The diabetic foot: pathophysiology and treatment

The importance of inflammation control for the treatment of chronic diabetic wounds

Diabetic chronic wounds cause massive levels of patient suffering and economic problems worldwide. The state of chronic inflammation arises in response to a complex combination of diabetes mellitus-related pathophysiologies. Advanced treatment options are available; however, many wounds still fail to heal, exacerbating morbidity and mortality. This review describes the chronic inflammation pathophysiologies in diabetic ulcers and treatment options that may help address this dysfunction either directly or indirectly. We suggest that treatments to reduce inflammation within these complex wounds may help trigger healing.

Impact of the Rapid Normalization of Chronic Hyperglycemia on the Receptor Activator of Nuclear Factor-Kappa B Ligand and the Osteoprotegerin System in Patients Living with Type 2 Diabetes: RANKL-GLYC Study

The RANKL-GLYC study aims to explore the impact of the rapid correction of chronic hyperglycemia on the receptor activator of nuclear factor-kappa B ligand (RANKL) and its antagonist osteoprotegerin (OPG). RANKL and OPG are considered the main factors in the pathophysiology of Charcot neuroarthropathy, a devastating complication of the joints that remains poorly understood. The study began recruiting patients in September 2021 and ends in June 2022; the final study results are scheduled for January 2023.

Tissue Oxygenation Measurements to Aid Scalpel Debridement Removal in Patients With Diabetes

BACKGROUND

Callus formation in the diabetic foot increases the risk of ulcer onset. It is standard procedure to remove these dead tissue layers to reduce rising pressures. In a surgical procedure known as scalpel debridement, or chiropody the callus tissue is removed up to the epidermal layer. Factors may influence the outcome of this surgical process such as clinician inexperience. In an effort to standardize the debridement process, tissue oxygenation (TO) measurements are obtained before and after to study the effect of debridement on callus tissue.

METHODS

Fifteen debridement cases were analyzed using near infrared (NIR) imaging to study changes in TO. The NIR-based device used in this study estimates effective changes in TO in terms of oxy-, deoxy-, total hemoglobin, and oxygen saturation. Weber contrasts between callus tissue and the surrounding normal tissue were compared following debridement for all TO parameters. In a secondary analysis, callus tissue was segmented into quadrants and a percent of significance (in terms of total TO change) was calculated using a t-test.

RESULTS

Results show majority of cases displayed greater than 80% as the significant change in TO following debridement, except in cases with the presence of blood clot (a common precursor for ulceration). In cases where incomplete debridement was suspected, a significant change in TO was still observed.

CONCLUSIONS

With extensive systematic studies in the future, NIR imaging technique to measure changes in TO may be implemented as a low-cost hand-held imaging device useful for objectively assessing the effectiveness of the scalpel debridement process.

Relationship between Plantar Pressure and Sensory Disturbance in Patients with Hansen's Disease-Preliminary Research and Review of the Literature

Orthoses and insoles are among the primary treatments and prevention methods of refractory plantar ulcers in patients with Hansen’s disease. While dynamic plantar pressure and tactile sensory disturbance are the critical pathological factors, few studies have investigated whether a relationship exists between these two factors. In this study, dynamic pressure measured using F-scan system and tactile sensory threshold evaluated with monofilament testing were determined for 12 areas of 20 feet in patients with chronic Hansen’s disease. The correlation between these two factors was calculated for each foot, for each clinical category of the foot (0–IV) and across all feet. A significant correlation was found between dynamic pressure and tactile sensation in Category II feet (n = 8, p = 0.016, r² = 0.246, Spearman’s rank test). In contrast, no significant correlation was detected for the entire foot or within the subgroups for the remainder of the clinical categories. However, the clinical manifestation of lesion areas showed high variability: (1) pressure concentrated, sensation lost; (2) margin of pressure concentration, sensation lost; (3) pressure concentrated, sensation severely disturbed but not lost; and (4) tip of the toe. These results may indicate that, even though there was a weak relationship between dynamic pressure and tactile sensation, it is important to assess both, in addition to the basics of orthotic treatment in patients with Hansen’s disease presenting with refractory plantar ulceration.

