Ulnar Neuropathy at Elbow in Patients With Type 2 Diabetes Mellitus

Demographics of Common Compressive Neuropathies in the Upper Extremity

BACKGROUND

The purpose of this study was to compare the demographic differences of the most common peripheral nerve compressions in the upper extremity-carpal tunnel syndrome (CTS), ulnar nerve compression (UNC) at the elbow, combined CTS and UNC, radial tunnel syndrome (RTS), and posterior interosseous nerve syndrome (PINS)-as a means to better understand the etiologies of each.

METHODS

A retrospective chart review was performed of all patients over the age of 18 years seen at our institution in the 2018 calendar year. International Classification of Diseases, Tenth Revision codes were used to identify patients with diagnoses of upper extremity peripheral nerve compressions. Demographic details and relevant comorbidities were recorded for each patient and compared with controls, who were seen the same calendar year with no neuropathies. χ2 analyses, independent-samples t tests, and multivariate logistic regressions were performed (P < .05).

RESULTS

A total of 7448 patients were identified. Those with CTS were mainly women, former smokers, and diabetic (all P < .001) and with a greater average body mass index (BMI) (P = .006) than controls. Patients with UNC were more often men and younger when compared with controls (both P < .001). A history of smoking, diabetes, and average BMI were similar between patients with UNC and controls (all P > .05). Those patients with combined CTS/UNC were mainly men, former smokers, and diabetic (all P < .001) when compared with controls. Patients with RTS/PINS were also mostly men (P = .007), diabetic (P = .042), and were more often current smokers (P < .001).

CONCLUSIONS

The demographics of patients with various compressive neuropathies were not homogeneous, suggesting different etiologies.

Electrophysiological Study of the Tibial Nerve Across the Tarsal Tunnel in Distal Symmetric Diabetic Polyneuropathy

OBJECTIVE

The aim of the study was to demonstrate abnormalities of motor conduction of the tibial nerve across the tarsal tunnel in type 2 diabetes.

DESIGN

One hundred twenty-four consecutive patients (mean age = 66.6 yrs, 62.1% male) with distal symmetric diabetic polyneuropathy clinically diagnosed were prospectively enrolled. Nerve conduction studies of deep peroneal, tibial, superficial peroneal, medial plantar, and sural nerves and standard needle electromyography in the lower limbs were performed. Demographic, anthropometric, and clinical findings were collected.

RESULTS

Motor conduction velocity of the tibial nerve across tarsal tunnel was slowed in 60.5% of patients; another 4% showed conduction block across tarsal tunnel without reduction of motor conduction velocity. Overall percentage of abnormalities across tarsal tunnel (64.5%) exceeds that of the sensory conduction velocities of proximal sural and superficial peroneal nerves. Abnormal tibial motor conduction velocity across tarsal tunnel represents the most common abnormality among all motor nerve conduction study parameters and significantly correlates with hemoglobin level, diabetic neuropathic index score, and diabetic complications frequency.

CONCLUSIONS

Tibial conduction abnormalities across tarsal tunnel are the most sensitive motor parameter in distal symmetric diabetic polyneuropathy, second only to conduction abnormalities of sensory/mixed distal nerves of the feet. The use of nerve conduction studies across tarsal tunnel of the tibial nerve may be useful in the electrophysiological protocol to confirm the diagnosis of distal symmetric diabetic polyneuropathy.

Risk factors of asymptomatic reduction of motor conduction velocity of the ulnar nerve across the elbow

INTRODUCTION

The aim of the study was to check the risk factors for subjects with motor conduction velocity (MCV) reduction of the ulnar nerve across the elbow without symptoms/signs of ulnar neuropathy at the elbow (UNE) using a database of a previous multicenter case-control study on UNE patients.

METHODS

From the previous database, we extracted all asymptomatic UNE (A-UNE) and matched for age and sex with a control and UNE groups with a ratio of 1:2. Anthropometric factors were measured and all participants filled in a questionnaire on demographic, lifestyle factors, and medical history. One-sample proportion test and univariate and multivariate logistic regression analyses were performed.

RESULTS

We enrolled 64 A-UNE, 124 UNE, and 124 controls (mean age 53 years). There were more males with A-UNE than females (74.2%). The predominantly or exclusively concerned side of A-UNE was the right. Logistic regression showed that A-UNE was associated with diabetes (OR = 2.99, 95% CI = 1.21-7.39) and width of cubital groove (CGW) (OR = 0.89, 95%  CI = 0.81-0.97).

DISCUSSION

Risk factors for A-UNE are different from UNE. The prevalence of right side in A-UNE was not due to particular elbow postures. Diabetes is a risk factor, probably because MCV reduction of the ulnar nerve across the elbow was an early manifestation of asymptomatic polyneuropathy in diabetes. A-UNE is associated with narrow CGW as already demonstrated in UNE, even if the OR was higher in UNE than in A-UNE. Only future longitudinal studies will be able to check whether the A-UNE subjects develop symptoms and signs of true mononeuropathy with time.

Rare diabetic neuropathies: It is not only distal symmetrical polyneuropathy

The prevalence of diabetes mellitus is increasing at an epidemic level, leading to a consequent increase of its chronic complications, including neuropathy. Diabetic neuropathy constitutes a heterogeneous group of disorders with distinct clinical presentations and pathophysiological mechanisms. These distinct forms may be categorised according to their clinical presentation as symmetrical (distal symmetrical polyneuropathy, autonomic and acute sensory neuropathy) and focal or multifocal (radiculoplexus neuropathies, entrapment syndromes, cranial palsies and other mononeuropathies). Additionally, people with diabetes may have neuropathies due to causes other than diabetes. The commonest forms of diabetic neuropathy are distal symmetrical polyneuropathy and autonomic neuropathy. However, clinicians should be aware that people with diabetes may suffer from less common forms of neuropathy and should be able to recognise their symptoms and signs. The recognition of the rare diabetic neuropathies is crucial, as they often lead to different clinical outcomes and require different management. The aim of the present narrative, non-systematic review is to outline the rare types of diabetic neuropathies.