Carpal tunnel syndrome. First manifestation of systemic lupus erythematosus

Carpal tunnel syndrome related to rheumatic disease (Review)

Carpal tunnel syndrome (CTS) is the most commonly occurring type of entrapment neuropathy in the world. Several conditions may contribute to the development of CTS, such as obesity, repetitive wrist movements, pregnancy, genetic predisposition and rheumatoid arthritis (RA) inflammation. CTS is characterized by a wide range of pathophysiological factors, including increased pressure, mechanical trauma and ischemic damage to the median nerve that runs through the wrist tunnel. In the present narrative literature review, the way rheumatic diseases (RDs) contribute to CTS occurrence is investigated. The epidemiological, clinical, paraclinical and pathogenesis aspects of the relationship are examined. CTS is the most common neurological finding in RA, and incidences of RA, psoriatic arthritis and CTS are closely related. The association of CTS with systemic lupus erythematosus, Sjögren's syndrome, Behcet's disease and systemic sclerosis is weaker. In these cases, the prevalence of CTS is similar to that in the general population. As the occurrence of CTS is increasing, understanding the common mechanism and making an early diagnosis are required to limit pain and costs. When patients with RD present with symptoms such as wrist pain, tingling sensations or numbness in their fingers, CTS should be suspected. This suspicion should not be interpreted in terms of RD. To accurately evaluate patients with RD, a detailed electrophysiological examination should be included in the evaluation process. A diagnostic algorithm should include neuromuscular ultrasound or magnetic resonance imaging for patients with RD.

Collagen gel contraction as a measure of fibroblast function in carpal tunnel syndrome

Noninflammatory subsynovial connective tissue (SSCT) fibrosis with nerve compression is a prominent feature of carpal tunnel syndrome (CTS). Studies have shown that SSCT matrix synthesis and material property changes in CTS are associated with increased activity of transforming growth factor (TGF)-β1. The aim of this study were to (1) investigate the ability of SSCT fibroblasts from CTS patients and unaffected individuals to contract a collagen gel ring and (2) determine how the addition of TGF-β1 affects this ability. SSCT fibroblasts from three normal cadavers and three age-matched female patients who had undergone surgery for CTS were used. Results showed patient cell-seeded gels had a significantly higher contraction rate (p < 0.001) than control cells, and fully contracted gel rings possessed a significantly higher tensile strength (p = 0.003) and stiffness (p < 0.001). Furthermore, TGF-β1 significantly intensified contraction rate (p < 0.001), tensile strength (p < 0.001), and stiffness (p < 0.001). In conclusion, SSCT cells from normal donors and CTS patients contract collagen gel rings differently, and this ability is affected by TGF-β1 treatment. This cell-seeded collagen gel model may be useful for developing new methods of stopping or eliminating the effect of TGF-β1 on the SSCT fibroblasts and surrounding matrix, which might aid in the identification of medical treatment for CTS.

Permeability of the subsynovial connective tissue in the human carpal tunnel: a cadaver study

BACKGROUND

The purpose of this study was to determine the permeability of the normal carpal tunnel subsynovial connective tissue.

METHODS

Subsynovial connective tissue samples (10mm(2)) were obtained from 10 fresh frozen human cadavers without a history of carpal tunnel syndrome. The thickness of the sample was measured using a charge-coupled device laser displacement system. Each specimen was tested for permeability in a closed pressure chamber at 13.8, 41.3, 68.9 and 96.5 kPa.

FINDINGS

Since permeated flow was very low in all specimens, the permeability could be calculated only for eight specimens at 96.5 kPa pressure and for three specimens at 68.9 kPa. The mean permeability at 96.5 kPa was mean 0.89 (SD 0.93)x10(-14)m(4)/Ns and at 68.9 kPa was mean 1.04 (SD 1.54)x10(-14)m(4)/Ns.

INTERPRETATION

The subsynovial connective tissue is the most characteristic tissue in the carpal tunnel; it is found in no other location in such abundance. It is well known that carpal tunnel syndrome is the result of increased pressure within the carpal tunnel. This lack of permeability in the subsynovial connective tissue may explain the predisposition of this region for pressure buildup and subsequent neuropathy.