TUG1 enhances high glucose-impaired endothelial progenitor cell function via miR-29c-3p/PDGF-BB/Wnt signaling

BACKGROUND

Diabetes is associated with the dysfunction of endothelial progenitor cells (EPCs), characterized as impaired angiogenesis, a phenomenon thought to be involved in the development of diabetic foot. lncRNA plays an essential role in microvascular dysfunction and signaling pathways in patients with diabetes. lncRNA taurine upregulated gene 1 (TUG1) participates in angiogenesis in various cells. However, the mechanisms of TUG1 activity in EPCs have not been elucidated.

METHODS

We isolated and then characterized EPCs from the peripheral blood of mice using immunofluorescence and flow cytometry. Western blot detected the wnt/β-catenin pathway in high glucose-treated EPCs. Bioinformatics analysis predicted a putative binding site for TUG1 on miR-29c-3p. The interactions among TUG1, platelet-derived growth factor-BB (PDGF-BB), and miR-29c-3p were analyzed by luciferase assays. In vivo, diabetic mouse ischemic limb was treated with normal saline or TUG1 overexpression lentiviruses.

RESULTS

We found that EPC migration, invasion, and tube formation declined after treatment with high glucose, but improved with TUG1 overexpression. Mechanically, wnt/β-catenin pathway and autophagy were involved in the function of TUG1 overexpression in high glucose-treated EPCs. Moreover, TUG1 regulates the PDGF-BB/wnt pathway and function of high glucose-treated EPCs via miR-29c-3p. In vivo, injection of TUG1 lentivirus in a diabetic mouse ischemic limb model stimulated angiogenesis.

CONCLUSIONS

Our findings suggest that TUG1 restores high glucose-treated EPC function by regulating miR-29c-3p/PDGF-BB/Wnt signaling.

The Evaluation of Foot Rockers on the Kinematic Parameters of Individuals With Diabetes

BACKGROUND

A variety of shoe modifications have been used to reduce the forces applied on the plantar surface of the foot in those with diabetes. Toe and heel rockers are 2 of the most common types used. The aim of this study is to evaluate the effect of these shoe modifications on the kinematics of both normal and diabetic individuals.

METHOD

Two groups of healthy and diabetic individuals were recruited for this study. The Qualysis motion analysis system was used to record the motions of participants while walking with shoes with toe and a combination of toe and heel rockers (combined). The effects of the type of rockers used and the effect of groups were determined using MANOVA.

RESULTS

Results of the study demonstrated no discernible difference between the spatiotemporal and range of motion of the ankle, knee, and hip joints while walking with a toe and combined rockers. There was also no difference between healthy and diabetic individuals in relation to these parameters (P value >.05).

CONCLUSION

Results of this study demonstrated no difference between the spatiotemporal and range of motion of lower-limb joints in healthy and diabetic individuals when walking with toe and combined rockers. Because the use of these rockers did not influence the kinematics of the joints while walking, it is recommended that they be used for this group of individuals if they influence the forces applied on the foot.

LEVELS OF EVIDENCE

Level IV.

Chronic Sciatic Neuropathy in Rat Reduces Voluntary Wheel-Running Activity With Concurrent Chronic Mechanical Allodynia

BACKGROUND

Animal models of peripheral neuropathy produced by a number of manipulations are assessed for the presence of pathologic pain states such as allodynia. Although stimulus-induced behavioral assays are frequently used and important to examine allodynia (ie, sensitivity to light mechanical touch; von Frey fiber test), other measures of behavior that reflect overall function are not only complementary to stimulus-induced responsive measures, but are also critical to gain a complete understanding of the effects of the pain model on quality of life, a clinically relevant aspect of pain on general function. Voluntary wheel-running activity in rodent models of inflammatory and muscle pain is emerging as a reliable index of general function that extends beyond stimulus-induced behavioral assays. Clinically, reports of increased pain intensity occur at night, a period typically characterized with reduced activity during the diurnal cycle. We therefore examined in rats whether alterations in wheel-running activity were more robust during the inactive phase compared with the active phase of their diurnal cycle in a widely used rodent model of chronic peripheral neuropathic pain, the sciatic nerve chronic constriction injury (CCI) model.

