Multiperspective assessment of peripheral nerve involvement in diabetic patients

Psychological and Biomechanical Aspects of Patient Adaptation to Diabetic Neuropathy and Foot Ulceration

PURPOSE OF REVIEW

The purpose of this review was to elucidate how psychological and biomechanical factors interrelate in shaping patients' experience with diabetic symmetric polyneuropathy (DSPN) and its sequela-diabetic foot ulceration (DFU).

RECENT FINDINGS

Recent findings emphasize the importance not only of neuropathic pain but also of other DSPN symptoms, such as unsteadiness. We highlight the negative spiral between unsteadiness, falls, and psychological distress. Moreover, unsteadiness is a key determinant of non-adherence to offloading resulting in the delayed DFU healing. While depression is an established predictor of incident DFU, findings linking depression and DFU healing remain inconclusive. Examination of physical activity in DFU development and healing represents the most recent application of research to this field. Research evidence indicates that DSPN markedly impairs physical and emotional functioning and suggests that there is an unmet need for the development of multifaceted interventions that address both psychological distress and biomechanical challenges experienced by patients with this debilitating complication of diabetes.

The effect of lower extremity nerve decompression on health-related quality of life and perception of pain in patients with painful diabetic polyneuropathy: a prospective randomized trial

AIMS

The aim of this study was to assess whether surgical decompression of nerves in the lower extremity in people with painful diabetic polyneuropathy would have an effect on health-related quality of life and to determine minimal clinically important differences in pain and quality of life scores.

METHODS

The design was a randomized controlled trial in which 42 participants with painful diabetic painful neuroapthy underwent unilateral decompression of nerves in their left or right leg, using the other leg as a control, with 12 months follow-up. Surgical decompression was performed at the tibial, superficial, deep and common peroneal nerves. Preoperatively, and at 6 and 12 months post operatively, a visual analogue scale for pain and the 36 item short-form health survey and EuroQual 5 Dimensions questionnaires were completed.

RESULTS

At 12 months follow-up, the visual analogue scale was significantly reduced, but decompression surgery did not significantly alter health-related quality of life scores. The minimal clinically important difference for visual analogue scale reduction was determined at 2.9 points decrease, a threshold reached by 42.5% of the study population.

CONCLUSIONS

Although decompression surgery does not influence health-related quality of life, it achieves a clinically relevant reduction of pain in ~42.5% of people with diabetic peripheral neuropathy. It can therefore be considered for patients who do not adequately respond to pain medication.

Changes in Neurologic Function Tests May Predict Neurotoxicity Caused by Ixabepilone

Purpose

To investigate baseline factors and neurologic function tests (NFTs) that may predict the development of grade 2 or higher peripheral neuropathy (PN) after treatment with ixabepilone, an epothilone microtubule-stabilizing agent with antitumor activity.

Patients and Methods

Advanced breast cancer patients were treated with ixabepilone (6 mg/m2) for 5 consecutive days every 3 weeks in a phase II clinical trial. Physical examinations, questionnaires, nerve conduction studies, and NFTs, including the Jebsen Test of Hand Function (JTH) and the Grooved Pegboard Test (GPT), were performed at baseline and during subsequent cycles.

Results

Forty-seven patients assessable for PN received a median of five cycles of therapy (range, one to 22 cycles). Nine of these patients developed grade 2 PN, and two developed grade 3 PN, with a median time to onset of 144 days (range, 6 to 189 days). Among these 11 patients, PN resolved in eight patients, with a median of 15 days (range, 6 to 346 days) after onset, but PN did not resolve in three patients during follow-ups at 76, 361, and 746 days after onset. GPT and changes of JTH scores at onset of PN were significantly different between patients with and without PN at comparable follow-up times (P = .006 and P = .002, respectively). Changes in GPT and JTH scores over the first two cycles were often associated with the development of PN by exploratory actuarial analysis.

Conclusion

Serious ixabepilone-induced neuropathy was relatively rare on the treatment schedule used. NFTs, such as JTH and GPT, may have utility for predicting PN, but further testing is needed.

Peripheral neuropathy induced by microtubule-stabilizing agents

Microtubule-stabilizing agents (MTSAs), including the taxanes and epothilones, are effective chemotherapeutic agents for the treatment of many cancers. Neuropathy is a major adverse effect of MTSA-based chemotherapy, with severe peripheral neuropathy (grade 3 or 4) occurring in as many as 30% of patients treated with a MTSA. MTSA-induced neuropathy usually resolves gradually after cessation of the treatment. The most reliable method to accurately assess MTSA-induced neuropathy is by clinical evaluation, although additional techniques are being developed and evaluated. Among MTSA-induced neuropathy, the most extensively studied is that induced by taxanes; such a neuropathy usually presents as sensory neuropathy and is more common with paclitaxel than docetaxel. The incidence of MTSA-induced neuropathy seems to depend on the MTSA dose per treatment cycle, the schedule of treatment, and the duration of the infusion. Although there have been several small clinical trials with neuroprotective agents, early recognition and supportive care are the best approaches for prevention and management of MTSA-induced neuropathy. In the future, research should focus on elucidating the mechanism of MTSA-induced neuropathy, developing reliable in vivo and in vitro preclinical models to study MTSA-induced neuropathy, developing a more reliable grading system for MTSA-induced neuropathy, developing more reliable methods for evaluating MTSA-induced neuropathy, and evaluating the efficacy of potential neuroprotective agents in clinical trials.

Quality of life and disability assessment in neuropathy: a multicentre study

Neuropathy can severely affect patients' quality of life (QoL), causing disability and decreased motor efficiency while modifying their perception of the external environment. We performed a large, multi-perspective, and multi-measurement assessment using validated clinical measurements of disability and QoL. With regard to general disability, more than 10% of patients needed assistance to walk. With regard to arm disability, about 10% of patients had severe disability defined as impairment in carrying out simple tasks. General disability was similar both in polyneuropathic and multi-neuropathic groups, but arm disability appeared more severe in multi-neuropathic patients. QoL profiles were highly deteriorated in our sample with respect to the Italian normative sample. All age brackets were highly impaired except for older patients for whom the QoL picture was only mildly impaired with respect to Italian norms. We believe that our study provides reliable data on QoL in patients with neuropathies and that it may represent a quantitative step forward in understanding the disability of patients with neuropathy.

Update on diabetic neuropathy

PURPOSE OF REVIEW

This review will focus on recent advances in the field of diabetic neuropathy, with an emphasis on distal symmetric sensory and sensorimotor polyneuropathy. Some new information in the areas of diabetic amyotrophy and diabetic autonomic neuropathy will also be reviewed.

RECENT FINDINGS

The pathogenesis of diabetic neuropathy is multifactorial. There is increasing evidence to link abnormalities in the polyol pathway to the pathogenesis of diabetic neuropathy. In addition, there appear to be abnormalities of nerve regeneration and of sodium and calcium channels. Aldose reductase inhibitors have shown promise in animal models for reversing neuropathy if started early and used for a sufficient time, but those used to date in human trials are probably not of sufficient potency. Neurotrophic factors and vascular endothelial growth factor both also show promise. Specific recommendations and pathways for diabetic foot care have been devised. Lamotrigine and bupropion represent new treatments for neuropathic pain. The role of impaired glucose tolerance is being explored as it relates to polyneuropathy.

SUMMARY

An increasing understanding of the pathogenetic mechanisms holds out promise for the effective treatment of diabetic neuropathy. The early detection of abnormal glucose metabolism is particularly important, as treatments will probably be most effective if administered early in the course of the neuropathy, when abnormalities of peripheral nerves are more likely to be reversible.