Where does spinal cord stimulation fit into the international guidelines for refractory painful diabetic neuropathy? a consensus statement

BACKGROUND

Although pharmacotherapy with anticonvulsants and/or antidepressants can be effective for many people with painful diabetic neuropathy (PDN), albeit with frequent side-effects, a critical juncture occurs when neuropathic pain no longer responds to standard first- and second-step mono- and dual therapy and becomes refractory. Subsequent to these pharmacotherapeutic approaches, third-line treatment options for PDN may include opioids (short-term), capsaicin 8% patches, and spinal cord stimulation (SCS).

AIM

This document summarizes consensus recommendations regarding appropriate treatment for refractory peripheral diabetic neuropathy (PDN), based on outcomes from an expert panel convened on December 10, 2022, as part of the Worldwide Initiative for Diabetes Education Virtual Global Summit, "Advances in the Management of Painful Diabetic Neuropathy."

PARTICIPANTS

Nine attendees, eminent physicians and academics, comprising six diabetes specialists, two pain specialists, and one health services expert.

EVIDENCE

For individuals with refractory PDN, opioids are a high-risk option that do not provide a long-term solution and should not be used. For appropriately selected individuals, SCS is an effective, safe, and durable treatment option. In particular, high-frequency (HF) SCS (10 kHz) shows strong efficacy and improves quality of life. To ensure treatment success, strict screening criteria should be used to prioritize candidates for SCS.

CONSENSUS PROCESS

Each participant voiced their opinion after reviewing available data, and a verbal consensus was reached during the meeting.

CONCLUSION

Globally, the use of opioids should rarely be recommended for refractory, severe PDN. Based on increasing clinical evidence, SCS, especially HF-SCS, should be considered as a treatment for PDN that is not responsive to first- or second-line monotherapy/dual therapy.

Alterations of tibialis anterior muscle activation pattern in subjects with type 2 diabetes and diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is associated with loss of motor units (MUs), which can cause changes in the activation pattern of muscle fibres. This study investigated the pattern of muscle activation using high-density surface electromyography (HD-sEMG) signals from subjects with type 2 diabetes mellitus (T2DM) and DPN. Thirty-five adults participated in the study: 12 healthy subjects (HV), 12 patients with T2DM without DPN (No-DPN) and 11 patients with T2DM with DPN (DPN). HD-sEMG signals were recorded in the tibialis anterior muscle during an isometric contraction of ankle dorsiflexion at 50% of the maximum voluntary isometric contraction (MVIC) during 30-s. The calculated HD-sEMG signals parameters were the normalised root mean square (RMS), normalised median frequency (MDF), coefficient of variation (CoV) and modified entropy (ME). The RMS increased significantly (p = 0.001) with time only for the DPN group, while the MDF decreased significantly (p < 0.01) with time for the three groups. Moreover, the ME was significantly lower (p = 0.005), and CoV was significantly higher (p = 0.003) for the DPN group than the HV group. Using HD-sEMG, we have demonstrated a reduction in the number of MU recruited by individuals with DPN. This study provides proof of concept for the clinical utility of this technique for identifying neuromuscular impairment caused by DPN.

Reduced vitamin D levels in painful diabetic peripheral neuropathy

AIM

Recent studies have reported an association between low vitamin D levels and diabetic peripheral neuropathy. However, many of these did not differentiate between people with painful diabetic peripheral neuropathy and those with painless diabetic peripheral neuropathy, or assess major confounding factors including sunlight exposure and daily activity. Our study addressed these limitations and evaluated vitamin D levels in people with carefully phenotyped diabetic peripheral neuropathy and controls.

METHODS

Forty-five white Europeans with Type 2 diabetes and 14 healthy volunteers underwent clinical and neurophysiological assessments. People with Type 2 diabetes were then divided into three groups (17 with painful diabetic peripheral neuropathy, 14 with painless diabetic peripheral neuropathy and 14 with no diabetic peripheral neuropathy). All had seasonal sunlight exposure and daily activity measured, underwent a lower limb skin biopsy and had 25-hydroxyvitamin D measured during the summer months, July to September.

RESULTS

After adjusting for age, BMI, activity score and sunlight exposure, 25-hydroxyvitamin D levels (nmol/l) (se) were significantly lower in people with painful diabetic peripheral neuropathy [painful diabetic peripheral neuropathy 34.9 (5.8), healthy volunteers 62.05 (6.7), no diabetic peripheral neuropathy 49.6 (6.1), painless diabetic peripheral neuropathy 53.1 (6.2); ANCOVAP = 0.03]. Direct logistic regression was used to assess the impact of seven independent variables on painful diabetic peripheral neuropathy. Vitamin D was the only independent variable to make a statistically significant contribution to the model with an inverted odds ratio of 1.11. Lower 25-hydroxyvitamin D levels also correlated with lower cold detection thresholds (r = 0.39, P = 0.02) and subepidermal nerve fibre densities (r = 0.42, P = 0.01).

CONCLUSIONS

We have demonstrated a significant difference in 25-hydroxyvitamin D levels in well-characterized people with painful diabetic peripheral neuropathy, while accounting for the main confounding factors. This suggests a possible role for vitamin D in the pathogenesis of painful diabetic peripheral neuropathy. Further prospective and intervention trials are required to prove causality between low vitamin D levels and painful diabetic peripheral neuropathy.

One-stop microvascular screening service: an effective model for the early detection of diabetic peripheral neuropathy and the high-risk foot

AIMS

To evaluate the feasibility of a one-stop microvascular screening service for the early diagnosis of diabetic distal symmetrical polyneuropathy, painful distal symmetrical polyneuropathy and the at-risk diabetic foot.

METHODS

People with diabetes attending retinal screening in hospital and community settings had their feet examined by a podiatrist. Assessment included: Toronto Clinical Neuropathy Score evaluation; a 10-g monofilament test; and two validated, objective and quick measures of neuropathy obtained using the point-of-care devices 'DPN-Check', a hand-held device that measures sural nerve conduction velocity and amplitude, and 'Sudoscan', a device that measures sudomotor function. The diagnostic utility of these devices was assessed against the Toronto Clinical Neuropathy Score as the 'gold standard'.

RESULTS

A total of 236 consecutive people attending the retinal screening service, 18.9% of whom had never previously had their feet examined, were evaluated. The prevalence of distal symmetrical polyneuropathy, assessed using the Toronto Clinical Neuropathy Score, was 30.9%, and was underestimated by 10-g monofilament test (14.4%). The prevalence of distal symmetrical polyneuropathy using DPN-check was 51.5% (84.3% sensitivity, 68.3% specificity), 38.2% using Sudoscan foot electrochemical skin conductance (77.4% sensitivity, 68.3% specificity), and 61.9% using abnormality in either of the results (93.2% sensitivity, 52.8% specificity). The results of both devices correlated with Toronto Clinical Neuropathy Score (P<0.001). A new diagnosis of painful distal symmetrical polyneuropathy was made in 59 participants (25%), and 56.6% had moderate- or high-risk foot. Participants rated the service very highly.

CONCLUSIONS

Combined, eye, foot and renal screening is feasible, has a high uptake, reduces clinic visits, and identifies painful distal symmetrical polyneuropathy and the at-risk foot. Combined large- and small-nerve-fibre assessment using non-invasive, quantitative and quick point-of-care devices may be an effective model for the early diagnosis of distal symmetrical polyneuropathy.

