Will the Real Neurologic Injury Please Stand Up? A Case Report

Case Diagnosis: Neurogenic Thoracic Outlet Syndrome (NTOS)

Case Description or Program Description: A 37-year-old female was referred to pain clinic following hospitalization for atraumatic, sudden onset weakness with inability to lift the left arm and associated pain and voice fatigue. She reported that for the past 3 years she had experienced waxing and waning numbness and tingling in the lateral forearm and thumb. She was treated conservatively for cervical radiculopathy and carpal tunnel syndrome with physical therapy, cervical traction, and bracing, providing minimal relief. MRI showed minimal surrounding edema of the scalenes, asymmetrical left increased T2 signal of C5 and C6 nerves, and no cervical ribs. Electromyogram (EMG) demonstrated C5-6 radiculopathy. Infection and neoplastic processes were ruled out. Ultrasound-guided anterior scalene trigger point injection was ordered and physical therapy was recommended.

Setting: Outpatient Pain Clinic

Assessment/Results: Intraprocedural ultrasound evaluation showed severely enlarged C5-6 nerve roots between the anterior and middle scalene muscles. Patient’s strength, range of motion, vocal symptoms, and pain improved dramatically after scalene injection of local anesthetic and triamcinolone. Physical and occupational therapies changed strategies to treat thoracic outlet syndrome and her symptoms have begun to improve. The patient is scheduled for a surgical resection of her first rib.

Discussion (relevance): NTOS can be a debilitating disease when left untreated. The average time from symptom onset to diagnosis specific consultation for NTOS has been estimated at 77.8 months. This is likely related to the inconsistent specificity and sensitivity data associated with diagnostic testing on ultrasound, angiography, venous dopplers and EMG as well as its vague presentation, often mimicking radiculopathy or mononeuropathy symptoms. Finding more consistent ways to correctly and quickly diagnose NTOS has the potential to improve patient outcomes and reduce suffering.

Conclusions: Ultrasound evaluation and local anesthetic and corticosteroid injection to the anterior scalene may be useful tools in helping diagnose thoracic outlet syndrome and warrants further study.