Obstetric Management of a Novel Superimposition of Facial Onset Sensory and Motor Neuronopathy on Parsonage Turner Syndrome

Abstract

Parsonage-Turner syndrome (PTS) is a rare neurologic disorder characterized by pain and weakness in the distribution of the brachial plexus. In severe cases, the phrenic nerve may be involved resulting in hemidiaphragm paralysis. Facial onset sensory and motor neuronopathy (FOSMN) is another rare disease that typically progresses slowly, with facial paresthesias preceding the onset of bulbar symptoms. A lack of corneal reflex is pathognomonic for FOSMN. This case is regarding a 35-year-old G7P1051 with known multi-episodic PTS involving the phrenic nerve that had been successfully managed for several years with intravenous immunoglobulin (IVIG) therapy. She presented at 28 weeks gestational age for an acute PTS flare with left upper extremity pain and weakness, and dyspnea. She received IVIG therapy with improvement of her symptoms and was discharged. She returned the day after discharge with left upper extremity paralysis, dysarthria, facial allodynia, and worsening dyspnea and dysphagia. After further evaluation by the Neurology, she received an additional diagnosis of FOSMN, a condition with limited treatment options. Despite aggressive immunotherapy, her dyspnea worsened, and she developed anarthria, trismus, and aphagia. She was delivered at 31 weeks gestational age due to continued clinical deterioration. By postpartum day 4, her dyspnea and dysphagia were resolved, and her speech was markedly improved. This is the first report of FOSMN onset in pregnancy, superimposition on PTS, and symptom abatement after delivery. This report is unique because it discusses management for conditions for which there are no formal neurologic or obstetric society guidelines on management in pregnancy. Our report highlights that in gravid individuals with maternal disease processes managed with immunotherapy, consideration should be given to the possibility that placental physiology may render previously effective immunotherapy less effective or ineffective during pregnancy.

J Clin Gynecol Obstet. 2023;12(3):88-92
doi: https://doi.org/10.14740/jcgo909