Is there a connection between postprandial hyperglycemia and IGT related sensory nerve dysfunction?

BACKGROUND AND AIMS

To assess the risk factors for sensory nerve dysfunction in subjects with isolated impaired glucose tolerance (IGT).

METHODS AND RESULTS

Seventy-two people with isolated IGT (WHO 1999 criteria) and 39 gender and age-matched healthy volunteers underwent detailed clinical and neurological assessment including quantitative sensory testing using the Neurometer device (current perception threshold measurement on four limbs at three different frequencies). Sensory nerve dysfunction was defined as at least two abnormalities on any frequencies on the upper or lower limbs. Sensory nerve dysfunction was more prevalent among subjects with IGT compared to controls (58.3 vs. 10.3%, OR: 11.23, 95%CI: 3.57-35.35). This association was not influenced by BMI, systolic and diastolic blood pressure, heart rate and autonomic neuropathy (multiple adjusted OR: 13.87, 95%CI: 3.18-60.58), but further adjustment for glycaemic measures abolished the association (OR: 1.58, 95%CI: 0.07-35.68). Assessing the components of glycaemic measures separately, the association between sensory nerve dysfunction and IGT was not affected by HbA1c (OR: 13.94, 95%CI: 1.84-105.5). It was, however, substantially attenuated by fasting plasma glucose (OR: 6.75, 95%CI: 1.33-34.27) while the significance was lost after adjustment for 120 min postload glucose level (OR: 3.76, 95%CI: 0.26-54.10). In the pooled population assessed, independent determinants of sensory nerve dysfunction were older age, 120 min glucose, higher height and cardiovascular autonomic neuropathy at near significance.

CONCLUSIONS

Sensory nerve dysfunction amongst subjects with IGT was not explained by cardiovascular covariates, only by glycaemic measures. In addition to 120 min glucose, cardiovascular autonomic neuropathy at borderline significance, age, and height were the independent determinants of sensory nerve dysfunction.

Are there different predictors of analgesic response between antidepressants and anticonvulsants in painful diabetic neuropathy?

BACKGROUND

To investigate baseline demographics and disease characteristics as predictors of the analgesic effect of duloxetine and pregabalin on diabetic peripheral neuropathic pain (DPNP).

METHODS

Based on data from the COMBO-DN study, a multinational clinical trial in DPNP, the potential impact of baseline characteristics on pain relief after 8-week monotherapy with 60 mg/day duloxetine or 300 mg/day pregabalin was assessed using analyses of covariance. Subgroups of interest were characterized regarding their baseline characteristics and efficacy outcomes.

RESULTS

A total of 804 patients were evaluated at baseline. A significant interaction with treatment was observed in the mood symptom subgroups with a larger pain reduction in duloxetine-treated patients having no mood symptoms [Hospital Anxiety and Depression Scale (HADS) depression or anxiety subscale score <11; -2.33 (duloxetine); -1.52 (pregabalin); p = 0.024]. There were no significant interactions between treatment for subgroups by age (<65 or ≥65 years), gender, baseline pain severity [Brief Pain Inventory Modified Short Form (BPI-MSF) average pain <6 or ≥6], diabetic neuropathy duration (≤2 or >2 years), baseline haemoglobin A1c (HbA1c) (<8% or ≥8%), presence of comorbidities and concomitant medication use.

CONCLUSIONS

Our analyses suggest that the efficacy of duloxetine and pregabalin for initial 8-week treatment in DPNP was consistent across examined subgroups based on demographics and disease characteristics at baseline except for the presence of mood symptoms. Duloxetine treatment appeared to be particularly beneficial in DPNP patients having no mood symptoms.

Phenotyping animal models of diabetic neuropathy: a consensus statement of the diabetic neuropathy study group of the EASD (Neurodiab)

NIDDK, JDRF, and the Diabetic Neuropathy Study Group of EASD sponsored a meeting to explore the current status of animal models of diabetic peripheral neuropathy. The goal of the workshop was to develop a set of consensus criteria for the phenotyping of rodent models of diabetic neuropathy. The discussion was divided into five areas: (1) status of commonly used rodent models of diabetes, (2) nerve structure, (3) electrophysiological assessments of nerve function, (4) behavioral assessments of nerve function, and (5) the role of biomarkers in disease phenotyping. Participants discussed the current understanding of each area, gold standards (if applicable) for assessments of function, improvements of existing techniques, and utility of known and exploratory biomarkers. The research opportunities in each area were outlined, providing a possible roadmap for future studies. The meeting concluded with a discussion on the merits and limitations of a unified approach to phenotyping rodent models of diabetic neuropathy and a consensus formed on the definition of the minimum criteria required for establishing the presence of the disease. A neuropathy phenotype in rodents was defined as the presence of statistically different values between diabetic and control animals in 2 of 3 assessments (nocifensive behavior, nerve conduction velocities, or nerve structure). The participants propose that this framework would allow different research groups to compare and share data, with an emphasis on data targeted toward the therapeutic efficacy of drug interventions.

Potential coeliac disease in Type 1 diabetes mellitus: does a positive antibody lead to increased complications?

BACKGROUND AND AIMS

Coeliac disease (CD) is more common in people with Type 1 diabetes and is associated with poorer glycaemic control, lipid profiles, nephropathy and retinopathy. Potential CD (positive serology but normal duodenal biopsy) is associated with neuropathy but patients with coexisting Type 1 diabetes were excluded. The aim was to determine whether potential CD is associated with increased microvascular complications in patients with Type 1 diabetes.

METHODS AND RESULTS

Four groups were recruited; 1) patients with Type 1 diabetes and potential CD, 2) patients with Type 1 diabetes and newly identified CD, 3) patients with Type 1 diabetes alone and 4) patients with CD alone. Glycaemic control, quality of life, lipid profile and microvascular complication rates were examined. As many as 76 individuals were included in the study: 22 in group 1, 14 in group 2, 24 in group 3 and 16 in group 4. There were no differences in age, gender, BMI and diabetes duration between the groups. Patients in group 1 had significantly lower total cholesterol compared to group 3 (p = 0.003) but higher than group 2 (p = 0.027). There were no significant differences in HbA1c, HDL cholesterol, cholesterol:HDL ratio, creatinine, quality of life scores or prevalence of neuropathy between individuals in group 1 and the other groups.

CONCLUSIONS

This is the first study to assess the effects of potential CD in patients with Type 1 diabetes. It appears that an enteropathy is required as well as antibody positivity in order to increase the risk of diabetes related complications. This pilot data requires further longitudinal validation.

Medical strategies to reduce amputation in patients with type 2 diabetes

Lower extremity amputation is a common and disabling complication of Type 2 diabetes. Whilst the introduction of specialist multidisciplinary teams has led to a reduction in the incidence of lower extremity amputation in some centres, the overall prevalence of diabetes-related amputation has actually increased in recent decades. The aetiology of diabetes-related amputation is complex, with neuropathy, macrovascular and microvascular disease contributing significantly. Ulceration, previous amputation, increasing diabetes duration and poor long-term control of glycaemia and lipids are important risk factors for amputation in populations with diabetes. Major randomized intervention trials of blood glucose-lowering or anti-hypertensive therapies in populations with diabetes have shown limited reductions in neuropathy and/or macrovascular disease, and no benefit on amputation rates. In contrast, a recent analysis from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study showed a significantly reduced rate of minor, but not major amputations in patients with Type 2 diabetes treated with fenofibrate. Mechanistic studies are clearly needed to understand the basis of this benefit.

