Recurrent Isolated Sixth Nerve Palsy in Childhood—Review on a Rare Phenomenon

Sixth nerve palsy is an ominous sign in pediatric neurology. Due to the long and tortuous course of the sixth (abducens) nerve, it is generally considered a sign of intracranial pathology. Sixth nerve palsy is associated with increased intracranial pressure and neoplasms, among other less frequent causes. In ∼5 to 15% of cases, no cause can be identified. These cases are classified as idiopathic or “benign” and recovery is typically complete. A recurrence of symptoms is very rare. We provide a rare case report of recurrent benign sixth nerve palsy in a 5-year-old child. In addition, we provide an overview of all earlier published cases of recurrent isolated sixth nerve palsy. To date, only 72 pediatric patients with recurrent isolated sixth nerve palsy have been reported. Young females with left-sided sixth nerve palsy and recent immunization are at risk of recurrence. Pathophysiological mechanisms have been discussed, but have yet to be clarified. Recurrent isolated sixth nerve palsy is only rarely associated with severe causes and the need for extensive investigation may be questioned.

Medial rectus disinsertion for management of chronic complete sixth nerve palsy

Purpose To report the outcomes of the medial rectus (MR) disinsertion procedure for the management of refractory esotropia (ET) with or without Abnormal head posture (AHP) in chronic complete sixth nerve palsy. Methods This is a retrospective case series of patients with sixth nerve palsy who suffered from residual ET and diplopia following the conventional strabismus surgeries and underwent MR disinsertion procedure between April 2017 and February 2020. This procedure was offered to the patients who declined to use prism and did not wish to perform surgery on the fellow eye. The demographic and clinical data, including sex, age, visual acuity, pre and postoperative angle of strabismus, duction limitations, results of forced duction and force generation tests, details of prior strabismus surgeries, orbital CT scan findings, and follow up duration were collected from the medical records. Results Six patients were enrolled in this study. Mean age was 35.0 ± 14.0 years, and mean follow-up was 15.3 ± 5.9 months. The ET at the Primary position (PP) was 35.0 ± 18.4 prism dioptre (PD) before MR disinsertion, which decreased to 14.2 ± 17.4 PD after MR disinsertion procedure. Four cases needed additional complementary surgeries to improve residual ET in PP. No case developed overcorrection. Abduction deficiency was −5.0 ± 1.3 before MR disinsertion, which improved to − 2.8 ± 0.5 units at last follow-up. The mean of induced adduction deficiency was − 2.9 ± 0.4 at last follow-up. Conclusions MR disinsertion can be considered in patients with chronic complete sixth nerve palsy and refractory diplopia when the conventional methods have failed.

Case Report: Unilateral Sixth Cranial Nerve Palsy Associated With COVID-19 in a 2-year-old Child

Children have been described to show neurological symptoms in acute coronavirus disease 2019 (COVID-19) and multisystemic inflammatory syndrome in children (MIS-C). We present a 2-year-old boy's clinical course of unilateral acute sixth nerve palsy in the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Onset of the palsy in the otherwise healthy boy occurred seven days after symptoms attributed to acute infection had subsided respectively 3 weeks after onset of respiratory symptoms. SARS-CoV-2 specific IgG was detected in serum as well as in cerebrospinal fluid. The patient showed a prolonged but self-limiting course with a full recovery after three and a half months. This case illustrates in a detailed chronological sequence that sixth cranial nerve involvement may occur as post-infectious, self-limiting complication of pediatric SARS-CoV-2-infection thus expanding the neurological spectrum of symptoms for children with COVID-19. Clinicians should be aware of the possibility of post-infectious sixth nerve palsy related to SARS-CoV-2-infection particularly in view of recent respiratory tract infection or confirmed cases of SARS-CoV-2-infection amongst the patient's close contacts.

Sixth Nerve Palsy in Children Etiology, Long-Term Course, and a Diagnostic Algorithm

Background Acute onset strabismus is worrisome for parents and physicians. This condition is sometimes attributed to sixth cranial nerve palsy, which may be secondary to various etiologies. Debate still exists about the appropriate diagnostic approach. Objective The objective of this study was to describe the common etiologies of sixth nerve palsy in our pediatric population and to suggest a clear, implementable diagnostic algorithm. Methods The authors conducted an electronic medical review of files of patients admitted to the pediatric department at Emek Medical Center between January 2014 and April 2020. They reviewed the medical records from the study period of patients with the following diagnoses according to the International Classification of Diseases 9: sixth nerve palsy, acute infective polyneuritis, Guillain-Barré syndrome, benign intracranial hypertension, malignant neoplasm of the brain, strabismus, myasthenia gravis, and multiple sclerosis. The authors extracted information regarding clinical presentation, previous history, and diagnostic work-up, including serological testing, cerebrospinal fluid testing, and neuroimaging. Final diagnosis and clinical follow-up were assessed. Results Seventeen patients with sixth nerve palsy were identified. The most common etiologies were increased intracranial hypertension and anti-GQ1B syndrome (3 patients each). Conclusions This is a retrospective study of patients diagnosed in one medical center. The suggested algorithm was not validated on a prospective study. The etiologies of sixth nerve palsy in children are variable. The authors suggest performing neuroimaging in all patients and considering serum and cerebrospinal fluid testing in selected patients. Initial neuroimaging combined with laboratory testing is useful and provides rational tools for proper diagnosis.

Longitudinal extensive transverse myelitis with sixth nerve palsy post ChAdOx1 nCov-19 vaccine: A case report and literature review

Concurrently with the quick development of COVID-19 vaccines globally, concerns about vaccination efficacy and safety are rising. Neurological complications such as transverse myelitis (TM) are major worries because they can cause lifelong disabilities, which may require long term care. Here, we report a case of longitudinal extensive transverse myelitis (LETM), with sixth nerve palsy in a young female occurring shortly after ChAdOx1 nCov-19 vaccine. The patient recalled developing strabismus, progressive ascending bilateral lower limb weakness, along with upper extremity paresthesia, abnormal sensation below T6 dermatomes, and difficulty in urination. She presented to the hospital with complete paralysis below the neck associated with urinary retention. Extensive diagnostic studies were performed to rule out alternative etiologies, including but not limited to demyelinating diseases, para-post infectious agents, paraneoplastic syndromes, tumors, and autoimmune diseases. She was treated with corticosteroids and discharged upon clinical improvement. However, the patient clinically deteriorated and intravenous immunoglobulin was administered. Unfortunately, the patient is still suffering from physical impairment. We suggested that LETM could be induced by an autoimmune process triggered molecule mimicry. In conclusion, safety monitoring of the COVID-19 vaccines is of great importance in the post marketing surveillance, particularly for rare adverse events.