People with systemic sclerosis (SSc) are at higher risk for degeneration of a main wrist nerve, a study suggests.
Although for many people this condition might be asymptomatic, early detection can help prevent further deterioration and problems with hand and finger movement.
The study, “Median neuropathy at the wrist in patients with systemic sclerosis: two-year follow-up study,” was published in the journal Reumatologia/Rheumatology.
SSc is an autoimmune disorder characterized by the excessive accumulation of collagen, commonly leading to skin thickening and internal organ scarring. Increased tightness of the skin around the wrist joint can compress the median nerve and lead to median neuropathy at the wrist (MNW) — the most common condition of peripheral nerve damage. The prevalence of this neuropathy is much higher among SSc patients compared with the general population.
To date, only one previous study, from Thailand, had evaluated the prevalence and presentation of this neuropathy among SSc patients. Now, researchers conducted a new study to have a better understanding of its prevalence.
The study included 50 patients (mean age 53 years) who had been diagnosed with SSc for about 10 years and were attending the scleroderma clinic in Srinagarind Hospital. The majority of the participants (72%) had diffuse cutaneous SSc, and most had common SSc-associated symptoms, such as Raynaud’s phenomenon, skin tightness, and hand deformity.
All patients answered questionnaires, underwent physical examination, and were assessed using an electrodiagnostic (EDX) test, which evaluates the function/responsiveness of muscles and nerves at baseline and after two years.
Results from the Boston questionnaire — which rates the severity of carpal tunnel syndrome (a condition that results from the compression of the median nerve in the wrist, at the carpal tunnel) — showed that 74% of participants had a lower severity of MNW, and 48% had a lower degree of difficulty in hand functioning.
In addition, 18% of patients had MNW-related symptoms such as weakness and numbness of the muscle that controls the thumb along the median nerve distribution.
Analysis of wrist nerve responsiveness before and after the two-year period revealed that MNW manifestations remained stable, with most patients with mild MNW remaining asymptomatic. Still, the frequencies of mild, moderate, and severe MNW were 28%, 22%, and 6% after two years. The number of patients with moderate or severe MNW increased from 10 to 14 within two years, with eight of those symptomatic after two years.
Researchers found that the EDX test results were mainly constant between baseline and two years later. Only 12 of 50 patients (24%) had a worse EDX result at the two-year mark.
The team did not find an association between MNW occurrence and SSc clinical parameters.
“The present study confirms that MNW commonly occurred in SSc patients. Therefore, SSc patients should be followed up in both clinical and EDX studies for MNW screening,” the researchers stated.
The team also noted that “SSc patients with asymptomatic MNW might need clinical follow-up for early diagnosis.”