2018 FSA Posters

P041: AUTONOMIC DYSFUNCTION IN MULTIPLE SCLEROSIS PRESENTING AS SEVERE PERIOPERATIVE HEMODYNAMIC INSTABILITY: A CASE REPORT
Gevalin Srisooksai, MD, Basma Mohamed, MD; University of Florida

Introduction: Multiple sclerosis (MS) is an immune-mediated neurodegenerative disease of the central nervous system (CNS) involving inflammation and demyelination of optic nerve, brain, and spinal cord. Anesthetic considerations for MS patients include altered response to neuromuscular blockers, avoidance of hyperthermia, post-operative urinary retention from neurogenic bladder, respiratory impairment, and aspiration precautions. Studies on cardiovascular autonomic dysfunction in MS are generally described in the neurology literature while the anesthesia literature is limited to few case reports. We present a case report of MS patients who underwent general anesthesia and experienced profound hypotension refractory to intravenous fluids and vasopressors.

Case Report: A 53 years old women with history of multiple sclerosis complicated by severe spasticity in bilateral lower extremities was scheduled for intrathecal baclofen pump placement. She was diagnosed with primary progressive MS at age 27 with main symptoms of bilateral leg weakness and gait difficulties. She was initially on interferon beta-1a at time of diagnosis but was discontinued due to incomplete control of disease progression. Her 2015 MRI showed T2 lesions in periventricular and brainstem regions. She has not been on any MS therapy as she had no clinical relapse until 2016, when she developed severe bilateral leg spasticity which rendered her wheelchair-bound. Reported MS-related symptoms included fatigue, diplopia, and memory deficits. She had no known cardiovascular diseases or symptoms. Her preoperative vital signs and labs were within normal limits. However, shortly after uneventful induction and intubation, her blood pressure severely plummeted to MAP of 30s, from baseline in the 90s. There was minimal responses to intravenous fluid boluses and high dosage vasopressors, including phenylephrine, ephedrine, vasopressin, and calcium. We were able to wean off her vasoactive medications towards emergence, and she was extubated and recovered without sequelae.

Discussion: This case report demonstrated possible severe cardiovascular autonomic neuropathy presenting as profound refractory hypotension in the perioperative settings. One mechanism dysautonomia in MS is central lesions which disrupt the pathways regulating autonomic function. Radiologically, cardiovascular autonomic dysfunction has been shown in some studies to be associated with MRI lesions in the brainstem as well as degree of spinal cord atrophy in MS, likely due to interruption in descending autonomic nervous system pathway. The patient had lesions in the brainstem which may in part explain the severe refractory hypotension after induction despite a relatively minor procedure. She also had primary progressive MS (PPMS), a more severely disabling form compared to relapsing-remitting MS (RRMS). Since baclofen pump is relatively low risk and short procedure, many confounding factors for perioperative hypotension such as major blood loss and fluid shifts can be ruled out.

Formal testing for the sympathovagal imbalance such as tilt table test can be a diagnostic challenge. More practical evaluation can include obtaining preoperative orthostatic vital signs and history. One should also consider reviewing MRI lesions in regions associated with autonomic dysfunction, obtaining as well as evaluation of disease progression and degree of physical disability. Review of prior anesthesia records for the individual’s hemodynamic response anesthetics and vasopressors can also provide valuable information.