METHODS

In adult male Sprague Dawley rats, baseline (BL) hindpaw threshold responses to light mechanical touch were assessed using the von Frey test before measuring BL activity levels using freely accessible running wheels (1 hour/day for 7 sequential days) to quantify the distance traveled. Running wheel activity BL values are expressed as total distance traveled (m). The overall experimental design was after BL measures, rats underwent either sham or CCI surgery followed by repeated behavioral reassessment of hindpaw thresholds and wheel-running activity levels for up to 18 days after surgery. Specifically, separate groups of rats were assessed for wheel-running activity levels (1 hour total/trial) during the onset (within first 2 hours) of either the (1) inactive (n = 8/group) or (2) active (n = 8/group) phase of the diurnal cycle. An additional group of CCI-treated rats (n = 8/group) was exposed to a locked running wheel to control for the potential effects of wheel-running exercise on allodynia. The 1-hour running wheel trial period was further examined at discrete 20-minute intervals to identify possible pattern differences in activity during the first, middle, and last portions of the 1-hour trial. The effect of neuropathy on activity levels was assessed by measuring the change from their respective BLs to distance traveled in the running wheels.

RESULTS

Although wheel-running distances between groups were not different at BL from rats examined during either the inactive phase of the diurnal cycle or active phase of the diurnal cycle, sciatic nerve CCI reduced running wheel activity levels compared with sham-operated controls during the inactive phase. In addition, compared with sham controls, bilateral low-threshold mechanical allodynia was observed at all time points after surgical induction of neuropathy in rats with free-wheel and locked-wheel access. Allodynia in CCI compared with shams was replicated in rats whose running wheel activity was examined during the active phase of the diurnal cycle. Conversely, no significant reduction in wheel-running activity was observed in CCI-treated rats compared with sham controls at any time point when activity levels were examined during the active diurnal phase. Finally, running wheel activity patterns within the 1-hour trial period during the inactive phase of the diurnal cycle were relatively consistent throughout each 20-minute phase.

CONCLUSIONS

Compared with nonneuropathic sham controls, a profound and stable reduction of running wheel activity was observed in CCI rats during the inactive phase of the diurnal cycle. A concurrent robust allodynia persisted in all rats regardless of when wheel-running activity was examined or whether they ran on wheels, suggesting that acute wheel-running activity does not alter chronic low-intensity mechanical allodynia as measured using the von Frey fiber test. Overall, these data support that acute wheel-running exercise with limited repeated exposures does not itself alter allodynia and offers a behavioral assay complementary to stimulus-induced measures of neuropathic pain.

Cardiovascular Autonomic Dysfunction Predicts Diabetic Foot Ulcers in Patients With Type 2 Diabetes Without Diabetic Polyneuropathy

We investigated the factors that might influence the development of diabetic foot ulcers (DFUs) in type 2 diabetes patients without diabetic polyneuropathy (DPN).From January 2000 to December 2005, a total of 595 patients who had type 2 diabetes without DPN between the ages of 25 and 75 years, and had no prior history of DFUs were consecutively enrolled in the study. A cardiovascular autonomic function test was performed to diagnose cardiovascular autonomic neuropathy (CAN) using heart rate variability parameters.The median follow-up time was 13.3 years. Among the 449 (75.4%) patients who completed the follow-up evaluation, 22 (4.9%) patients developed new ulcers, and 6 (1.3%) patients underwent the procedure for lower extremity amputations. The patients in the DFUs group had a longer duration of diabetes, higher baseline HbA1c levels, higher rates of nephropathy, and CAN. A Cox hazard regression analysis results revealed that the development of DFUs was significantly associated with the presence of CAN (normal vs definite CAN; HR, 4.45; 95% confidence interval, 1.29-15.33) after adjusting for possible confounding factors.The development of DFUs was independently associated with CAN in patients with type 2 diabetes without DPN. We suggested the importance of CAN as a predictor of DFUs even in the patients without DPN, and the need to pay attention to patients with definite CAN and type 2 diabetes.

Effect of the blood HbA1c level on surgical treatment outcomes of diabetics with ankle fractures

OBJECTIVE

To investigate whether blood haemoglobin A 1c (HbA1c) levels was predicative of diabetic patients' responsiveness to surgical treatment of ankle fractures.

