Magnetic resonance imaging features of COVID-19-related cranial nerve lesions.

The complete features of the neurological complications of coronavirus disease 2019 (COVID-19) still need to be elucidated, including associated cranial nerve involvement. In the present study we describe cranial nerve lesions seen in magnetic resonance imaging (MRI) of six cases of confirmed COVID-19, involving the olfactory bulb, optic nerve, abducens nerve, and facial nerve. Cranial nerve involvement was associated with COVID-19, but whether by direct viral invasion or autoimmunity needs to be clarified. The development of neurological symptoms after initial respiratory symptoms and the absence of the virus in the cerebrospinal fluid (CSF) suggest the possibility of autoimmunity.

Delayed diagnosis of lyme neuroborreliosis presenting with abducens neuropathy without intrathecal synthesis of Borrelia antibodies.

Lyme borreliosis is the most common tick-born infection in Europe. Global climate change expanding the range of tick vectors and an increase in the incidence suggest that this disease will remain an important health issue in the forthcoming decades. Lyme borreliosis is a multisystem organ disorder affecting the nervous system in 10% to 15% of cases. Lyme neuroborreliosis can present with any disorder of the central and peripheral nervous systems. The neuro-ophthalmological manifestations are a rare feature of the disease. The intrathecal synthesis of Borrelia burgdorferi antibodies is of diagnostic importance, but in rare cases, immunoglobulins against the Borrelia burgdorferi antigen may not be detected. We report a case of possible Lyme neuroborreliosis presenting with sixth cranial nerve neuropathy at the onset of the disease further developing into typical meningoradiculitis and multiple mononeuropathy. Surprisingly, Borrelia burgdorferi antibodies were not detected in the cerebrospinal fluid.

Isolated abducens nerve palsy as a regional variant of Guillain-Barré syndrome.

The authors reviewed clinical profiles and laboratory findings for 100 cases of abducens nerve paresis without impairment of the other cranial nerves, limb weakness, and ataxia throughout the clinical course. Review of the medical records of 9300 patients referred to our neuoroimmunological laboratory for serum anti-ganglioside antibody testing. Information was obtained from each primary physician on symptoms of preceding infection; initial symptoms; neurological signs during the illness; the clinical course; treatment provided; and outcome. Isolated abducens nerve paresis was present in 100 patients and bilateral paresis in 29. Tentative diagnoses made by the primary physicians on request of anti-ganglioside antibody testing were abducens nerve palsy (n = 68), Fisher syndrome (n = 14), acute ophthalmoparesis without ataxia (n = 14). Symptoms of infection anteceded in 63. Tendon reflexes were absent or decreased in 27. Distal paresthesias were experienced by seven. Serum anti-GQ1b antibody was positive in 25. These findings suggest that some cases of isolated abducens nerve palsy can be categorized as a regional variant of Guillain-Barré syndrome or mild form of Fisher syndrome.