Isolated abducens nerve palsy in a patient with asymptomatic SARS-CoV-2 infection

Isolated Sixth Nerve Palsy and COVID-19: A Recurrent Case in a 7-Month-Old Child and Analysis of Reported Cases

BACKGROUND

With the SARS-CoV-2 pandemic (COVID-19), data on central and peripheral nervous system involvement, including those causing cranial nerve 6 (CN6) palsy, have been limited to case reports. To extract clinically relevant features of COVID-19-related CN6 palsy, we report on a recurrent pediatric case and analysis of reported cases associated with infection or immunization.

METHODS

A PubMed search revealed 18 cases of isolated CN6 palsy in addition to the index case (n = 19). Clinical characteristics, workup, and temporal associations between systemic symptoms onset or vaccination, symptoms onset, and resolution were compiled and analyzed.

RESULTS

The median age of CN6 onset was 43 years (interquartile range [IQR]: 28-52). Sixteen cases (84.2%) were associated with COVID-19 illness and 3 (15.8%) were associated with COVID-19 vaccination. Four cases (23.5%) had positive neuroimaging findings. The median latency from first COVID-19 symptoms or vaccination to onset of CN6 palsy was 6 days (IQR: 2.3-16), and the median time from onset to resolution was 30 days (IQR: 14-60). Latency to onset of CN6 palsy was significantly and directly associated with time to resolution (R 2 = 0.401, P = 0.010). Patients who had a positive SARS-CoV-2 antibody test had significantly longer days from symptoms to onset (6.0 vs 24.5, P = 0.030), and patients with a positive SARS-CoV-2 polymerase chain reaction test had a significantly shorter time to resolution (17.50 vs 90, P = 0.042).

CONCLUSIONS

Isolated CN6 palsy from COVID-19 is rare, can occur in infants as young as 7 months, and can be recurrent. Longer latency from systemic symptoms onset portends greater recovery times, and this relationship may reflect multiple mechanisms by which COVID-19 (and/or an immune response thereto) causes cranial neuropathies with direct clinical relevance.

Abducens Nerve Palsy in a Patient with COVID-19: A Case Report

Numerous neurological manifestations associated with COVID-19 have been reported. However, abducens nerve palsy (ANP) associated with COVID-19 is very rare and mostly related to accompanying respiratory symptoms. Here we present a 29-year-old woman with unilateral ANP manifesting with diplopia and positive SARS-CoV-2 S antibodies, which were checked later. On admission, she had signs of viral pneumonia in thorax CT without any respiratory symptoms. Her cranial neuroimaging revealed no abnormality. Following treatment with favipiravir 2x1600 mg loading dose and then 2x600mg daily maintenance, dexamethasone 8 mg/day and enoxaparin 6000 IU/day, her CT findings recovered completely whereas her ANP only partially resolved. One week after the end of COVID-19 treatment, she also developed Herpes simplex keratitis which was successfully treated with valacyclovir. It should be kept in mind that isolated abducens nerve palsy may be the only finding of COVID-19 cases without any respiratory symptoms.

Abducens Nerve Palsy Due to Neurovascular Compression

BACKGROUND

Neurovascular compression (NVC) as the cause of abducens nerve palsy is an infrequent event. Only a small number of cases have been reported in the literature, and the efficacy of microvascular decompression (MVD) for abducens nerve palsy remains unclear.

METHODS

We reviewed previously reported cases of abducens nerve palsy caused by NVC and added our own cases. We analyzed the clinical characteristics of vascular compression abducens nerve palsy and assessed the indication for MVD.

RESULTS

Twenty-two patients with isolated abducens nerve palsy due to vascular compression were confirmed in total, consisting of 20 patients (19 publications) from the literature search and 2 cases from our experienced cases. All patients had no possible causes for isolated abducens nerve palsy except the NVC on the nerve root. Unlike the sudden onset in the typical abducens nerve palsy, all patients demonstrated gradual development of the symptom in NVC-related abducens palsy. Careful observation was the most common strategy in most patients; however, no noticeable improvement was reported in the conservative treatment. Surgical intervention was performed in 6 patients after observation for several months and showed favorable outcomes in all cases.

CONCLUSIONS

Vascular compression could be a potential cause of abducens nerve palsy. Gradual onset or episodic symptom of abducens palsy with a definitive radiological finding of vascular compression deserves considering MVD for abducens nerve palsy.

COVID-19 and sudden-onset ocular neurogenic palsy in prior healthy patients: a systematic review

BACKGROUND

The aim of this systematic review is to identify cases of neurogenic ocular palsy in the presence of COVID-19 and to document patient characteristics, type of palsy and possible aetiologies.

METHODS

A systematic search of PubMed, Medline and CINAHL databases was conducted on the 6th of January 2023 to identify cases of neurogenic ocular palsy in patients with current or previous COVID-19 infection. Data were pooled to summarise the neurogenic palsy, patient clinical characteristics and proposed palsy mechanisms.

RESULTS

The combined database search yielded 1197 articles. Of these, 23 publications consisting of 25 patients met the inclusion criteria. Most patients were male (68%) and ranged in age from 2 to 71 years (median=32.7, SD=21.4). Seven patients (28%) were children aged 2 to 10 years old. Abducens palsies were most common (68%) and the most common ocular presentation was diplopia (76%) with an average time of onset 15 days from testing positive to COVID-19 or having symptoms of the virus. Proposed mechanism of development of a neurogenic palsy secondary to COVID-19 infection was classified into one of three categories: vascular/thrombotic, a viral neuro-invasive or inflammatory virus-mediated immune response.