Serological testing for coeliac disease in Type 1 diabetes mellitus: is immunoglobulin A level measurement necessary?

AIMS

Immunoglobulin A (IgA) measurement is advocated when case finding for coeliac disease in patients with Type 1 diabetes mellitus. Currently, there is a paucity of contemporary studies assessing IgA deficiency in Type 1 diabetes. This study evaluates the prevalence of IgA deficiency in individuals with Type 1 diabetes, compared with patients with coeliac disease and control subjects. In addition, we evaluate whether routine IgA measurement is justifiable when case finding for coeliac disease in patients with Type 1 diabetes.

METHODS

All patients were assessed using IgA endomysial antibodies, IgA anti-tissue transglutaminase antibodies and total IgA levels. Altogether, 2434 individuals were tested: 1000 patients with Type 1 diabetes, 234 patients with coeliac disease and 1200 population control subjects. Definitive IgA deficiency was defined as total IgA levels < 0.07 g/l.

RESULTS

The prevalence of IgA deficiency was significantly more common in patients with Type 1 diabetes (0.9%, n = 9/1000; P = 0.036) and coeliac disease (1.29%, n = 3/234; P = 0.041) when compared with population control subjects (prevalence of 0.17%, 2/1200). No statistical difference between Type 1 diabetes and coeliac disease for IgA deficiency was identified (P = 0.87). Of patients in the group with Type 1 diabetes, 3.3% (33/1000) had coeliac disease, and of those only one patient had IgA deficiency leading to an antibody-negative presentation. Both IgA-deficient individuals within the population control subjects had normal duodenal biopsies and no relevant symptoms.

CONCLUSIONS

IgA deficiency is more common in Type 1 diabetes compared with population control subjects. Despite this, very few individuals with Type 1 diabetes and IgA deficiency appear to have villous atrophy on biopsy. These outcomes question the practice of routine IgA measurement when case finding for coeliac disease in patients with Type 1 diabetes.

A simple new non-invasive sweat indicator test for the diagnosis of diabetic neuropathy

A simple non-invasive indicator test (Neuropad(®)) has been developed for the assessment of sweating and, hence, cholinergic innervation in the diabetic foot. The present review summarizes current knowledge on this diagnostic test. The diagnostic ability of this test is based on a colour change from blue to pink at 10 min, with excellent reproducibility, which lends itself to patient self-examination. It has a high sensitivity (65.1-100%) and negative predictive value (63-100%), with moderate specificity (32-78.5%) and positive predictive value (23.3-93.2%) for the diagnosis of diabetic peripheral neuropathy. It also has moderate to high sensitivity (59.1-89%) and negative predictive value (64.7-91%), but low to moderate specificity (27-78%) and positive predictive value (24-48.6%) for the diagnosis of diabetic cardiac autonomic neuropathy. There are some data to suggest that Neuropad can detect early diabetic neuropathy, but this needs further evaluation. It remains to be established whether this test can predict foot ulceration and amputation, thereby contributing to the identification of high-risk patients.

Autonomic dysfunction and circadian blood pressure variations in people with impaired glucose tolerance

AIMS

To assess circadian blood pressure variability in people with impaired glucose tolerance and a healthy control population.

METHODS

Seventy-five people with impaired glucose tolerance and 40 healthy volunteers (frequency matched on 10-year age bands and sex) underwent a detailed neurological assessment. Autonomic neuropathy was detected by the five standard cardiovascular autonomic tests and heart rate variability was characterized by the triangle index. Diurnal indices were assessed by 24-h ambulatory blood pressure monitoring. Systolic and diastolic diurnal indices were defined as: (mean daytime blood pressure - mean night-time blood pressure) × 100/mean daytime blood pressure.

RESULTS

Mean 24-h systolic and diastolic blood pressure was significantly higher in the group with impaired glucose tolerance compared with the control group [126 ± 12 (mean ± SD) vs. 117 ± 10, 75 ± 7 vs. 71 ± 6 mmHg, both P < 0.05). Systolic and diastolic diurnal indices and heart rate variability triangular index were significantly lower in people with impaired glucose tolerance compared with control subjects (9.1 ± 7.8 vs. 13.2 ± 5.4, 14.5 ± 9.7 vs. 18.4 ± 7.1 mmHg, 28.0 ± 8.4 vs. 39.5 ± 9.3, all P < 0.05). Differences in mean diastolic blood pressure, heart rate variability triangular index and the frequency of non-dippers between those with impaired glucose tolerance and control subjects seemed to be independent of BMI and the presence of cardiovascular autonomic neuropathy, as simultaneous adjustment for BMI and cardiovascular autonomic neuropathy had no major effect on the results.

CONCLUSION

Our data suggest that people with impaired glucose tolerance have increased diastolic blood pressure and abnormal circadian blood pressure regulation, independent of obesity and the presence of cardiovascular autonomic neuropathy.

Frequency-modulated electromagnetic neural stimulation (FREMS) as a treatment for symptomatic diabetic neuropathy: results from a double-blind, randomised, multicentre, long-term, placebo-controlled clinical trial

AIMS/HYPOTHESIS

The aim was to evaluate the efficacy and safety of transcutaneous frequency-modulated electromagnetic neural stimulation (frequency rhythmic electrical modulation system, FREMS) as a treatment for symptomatic peripheral neuropathy in patients with diabetes mellitus.

METHODS

This was a double-blind, randomised, multicentre, parallel-group study of three series, each of ten treatment sessions of FREMS or placebo administered within 3 weeks, 3 months apart, with an overall follow-up of about 51 weeks. The primary endpoint was the change in nerve conduction velocity (NCV) of deep peroneal, tibial and sural nerves. Secondary endpoints included the effects of treatment on pain, tactile, thermal and vibration sensations. Patients eligible to participate were aged 18-75 years with diabetes for ≥ 1 year, HbA(1c) <11.0% (97 mmol/mol), with symptomatic diabetic polyneuropathy at the lower extremities (i.e. abnormal amplitude, latency or NCV of either tibial, deep peroneal or sural nerve, but with an evocable potential and measurable NCV of the sural nerve), a Michigan Diabetes Neuropathy Score ≥ 7 and on a stable dose of medications for diabetic neuropathy in the month prior to enrolment. Data were collected in an outpatient setting. Participants were allocated to the FREMS or placebo arm (1:1 ratio) according to a sequence generated by a computer random number generator, without block or stratification factors. Investigators digitised patients' date of birth and site number into an interactive voice recording system to obtain the assigned treatment. Participants, investigators conducting the trial, or people assessing the outcomes were blinded to group assignment.

