High prevalence of wild-type transthyretin deposition in patients with idiopathic carpal tunnel syndrome: a common cause of carpal tunnel syndrome in the elderly

Carpal tunnel syndrome is the most common type of entrapment neuropathy. However, the cause of carpal tunnel syndrome remains unclear in most cases. Senile systemic amyloidosis, induced by wild-type transthyretin deposition, is a prevalent aging-related disorder and often accompanied by carpal tunnel syndrome. In this study, we measured the frequency of unrecognized wild-type transthyretin deposition in patients with idiopathic carpal tunnel syndrome. One hundred twenty-three patients with carpal tunnel syndrome, including 100 idiopathic patients, treated by carpal tunnel release surgery were analyzed. Tenosynovial tissues obtained at surgery were analyzed by Congo red and immunohistochemical staining. If staining for transthyretin was positive, the entire transthyretin gene was analyzed by direct DNA sequencing. We also analyzed tenosynovial tissues from 32 autopsy cases as controls. Thirty-four patients (34.0%) with idiopathic carpal tunnel syndrome showed amyloid deposition in the tenosynovial tissue, and all amyloid showed specific immunolabeling with antitransthyretin antibody. Direct DNA sequencing of the entire transthyretin gene did not reveal any mutations, indicating that all amyloid deposits were derived form wild-type transthyretin. Statistical analysis using logistic regression showed that the prevalence of transthyretin deposition in the idiopathic carpal tunnel syndrome group was significantly higher than that in controls (odds ratio, 15.8; 95% confidence interval, 3.3-5.7), and age and male sex were independent risk factors for transthyretin amyloid deposition. Our results demonstrate that wild-type transthyretin deposition is a common cause of carpal tunnel syndrome in elderly men. It is likely that many patients develop carpal tunnel syndrome as an initial symptom of senile systemic amyloidosis.     

Silent period in carpal tunnel syndrome

The silent period is a misunderstood electrophysiological phenomenon leading to several different hypotheses explaining its electrogenesis. It has been studied by different authors and different methodologies giving a wide variability of results, therefore an exact pattern of its normal values does not exist. This work was undertaken to define the normal morphology and duration of the silent period obtained by supramaximal stimulus of the median nerve, during maximum isometric effort of the abductor pollicis brevis muscle against resistance, using 20 adult volunteers without neurological alterations. The normal median duration was 104.6 milliseconds. The same methodology was applied to 20 hands from 20 patients with carpal tunnel syndrome. The silent period showed many types of morphological alterations, but the major alteration observed was a tendency to temporal elongation. No correlation between the severity of the carpal tunnel syndrome and the silent period alterations were observed.     

Needle electromyography in carpal tunnel syndrome

The role of needle electromyography (EMG) in the routine evaluation of carpal tunnel syndrome (CTS) is not clear. The aim of this study was to determine if needle EMG examination of the thenar muscles could provide useful information in addition to the nerve conduction (NC) studies. Electrophysiologic procedures performed on 84 patients (103 hands) consistent with CTS were reviewed. The median thenar motor NC data were matched with the needle EMG findings in the abductor pollicis brevis (APB) muscle. The severity of the needle EMG findings in the APB muscle correlated well with the severity of the motor NC data. As the thenar compound muscle action potential amplitude decreased and the degree of nerve conduction slowing and block across the wrist increased, there was a corresponding increase in the number of enlarged motor units and decrease in the recruitment pattern in the needle EMG findings. Needle EMG examination confined to the thenar muscles in CTS does not seem to provide any further information when the NC data had already established this diagnosis, and it should not be performed routinely.     

Autosomal dominant carpal tunnel syndrome

Carpal tunnel syndrome is common in adults and is usually sporadic and idiopathic. When carpal tunnel syndrome is inherited, it is often the manifestation of a systemic disease. We report carpal tunnel syndrome in an otherwise healthy woman aged 35 years. Family history reveals that her daughter, her sister and a sister's daughter, an aunt, a first cousin, her father and the paternal grandmother are also affected. The age of onset of the disease in this family was between 9 and 52 years of age. The family in this paper demonstrates an interesting pattern of inheritance with earlier onset of symptoms in subsequent generations, suggestive of anticipation.     

The cutaneous silent period in carpal tunnel syndrome

OBJECTIVES: The cutaneous silent period (CSP), a sustained voluntary contraction following a painful stimulus applied over the appropriate dermatome produces a brief period of electrical silence, may be useful if the routine nerve conduction studies and needle electromyography are insufficient to diagnose entrapment neuropathies. MATERIAL AND METHODS: To investigate whether symptomatic or asymptomatic patients with entrapment neuropathies are differed in terms of CSP, one hundred fifty four hands of 58 patient and 19 controls were studied according to the clinical and electrophysiological findings. RESULTS: CSP latency and duration could be affected in severe forms of entrapment neuropathies. However, even in patients with dysesthetic pain -which lead to the belief that small fibers may be involved-, results of electrophysiological evaluation could not support the clinical findings. CONCLUSION: In this study it was suggested that CSP studies provide no additional information in entrapment neuropathies.     

