Bilateral carpal tunnel syndrome: contralateral effect following corticosteroid injection

Background: Carpal tunnel syndrome (CTS) is the most common compressive mononeuropathy and often presents bilaterally. Corticosteroid injections are a standard conservative treatment. Contralateral improvement following unilateral injection has been reported but remains poorly understood. Case presentation: An 81-year-old male with bilateral CTS confirmed by electroneuromyography was administered a single ultrasound-guided corticosteroid injection to the left wrist. At 30-day follow-up, the patient reported complete resolution of symptoms in both hands. At 6 months, he remained asymptomatic and follow-up nerve conduction studies demonstrated bilateral improvement. Conclusion: This case supports the hypothesis that unilateral corticosteroid injection may result in bilateral symptom relief in patients with CTS, possibly mediated by central neural mechanisms. These findings may influence treatment strategies, although further studies are needed to clarify underlying mechanisms and long-term outcomes.