RESULTS

Patients (n = 110) with symptomatic neuropathy were randomised to FREMS (n = 54) or placebo (n = 56). In the intention-to-treat population (50 FREMS, 51 placebo), changes in NCV of the three examined nerves were not different between FREMS and placebo (deep peroneal [means ± SE]: 0.74 ± 0.71 vs 0.06 ± 1.38 m/s; tibial: 2.08 ± 0.84 vs 0.61 ± 0.43 m/s; and sural: 0.80 ± 1.08 vs -0.91 ± 1.13 m/s; FREMS vs placebo, respectively). FREMS induced a significant reduction in day and night pain as measured by a visual analogue scale immediately after each treatment session, although this beneficial effect was no longer measurable 3 months after treatment. Compared with the placebo group, in the FREMS group the cold sensation threshold was significantly improved, while non-significant differences were observed in the vibration and warm sensation thresholds. No relevant side effects were recorded during the study.

CONCLUSIONS/INTERPRETATION

FREMS proved to be a safe treatment for symptomatic diabetic neuropathy, with immediate, although transient, reduction in pain, and no effect on NCV.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01628627.

FUNDING

The clinical trial was sponsored by Lorenz Biotech (Medolla, Italy), lately Lorenz Lifetech (Ozzano dell'Emilia, Italy).

Small fibre neuropathy: role in the diagnosis of diabetic sensorimotor polyneuropathy

Small fibres constitute 70-90% of peripheral nerve fibres and regulate several key functions such as tissue blood flow, temperature and pain perception as well as sweating, all of which are highly relevant to the clinical presentation and adverse outcomes associated with foot ulcerations in patients with diabetes. Recent studies demonstrated significant abnormalities in the small fibres in subjects with impaired glucose tolerance and diabetes, despite normal electrophysiology, suggesting that the earliest nerve fibre damage is to the small fibres. Unfortunately, guidelines and consensus statements focus on large fibres and continue to advocate electrophysiology as a diagnostic modality and as a primary end point for the assessment of therapeutic benefit. (In part, this reflects the difficulties in quantifying small fibre dysfunction and damage.) We have therefore critically assessed currently available techniques that measure small fibre dysfunction in diabetic neuropathy, using quantitative sensory and sudomotor testing. We have assessed the role of identifying structural damage by quantifying intraepidermal nerve fibre density in skin biopsies and corneal nerve morphology using corneal confocal microscopy. Finally, we propose a definition for diabetic neuropathy that incorporates small fibre damage.

Management strategies for gastrointestinal, erectile, bladder, and sudomotor dysfunction in patients with diabetes

There are substantial advances in understanding disordered gastrointestinal autonomic dysfunction in diabetes. It occurs frequently. The underlying pathogenesis is complex involving defects in multiple interacting cell types of the myenteric plexus as well. These defects may be irreversible or reversible. Gastrointestinal symptoms represent a major and generally underestimated source of morbidity for escalating health care costs in diabetes. Acute changes in glycaemia are both determinants and consequences of altered gastrointestinal motility. 35-90% of diabetic men have moderate-to-severe erectile dysfunction (ED). ED shares common risk factors with CVD. Diagnosis is based on medical/sexual history, including validated questionnaires. Physical examination and laboratory testing must be tailored to patient's complaints and risk factors. Treatment is based on PDE5-inhibitors (PDE5-I). Other explorations may be useful in patients who do not respond to PDE5-I. Patients at high cardiovascular risk should be stabilized by their cardiologists before sexual activity is considered or ED treatment is recommended. Estimates on bladder dysfunction prevalence are 43-87% of type 1 and 25% of type 2 diabetic patients, respectively. Common symptoms include dysuria, frequency, urgency, nocturia and incomplete bladder emptying. Diagnosis should use validated questionnaire for lower urinary tract symptoms. The type of bladder dysfunction is readily characterized with complete urodynamic testing. Sudomotor dysfunction is a cause of dry skin and is associated with foot ulcerations. Sudomotor function can be assessed by thermoregulatory sweat testing, quantitative sudomotor axon reflex test, sympathetic skin response, quantitative direct/indirect axon reflex testing and the indicator plaster.

Painful diabetic peripheral neuropathy: consensus recommendations on diagnosis, assessment and management

Painful diabetic peripheral neuropathy (DPN) is common, is associated with significant reduction in quality of life and poses major treatment challenges to the practising physician. Although poor glucose control and cardiovascular risk factors have been proven to contribute to the aetiology of DPN, risk factors specific for painful DPN remain unknown. A number of instruments have been tested to assess the character, intensity and impact of painful DPN on quality of life, activities of daily living and mood. Management of the patient with DPN must be tailored to individual requirements, taking into consideration the co-morbidities and other factors. Pharmacological agents with proven efficacy for painful DPN include tricyclic anti-depressants, the selective serotonin and noradrenaline re-uptake inhibitors, anti-convulsants, opiates, membrane stabilizers, the anti-oxidant alpha-lipoic acid and topical agents including capsaicin. Current first-line therapies for painful DPN include tricyclic anti-depressants, the serotonin and noradrenaline re-uptake inhibitor duloxetine and the anti-convulsants pregabalin and gabapentin. When prescribing any of these agents, other co-morbidities and costs must be taken into account. Second-line approaches include the use of opiates such as synthetic opioid tramadol, morphine and oxycodone-controlled release. There is a limited literature with regard to combination treatment. In extreme cases of painful DPN unresponsive to pharmacotherapy, occasional use of electrical spinal cord stimulation might be indicated. There are a number of unmet needs in the therapeutic management of painful DPN. These include the need for randomized controlled trials with active comparators and data on the long-term efficacy of agents used, as most trials have lasted for less than 6 months. Finally, there is a need for appropriately designed studies to investigate non-pharmacological approaches.

Aggressive and devastating neuropathy: the consequence of untreated slow-onset type 1 diabetes

Though type 1 diabetes (T1D) is described to be a disease of acute onset, there is strong evidence for a period of subclinical hyperglycaemia leading up to diagnosis. We describe two clinical cases with a prolonged and insidious onset of T1D, where neurological complications were present at the time of diagnosis. In both, there was an initial rapid and debilitating progression in neurological as well as other microvascular complications, but with a subsequent stabilization in complications over the next few years. These rare and unusual cases illustrate the variable nature of the natural history of T1D as well as its microvascular complications.

Immunological and C-peptide studies of patients with diabetes in northern Ethiopia: existence of an unusual subgroup possibly related to malnutrition

AIMS/HYPOTHESIS

Surveys in northern Ethiopia have demonstrated that apparent type 1 diabetes occurs more frequently than elsewhere in Africa and, indeed, in other parts of the world. We therefore investigated in detail a cohort of diabetic patients from this region to clarify the nature of this type of diabetes.

METHODS

All patients attending the diabetic clinic at Mekelle Hospital in the Tigray region of northern Ethiopia were investigated over a 6 week period. Clinical, demographic and anthropometric data were collected, as well as measurements of HbA(1c), fasting lipid profile, fasting serum C-peptide and serum markers of beta cell autoimmunity, i.e. islet antigen-2 and GAD antibodies (GADA).

RESULTS

Of 105 patients seen, 69 (66%) were on insulin treatment and had been from or close to diagnosis. Their median age and diabetes duration were 30 and 5 years, respectively, with a male excess of 2:1. Median BMI was 20.6 kg/m². Despite these clinical characteristics suggestive of type 1 diabetes, only 42 of 69 (61%) patients were C-peptide-negative and 35% GADA-positive. Overall, 38 (36%) of the total group (n = 105) had immunological or C-peptide characteristics inconsistent with typical type 1 or type 2 diabetes. The clinical characteristics, local prevalence of undernutrition, and GADA and C-peptide heterogeneity suggest a malnutrition-related form of diabetes.

