Ultrasonography for the Diagnosis of Carpal Tunnel Syndrome in Diabetic Patients: Missing the Mark?

PURPOSE: Diabetes mellitus (DM) and carpal tunnel syndrome (CTS) are common pathologies. The diagnosis of CTS can be facilitated by the use of an ultrasound-based wrist-to-forearm ratio (WFR) of the nerve diameter. However, the applicability of WFR in DM-patients is not yet clear. MATERIALS AND METHODS: 233 wrists of 153 patients were examined. Cross-sectional areas (CSA) of the median nerve were obtained using a linear array probe. The WFR was calculated. RESULTS: Diabetics with CTS had significantly lower WFR values than non-diabetics with CTS (p = 0.002). There was no difference between the WFR of diabetics with and without CTS (p = 0.06). The diagnostic accuracy between diabetics with and without CTS was low for measurements of WFR (ROC AUC = 0.630, 95 % CI 0.541 - 0.715, p = 0.011). CONCLUSION: Our findings suggest that the WFR has a low diagnostic accuracy in diabetic patients with CTS and should be used with caution in those patients. KEY POINTS: · The diagnostic accuracy of WFR is low in patients with DM. · WFR should not be used in patients with DM. · The sonographic evaluation of the median nerve in patients with DM should focus on morphological changes. CITATION FORMAT: · Steinkohl F, Loizides A, Gruber L et al. Ultrasonography for the Diagnosis of Carpal Tunnel Syndrome in Diabetic Patients: Missing the Mark?. Fortschr Röntgenstr 2019; 191: 117 - 121.

Continuous administration of heparin in patients with deep vein thrombosis can increase plasma levels of diamine oxidase.

Besides its anticoagulant activity, the sulfated polysaccharide heparin has numerous other biological effects. Especially the antiinflammatory and immunoregulatory properties of heparin may be associated with its ability to release the histamine-degrading enzyme diamine oxidase (DAO) from tissue-bound sites into the circulation. Whereas DAO activity is at the limits of detection in normal human plasma, the application of heparin leads to a significant increase of plasma DAO activity. However, previously, only the effect of bolus injection of unfractionated heparin (UFH) had been studied. To investigate DAO release during continuous heparin infusion, 28 patients with deep vein thrombosis (DVT) undergoing heparin therapy were analyzed. Whereas continuous heparin infusion did not lead to any increase of plasma DAO activity in 12 patients (43%), 6 patients (21%) showed a single elevated and 10 patients (36%) permanently elevated plasma DAO activity. The groups of patients exhibiting different DAO release responses did not differ in age, sex, body weight, concomitant diseases, heparin infusion rates, coagulation indices, location and extension of thrombosis, or clinical outcome. However, the rate of idiopathic DVT was significantly higher in the group of patients releasing DAO. This study shows, for the first time, that continuous heparin infusion can lead to DAO release and that individuals exhibit considerable differences in their release response. Although the significance of heparin-induced DAO release needs further clarification, our results indicate that postheparin plasma DAO activity could be an interesting parameter correlated with idiopathic DVT.