Foster Kennedy Syndrome: A Case Report

Foster Kennedy Syndrome is a classic, yet rare, neuro-ophthalmologic syndrome due to an intracranial mass, most often a tumor, that consists of optic atrophy on the same side of the lesion and contralateral papilledema. We present the case of a 48-year-old female patient with decreased visual acuity and the typical clinical features described above due to a sphenoid wing meningioma. Although not a common condition, Foster Kennedy Syndrome should always be kept in mind in a patient with visual disturbances secondary to an intracranial mass.

Mitochondrial Retinopathies

The retina is an exquisite target for defects of oxidative phosphorylation (OXPHOS) associated with mitochondrial impairment. Retinal involvement occurs in two ways, retinal dystrophy (retinitis pigmentosa) and subacute or chronic optic atrophy, which are the most common clinical entities. Both can present as isolated or virtually exclusive conditions, or as part of more complex, frequently multisystem syndromes. In most cases, mutations of mtDNA have been found in association with mitochondrial retinopathy. The main genetic abnormalities of mtDNA include mutations associated with neurogenic muscle weakness, ataxia and retinitis pigmentosa (NARP) sometimes with earlier onset and increased severity (maternally inherited Leigh syndrome, MILS), single large-scale deletions determining Kearns–Sayre syndrome (KSS, of which retinal dystrophy is a cardinal symptom), and mutations, particularly in mtDNA-encoded ND genes, associated with Leber hereditary optic neuropathy (LHON). However, mutations in nuclear genes can also cause mitochondrial retinopathy, including autosomal recessive phenocopies of LHON, and slowly progressive optic atrophy caused by dominant or, more rarely, recessive, mutations in the fusion/mitochondrial shaping protein OPA1, encoded by a nuclear gene on chromosome 3q29.

Idiopathic intracranial hypertension leading to bilateral optic atrophy in a patient with recent COVID-19 infection: a case report

Neurologic complications are common in patients hospitalised with COVID-19 infection. Most common complications are myalgias, headaches, encephalopathy and dizziness. Uncommon complications are stroke, motor and sensory deficits, seizures, ataxia and movement disorders. Multiple neuro-ophthalmological manifestations have also been reported in association with COVID-19. These complications may be the result of a range of pathophysiological mechanisms like hypoxic neuronal injury during active COVID-19 infection, RAS dysfunction, immune dysfunction and direct injury by the virus etc throughout the course of the disease. Here we reported a case of neuro-ophthalmic complication of Idiopathic intracranial hypertension (IIH) followed by bilateral optic atrophy in a middle-aged man with recent COVID-19 infection. He presented to the emergency with complaints of headache, dizziness and sudden painless bilateral diminution of vision for 3 days. His fundus examination was suggestive of bilateral papilledema, his MRI brain was normal and opening pressure of CSF was raised on lumbar puncture. His MRV was normal, there was no evidence of CSVT. He was started on steroids and acetazolamide. His headache improved but there was no improvement in visual acuity. Repeat fundus showed pale disc and MRI orbit was suggestive of bilateral optic atrophy.

Mitochondrial OPA1 deficiency causes reversible defects in adult neurogenesis-associated spatial memory in mice

Mitochondria are integrative hubs central to cellular adaptive pathways. Such pathways are critical in highly differentiated post-mitotic neurons, the plasticity of which sustains brain function. Consequently, defects in mitochondrial dynamics and quality control appear instrumental in neurodegenerative diseases and may also participate in cognitive impairments. To directly test this hypothesis, we analyzed cognitive performances in a mouse mitochondria-based disease model, due to haploinsufficiency in the mitochondrial optic-atrophy-type-1 (OPA1) protein. While in Dominant Optic Atrophy (DOA) models, the known main symptoms are late onset visual deficits, we discovered early impairments in hippocampus-dependent spatial memory attributable to defects in adult neurogenesis. Moreover, less connected hippocampal adult-born neurons showed a decrease in mitochondrial content. Remarkably, modulating mitochondrial function through voluntary exercise or pharmacological treatment restored spatial memory. Altogether, our study identifies a crucial role for OPA1-dependent mitochondrial functions in adult neurogenesis, and thus in hippocampal-dependent cognitive functions. More generally, our findings show that adult neurogenesis is highly sensitive to mild mitochondrial defects, generating impairments in spatial memory that can be detected at an early stage and counterbalanced by physical exercise and pharmacological targeting of mitochondrial dynamics. Thus, early amplification of mitochondrial function appears beneficial for late-onset neurodegenerative diseases.