CONCLUSIONS/INTERPRETATION

Not all patients in northern Ethiopia with apparent type 1 diabetes appear to have the form of disease seen in Europids; their disease may, in fact, be related to malnutrition.

Abnormal liver function tests in patients with Type 1 diabetes mellitus: prevalence, clinical correlations and underlying pathologies

AIMS

To determine the prevalence of elevated alanine transaminase (ALT) in a large cohort of patients with Type 1 diabetes and to examine the clinical correlations and causes. Methods Patients with Type 1 diabetes mellitus were prospectively recruited and ALT, glycated haemoglobin and lipid profile were measured. Patients with Type 2 diabetes mellitus were recruited as a comparison group.

PATIENTS

with abnormal ALT were investigated for underlying causes. Prevalence of abnormal ALT was analysed at three separate cut-offs and multivariable analysis used to identify independent risk factors.

RESULTS

Nine hundred and eleven with Type 1 diabetes and 963 with Type 2 diabetes were included. The prevalence of elevated ALT was dependent on the cut-off value: > 30 IU/l in males and > 19 IU/l in females, > 50 and > 63 IU/l was 34.5, 4.3 and 1.9%, respectively, in Type 1 diabetes and 51.4, 8.2 and 3.7%, respectively, in Type 2 diabetes. In Type 1 diabetes an elevated ALT was associated with worse glycaemic control, age > 55 years and elevated triglycerides. Investigation of these patients revealed a cause in 43.6% of patients, predominantly non-alcoholic fatty liver disease (NAFLD).

CONCLUSIONS

Elevated ALT is not uncommon in Type 1 diabetes and is associated with NAFLD-related risk factors. Patients with Type 1 diabetes and elevated ALT should be investigated as significant abnormalities may be found which are amenable to interventions.

A sub-Saharan African perspective of diabetes

Diabetes mellitus is an important and increasing cause of morbidity and mortality in sub-Saharan Africa. Accurate epidemiological studies are often logistically and financially difficult, but processes of rural-urban migration and epidemiological transition are certainly increasing the prevalence of type 2 diabetes. Type 1 disease is relatively rare, although this may be related to high mortality. This diabetic subgroup appears to present at a later age (by about a decade) than in Western countries. Variant forms of diabetes are also described in the continent; notably 'atypical, ketosis-prone' diabetes, and malnutrition-related diabetes mellitus. These types sometimes make the distinction between type 1 and type 2 diabetes difficult. Interestingly, this is also a current experience in the developed world. As more detailed and reliable complication studies emerge, it is increasingly apparent that African diabetes is associated with a high complication burden, which is both difficult to treat and prevent. More optimistically, a number of intervention studies and twinning projects are showing real benefits in varying locations. Future improvements depend on practical and sustainable support, coupled with local acceptance of diabetes as a major threat to the future health and quality of life of sub-Saharan Africans.

Thalamic neuronal dysfunction and chronic sensorimotor distal symmetrical polyneuropathy in patients with type 1 diabetes mellitus

AIMS/HYPOTHESIS

Although clear peripheral nerve pathological abnormalities have been demonstrated in diabetic peripheral neuropathy (DPN), there is little information with regard to brain involvement. Our aim was to use in vivo proton magnetic resonance specroscopy (H-MRS) in patients with DPN in order to assess the neuro-chemical status of the thalamus, which acts as the gateway to the brain for somatosensory information.

METHODS

Participants included 18 type 1 diabetic men (eight without DPN, ten with DPN) and six non-diabetic healthy volunteers, who all underwent detailed clinical and neurophysiological assessments yielding a Neuropathy Composite Score (NCS) derived from Neuropathy Impairment Score of the Lower Limbs plus seven tests of nerve function prior to investigation via a single-voxel H-MRS technique, which was used to sample ventral posterior thalamic parenchyma. Spectroscopic resonances including those due to N-acetyl aspartate (NAA) were assessed at both short and long echo-time, providing putative indicators of neuronal function and integrity, respectively.

RESULTS

At long echo-time we observed significantly lower NAA:creatine (p = 0.04) and NAA:choline (p = 0.02) ratios in DPN patients than in the other groups. No group differences were detected at short echo-time. We found a significant positive association between both sural amplitude (rho = 0.61, p = 0.004) and nerve conduction velocity (r = 0.58, p = 0.006) and NAA:creatine signal among participants with diabetes. Vibration detection threshold (rho = -0.70, p = 0.004) was significantly related to NAA:choline ratio. Heart rate variability with deep breathing (rho = -0.46, p = 0.05) and NCS (rho = -0.53, p = 0.03) were significantly related to NAA:creatine ratio.

CONCLUSIONS/INTERPRETATION

The significantly lower NAA:creatine ratio in DPN is suggestive of thalamic neuronal dysfunction, while the lack of difference in short echo-time between the groups does not suggest neuronal loss. Taken together with the observed correlations between NAA and neurophysiological assessments, these findings provide evidence for thalamic neuronal involvement in DPN.

Diabetic complications and glycaemic control in remote North Africa

BACKGROUND

Delivery of diabetes services in resource-poor areas of Africa is difficult. Control is often poor and complications are common. However, adequate robust surveys are uncommon, particularly in remote rural areas. This makes needs assessment difficult and health-care planning impossible.

AIM

To accurately assess the glycaemic control and burden of complications in a group of diabetic patients from a remote area of a resource-limited north African country.

DESIGN

Prospective cohort study.

METHODS

Over a 6-week period, all patients attending the diabetic clinic at Mekelle Hospital in northern Ethiopia were intensively assessed, using imported western technology as necessary. Glycated haemoglobin (HbA(1c)), lipid profile, serum creatinine and urinary albumin-creatinine ratio were measured. Complications were assessed as accurately as possible, including examination of fundi by an ophthalmic specialist, and biosthesiometry for neuropathy.

RESULTS

There were 105 patients, mean (+/- SD) age 41 +/- 16 years and diabetes duration 7 +/- 6 years. There were 74 (70%) males, and 69 (66%) on insulin. Median body mass index was low at 20.6 kg/m(2), but mean HbA(1c) high at 11.3 +/- 2.8% (68% had an HbA(1c) over 10.0%). Cataract (12%), retinopathy (21%), neuropathy (41%) and microalbuminuria (51%) were common; but nephropathy (2%) was rare, as was large vessel disease (6% had peripheral vascular disease, and none had coronary artery disease or cerebrovascular disease). Risk factors such as hypertension (5%) and smoking (2%) were uncommon, and lipid profiles were generally good.

DISCUSSION

We conclude that in this severely resource-limited area of North Africa, glycaemic control amongst diabetic patients is very poor. Neuropathy, retinopathy and microalbuminuria are common; but large vessel disease risk factors are beneficial, and macroangiopathy prevalence is low. Scattered populations, shortage of drugs and insulin and lack of diabetes team care are major factors behind these serious issues of diabetic control and complications.

Relationship between autonomic neuropathy and hypertension--are we underestimating the problem?

