Susan J. Benbow

Electrical spinal-cord stimulation for painful diabetic peripheral neuropathy.

BACKGROUND Conventional treatment for painful peripheral diabetic neuropathy is largely symptomatic and often ineffective, with unacceptable side-effects. We tested electrical spinal-cord stimulation for the management of chronic neuropathic pain. METHODS Ten diabetic patients who did not respond to conventional treatment (mean age 51 [SD 9.3] years, six with type II diabetes, mean duration of diabetes 12 [6.3] years, mean duration of neuropathy 5 [2.1] years) were studied. The electrode was implanted in the thoracic/lumbar epidural space. Immediate neuropathic pain relief was assessed by visual analogue scale (VAS) after connecting the electrode, in a random order, to a percutaneous electrical stimulator or to a placebo stimulator. Exercise tolerance was assessed on a treadmill. FINDINGS Eight subjects had statistically significant pain relief with the electrical stimulator (p < 0.02) and were therefore converted to a permanent system. Statistically significant relief of both background and peak neuropathic pain was achieved at 3 months (n = 7, p = 0.016), at 6 months (n = 7, p = 0.03), and at the end of the study (14 months, n = 7, background pain p = 0.06, peak pain p = 0.03). One patient died 2 months after the start of the study of unrelated cause while continuing to benefit from treatment and another patient ceased to benefit at 4 months. McGill pain questionnaire scores with the stimulator turned off did not change significantly from baseline scores, indicating that the severity of the underlying pain was unaltered. However, with the stimulator turned on, there was a statistically significant (p < 0.05) improvement in all four components of the score, by the end of the study. At the end of the study, six patients continued to gain significant pain relief and used the stimulator as the sole treatment for their neuropathic pain. For example, median background and peak pain scores at the end of study, were, respectively, 77 and 81 with the stimulator off and 23 and 20 with the stimulator on. Exercise tolerance significantly improved at 3 months (n = 7, median % increase 85 [IQR, 62-360], p = 0.015) and at 6 months (n = 6, 163 [61-425], p = 0.0007). Electrophysiological tests, vibration perception-threshold, and glycaemic control were unchanged. INTERPRETATION Electrical spinal-cord stimulation offers a new and effective way of relieving chronic diabetic neuropathic pain and improves exercise tolerance. The technique should be considered in patients with neuropathic pain who do not respond to conventional treatment.

A Prospective Study of Painful Symptoms, Small‐fibre Function and Peripheral Vascular Disease in Chronic Painful Diabetic Neuropathy

Fifty diabetic patients with chronic painful sensorimotor neuropathy were studied prospectively to clarify the natural history of this condition and the roles of small‐fibre damage and concomitant peripheral vascular disease (PVD). Initially, 30 patients had no significant PVD (ankle:brachial Doppler ratio > 1.0). Pain was assessed using a visual analogue scale (0–10 cm), and small‐fibre function by thermal limen (TL), heat‐pain threshold (HPT), and weighted pinprick threshold (PPT). At follow‐up, on average 3.6 years later (range 3.0–4.1), 11 patients had died (6 with PVD) and contact had been lost with 6. Pain scores fell in subjects without PVD (n = 24; median (range), from 4.8 (0.5–10.0) to 2.0 (0.0–9.2) cm, p < 0.001) and also in those with PVD (n = 9; from 5.1 (2.0–8.2) to 2.1 (0.0–8.0) cm, p < 0.05). Seven patients (5 without PVD) became pain‐free; at presentation, these 7 patients had experienced pain for a shorter period of time. Despite this symptomatic improvement, small‐fibre function generally deteriorated in both groups, with significant worsening (p < 0.05) of HPT and PPT in patients without PVD, and in HPT and TL in patients with PVD. Neuropathic pain therefore tends to improve with time and can resolve completely. By contrast, small‐fibre function continues to deteriorate, indicating that these peripheral measures do not predict the evolution of painful symptoms. The presence or absence of PVD does not appear to affect the natural history of neuropathic pain or its symptomatology.

Electrical spinal cord stimulation in the long‐term treatment of chronic painful diabetic neuropathy

Aims  Electrical spinal cord stimulation (ESCS) is a technique for the management of chronic painful diabetic neuropathy (CPDN) affecting the lower limbs. We assessed the efficacy and complication rate of ESCS implanted at least 7 years previously in eight patients.

