Ultrasound changes of the carpal tunnel in patients receiving long-term hemodialysis: a cross-sectional and longitudinal study

Diagnosis of carpal tunnel syndrome in non-diabetic patients with hemodialysis using ultrasound: Is it a useful adjunctive tool?

OBJECTIVE

(1) To examine the ultrasound (US) characteristics in patients with hemodialysis-related carpal tunnel syndrome (H-CTS) and (2) to evaluate the accuracy of a proposed US parameter-dynamic ratio of median nerve-to-hamate hook distance (RMHD) in diagnosis of H-CTS.

DESIGN

A case-control study.

SETTING

In a tertiary medical center and a secondary hospital from Nov. 2017 to Mar. 2021.

PARTICIPANTS

Consecutive non-diabetes patients under hemodialysis were recruited and divided into a hemodialysis without CTS (H-Control) group and an H-CTS group. Age-matched volunteers without diabetes or upper extremity disorders were enrolled as the Control group.

INTERVENTION

Ultrasound examinations by two operators blinded to the patient's clinical information.

MAIN OUTCOME MEASURES

US parameters including cross-sectional area of the median nerve at the carpal tunnel inlet (CSA-I) and outlet (CSA-O), the flattening ratio of the median nerve at the inlet (FR-I) and outlet (FR-O), and RMHD.

RESULTS

Handedness and arteriovenous fistula showed no associations with CSA-I/O and FR-I/O. Compared with Control group (n=69), the CSA-I was significantly larger in the H-Control group (n=63) and H-CTS group (n=76) (p<0.05). There were no significant differences in the FR-I/-O among the three groups. For the second aim, in the H-CTS group(n=38), there was a significantly lower RMHD compared with both the Control (n=20) and H-Control groups (n=30) (0.1%±2.2% versus 3.5±2.3% and 3.8±1.7%, p<0.05). An RMHD cutoff value of <2.7% yielded a specificity of 80.0%, a sensitivity of 94.7%, and an overall accuracy of 88.2% in the diagnosis of H-CTS.

CONCLUSIONS

Neither CSA-I/-O or FR-I/-O have a role in the diagnosis of H-CTS. RMHD might be a useful US parameter in the diagnosis of CTS in non-diabetic patients undergoing hemodialysis.

Recent Advances in Ultrasound Diagnosis of Carpal Tunnel Syndrome

With the widespread use of high-resolution ultrasonography, ultrasonic examination has been shown to be useful as a diagnostic method for carpal tunnel syndrome. The main advantages of ultrasonography are that it is simple, quick, non-invasive, and economical. Another advantage is that tissue dynamics can be observed with real-time imaging. In recent reports, it has been shown that ultrasonic examination can provide similar diagnostic accuracy as nerve conduction study in the diagnosis of carpal tunnel syndrome. It has been expected that ultrasound demand in daily medical care will continue to increase. Ultrasonography in carpal tunnel syndrome shows an enlarged median nerve in proximal carpal tunnel, thickening of the flexor retinaculum, and edema around flexor tendons in cross-sectional images. In addition, with the introduction of new technologies such as ultrasonic elastography and speckle tracking, it has become possible to quantify dynamics and material property changes of nerves, tendons, and their surrounding structures. In this review, we describe recent advancements of carpal tunnel syndrome diagnosis based on ultrasound dynamic images, and discuss its pathology.

Recent Advances in Ultrasound Diagnosis of Carpal Tunnel Syndrome

With the widespread use of high-resolution ultrasonography, ultrasonic examination has been shown to be useful as a diagnostic method for carpal tunnel syndrome. The main advantages of ultrasonography are that it is simple, quick, non-invasive, and economical. Another advantage is that tissue dynamics can be observed with real-time imaging. In recent reports, it has been shown that ultrasonic examination can provide similar diagnostic accuracy as nerve conduction study in the diagnosis of carpal tunnel syndrome. It has been expected that ultrasound demand in daily medical care will continue to increase. Ultrasonography in carpal tunnel syndrome shows an enlarged median nerve in proximal carpal tunnel, thickening of the flexor retinaculum, and edema around flexor tendons in cross-sectional images. In addition, with the introduction of new technologies such as ultrasonic elastography and speckle tracking, it has become possible to quantify dynamics and material property changes of nerves, tendons, and their surrounding structures. In this review, we describe recent advancements of carpal tunnel syndrome diagnosis based on ultrasound dynamic images, and discuss its pathology.