METHODS

The relationship between blood HbA1c levels and surgical treatment outcomes of 21 diabetic patients undergoing open reduction internal fixation (ORIF) for ankle fractures was analyzed with Pearson correlation testing and t testing. All patients were treated with ORIF using standard surgical techniques. Treatment outcomes were defined using radiological outcome, the American Orthopaedic Foot and Ankle Score (AOFAS) ankle-hindfoot scale score, surgical revision rate, and complication rate.

RESULTS

HbA1c levels were found to have a statistically significant correlation with poor radiological outcomes (r = 0.547) and AOFAS ankle-hindfoot scores (r = -0.592). Additionally, though rates of poor radiological outcome, revision, and complication were high in the diabetic population as a whole, these rates were considerably higher among individuals with elevated HbA1c (≥6.5%) and considerably lower among individuals with lower HbA1c (<6.5%) levels.

CONCLUSION

Blood HbA1c levels appear to be predictive of risk and complication rates in the surgical treatment outcomes of diabetic patients with ankle fractures.

Histopathologic characteristics of bone infection complicating foot ulcers in diabetic patients

BACKGROUND

A universally accepted histopathologic classification of diabetic foot osteomyelitis does not currently exist. We sought to evaluate the histopathologic characteristics of bone infection found in the feet of diabetic patients and to analyze the clinical variables related to each type of bone infection.

METHODS

We conducted an observational prospective study of 165 diabetic patients with foot ulcers who underwent surgery for bone infection. Samples for microbiological and histopathologic analyses were collected in the operating room under sterile conditions.

RESULTS

We found four histopathologic types of osteomyelitis: acute osteomyelitis (n = 46; 27.9%), chronic osteomyelitis (n = 73; 44.2%), chronic acute osteomyelitis (n = 14; 8.5%), and fibrosis (n =32; 19.4%). The mean ± SD time between the initial detection of ulcer and surgery was 15.4 ± 23 weeks for acute osteomyelitis, 28.6 ± 22.4 weeks for chronic osteomyelitis, 35 ± 31.3 weeks for chronic acute osteomyelitis, and 27.5 ± 27.3 weeks for the fibrosis stage (analysis of variance: P = .03). Bacteria were isolated and identified in 40 of 46 patients (87.0%) with acute osteomyelitis, 61 of 73 (83.5%) with chronic osteomyelitis, 11 of 14 (78.6%) with chronic acute osteomyelitis, and 25 of 32 (78.1%) with fibrosis.

CONCLUSIONS

Histopathologic categorization of bone infections in the feet of diabetic patients should include four groups: acute, chronic, chronic acute, and fibrosis. We suggest that new studies should identify cases of fibrosis to allow comparison with the present results.

Inter-observer reproducibility of probing to bone in the diagnosis of diabetic foot osteomyelitis

AIMS

The objectives of our study were (i) to analyse the inter-observer reproducibility or diagnostic variability of the probing-to-bone test, depending on the training of the professional involved, and (ii) to assess whether the probing-to-bone test can be extrapolated to any professional specialty that deals with these patients.

METHODS

This was a cross-sectional study, involving 75 patients with diabetic foot ulcer and clinical suspicion of osteomyelitis. A registration sheet was completed for all patients involved in the research study, gathering data relative to the results of the probing-to-bone test performed by three observers. Observer 1 was a very experienced professional with several years of experience in the treatment of the diabetic foot; observer 2 was a medium-experienced professional whose experience ranges from 6 to 12 months in the treatment of the diabetic foot; observer 3 was a healthcare professional without experience in the treatment of the diabetic foot. Data were gathered confidentially by a fourth researcher.

RESULTS

The results showed a kappa index of 0.593 (95% CI 0.407-0.778) between observer 1 and observer 2, 0.397 (95% CI 0.188-0.604) between observer 1 and observer 3 and 0.53 (95% CI 0.335-0.725) between observer 2 and observer 3.

CONCLUSIONS

The probing-to-bone test demonstrated moderate to fair concordance with an experienced examiner, although the degree of concordance is not significant between groups.