DISCUSSION

This study suggests that COVID-19 infection may be linked to oculomotor, trochlear and abducens nerve palsies and the underlying mechanisms may vary but are difficult to definitively establish. Further studies investigating the onset of neurogenic palsy secondary to COVID-19 infection is required.

An eye to the future: Acute and long-term neuro-ophthalmological and neurological complications of COVID-19

COVID-19 has had a significant impact on the global population and has produced compelling evidence of non-pulmonary organ dysfunction, including the nervous system. It is vital that specialists in ophthalmology and neurology are informed of the potential complications of COVID-19 and gain a deeper understanding of how COVID-19 can cause diseases of the nervous system. In this review we detail four possible mechanisms by which COVID-19 infection may result in neurological or neuro-ophthalmological complications: (1) Toxic and metabolic effects of severe pulmonary COVID-19 disease on the neural axis including hypoxia and the systemic hyper-inflammatory state, (2) endothelial dysfunction, (3) dysimmune responses directed again the neuroaxis, and (4) direct neuro-invasion and injury by the virus itself. We explore the pathological evidence for each of these and how they may link to neuro-ophthalmological disorders. Finally, we explore the evidence for long-term neurological and neuro-ophthalmological complications of COVID-19, with a focus on neurodegeneration.

Cranial Nerve Impairment Associated With COVID-19 Infections: A Systematic Review

The COVID-19 pandemic has created huge economic and healthcare burdens. In most cases, the virus affects the lungs and causes respiratory symptoms. Additionally, its impact on the cranial nerves remains unclear. We thus aimed to investigate cranial nerve dysfunction in patients with COVID-19 infection.  We conducted a systematic literature search of relevant and eligible literature in five databases: PubMed, Web of Science, Medline, EBSCO, and Google Scholar.  Our sample included 21 case reports, one case series with 29 patients, and one analytical study with 135 cases. Participant ages ranged from 23 months to 72 years (mean age of 47.5 ± 19.02). The mean time from respiratory symptoms to the onset of neurological signs was (9.6 ± 7.4) days, and the mean recovery time was (16.3 ± 15.3) days.  Cranial nerve impairment associated with COVID-19 infection has affected a large population, from infants to the elderly. Facial and abducent nerves were the most commonly affected cranial nerves with reported good prognosis or complete recovery within a few days to weeks. Olfactory dysfunctions were widely detected among COVID-19 patients.

Efferent neuro-ophthalmic complications of coronavirus disease 2019

PURPOSE OF REVIEW

We set out to describe efferent neuro-ophthalmological complications that have been reported in association with coronavirus disease 2019 (COVID-19) infection. We describe syndromes affecting ocular motility and elaborate on mechanisms of disease, including para-infectious inflammation, hypercoagulability, endothelial damage, and direct neurotropic viral invasion. Despite global vaccination programs, COVID-19 continues to pose an international threat that may rarely result in diplopia or nystagmus.

RECENT FINDINGS

Efferent complications include cranial nerve palsies leading to diplopia, either isolated or in association with Miller Fisher syndrome. Nystagmus has been observed in the setting of hemorrhagic acute necrotizing encephalopathy and brainstem infarcts, and opsoclonus syndrome has been described.

SUMMARY

Observed neuro-ophthalmic associations need to be confirmed through larger comparative studies. Meanwhile, the range of possible complications should be recognized by neurologists and ophthalmologists alike, to facilitate faster diagnosis and treatment of both COVID-19 and its neuro-ophthalmic manifestations.

Diplopia, COVID-19 and Vaccination: Results from a Cross-Sectional Study in Croatia

The aim of this study was to explore diplopia as a symptom of undetected COVID-19 infection or as a possible side effect of COVID-19 vaccination. We examined 380 patients with diplopia admitted to the Department of Ophthalmology of the University Hospital Centre Sestre milosrdnice in Zagreb, Croatia, from July 2020 to June 2022. After excluding patients with confirmed organic underlying diplopia causes or monocular diplopia, we linked the patient information with the national COVID-19 and vaccination registries. Among the 91 patients included in this study, previously undetected COVID-19 infection as the possible cause of diplopia was confirmed in five of them (5.5%). An additional nine patients (9.9%) were vaccinated within one month from the onset of their symptoms, while the remaining 77 had neither and were therefore considered as controls. The breakdown according to the mechanism of diplopia showed no substantial difference between the vaccinated patients and the controls. We detected marginally insignificant excess abducens nerve affection in the COVID-positive group compared with that in the controls (p = 0.051). Post-vaccination diplopia was equally common in patients who received vector-based or RNA-based vaccines (21.4 vs. 16.7%; p = 0.694). COVID-19 testing should be performed for all cases of otherwise unexplained diplopia. The risk of post-vaccination diplopia was similar in both types of vaccines administered, suggesting a lack of evidence linking specific vaccine types to diplopia.

The Immediate Onset of Isolated and Unilateral Abducens Nerve Palsy Associated with COVID-19 Infection: A Case Report and Literature Review

Cranial nerve palsy associated with coronavirus disease 2019 (COVID-19) is rare. We herein report the first Asian case of the immediate onset of isolated and unilateral abducens nerve palsy (ANP) accompanied with COVID-19 infection. A 25-year-old man developed diplopia one day after the COVID-19 symptom onset. Neurological examination revealed limitation of left eye abduction without ataxia and hyporeflexia. Negative anti-ganglioside antibody results and mild albuminocytological dissociation were noted. The patient was diagnosed with left ANP accompanied by COVID-19 infection. The ANP spontaneously recovered without treatment. ANP can develop during the early phase of COVID-19 infection and adversely affect patients' quality of life.