Recent Advances in Ultrasound Diagnosis of Carpal Tunnel Syndrome

With the widespread use of high-resolution ultrasonography, ultrasonic examination has been shown to be useful as a diagnostic method for carpal tunnel syndrome. The main advantages of ultrasonography are that it is simple, quick, non-invasive, and economical. Another advantage is that tissue dynamics can be observed with real-time imaging. In recent reports, it has been shown that ultrasonic examination can provide similar diagnostic accuracy as nerve conduction study in the diagnosis of carpal tunnel syndrome. It has been expected that ultrasound demand in daily medical care will continue to increase. Ultrasonography in carpal tunnel syndrome shows an enlarged median nerve in proximal carpal tunnel, thickening of the flexor retinaculum, and edema around flexor tendons in cross-sectional images. In addition, with the introduction of new technologies such as ultrasonic elastography and speckle tracking, it has become possible to quantify dynamics and material property changes of nerves, tendons, and their surrounding structures. In this review, we describe recent advancements of carpal tunnel syndrome diagnosis based on ultrasound dynamic images, and discuss its pathology.

Utility of Ultrasonography of the Median Nerve With a High-Frequency Probe for the Diagnosis of Dialysis-Related Carpal Tunnel Syndrome

This cross-sectional study aimed to determine the utility of ultrasonography with improved resolution using a high-frequency probe for dialysis-related carpal tunnel syndrome (CTS). This study targeted 125 hemodialysis patients at our hospital. A 12 MHz probe was placed on the carpal tunnel area to identify the median nerve. The compression rate of the nerve was calculated by measuring the smallest diameter of the compressed nerve and largest diameter of the unaffected part. To quantify CTS symptoms, we determined the presence of Tinel's sign, measured pinch strength, and used questionnaires to assess numbness and pain. The association of these clinical data with the compression rate was examined. Mean compression rate was 12.1 ± 1.1%. The compression rate cutoff value for those positive with Tinel's sign was 25%, (sensitivity and specificity were 0.80 and 0.91, respectively), and that for those with a history of CTS surgery was 25% (sensitivity and specificity were 0.67 and 0.89, respectively). Multiple regression analysis identified duration of dialysis, β2-microglobulin(β2-Mg) concentration, positivity for Tinel's sign, history of CTS surgery, and pinch strength as independent compression rate determinants. Notably, compression rates were significantly higher in patients with a ≥4-year duration of dialysis and a β2-Mg level of 20 mg/L or more. The compression rate of the median nerve measured by an improved ultrasound device significantly correlated with clinical symptoms, medical history, and serological features associated with dialysis-related CTS. Because ultrasonography is non-invasive, the examination might be a simple method especially for early diagnosis of dialysis-related CTS.

Uremic neuropathy

Polyneuropathy is a common complication of end-stage renal failure especially when treatment with periodic hemodialysis is started too late. Large myelinated fibers bear the brunt of the many biological changes associated with renal failure. Nerve conduction slowing is common in this setting. Compression of the median nerve in the carpal tunnel commonly occurs in these patients, as a result of amyloid deposits at this site. End-stage renal failure in diabetic patients is often associated with severe distal motor and sensory deficits. Improved quality of periodic hemodialysis and renal transplantation have dramatically reduced the prevalence and severity of peripheral neuropathy in these patients.