BACKGROUND

Cardiac autonomic neuropathy (CAN) is associated with significant morbidity and mortality in diabetes and the risk is even greater in those with hypertension.

AIMS

The aim of our study was to investigate the relationship between CAN and 24-h blood pressure profile in normoalbuminuric patients with Type 2 diabetes mellitus.

METHODS

Seventy patients with Type 2 diabetes (31 without CAN, 39 with CAN), who had no history of hypertension, and 29 healthy volunteers underwent five standard cardiovascular reflex tests to assess autonomic function and 24-h ambulatory blood pressure monitoring.

RESULTS

Twenty-four-hour mean systolic blood pressure, blood pressure load and hyperbaric impact values were significantly higher in diabetic patients with CAN compared with control subjects and diabetic patients without CAN (P < 0.05). In spite of normal clinic blood pressures, 54% of diabetic subjects with CAN and 29% without CAN were hypertensive (systolic blood pressure load > 20%, P < 0.05). In the diabetes group as a whole, Valsalva ratio, postural systolic blood pressure changes and diastolic blood pressure responses during sustained handgrip correlated significantly and negatively with 24-h mean systolic blood pressure (P < 0.01, P < 0.001, P < 0.05) and blood pressure load (P < 0.05, P < 0.001, P < 0.05).

CONCLUSIONS

Cardiovascular autonomic neuropathy is independently associated with hypertension in normoalbuminuric Type 2 diabetic patients with no history of hypertension. Relying on clinic blood pressures in subjects with CAN could lead to a failure to diagnose hypertension in over half of cases. All normotensive patients with CAN should be screened for hypertension using ambulatory blood pressure monitoring in order to institute early aggressive interventions to improve their long-term outlook.

Sural nerve pathology in diabetic patients with minimal but progressive neuropathy

AIMS/HYPOTHESIS

The early pathological features of human diabetic neuropathy are not clearly defined. Therefore we quantified nerve fibre and microvascular pathology in sural nerve biopsies from diabetic patients with minimal neuropathy.

METHODS

Twelve diabetic patients underwent detailed assessment of neuropathy and fascicular sural nerve biopsy at baseline, with repeat assessment of neuropathy 8.7+/-0.6 years later.

RESULTS

At baseline, neuropathic symptoms, neurological deficits, quantitative sensory testing, cardiac autonomic function and peripheral nerve electrophysiology showed minimal abnormality, which deteriorated at follow-up. Myelinated fibre density, fibre and axonal area, and g-ratio were normal but teased fibre studies showed paranodal abnormalities (p<0.001), segmental demyelination (p<0.01) and remyelination (p<0.01) without axonal degeneration. Unassociated Schwann cell profile density (p<0.04) and unmyelinated axon density (p<0.001) were increased and axon diameter was decreased (p<0.007). Endoneurial capillaries demonstrated basement membrane thickening (p<0.006), endothelial cell hyperplasia (p<0.004) and a reduction in luminal area (p<0.007).

CONCLUSIONS/INTERPRETATION

The early pathological features of human diabetic neuropathy include an abnormality of the myelinated fibre Schwann cell and unmyelinated fibre degeneration with regeneration. These changes are accompanied by a significant endoneurial microangiopathy.

Risk factors for cardiac autonomic neuropathy in type 1 diabetes mellitus

AIMS/HYPOTHESIS

Cardiac autonomic neuropathy (CAN) is associated with increased morbidity and mortality in type 1 diabetes. Apart from glycaemic control, risk factors for CAN have not been extensively studied.

METHODS

As part of the EURODIAB Prospective Complications Study, CAN--defined as either a loss of heart rate variability or postural hypotension on standing--was assessed at baseline and follow-up (7.3+/-0.6 years from baseline) in patients with type 1 diabetes.

RESULTS

Follow-up measurements were available for 956 participants without CAN at baseline (age at baseline 31.3+/-8.9 years, duration of diabetes 13.5+/-8.3 years). During follow-up, 163 (17%) subjects developed CAN, yielding an incidence of 23.4 per 1,000 person-years. Blood pressure, weight, the presence of cardiovascular disease, albuminuria, distal symmetrical polyneuropathy (DSP) and retinopathy at baseline were associated with the incidence of CAN after adjustment for sex, duration of diabetes and HbA(1)c. In a multivariate regression model, baseline factors associated with an increased risk of developing CAN were age [odds ratio (OR)=1.3 per decade, 95% CI 1.1-1.7], HbA(1)c (OR=1.2 per percentage point, 95% CI 1.1-1.4), systolic blood pressure (OR=1.1 per 10 mmHg, 95% CI 1.0-1.3), feeling faint on standing (OR=2.0, 95% CI 1.2-3.2), DSP (OR=1.9, 95% CI 1.2-3.0) and retinopathy (OR=1.7, 95% CI 1.1-2.6).

CONCLUSION/INTERPRETATION

This study confirms the importance of exposure to hyperglycaemia as a risk factor for CAN. A small set of variables, including HbA(1)c, hypertension, DSP and retinopathy, predict the risk of CAN. Clinical trials are needed to address the impact of intensive antihypertensive treatment on CAN in type 1 diabetes.

A new autologous keratinocyte dressing treatment for non-healing diabetic neuropathic foot ulcers

AIMS

To evaluate the use of a new cell-tailored carrier surface (TranCell) for delivery of autologous keratinocytes to promote wound healing in patients with chronic neuropathic foot ulcers.

METHODS

TranCell is a sterile medical grade polymer coated with a plasma-polymerized functional surface containing 20% carboxylic acid which enables keratinocytes to attach and proliferate. Six diabetic patients with neuropathic ulcers resistant to conventional therapy were treated with weekly applications of autologous keratinocytes delivered on TranCell. A split-thickness skin biopsy was taken from each patient followed by isolation, expansion and freezing down of keratinocytes. Keratinocytes were thawed and seeded on TranCell 48 h prior to application. This procedure was repeated weekly in addition to conventional therapy until wound healing was achieved.

RESULTS

Complete healing was achieved in six out of nine ulcers in six patients, a reduction in ulcer size was achieved in one ulcer and no response was seen in one ulcer. Treatment was discontinued in one patient due to development of Methicillin-Resistant Staphylococcus aureus (MRSA) after only three applications of TranCell. Wound healing took 6-17 applications over 6-20 weeks. There were no recurrences in the healed ulcers after a follow-up of 6 months.

CONCLUSIONS

TranCell delivery of autologous cells is a promising treatment for chronic diabetic foot ulcers with no side-effects and no recurrence in the healed ulcers.

Increased sural nerve epineurial blood flow in human subjects with painful diabetic neuropathy

AIMS/HYPOTHESIS

The pathogenesis of painful diabetic neuropathy remains unknown. As a consequence we still do not have any effective, rational treatments and a greater understanding of the mechanisms is urgently required. Previous studies have shown no consistent morphological differences in the nerves of patients with and without painful neuropathy. The aim of this study was to compare epineurial haemodynamics in patients with chronic painful and painless neuropathy.

METHODS

The techniques of microlightguide spectrophotometry and fluorescein angiography were used to measure epineurial intravascular oxygen saturation and blood flow respectively. Eleven patients with painful and eight with painless neuropathy were studied, with the groups matched carefully in terms of severity of neuropathy and diabetes control.

