1526 - Medial Brachial Fascial Compartment Syndrome: An Unusual Cause of Median and Ulnar Neuropathy

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Co-Author(s)

FI

Franchesca M. Inay, BS

Medical Student
University of Pittsburgh School of Medicine
Pittsburgh, Pennsylvania, United States

Presenting Author(s)

DR

Dilan Rivedi, B.S

Medical student
Kansas City University
Edgewater, New Jersey, United States

Co-Author(s)

CC

Clay Coppinger, DO

Resident Physician
Montefiore/Einstein
Yonkers, New York, United States

Corresponding Author(s)

AW

Aye Mon Win, DO

Medical Director of Inpatient Rehabilitation
Montefiore Medical Center
Bronx, New York, United States

Submitter(s)

FI

Franchesca M. Inay, BS

University of Pittsburgh School of Medicine
Pittsburgh, Pennsylvania, United States

Case Diagnosis: Median and ulnar neuropathy secondary to medial brachial fascial compartment syndrome (MBFCS)

Case Description: A 58-year-old woman with vanishing bile duct syndrome awoke from liver transplantation surgery with acute left-hand pain, numbness, and weakness. Doppler ultrasound showed a small pseudoaneurysm in the left brachial artery at the site of an intraoperative arterial line. Repair was deferred due to the presence of intact distal pulses. On postoperative day six, vascular surgery repaired the pseudoaneurysm and identified a hematoma within the medial brachial compartment, which was subsequently evacuated. The patient presented to the outpatient rehabilitation clinic six months later with persistent symptoms. Examination revealed atrophy in the left thenar and first dorsal interosseous muscle, index finger contractures, and decreased light-touch sensation in the lateral three digits. Electrodiagnostic testing demonstrated absent sensory responses in the left median and ulnar nerves, along with prolonged distal latency and low compound muscle action potential amplitude at the median nerve.

Discussions: Clinical and electrodiagnostic findings were consistent with severe proximal median neuropathy and concomitant ulnar neuropathy. Symptom onset after brachial artery catheterization with pseudoaneurysm and medical compartment hematoma suggests MBFCS as the cause of nerve injury. Although uncommon, MBFCS has been reported to cause permanent hand dysfunction if not recognized and treated promptly. Studies indicate that urgent surgical decompression, ideally within four hours of diagnosis, is needed to minimize persistent deficits. Importantly, preserved distal pulses do not exclude neurologically detrimental compartment syndrome, as pressures sufficient to impair microneural blood supply are far lower than those needed to compromise arterial flow.

Conclusions:
Acute sensorimotor changes to the hand in the setting of arterial line placement warrant evaluation for MBFCS. Timely diagnosis and intervention can minimize permanent disability associated with this condition.