Objective:

We aim to explore a misdiagnosis of comorbid functional stridor in a case of anti-GQ1b antibody syndrome.

Background:

Comorbid neuro-inflammatory and functional neurological disorders are diagnostically challenging, yet misdiagnosis can pose significant harm to patients demanding careful adherence to diagnostic algorithms. Inspiratory stridor and vision loss are potentially critical symptoms necessitating careful neurologic evaluation, for which fewer descriptions of comorbid causes are described in the literature.

Design/Methods:

This is a case report and literature review using PubMed.

Results:

A 27-year-old female presented with one month of progressing inspiratory stridor. It had been previously attributed to progression of her recent diagnosis of multiple sclerosis for which she was prescribed ofatumumab, but did not respond to multiple rounds of high dose methylprednisone. The stridor was accompanied by recurrent bouts of pre-orbital cellulitis. Direct laryngoscopy demonstrated paradoxical inspiratory adduction of her vocal cords coinciding with stridor, and no further localizing inflammatory cause was identified. Her stridor gradually improved with counseling and she has had no radiographic or clinical progression off treatment. On review of her history and evaluation, she had only experienced vision deficits with mild encephalopathy, ataxia, and diplopia six months prior and had multiple red flags arguing against fulfillment of McDonald’s criteria. Rather, she had elevated intrathecal IgG synthesis and cranial nerve enhancement on MRI, and tested positive for GQ1b antibodies. A literature review identified fewer cases of stridor and laryngeal involvement in central neuro-inflammatory syndromes.

Conclusions:

Paradoxical inspiratory vocal cord adduction is characteristic of psychogenic stridor. Prompt recognition via direct laryngoscopy can spare potentially unnecessary investigations and immunosuppression, for which our patient likely experienced opportunistic infections. Carefully localizing symptoms to inflammatory changes and evaluating for red flags within neuroinflammatory diagnostic criteria are important to recognize comorbid functional disease.