Diagnostics, theragnostics, and the personal health server: fundamental milestones in technology with revolutionary changes in diabetic foot and wound care to come

Over the past generation, significant advances in care have led to reductions in amputation worldwide. However, it may be argued that the most potent advances in healing have been in organization of care. Technologies are now emerging that may allow further enhancements of organization and integration of care while also bringing in much needed bedside, chairside, and in-home diagnostics to identify key points in healing and potential early warning signs for recurrence. This article reviews what are believed to be 6 key areas of change over the next generation. These include portability, durability, automation, intelligence, ubiquity, and afford-ability, all yielding specific advances in wound diagnostics. The authors believe that devices will be organized into personal health servers in cloud-synchronized devices already existing in the home (eg, a scale), the clinic, and on (or in) the patient.

The treatment of diabetic foot infections

Successful treatment of infection in the feet of patients with diabetes mellitus remains a challenge. Although the diagnosis of infection remains a clinical decision, presentation in feet rendered insensate from diabetic neuropathy plus co-existing vascular insufficiency means presentation is often atypical. Wounds frequently yield polymicrobial growth and differentiating commensal from pathogenic organisms can be difficult; isolates from diabetic foot wounds are often multidrug resistant. Affected patients often have many other co-morbidities, which not only affect the choice of appropriate antimicrobial regimen but also impede healing. Further, much contention surrounds the management of osteomyelitis, with the merits and role of surgery still undecided. In this review we briefly consider the epidemiology and pathogenesis of diabetic foot disease, before discussing emerging best microbiological practice and how this fits with the multidisciplinary approach required to tackle this difficult clinical problem.

Complexity of factors related to outcome of neuropathic and neuroischaemic/ischaemic diabetic foot ulcers: a cohort study

AIMS/HYPOTHESIS

We sought to identify factors related to short-term outcome of foot ulcers in patients with diabetes treated in a multidisciplinary system until healing was achieved.

METHODS

Consecutively presenting patients with diabetes and worst foot ulcer (Wagner grade 1-5, below ankle) (n = 2,511) were prospectively followed and treated according to a standardised protocol until healing was achieved or until death. The number of patients lost to dropout was 31. The characteristics of the remaining 2,480 patients were: 1,465 men, age 68 +/- 15 years (range 18-96), type 1 diabetes 18%, type 2 diabetes 82% and insulin-treated 62%.

RESULTS

The healing rate without major amputation in surviving patients was 90.6% (n = 1,867). Sixty-five per cent (n = 1,617) were healed primarily, 9% (n = 250) after minor amputation and 8% after major amputation; 17% (n = 420) died unhealed. Out of 2,060 surviving patients, 1,007 were neuroischaemic (48.8%). In a multiple regression analysis, primary healing was related to co-morbidity, duration of diabetes, extent of peripheral vascular disease and type of ulcer. In neuropathic ulcers, deep foot infection, site of ulcer and co-morbidity were related to amputation. Amputation in neuroischaemic ulcers was related to co-morbidity, peripheral vascular disease and type of ulcer. Age, sex, duration of diabetes, neuropathy, deformity and duration of ulcer or site of ulcer did not have an evident influence on probability of amputation.

CONCLUSIONS/INTERPRETATION

Patients with diabetic foot ulcer suffer from multi-organ disease. Factors related to outcome are correspondingly complex.

The pro-inflammatory environment in recalcitrant diabetic foot wounds

Lower extremity ulceration is one of the serious and long-term diabetic complications rendering a significant social burden in terms of amputation and quality-of-life reduction. Diabetic patients experience a substantial wound-healing deficit. These lesions are featured by an exaggerated and prolonged inflammatory reaction with a significant impairment in local bacterial invasion control. Experimental and clinical evidences document the deleterious consequences of the wound's pro-inflammatory phenotype for the repair process. From a biochemical standpoint, hyperinflammation favours wound matrix degradation, thus, amplifying a pre-existing granulation tissue productive cells' invasiveness and recruitment deficit. Tumour necrosis factor perpetuates homing of inflammatory cells, triggers pro-apoptotic genes and impairs reepithelialisation. Advanced glycation end-products act in concert with inflammatory mediators and commit fibroblasts and vascular cells to apoptosis, contributing to granulation tissue demise. Therapeutic approaches aimed to downregulate hyperinflammation and/or attenuate glucolipotoxicity may assist in diabetic wound healing by dismantling downstream effectors. These medical interventions are demanded to reduce amputations in an expanding diabetic population.

