Anti-NMDA Receptor Encephalitis — Paroxysmal Sympathetic Hyperactivity (PSH) — Clinical Pathway: Inpatient

Anti-NMDA Receptor Encephalitis Clinical Pathway — Inpatient

Paroxysmal Sympathetic Hyperactivity (PSH)

PSH most frequently occurs soon after an acute brain injury and has been observed in children and adults with anti-NMDARE. Core clinical features of PSH include tachycardia, hypertension, tachypnea, central fever, diaphoresis, and/or increased muscle tone with possible dystonic posturing. Episodes have a rapid onset and are changes in core vital signs and clinical features that occur simultaneously for multiple days. They are most often triggered by noxious stimulation, such as acute pain, suctioning, loud noises, repositioning, urinary retention, increased tone, acute illness, but they can also occur without apparent trigger.

The term PSH was established as the standard by a consensus committee in 2014. Nomenclature to describe this constellation of cardiovascular and physical symptoms has varied over time and includes over 30 historical terms such as “dysautonomia”, “sympathetic storm”, and “autonomic storming”.

Non-pharmacologic Management

PSH can be triggered by a variety of interventions as listed above. Many of the contributing factors can be managed or avoided by prevention and treatment strategies. Some strategies include:

  • Avoidance of noxious stimuli
    • Clustering care when able/appropriate
    • Control light and noise in the child's room
    • Daily review of need for tubes/lines
  • Continued evaluation of child's environment for noxious stimuli (e.g., diaper change, IV infiltrate, laying on lines or cords, irritation by clothing)
  • Use of appropriate preventative strategies when triggering therapies are indicated
  • Identification and appropriate treatment and/or prevention of urinary retention and constipation
  • Involvement of Child Life, PT/OT

Pharmacologic Management

The below management and dosing strategies are not validated and come from one group’s experience in one tertiary medical center.

There is no standard of care for pharmacologic intervention for PSH. The choice of medications must be tailored based on child-specific vital signs, clinical status, and clinical effects. Therapies should always be evaluated for drug-disease contraindications, drug-drug interactions, and clinical effects. For ongoing management, please work with the primary service, clinical pharmacy, and PM&R.

Medications

PSH Symptom Targeted Baclofen Benzodiazepines Bromocriptine Clonidine Dantrolene Dexmedetomidine* Gabapentin Opioids Propranolol
Agitation   Yes   Yes   Yes Yes Yes Yes
Hypertension       Yes   Yes   Yes Yes
Tachycardia       Yes   Yes   Yes Yes
Diaphoresis     Yes       Yes    
Hyperthermia     Yes   Yes   Yes   Yes
Hypertonia Yes Yes Yes Yes Yes   Yes    
Tachypnea               Yes  
Abortive Therapy of Acute Episodic Symptoms   Yes   Yes   Yes   Yes  
Maintenance/Prophylaxis Yes Yes Yes Yes Yes Yes Yes Yes Yes
*Dexmedetomidine is restricted to children located in an intensive care unit (ICU)

Therapy De-escalation

Many of these pharmacotherapies require a wean prior to discontinuation. Please work with clinical pharmacy and/or the managing service to determine an appropriate plan for therapy de-escalation.

References