The prediction of diabetic neuropathic plantar foot ulceration by liquid-crystal contact thermography

OBJECTIVE To assess whether the development of plantar foot ulceration could be predicted from the mean plantar foot temperature (MFT), as assessed by liquid-crystal contact thermography (LCT), in patients with peripheral neuropathy. RESEARCH DESIGN AND METHODS Fifty patients with painful diabetic sensorimotor neuropathy were studied prospectively. Initially, 30 patients had no significant peripheral vascular disease (PVD) (ankle:brachial systolic blood pressure ratio >1.0). LCT was used to assess the MFT from eight standard plantar sites. RESULTS Initial MFT was higher in the patients without PVD (28.2 ± 2.9°C, mean ± SD) than in patients with PVD (25.6 ± 1.9°C, P < 0.001) and in nondiabetic control subjects (25.7 ± 2.1°C, P < 0.001). At review, on average 3.6 (range 3.0–4.1) years later, 11 patients had died (6 of whom had PVD), and one was lost to follow-up. Six patients (seven feet) from the group without PVD had developed neuropathic plantar foot ulcers. The initial MFT was significantly higher in these seven feet (30.5 ± 2.6°C) than in the 38 feet of the 19 survivors in this group (27.8 ± 2.3°C, P < 0.01). Only one patient with PVD developed a plantar ulcer, although four required foot surgery for ischemie feet. CONCLUSIONS LCT is a simple, inexpensive, and noninvasive method of identifying the neuropathic foot at increased risk of ulceration. Patients with high plantar foot temperatures are at increased risk of neuropathic foot ulceration. A normal or low MFT in the neuropathic foot is a marker of PVD, which confers an increased risk of ischemie foot disease.

The natural history of chronic painful peripheral neuropathy in a community diabetes population

Aims  To examine the natural history of chronic painful diabetic neuropathy (CPDN).

Pituitary tumours presenting in the elderly: management and outcome

In elderly patients there are few data on the efficacy and safety of pituitary surgery and radiotherapy (DXT). The aim of the present study was to assess the mode of presentation, treatment and outcome of patients >64 years with a pituitary tumour presenting to a regional neuroendocrine service.

Brittle diabetes in the elderly.

Severely unstable, or brittle, diabetes can be disruptive to patients, carers and diabetes care teams. The peak age-group for brittle diabetes is 15–30, but there are reports of its occurrence in much older patients. To explore the characteristics and cause of brittle instability perceived by diabetologists in elderly patients we circulated a questionnaire to all UK hospital diabetic clinics for adults. 130 (56%) of 231 replied. Reports were obtained on 55 patients fulfilling our criteria for ‘elderly brittle diabetes’–namely, age ≤ 60 years, on insulin treatment, and experiencing life-disrupting glycaemic instability of any kind associated with frequent or long admissions to hospital. Further information was obtained by a research nurse who visited the relevant clinics. The mean age of patients was 74 years (range 60–89) and 71 % were female. The brittleness was classed as mixed glycaemic instability in 22 (44%), recurrent ketoacidosis in 16 (29%) and recurrent hypoglycaemia in 15 (27%). In 2 cases there was insufficient information for classification. The diabetes care team judged the brittleness to have multiple origins in two-thirds of the cases: problems with memory or behaviour were rare, and in only 4 cases was deliberate manipulation of therapy considered a possibility. 84% of the patients were living independently. In younger patients the principal manifestation of brittle diabetes is recurrent ketoacidosis. The present survey, though possibly subject to ascertainment bias, indicates that the patterns of instability and their causation may be different in elderly patients. With the growing use of insulin in the elderly, brittle diabetes is likely to be encountered increasingly often in this age-group.

Smoking habits and painful diabetic neuropathy

In order to assess the relationship between chronic painful diabetic neuropathy and current--or lifetime--smoking habits, the smoking history of 49 diabetic patients was investigated and compared with that of 23 diabetic patients without chronic pain (age 51.0 +/- 1.9 years, mean +/- SEM). Current level of nicotine intake was measured using urinary cotinine (a nicotine metabolite), and expressed as cotinine/creatinine ratio (COT/Cr), and lifetime smoking load by pack years (20 cigarettes per day for 1 year equals 1 pack year). Current pain intensity was evaluated using a visual analogue scale (VAS). The presence of chronic painful diabetic neuropathy was based on clinical history and examination. Of those patients with painful neuropathy, 26% were current smokers (age 54.2 +/- 3.2 years, mean +/- SEM), 31% ex-smokers (age 57.0 +/- 2.9 years), and 43% lifelong nonsmokers (age 58.0 +/- 2.9 years). Pain duration and intensity were similar in all three groups. COT/Cr levels were similar in current diabetic smokers with pain [5.0 (0.2-10.6) micrograms/mg] and the diabetic control group of smokers without pain [6.8 (1.8-13.3) micrograms/mg, NS]. There was no relationship between VAS and either COT/Cr levels or pack years in current smokers, or between duration of pain and pack years in diabetic current or ex-smokers. In conclusion, we found no relationship between current or previous levels of smoking and severity or duration of chronic painful diabetic neuropathy.