Ankle fractures in diabetics

Treatment of the diabetic patient with ankle fracture presents a unique set of challenges to the surgeon. The care of these patients should follow a multidisciplinary approach with a team of orthopedic and vascular surgeons, internists, anesthesiologists, nurses, and diabetic educators. Meticulous preoperative planning, intraoperative technique, and postoperative care can be decrease potential limb-threatening complications; however, complications will occur despite excellent care. Early recognition and treatment of preoperative complications is imperative. These patients require close attention for long periods, and the surgeon should plan on building a strong relationship with these patients.

Relationship between sympathetic skin response and power spectral analysis of heart rate variation in patients with type 2 diabetes

We measured sympathetic skin response (SSR), a measure of sympathetic sudomotor function, and compared SSR with other quantitative neurological tests including power spectral analysis (PSA) of heart rate variations in 60 type 2 diabetic subjects. SSR was detected in all 20 age-matched healthy subjects but was absent in 17 patients with type 2 diabetes (28%) (P<.01). Even after exclusion of diabetic patients with absent SSR, the SSR amplitude in diabetic patients was significantly lower than in healthy subjects (P<.05). Both the low frequency power of R-R intervals, which reflects both cardiac sympathetic and parasympathetic function, and the postural fall in systolic blood pressure were significantly lower in the diabetic patients with absent SSR than in those with present SSR (P<.05 and.001, respectively). However, we found no significant difference in the high frequency power of R-R intervals, which reflects accurately cardiac parasympathetic function, between the diabetic patients with absent SSR and those with present SSR. In the diabetic patients with present SSR, SSR amplitude was also positively correlated with the postural fall in systolic blood pressure, low-frequency (LF) power, and high-frequency (HF) power. These results suggest that SSR is a useful and sensitive method for evaluating diabetic autonomic neuropathy, and that sympathetic sudomotor neuropathy may be preceded by cardiac parasympathetic neuropathy in patients with type 2 diabetes.

Results of blood inflammatory markers are associated more strongly with toe-brachial index than with ankle-brachial index in patients with type 2 diabetes

OBJECTIVE

Three blood markers of inflammation (high-sensitivity C-reactive protein [hsCRP], interleukin [IL]-6, and fibrinogen) were compared with markers of atherosclerotic cardiovascular disease (CVD) (history of stroke or cardiac ischemia and measured toe-brachial index [TBI]) to determine whether inflammatory markers are associated with atherosclerosis in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Of 103 patients with type 2 diabetes, 26 had CVD. TBI was plethysmographically determined in both great toes. Serum hsCRP was immunonephelometrically determined. Plasma IL-6 was measured by an enzyme immunoassay.

RESULTS

Both ABI and TBI were lower in diabetic patients with CVD than in those without CVD (1.05 +/- 0.19 vs. 1.14 +/- 0.09, P < 0.05, and 0.75 +/- 0.20 vs. 0.95 +/- 0.21, P < 0.001, respectively). By linear regression, right TBI but not right ABI showed a significant negative correlation with serum hsCRP (r = -0.372, P < 0.01) and plasma fibrinogen (r = -0.224, P < 0.05). Serum hsCRP was also negatively correlated with lower TBI, but not lower ABI. We found no significant correlation between plasma IL-6 and ABI or TBI.

CONCLUSIONS

TBI was strongly associated with CVD, serum hsCRP, and plasma fibrinogen. Of these inflammatory markers, serum hsCRP may be the most promising marker for vascular inflammation.

Lower extremity amputations in diabetic Mexican American elders: incidence, prevalence and correlates

This study was designed to determine the incidence and prevalence of amputations in diabetic Mexican American elders and to identify correlates of lower extremity amputations. Data for this study came from baseline and two follow-up interviews of the Hispanic Established Population for the Epidemiological Study of the Elderly (EPESE) conducted in five southwestern states (Texas, California, New Mexico, Colorado and Arizona) in 1993-1994. Of the 3050 subjects aged 65 and older, 690 reported diabetes, and from these, 60 (8%) reported having at least one lower extremity amputation. Losing a leg was the most common type of amputation (53%). Twelve percent of respondents reported a new amputation and 40% of amputees reported a second amputation during follow-up. Mortality among amputees was 46% during a 5-year follow-up. Multiple logistic regression analysis showed that being male and having eye problems, hip fracture and diabetes for 10 or more years were significantly associated with lower extremity amputations at baseline, whereas obesity, stroke and 10 or more years with diabetes were significantly associated with new amputations at 5-year follow-up. Gender and disease history were associated with lower extremity amputations at baseline and follow-up. These variables may be useful in developing patient education and intervention programs.

