203 - Expanding the Neurostorming Differential: A Case of Acute Disseminated Encephalomyelitis with Paroxysmal Sympathetic Hyperactivity and Impact on Therapy Engagement

Acute disseminated encephalomyelitis (ADEM) is a monophasic, immune-mediated demyelinating disorder characterized by multifocal neurological deficits. Paroxysmal Sympathetic Hyperactivity (PSH), a well-recognized complication of severe traumatic brain injury (TBI), is rarely reported in adult-onset demyelinating syndromes, yet can markedly affect rehabilitation outcomes.

Case Description: A 39-year-old previously independent male presented with encephalopathy, right hemiparesis, and imbalance two weeks following a viral prodrome. Continuous VEEG ruled out epileptiform changes. MRI demonstrated multifocal demyelinating lesions, and he was diagnosed with ADEM with baseline Coma Recovery Scale-Revised (CRS-R) score of 6/23. Despite aggressive immunotherapy (steroids, IVIG, plasma exchange), his course was complicated by persistent encephalopathy, spastic quadriparesis, dysphagia requiring PEG, tracheostomy dependence, and bruxism. During inpatient rehabilitation (IPR), gabapentin, baclofen, and lorazepam were tapered early in an effort to reduce barriers to consciousness assessment and maximize therapy participation. This unmasked recurrent episodes of excessive sympathetic activity consistent with PSH, which limited arousal, impaired therapy tolerance, and exacerbated caregiver distress. A multidisciplinary program addressed autonomic instability through sympatholytic titration, spasticity management, nonverbal communication supports, structured therapy pacing, and family education.

Discussions: This case highlights an underrecognized complication of adult-onset ADEM: PSH. While extensively described in TBI literature, dysautonomia in demyelinating or autoimmune encephalitic syndromes remains poorly characterized. For physiatrists, this represents more than a diagnostic curiosity; it impacts rehabilitation strategy. Failure to recognize PSH risks misattribution to anxiety, pain, or infection, delaying targeted intervention. By broadening the differential for autonomic lability to include ADEM and related conditions, rehabilitation teams can anticipate destabilization during sedation reduction and proactively adapt care plans.

Conclusions: PSH, though classically linked to TBI, can also complicate autoimmune demyelinating syndromes including ADEM. By recognizing it in this broader context, physiatrists can consider a slower wean of sedating medications while closely monitoring exacerbation of PSH.