RESULTS

Intravascular oxygen saturation was higher in the painful neuropathy group compared to those without pain (median 73.8% vs 67.7%, respectively; p=0.021). Fluorescein rise time was also faster in those with painful symptoms (median 18.3 s vs 53.6 s; p=0.046) indicating higher epineurial blood flow in these subjects.

CONCLUSION/INTERPRETATION

These results indicate that there are distinct differences in haemodynamics within the epineurium of the sural nerve in subjects with painful and painless neuropathy. Haemodynamic factors could therefore have an important role in the pathogenesis of neuropathic pain and might offer further insight into potential treatments for this distressing condition.

Surgical presentation of ischaemic hepatitis

Intestinal ischaemia typically presents with signs suggestive of an acute surgical abdomen. A raised serum lactate may substantiate the diagnosis. The first case of ischaemic hepatitis mimicking intestinal ischaemia is reported. The recognition of markedly deranged transaminases allows the clinician to differentiate the two diagnoses and potentially avoid the risks incurred with laparotomy.

Autonomic neuropathy is associated with increased cardiovascular risk factors: the EURODIAB IDDM Complications Study

AIMS

To assess the prevalence of and risk factors for autonomic neuropathy in the EURODIAB IDDM Complications Study.

METHODS

The study involved the examination of randomly selected Type I (insulin-dependent) diabetic patients from 31 centres in 16 European countries. Neuropathic symptoms and two tests of autonomic function (changes in heart rate and blood pressure from lying to standing) were assessed and data from 3007 patients were available for the present analysis. Autonomic neuropathy was defined as an abnormality of at least one of the tests.

RESULTS

The prevalence of autonomic neuropathy was 36% with no sex differences. The frequency of one and two abnormal reflex tests was 30% and 6%, respectively. The R-R ratio was abnormal in 24% of patients while 18% had orthostatic hypotension defined as a fall in systolic blood pressure > 20 mmHg on standing. Significant correlations were observed between autonomic neuropathy and age (P < 0.01), duration of diabetes (P < 0.0001), HbA1c (P < 0.0001), diastolic blood pressure (P < 0.05), lower HDL-cholesterol (P < 0.01), the presence of retinopathy (P < 0.0001) and albuminuria (P < 0.0001). New associations have been identified from the study: the strong relationship of autonomic neuropathy to cigarette smoking (P < 0.01), total cholesterol/HDL-cholesterol ratio (P < 0.05) and fasting triglyceride (P < 0.0001). As a key finding, autonomic neuropathy was related to the presence of cardiovascular disease (P < 0.0001). All analyses were adjusted for age, duration of diabetes and HbA1c. However, data have been only partly confirmed by logistic regression analyses. Frequency of dizziness on standing up was 18%, while only 4% of patients had nocturnal diarrhoea and 5% had problems with bladder control.

CONCLUSION

Cardiovascular reflex tests, even in the form of the two tests applied, rather than a questionnaire, seem to be appropriate for the diagnosis of autonomic neuropathy. The study has identified previously known and new potential risk factors for the development of autonomic neuropathy, which may be important for the development of risk reduction strategies. Our results may support the role of vascular factors in the pathogenesis of autonomic neuropathy.

Charcot neuroarthropathy in diabetes mellitus

Charcot neuroarthropathy has been recognised for over 130 years and yet it remains a major cause of morbidity for patients with diabetes mellitus and a continuing challenge for physicians. It is rare but it seems to be increasing in prevalence and this provides hope that with larger studies it will soon be possible to clarify the natural history and optimal treatment regimens. The underlying cause is thought to be trauma in a neuropathic foot that leads to a complex series of pathological processes culminating in bone and joint destruction and subsequent deformity. The acute reaction is often misdiagnosed and many patients present late with established deformity. Even when the diagnosis is considered at an early stage there are no definitive criteria or tests to confirm charcot neuroarthropathy and a high index of suspicion is necessary in any diabetic patient with a swollen warm foot in the presence of somatic or autonomic neuropathy. Treatment has traditionally involved the use of various methods to avoid weight bearing but recent work has begun to suggest that bisphosphonates might be able to arrest the acute process. In the long term, treatment involves a multidisciplinary approach aimed at providing appropriate footwear to reduce plantar pressures and avoid foot ulceration; in some circumstances this involves surgical correction of deformities before adequate footwear can be supplied. Further studies of the emerging treatments for Charcot neuroarthropathy are needed to provide long-term outcome data on morbidity and deformity.

Measurement of somatic neuropathy for clinical practice and clinical trials

Distal sensory polyneuropathy is a common and unpleasant complication of diabetes mellitus. It is the main initiating factor for foot ulceration. The increasing prevalence of diabetes has important associated health implications, both in terms of morbidity and mortality, and results in the consumption of scarce medical resources. Identification of somatic neuropathy in clinical practice is therefore important for targeted educational and other interventions. In this article, we describe methods for detecting somatic neuropathy in clinical practice and highlight those tests that are proven to be predictors of foot ulceration. The approach for detecting and characterizing somatic neuropathy for clinical trials, however, differs significantly. These methods must ideally have high levels of reproducibility, sensitivity, and specificity. Currently, several neurophysiologic tests are employed in clinical trials in order to accurately characterize diabetic neuropathy. The recent introduction of the computer-assisted programs for the measurement of sensory modalities for clinical trials has been a major advance. Due to their invasive nature and associated morbidity, nerve biopsy studies are no longer used in clinical trials. Recently, using magnetic resonance imaging (MRI), significant spinal cord atrophy has been demonstrated in established neuropathy. If this observation proves to be an early feature, then a relatively rapid, noninvasive MRI technique may be used in the future to characterize diabetic neuropathy.

Vascular factors and metabolic interactions in the pathogenesis of diabetic neuropathy

Diabetes mellitus is a major cause of peripheral neuropathy, commonly manifested as distal symmetrical polyneuropathy. This review examines evidence for the importance of vascular factors and their metabolic substrate from human and animal studies. Diabetic neuropathy is associated with risk factors for macrovascular disease and with other microvascular complications such as poor metabolic control, dyslipidaemia, body mass index, smoking, microalbuminuria and retinopathy. Studies in human and animal models have shown reduced nerve perfusion and endoneurial hypoxia. Investigations on biopsy material from patients with mild to severe neuropathy show graded structural changes in nerve microvasculature including basement membrane thickening, pericyte degeneration and endothelial cell hyperplasia. Arterio-venous shunting also contributes to reduced endoneurial perfusion. These vascular changes strongly correlate with clinical defects and nerve pathology. Vasodilator treatment in patients and animals improves nerve function. Early vasa nervorum functional changes are caused by the metabolic insults of diabetes, the balance between vasodilation and vasoconstriction is altered. Vascular endothelium is particularly vulnerable, with deficits in the major endothelial vasodilators, nitric oxide, endothelium-derived hyperpolarising factor and prostacyclin. Hyperglycaemia and dyslipidaemia driven oxidative stress is a major contributor, enhanced by advanced glycation end product formation and polyol pathway activation. These are coupled to protein kinase C activation and omega-6 essential fatty acid dysmetabolism. Together, this complex of interacting metabolic factors accounts for endothelial dysfunction, reduced nerve perfusion and function. Thus, the evidence emphasises the importance of vascular dysfunction, driven by metabolic change, as a cause of diabetic neuropathy, and highlights potential therapeutic approaches.