Sonographic subclinical entheseal involvement in dialysis patients

Long-term dialysis treatment can be associated with several musculoskeletal complications. Entheseal involvement in dialysis patients remains rarely studied as its prevalence is underestimated due to its often asymptomatic presentation. The aims of the study were to determine the prevalence of subclinical enthesopathy in haemodialysis and peritoneal dialysis patients at the lower limb level, to investigate the inter-observer reliability of ultrasound assessment and to analyse the influence of biometric and biochemical parameters. Ultrasound examination was conducted at the entheses of the lower limbs level in 33 asymptomatic dialysis patients and 33 healthy adopting the Glasgow Ultrasound Enthesitis Scoring System (GUESS). The inter-observer reliability was calculated in 15 dialysis patients. Ultrasound found at least one sign of enthesopathy in 165 out of 330 (50%) entheses of dialysis patients. In healthy subjects, signs of enthesopathy were present in 54 out of 330 (16.3%) entheses (p < 0.0001). No power Doppler signal was detected in healthy controls, in contrast to four of 330 entheses of dialysis patients. No US signs of soft tissue amyloid deposits were found. The GUESS score was significantly higher in dialysis patients than in controls (p < 0.0001). There was no difference in terms of enthesopathy between haemodialysis and peritoneal dialysis. Dialysis duration resulted to be the most important predictor for enthesopathy (p = 0.0004), followed by patient age (p = 0.02) and body mass index (p = 0.035). Parathormone, calcium, phosphorus, C-reactive protein, cholesterol and triglycerides apparently did not play a relevant role in favour of enthesopathy. The inter-observer reliability showed an excellent agreement between sonographers with different degree of experience. Our results demonstrated a higher prevalence of subclinical enthesopathy in both haemodialysis and peritoneal dialysis patients than in healthy subjects. Follow-up will provide further information with respect to the predictive value of US findings for the development of symptomatic dialysis-related arthropathy.

The usefulness of ultrasonography in the diagnosis of carpal tunnel syndrome

This study assessed the use of ultrasound in the diagnosis of carpal tunnel syndrome and to determine the best ultrasound criterion for diagnosis. Forty wrists of 27 patients with surgically proven moderate and severe carpal tunnel syndrome and 30 wrists of 15 controls were examined. Measurements of the cross-sectional area and the anteroposterior diameter of the median nerve at the inlet and outlet of the carpal tunnel were obtained. Patients also underwent electrophysiological evaluation. Median nerve ultrasonographic measurements were significantly higher in patients. The cross-sectional area of the median nerve at the tunnel inlet was found to be the most useful diagnostic criterion. The optimal cut-off value was 6.5 mm2 (sensitivity 89.5%, specificity 93%). Ultrasound parameters failed to correlate with the electrophysiological findings. The usefulness of ultrasonography in the diagnosis of carpal tunnel syndrome is discussed.

Acromegaly and end-stage renal disease: a diagnostic challenge

Chronic renal failure is associated with an impairment of the GH/IGF-I axis. We report the diagnostic challenges in a 72-yr-old female suffering from end-stage renal disease and presenting with clinical findings suggestive of acromegaly. GH was not suppressed during an oral glucose tolerance test, but rose paradoxically. However, serum IGF-I levels were within the normal range. IGF-binding proteins (IGFBP)-2 and -3 were markedly elevated and GH-binding protein (GHBP) was diminished. Clinical findings suspicious of acromegaly could be ascribed to pre-existing characteristics and consequences of end-stage renal disease. This suggested that the disturbances of the GH/IGF-I axis in our patient were due to chronic renal disease, rather than acromegaly. In the work-up for acromegaly, clinicians should be alerted to GH resistance in chronic renal failure.

Beta-2 microglobulin in ESRD: an in-depth review

Beta-2 microglobulin is the most widely studied low-molecular-weight protein in end-stage renal disease. It is known to cause dialysis-related amyloidosis (DRA), by virtue of its retention when renal function fails, its deposition in tissues, its aggregation into fibrils, and its ability to become glycosylated. The onset of DRA may be protracted by the use of noncellulosic membranes, especially when high-volume hemodiafiltration is used in the treatment of renal failure. Adsorptive methods have been developed to improve the removal of beta-2 microglobulin. There seems to be a relative risk reduction in mortality when patients are treated with dialysis membranes that have a higher clearance of beta-2 microglobulin.