Hypothenar hammer syndrome: case report and review

Hypothenar hammer syndrome is a rare vascular overuse syndrome characterized by post-traumatic vascular insufficiency of the hand from repetitive compression over the hypothenar eminence. Patients with occupations predisposing to repetitive use of the hypothenar eminence as a tool are at high risk. Repetitive trauma compresses a superficial segment of the ulnar artery against the hook of hamate as it exits Guyon's canal, damaging the intimal layer of the artery and causing vasospasm, platelet aggregation, and thrombus formation, leading to pain and paresthesias that eventually progress to claudication and ischemia.

The main objectives of this case report are to describe a representative example of hypothenar hammer syndrome and review common aspects of this clinical entity.

We describe the case of a 71-year-old man working as a car mechanic who presented with right-hand pain of several months' duration that was noted to have swelling and pain over the hypothenar eminence with associated paresthesias of the fifth digit. Duplex ultrasound imaging confirmed the presence of a dilated ulnar artery with arterial thrombus characteristic of hypothenar hammer syndrome. Conservative treatment, including cessation of activities that utilize the hypothenar region, was instituted with improvement in symptoms on follow-up evaluation.

This case report illustrates a rare clinical condition that with prompt and early identification by Emergency Physicians can prevent significant morbidity and progression of disease. The epidemiology, clinical features, and diagnosis are discussed along with a review of the relevant literature regarding available treatment options.