Spinal-cord involvement in diabetic peripheral neuropathy

The pathogenesis of diabetic distal symmetrical polyneuropathy (DSP) is poorly understood but there is some evidence that the disease process might extend beyond peripheral nerves. We used magnetic-resonance imaging to measure spinal-cord cross-sectional area in diabetic patients with and without DSP and in healthy controls. There were significant differences in cord area between the groups at C4/5 and T3/4 (p=0.004 and p=0.033, respectively), with a smaller cord area in those with DSP compared with controls (p=0.001 and p=0.016 for C4/5 and T3/4, respectively). These results indicate that DSP is not simply a disease of the peripheral nerve and that there is substantial involvement of the spinal cord.

Blood pressure response to standing in the diagnosis of autonomic neuropathy: the EURODIAB IDDM Complications Study

Autonomic neuropathy is associated with poor prognosis. Cardiovascular reflexes are essential for the diagnosis of autonomic nerve dysfunction. Blood pressure response to standing is the most simple test for the evaluation of sympathetic integrity, however it is still discussed which diagnostic criteria of abnormal response should be considered as optimal. The EURODIAB IDDM Complications Study involved the examination of randomly selected Type 1 diabetic patients from 31 centres in 16 European counties. Data from 3007 patients were available for the present evaluation. Two tests of autonomic function (response of heart rate /R-R ratio/ and blood pressure from lying to standing) just as the frequency of feeling faint on standing up were assessed. R-R ratio was abnormal in 24% of patients. According to different diagnostic criteria of abnormal BP response to standing (>30 mmHg, >20 mmHg, and >10 mmHg fall in systolic BP), the frequency of abnormal results was 5.9%, 18% and 32%, respectively (p < 0.001). The frequency of feeling faint on standing was 18%, thus, it was identical with the prevalence of abnormal blood pressure response to standing when >20 mmHg fall in systolic blood pressure was considered as abnormal. Feeling faint on standing correlated significantly with both autonomic test results (p < 0.001). A fall >20 mmHg in systolic blood pressure after standing up seems to be the most reliable criterion for the assessment of orthostatic hypotension in the diagnosis of autonomic neuropathy in patients with Type 1 diabetes mellitus.

'Sausage toe': a reliable sign of underlying osteomyelitis

AIMS

To follow-up patients with a 'sausage' deformity of the toe associated with local neuropathic ulceration to confirm the diagnosis of underlying osteomyelitis. This was based on our observation that some diabetic patients with suspected pedal osteomyelitis with a local neuropathic ulcer have a 'sausage' deformity of a toe.

METHODS

Over a period of 2 years, 14 patients with foot ulcers, who were observed to have the 'sausage' deformity of a toe in the diabetic foot clinic were followed up and investigated.

RESULTS

Underlying osteomyelitis was confirmed in six on the very first X-ray examination. A further seven had osteomyelitis diagnosed on bone scanning. Both the X-ray and the bone scan were equivocal in one patient, whose ulcer only healed after an 8-week course of antibiotics. Antibiotic therapy was successful in 11 patients and three patients required amputation of the affected toe. Following successful treatment, there was full resolution of the 'sausage toe' in the majority.

CONCLUSIONS

The appearance of a 'sausage toe' should alert the physician of the possibility of underlying osteomyelitis in diabetic foot, so that prompt treatment can be commenced with antibiotics.

Characteristics of insulin requiring diabetes in rural northern Ethiopia--a possible link with malnutrition?

We have examined 100 consecutive insulin-treated diabetic patients from the Diabetic Clinic at Mekelle Hospital in Tigray, Northern Ethiopia; an area of low socio-economic status recently affected by severe famine. The study was conducted over a six month period (1997). Mean age of onset of diabetes was 27 +/- 10 y (SD) and there was a male excess (3.1:1.0). Body Mass index (BMI) at diagnosis was very low at 15.8 +/- 2.8. Because of erratic insulin supply 48 (48%) had interrupted insulin treatment in the past for a mean duration of 9 +/- 12 weeks (range 1-78). Despite this, only 2 (4%) developed ketoacidosis (DKA). The patients thus have features suggestive of malnutrition-related diabetes mellitus (MRDM) possibly of the "malnutrition-modulated" (MMDM) type in view of the apparent absence of overt exocrine pancreatic disease. The famine in this area 10 years previously may be of relevance to the aetiology of diabetes in these patients.

Early identification of diabetic foot ulcers that may require intervention using the micro lightguide spectrophotometer

OBJECTIVE

Adequate tissue oxygenation is known to be essential for the healing of diabetic foot ulcers, but hypoxia has also been shown to be a potent stimulus for growth. There are no studies looking specifically at ulcer oxygen levels during the healing process. We measured the serial microvascular oxygen saturation (SaO2) of the foot ulcer, the ulcer margin, and a control site using the Erlangen micro lightguide spectrophotometer (EMPHO II; Bodenseewerk Geratetechnik, Erlangen, Germany) to study serial changes during healing.

RESEARCH AND DESIGN METHODS

Studied over 9 months were 14 patients with neuropathy with a total of 24 foot ulcer sites. Of these patients, four (seven ulcers) had significant ischemia as determined by the ankle-brachial pressure index (ABPI) and transcutaneous oxygen tension.

RESULTS

Of 21 ulcer sites with serial measurements, only 13 ulcers healed. In those ulcers, a significant reduction (P<0.05) in SaO2 occurred with healing. SaO2 dropped from 58% at initial presentation (mean area 2.6 cm2) to 47% at midsize (mean area 1.2 cm2 at 5.2 weeks) and finally reduced to 45% just before it healed. Similar trends were also seen around the margin of the ulcers (initial 49%, midsize 45%, and final 41%; P = 0.1). However, there were no such changes on the control sites (43, 40, and 40%; P = 0.5) or within the eight ulcers that did not heal (46, 42, and 53%; P = 0.2).

CONCLUSIONS

Serial microvascular oxygen measurements may be used to identify at an early stage those ulcers that are unlikely to heal and, therefore, need surgical intervention.

Digital imaging: an accurate and easy method of measuring foot ulcers

AIMS

A progressive reduction in the area of foot ulcer on serial measurement is traditionally done by tracing the margin of the ulcer on a transparent film and counting the number of squares on a graph paper underneath. We set out to use and validate the measurement of foot ulcers using a digital imaging technique and compare this with the traditional method.

METHODS

Thirty diabetic foot ulcers (18 patients) were studied over 10 weeks. Each ulcer was traced by three independent observers with a pen over a flexigrid Opsite film and digital photographs were taken. Each observer calculated the area of an ulcer first using a 1-mm2 graph paper and then with the computer software. For each ulcer we calculated the mean area using measurements from all the observers. We then calculated the deviation from this mean for each observer.

RESULTS

There was significantly less interobserver variation using the digital image than the traditional method with mean coefficient of variation (CV) 16% vs. 27%; P = 0.05.

CONCLUSIONS

The digital imaging method was faster and easier to use and the patients preferred it, as it was a noncontact method. In addition it also provides a photographic record for comparison.