a rare idiopathic disorder characterized by vasculitis confined to the brain and spinal cord. The clinical spectrum of PACNS remains poorly understood given its diverse and nonspecific clinical manifestations. Headache is the most common symptom, occurring in roughly 60% of patients. Ocular abnormalities occur in 41% of cases, including visual-field defect (18%), diplopia (14%), blurred vision or decreased visual acuity (11%), and papilledema (4.3%).

Diagnosing PACNS frequently involves a combination of clinical findings: an unexplained neurological deficit, laboratory workup that rules out secondary causes of central nervous system vasculitis, imaging findings, and/or histopathologic features of vasculitis on brain biopsy.

Treatment of PACNS includes induction therapy of high-dose glucocorticoids and cyclophosphamide with periodic reassessment of neurologic symptoms and neuroimaging for treatment response. Maintenance therapy with a corticosteroid-sparing immunosuppressive agent, such as azathioprine, is typically started after 4 to 6 months. Favorable response to treatment is reportedly greater than 80%.

The patient's cognitive function showed remarkable improvement following induction of glucocorticoids in combination with cyclophosphamide at 7-month follow-up.

Source: Alex Pai; Steven Carter; Lilangi S. Ediriwickrema; JAMA Ophthalmology Clinical Challenge

doi:10.1001/jamaophthalmol.2021.0096