Pharyngeal-Cervical-Brachial Variant of Guillain-Barré Syndrome: A Rare SARS-CoV-2 Infection-Associated Neurological Complication.

To the Editor: Guillain–Barré Syndrome (GBS) as a neurological complication of SARS-CoV-2 infection has been reported in children [1, 2]. Pharyngeal–cervical–brachial (PCB) variant is one of the rare variants characterized by muscle weakness extending from the oropharyngeal and neck area to proximal upper extremities. Though there are isolated case reports of PCB variant in children [3], its association with SARS-CoV-2 infection has not been described previously.

A 17-y-old boy presented with progressive weakness of bilateral upper limbs, change in voice, nasal regurgitation of feeds for the past 10 d. He had high-grade fever with cough 1 wk before the onset of illness. Examination revealed dysarthria, nasal intonation of voice with absent gag reflex. Bilateral upper limbs had power of 2/5 with absent deep-tendon reflexes and the lower limbs had power 4/5, reflexes 1+. There was weakness of flexors of the neck, but no diaphragmatic muscle or sensory involvement.

RT-PCR for SARS-CoV-2 was positive. Examination of cerebrospinal fluid (CSF) revealed albuminocytological dissociation. MRI of the brain and cervical spine were normal. Nerve-conduction study (NCS) was suggestive of motor and sensory axonal polyneuropathy. A diagnosis of PCB variant of GBS was formulated. The child was administered intravenous immunoglobulin (2 g/kg over 5 d) along with supportive and rehabilitative care. The weakness plateaued and started improving in the follow-up.

The hypothesized theories behind pathogenesis of GBS secondary to virus include formation of autoantibodies or direct neurotoxic effects of virus. The most common antibodies identified in PCB variant include GT1a antibodies with their receptors concentrated in peripheral nerves innervating oropharyngeal and cervicobrachial musculature [4].

A thorough clinical evaluation, supported by the CSF examination and NCS, helps in arriving at the diagnosis and excluding a differential diagnosis like intracranial space occupying lesion, postdiphtheritic polyneuropathy, and botulism. Early recognition of this variant is imperative in order to avoid unnecessary investigations and inappropriate treatment.