Ep 156 – Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, primarily affecting the median nerve at the level of the wrist. The condition results from compression of the median nerve within the carpal tunnel, leading to sensory and motor impairments in the affected hand. There are a range of causes for the condition, and treatments range from simple conservative measures to surgery. In this episode, Dr Roger Henderson looks at how to recognise the condition, some of the clinical and diagnostic tests available, when to refer to secondary care and management options including both surgical and non-surgical measures.

Key take-home points

• CTS is the most common entrapment neuropathy, primarily affecting the median nerve at the level of the wrist.
• The condition results from compression of the median nerve within the carpal tunnel, leading to sensory and motor impairments in the affected hand.
• The peak age of onset is around the late 50s for women and the late 70s for men, and among younger individuals there is a higher prevalence in females than males, with a female-to-male ratio of about 3:1.
• Risk factors include gender, inflammatory conditions, obesity, pregnancy, diabetes and hypertension.
• CTS is characterised by sensations of tingling, numbness or pain affecting the areas supplied by the median nerve, which typically include the thumb, index finger, middle finger and the palm-side half of the ring finger.
• Pain is often worse at night and causes waking with the patient hanging the affected hand out of the bed to try to ease symptoms. It is also worsened by prolonged wrist flexion activities such as typing, driving or holding a phone.
• Weakness may be noted in both the hand grip and when opposing the thumb, due to involvement of the abductor pollicis brevis and opponens pollicis muscles.
• If there is any doubt about the diagnosis, nerve conduction studies should be undertaken. Electroneurography is usually now the gold-standard investigation for CTS.
• Patients with a clinical diagnosis of CTS who have not had confirmation by investigations should be managed conservatively.
• If further treatment is required, patients should be referred for electroneurography to classify the severity of CTS and guide management.
• Untreated CTS can spontaneously improve in up to one-third of patients.
• Refer the patient if uncertain about the diagnosis, or when treatments have failed to work after 3 months. Refer patients with severe symptoms, especially if there is motor weakness of the thumb or persistent sensory or motor disturbance.
• Conservative options include wrist splinting, steroid injections, hand therapy and ultrasound.
• Carpal tunnel release surgery is indicated for severe cases with motor weakness, muscle atrophy or failed conservative management.
• Up to 90% of mild-to-moderate CTS cases respond well to conservative management measures, although some degree of recurrence is seen in one in three patients within 5 years, even after surgical treatment.

Key references

1. Osiak K, et al. Folia Morphol (Warsz). 81(4):851-862. doi: 10.5603/FM.a2021.0121.
2. Karjalainen TV, et al. Cochrane Database Syst Rev. 2023;2(2):CD010003. doi: 10.1002/14651858.CD010003.pub2.
3. Ashworth NL, et al. Cochrane Database Syst Rev. 2023;2(2):CD015148. doi: 10.1002/14651858.CD015148.
4. Schäfer L, et al. Life (Basel). 2022;12(4):533. doi: 10.3390/life12040533.
5. Mende K, et al. J Pers Med. 2023;13(4):610. doi: 10.3390/jpm13040610.
6. Currie KB, et al. JAMA 2022;327(24):2434-2445. doi: 10.1001/jama.2022.8481.
7. von Bergen TN, et al. Hand (N Y). 2023;18(1_suppl):100S-105S. doi: 10.1177/15589447221085700.