Symptoms of Carpal Tunnel Syndrome
– Numbness and tingling in the thumb, index finger, middle finger, and the thumb side of the ring finger
– Symptoms are typically most troublesome at night
– Pain without tingling is not characteristic of carpal tunnel syndrome
– The numbness can be described as painful
– Untreated carpal tunnel syndrome can cause loss of sensibility, weakness, and muscle shrinkage
Risk Factors for Carpal Tunnel Syndrome
– Genetics is the strongest risk factor for carpal tunnel syndrome
– Work-related factors such as vibration, wrist extension or flexion, hand force, and repetition increase the risk
– Other conditions like wrist fracture or rheumatoid arthritis can also cause carpal tunnel syndrome
– After wrist fracture, swelling, bleeding, and deformity can compress the median nerve
– Rheumatoid arthritis can cause compression due to the enlarged synovial lining of the tendons
Diagnosis and Treatment of Carpal Tunnel Syndrome
– Diagnosis can be made based on characteristic symptoms and signs
– Electrodiagnostic tests can be used to measure carpal tunnel syndrome
– Wearing a wrist splint can help reduce symptoms and awakenings at night
– Corticosteroid injections may or may not alleviate symptoms better than simulated injections
– Surgery to cut the transverse carpal ligament is the only known disease-modifying treatment
Anatomy and Pathophysiology of Carpal Tunnel Syndrome
– The carpal tunnel is an anatomical compartment located at the base of the palm
– Nine flexor tendons and the median nerve pass through the carpal tunnel
– The median nerve provides sensation to the thumb, index finger, long finger, and half of the ring finger
– The carpal tunnel is bordered by the carpal bones and the flexor retinaculum
– Increased pressure in the carpal tunnel can squeeze the median nerve
– Prolonged pressure can lead to physiological changes in the nerve, including breakdown of the blood-nerve barrier and edema formation
– Continued compression can result in demyelination and axon damage, leading to sensory symptoms and muscle weakness
– The critical pressure necessary to disrupt the blood supply of a nerve depends on diastolic/systolic blood pressure and can be affected by wrist movement/position.
Epidemiology and Other Factors of Carpal Tunnel Syndrome
– Carpal tunnel syndrome (CTS) affects one out of ten people during their lifetime.
– CTS is the most common nerve compression syndrome.
– Prevalence of CTS varies based on how it is defined and whether people are seeking care.
– Population-based studies show no relationship between CTS and gender.
– Prevalence of CTS increases with age.
– Most cases of CTS have an unknown cause, referred to as idiopathic median neuropathy at the carpal tunnel (IMNCT).
– Genetic factors are believed to be the most important determinants of developing CTS due to IMNCT.
– A genome-wide association study identified 50 genomic loci significantly associated with CTS.
– Factors that may contribute to symptoms, but have not been experimentally associated with neuropathy, include obesity and diabetes mellitus.
– Obesity is associated with a higher likelihood of being diagnosed with CTS.
– Chronic compression is a major cause of CTS, but there may be other causes.
– The theory of nerve scarring suggests that adherence between the mesoneurium and epineureum prevents nerve gliding during wrist/finger movements, causing repetitive traction injuries.
– The double crush syndrome proposes that compression at two separate points (e.g., neck and wrist) impairs normal nerve function.
– These alternative theories describe different forms of nerve entrapment.
– Their speculative nature requires further research to establish their validity. Source: https://en.wikipedia.org/wiki/Carpal_tunnel_syndrome
This article may be too technical for most readers to understand. (July 2022) |
Carpal tunnel syndrome (CTS) is the collection of symptoms and signs associated with median neuropathy at the carpal tunnel. Most CTS is related to idiopathic compression of the median nerve as it travels through the wrist at the carpal tunnel (IMNCT). Idiopathic means that there is no other disease process contributing to pressure on the nerve. As with most structural issues, it occurs in both hands, and the strongest risk factor is genetics.
| Carpal tunnel syndrome | |
|---|---|
 | |
| Untreated carpal tunnel syndrome, showing shrinkage (atrophy) of the muscles at the base of the thumb. | |
| Specialty | Orthopedic surgery, plastic surgery, neurology |
| Symptoms | Numbness, tingling in the thumb, index, middle finger, and half of ring finger. |
| Causes | Compression of the median nerve at the carpal tunnel |
| Risk factors | Genetics, work tasks |
| Diagnostic method | Based on symptoms, physical examinations, electrodiagnostic tests |
| Differential diagnosis | Peripheral neuropathy, Radiculopathy, Plexopathy |
| Prevention | None |
| Treatment | Wrist splint, corticosteroid injections, surgery |
| Frequency | 5–10% |
Other conditions can cause CTS such as wrist fracture or rheumatoid arthritis. After fracture, swelling, bleeding, and deformity compress the median nerve. With rheumatoid arthritis, the enlarged synovial lining of the tendons causes compression.
The main symptoms are numbness and tingling in the thumb, index finger, middle finger and the thumb side of the ring finger. People often report pain, but pain without tingling is not characteristic of IMNCT. Rather, the numbness can be so intense that it is described as painful.
Symptoms are typically most troublesome at night. Many people sleep with their wrists bent, and the ensuing symptoms may lead to awakening. Untreated, and over years to decades, IMNCT causes loss of sensibility and weakness and shrinkage (atrophy) of the muscles at the base of the thumb.
Work-related factors such as vibration, wrist extension or flexion, hand force, and repetition increase the risk of developing CTS. The only certain risk factor for IMNCT is genetics. All other risk factors are open to debate. It is important to consider IMNCT separately from CTS in diseases such as rheumatoid arthritis.
Diagnosis of IMNCT can be made with a high probability based on characteristic symptoms and signs. IMNCT can be measured with electrodiagnostic tests.
People wake less often at night if they wear a wrist splint. Injection of corticosteroids may or may not alleviate better than simulated (placebo) injections. There is no evidence that corticosteroid injection alters the natural history of the disease, which seems to be a gradual progression of neuropathy.
Surgery to cut the transverse carpal ligament is the only known disease modifying treatment.
