Mr. P, aged 31 years, is a right-hand-dominant male who was a restrained driver in a motor-vehicle accident that occurred approximately one week prior to his presentation to the orthopedic clinic for follow-up.

The patient stated that during the accident he “jammed” his left ring finger and also forcibly jammed his left hand and wrist into the steering wheel. Mr. P denied hitting his head or losing consciousness.

Since the time of the accident Mr. P had experienced nearly constant numbness and tingling in his hand, which was exacerbated by forward elevation of his shoulder (elevation of the arm) to approximately 90 degrees. He also complained of decreased grip strength as well as intermittent coolness and blanching in his left hand.

Mr. P denied Reynaud disease, carpal tunnel syndrome, or any other significant medical or surgical history. He was employed as a local truck driver and denied a history of repetitive motion injury or use of vibratory tools or equipment.

His symptoms were not exacerbated by sneezing, coughing, or straining, and he said he had no nausea, headache, or visual disturbances. All other review of systems was unremarkable. Mr. P did have a 10-pack-year history of smoking, and consumed alcohol socially. He denied illicit drug use.

1. Physical Exam, X-Rays

No significant erythema, edema, or ecchymosis was appreciated about the left upper extremity compared with the contralateral side. A superficial abrasion was located centrally on the volar aspect of the left wrist. Grip strength was possibly weaker on the left side than on the right side.

The patient demonstrated full active range of motion in all metacarpophalangeal and interphalangeal joints as well as in his wrist, elbow, and shoulder without discomfort—no symptoms of impingement were elicited with active or passive shoulder range of motion. No significant pain was elicited with deep palpation about the hand, wrist, elbow, or shoulder. 

Mr. P had a 2+ radial pulse on his left, with sluggish capillary refill in his distal extremity, compared with the contralateral side. Additionally, the left hand was cooler to the touch compared with the contralateral side. The radial, median, ulnar, and axillary nerves had motor function grossly intact.

The patient did report numbness and tingling with light palpation, affecting his index through small fingers, with an increase in these symptoms in the ulnar distribution. This finding was exacerbated by forward elevation of the shoulder to 90 degrees and above, particularly throughout the ring and small fingers.

Sensation was intact and normal through the thumb. Tinel’s sign of the median nerve was negative, as were Phalen’s test and Spurling’s test.

Radiographs of Mr. P’s left hand and wrist did not reveal any osseous injury. Furthermore, normal alignment of all carpals, metacarpals, and phalanges was appreciated. No imaging of the proximal extremity was obtained initially.

2. Diagnosis

Given the patient’s symptoms, mechanism of injury, and physical-examination findings of an abrasion over the volar wrist, an initial differential diagnosis was acute carpal tunnel syndrome. Any trauma about the wrist can result in swelling, which, in turn, can lead to compression of the median nerve within the flexor retinaculum (carpal tunnel).

Carpal tunnel syndrome did not, however, account for the fact that only a portion of the median nerve sensory distribution was affected, or the fact that the patient’s neurologic symptoms were exacerbated by the elevation of his arm at the shoulder. As a result, pathology of more proximal neurological structures needed to be considered. 

A clinical diagnosis of thoracic outlet syndrome (TOS) was made based on Mr. P’s symptoms and physical-examination findings. While a multitude of imaging studies and provocative maneuvers can aid in the diagnosis of TOS, many of these have low diagnostic sensitivity and specificity and/or are associated with significant costs.

By forming a working diagnosis of TOS based on history and physical-examination findings, we were able to try conservative, low-cost, and noninvasive therapies before moving on to more complex diagnostics and diagnoses.

This article originally appeared on Clinical Advisor