微移技术在腕管综合征中的应用价值

目的：探讨微移技术（inching）在腕管综合征（CTS）中的应用价值。方法：对符合临床诊断标准的41例CTS患者和32例正常对照者,均进行微移技术、常规法及比较法的神经传导检测,比较三者对诊断CTS的敏感性及特异性。结果：微移技术检测显示CTS组在腕下2cm至腕下3cm节段的正中神经潜伏期差值显著长于对照组,并且检测的敏感性最高（92．7％）,明显高于常规法及比较法（除外正中／尺神经环指－腕末端感觉潜伏期差）,阳性预测值及阴性预测值均大于90％,具有较高的诊断价值。结论：微移技术检测是一个敏感、安全、简便、实用的方法,对CTS的诊断、定位及治疗方式的选择均有重要意义。     

MR imaging and electrophysiological evaluation in carpal tunnel syndrome

The objective of this study was to compare the MRI findings of wrists in patients diagnosed with CTS with those of the healthy controls, and to evaluate the correlation between the MRI differences and the electrophysiological findings in the patient group. This study involved 55 wrists, 30 of which were clinically and electrophysiologically diagnosed with CTS and 25 healthy controls. These 55 wrists were evaluated electrophysiologically, and in terms of median nerve diameter, ratio of median nerve diameter at psiform bone level to distal radio-ulnar joint level, the flexor retinaculum bulging ratio and the median nerve intensity by MRI. When the patient group, which were clinically and electrophysiologically diagnosed with CTS, and the healthy control group were compared, a significant difference (p < 0.001) was observed between the two in terms of median nerve diameters (at psiform bone level: 8.47 +/- 1.41mm and 2.91 +/- 1.01 mm, distal radio-ulnar joint level: 4.04 +/- 1.06 mm and 2.42 +/- 0.95 mm), ratio of median nerve diameter at psiform bone level to distal radio-ulnar joint level (2.17 +/- 0.54 and 1.25 +/- 0.12), their flexor retinaculum bulging ratios (26.21 +/- 5.98% and 7.27 +/- 4.53%) and their median nerve intensities. In the patient group, no significant correlation between MRI and the electrophysiological findings was found (p > 0.05). According to the data obtained from the study, we believe that the MRI examination of structural changes that occur in the carpal tunnel, neighboring structures and the median nerve would be useful in the diagnosis of CTS, especially in cases with suspected clinical and electrophysiological diagnosis.     

Refractory studies in early detection of carpal tunnel syndrome

We studied refractory periods of the median sensory nerves in 10 patients with mild carpal tunnel syndrome (CTS), and compared them with the median sensory refractory studies on normal subjects. Our data showed that relative refractory period (RRP) studies are useful in diagnosing early CTS.     

Chemical heterogeneity of amyloid in the carpal tunnel syndrome

Summary 140 biopsies from 108 patients afflicted with the carpal tunnel syndrome were studied, 27 of whom showed deposition of amyloid, in 6 of them to such an extent that the amyloid was considered significant in the pathogenesis of the carpal tunnel syndrome. Morphologically, vessels and ligaments were affected and especially the peritendinous structures. As it was always part of generalized amyloidosis, the amyloid in the carpal tunnel consisted immunohistologically of amyloid A in three cases (including one case with simultaneous amyloid deposition of the AA- and the AB-type), of amyloid A in one case, of amyloid of prealbumin origin in seventeen cases and of AB-amyloid in eight cases. We also described for the first time the manifestation of generalized senile amyloidosis (ASs) in the carpal tunnel. Deposition of amyloid of-2-microglobulin type (AB) in the carpal tunnel was particularly frequent and massive.This paper presents a part of the doctor thesis of K. Stein     

Acute carpal tunnel syndrome due to filarial infection

A case of acute carpal tunnel syndrome (CTS) due to filarial infection is reported in a resident of Newfoundland, Canada. The patient presented with classical symptoms and signs of acute CTS and a filarial worm was identified in synovial tissue removed during surgery that was morphologically consistent with the genus Brugia. Antifilarial antibodies were present in serum. Surgical removal of the infected tissue, without administration of antifilarial drugs, proved adequate in eradicating the infection and a subsequent serum sample was negative for antifilarial antibodies. The patient remains asymptomatic more than two years after surgery. This case is unusual in its clinical presentation and geographic location.     

Age and the severity of carpal tunnel syndrome

Several studies have shown an increased incidence of Carpal Tunnel Syndrome (CTS) with increasing age, as well as a longer Median sensory latency in older CTS patients. In this study, data was analyzed from 19 patients with bilaterally normal UE EMG/NCS and no symptoms of CTS (38 hands), as well as 18 patients with unilateral CTS and 21 with bilateral CTS (60 hands) to determine the effect of age on the severity of nerve conduction abnormalities associated with CTS. Most of these parameters showed increasing severity with age. Median motor latency rises sharply with age (r = .41, p = .001), and amplitude falls (r = .34, p = .008). Median sensory rises significantly with age in CTS patients (r = .42, p = .001) and amplitude falls (r = .29, p = .022). Furthermore, the (Median-Ulnar) motor and sensory latency differences both rise with age (r = .40, p = .001, and r = .35, p = .004 respectively). This is crucial, for an increase in Median motor or sensory latency with age could represent a similar degree of pathologic slowing superimposed on normally slower conduction with age. However, the sharp rise in the (Median-Ulnar) latency differences (from 2.2 msecs at age 40 to 3.8 msecs at age 70 for motor, and 1.6 msecs to 2.5 msecs for sensory) shows that the compression is more severe with age.     

α-硫辛酸联合甲钴胺治疗腕管综合征疗效电生理学观察

目的:探讨α-硫辛酸在腕管综合征(CTS)治疗中的作用.方法:72例CTS患者随机分为两组:对照组:给予甲钴胺+维生素B1治疗;硫辛酸组:在给予甲钴胺+维生素B1的同时联合应用α-硫辛酸治疗.于治疗前后行神经电生理检查,评价治疗效果.结果:硫辛酸组总有效率为91％,优于对照组(有效率为70％).两组经治疗后感觉神经传导速度、感觉神经动作电位波幅均有提高,但硫辛酸组感觉神经传导速度提高更明显.两组对复合肌动作电位波幅改变均不明显.结论:CTS早期应用甲钴胺联合α-硫辛酸能起到更好的治疗效果.