Antiseizure medications and thyroid hormone homeostasis: Literature review and practical recommendations.

Thyroid hormones play an essential role in central nervous system development, normal physiological brain function, and repair mechanisms. On one hand, thyroid hormone alterations influence cortical excitability, and on the other hand antiseizure medications (ASMs) are associated with alterations in thyroid hormone metabolism. Although this interaction has long been described, and epilepsy is a common and chronic neurological disease, studies describing the interplay are often small and retrospective. We performed a systematic review of the current literature on epilepsy, ASMs, and thyroid hormone metabolism according to PRISMA guidelines. Forty-seven studies were included. Most studies were retrospective cross-sectional studies (n = 25) and investigated thyroid function alterations in patients on older ASMs such as phenobarbital, phenytoin, carbamazepine, and valproate. Overall, almost one third of patients with epilepsy had thyroid hormone alterations, especially patients on valproate (25%) and carbamazepine (10%-25%). Studies with patients receiving polytherapy are scarce, but reported a higher risk for hypothyroidism in patients with older age (p = .004), female sex (p = .014), longer duration of epilepsy (p = .001), intractable epilepsy (p = .009), and polytherapy. Studies on newer ASMs are also limited, and further studies on an interplay with thyroid hormone homeostasis are essential to improve the care for epilepsy patients. ASMs are associated with alterations in thyroid hormone metabolism. Thyroid function monitoring is indicated in patients on ASMs, especially those with refractory epilepsy and those on polytherapy. We provide a practical guidance for thyroid function monitoring for the clinician taking care of patients on ASMs.

Susac syndrome complicating a SARS-CoV-2 infection.

In 2020 the world was captivated by the COVID-19 pandemic. Current scientific evidence suggests an interaction of SARS-CoV-2 and the human immune system. Multiple cases were reported of patients with COVID-19 presenting with encephalopathy, confusion or agitation, stroke, and other neurologic symptoms. We present a case of a 40-year-old man diagnosed with Susac syndrome after COVID-19, presenting with acute sensorineural hearing loss, encephalopathy, a splenial "snowball-like" lesion, and branch retinal artery occlusions with distal arterial wall hyperintensity. Although the pathophysiology of Susac syndrome remains unclear, this case is in line with the ongoing debate about the influence of SARS-CoV-2 on the human immune system. Corticosteroid treatment was initiated, followed by two treatments with rituximab, with clinical improvement of the symptomatology. Maintenance treatment currently consists of mycophenolic acid (MPA). Future research will need to focus on the underlying mechanisms for COVID-19-associated (autoimmune) complications.

Two siblings with Heimler syndrome caused by PEX1 variants: follow-up of ophthalmologic findings.

BACKGROUND: Heimler syndrome (OMIM number #234580 and #616617) is a rare condition comprising sensorineural hearing loss (SNHL), nail abnormalities and amelogenesis imperfecta. In addition, patients with this syndrome can have retinal dystrophies. Heimler syndrome is caused by bi-allelic pathogenic variants in the PEX1 or PEX6 gene. Only few patients with this syndrome have been reported. We hereby describe two siblings with genetically confirmed Heimler syndrome and provide imaging of the ocular phenotype. MATERIALS AND METHODS: The medical records of the siblings were reviewed retrospectively. RESULTS: Both brother and sister were diagnosed with SNHL and amelogenesis imperfecta of the permanent teeth; one of the affected siblings also had nail abnormalities. Both patients presented to the ophthalmology department with suboptimal visual acuity, fundus abnormalities and intraretinal cystoid spaces. Full-field electroretinogram revealed a cone-rod dysfunction. A genetic analysis revealed a homozygous likely pathogenic variant c.3077 T > C (p.Leu1026Pro) in the PEX1 gene in both siblings. The parents are heterozygous carriers of the variant. CONCLUSION: We recommend performing regular ophthalmic examination in patients with Heimler syndrome since the ophthalmic manifestations can manifest later in life. Our patients presented with cone-rod dystrophy and intraretinal cystoid spaces. Review of the literature shows that the ocular phenotype can be very variable in patients with Heimler syndrome.