Elevation of von Willebrand factor in plasma in diabetic patients with neuropathic foot ulceration

AIMS

The present study examines the relationship between markers of endothelial dysfunction and diabetic neuropathy or consequent neuropathic foot ulceration in patients with Type 2 diabetes mellitus.

METHODS

We studied 65 Type 2 diabetic patients including 25 diabetic patients without neuropathy, 27 with neuropathy but no history of foot ulceration, and 13 with neuropathic ulceration. Plasma concentrations of von Willebrand factor (vWF) and soluble thrombomodulin (TM), measures of endothelial dysfunction, were determined by enzyme immunoassays. We performed various tests quantifying aspects of diabetic neuropathy including vibration perception threshold (VPT; for sensory neuropathy), coefficient of variation of R-R intervals (CVR-R; for cardiac autonomic neuropathy), and cold-induced vasodilation in the great toe for peripheral sympathetic neuropathy.

RESULTS

CVR-R and cold-induced vasodilation were significantly diminished in patients with neuropathic foot ulceration compared with patients with neuropathy but no history of foot ulceration. Plasma vWF concentrations were positively correlated with VPT and cold-induced vasodilation test, and were inversely correlated with CVR-R. Multivariate analysis disclosed that VPT and percentage vasodilation were independent factors for plasma vWF. Plasma vWF was significantly elevated in patients with foot ulceration compared with patients without neuropathy or those with neuropathy but not foot ulceration. However, plasma TM concentrations did not differ between the three groups.

CONCLUSIONS

Diabetic patients with neuropathic foot ulceration had severe impairment of cardiac autonomic and peripheral sympathetic nerves. Elevation of vWF in plasma was associated with neuropathic foot ulceration, linking endothelial dysfunction to foot ulceration.

Fibrinogen adsorption in the diabetic foot syndrome and peripheral arterial occlusive disease: first clinical experience

The elimination of fibrinogen from plasma improves plasma viscosity and whole-blood viscosity. For extracorporeal adsorption of fibrinogen, the pentapeptide gly-pro-arg-pro-lys was coupled to sepharose CL-4B3. Adsorbers containing 135 ml of coupled sepharose CL-4B were used to eliminate fibrinogen from the plasma of 7 men and 3 women (48-75 years old). Nine patients suffered from diabetes mellitus, 1 patient from peripheral arterial occlusive disease, and 5 patients were on regular hemodialysis. Treatments were scheduled on Days 1, 2, 4, 6, 8, 10, 13, 16, 19, 22, 25, and 28. One hundred forty-four treatments with fibrinogen adsorption were performed. No clinical side effects due to the fibrinogen adsorption procedure were observed. In these 10 patients, fibrinogen concentration before the first treatment was 473.7 +/- 183.7 mg/dl. In the first treatment session, fibrinogen concentration was lowered to 241.4 +/- 125.8 mg/dl by treating 4,270 +/- 1,180 ml of plasma. In the following 134 treatments, the pretreatment concentration of fibrinogen was 262.6 +/- 83.4 mg/dl, and the posttreatment concentration was 120.6 +/- 37.2 mg/dl. The mean amount of plasma treated was 3,737 +/- 1,643 ml, and the mean duration of a treatment session (except first treatment) was 143.7 +/- 63.1 min. In 7 patients, a mean posttreatment fibrinogen concentration of < or = 123 mg/dl was obtained; in the other patients, concentrations of 133, 177, and 184 mg/dl were obtained. Yet, the decrease of fibrinogen concentration was also pronounced in these 3 patients: -82%, -67%, and -73%, respectively. During the treatment period of 28 days, wound healing was observed in 9 of the 10 patients. In conclusion, affinity chromatography using the pentapeptide gly-pro-arg-pro-lys is an effective, selective, and safe procedure to lower fibrinogen concentration in plasma. It could be a therapeutic option in severe blood vessel disease in which drug therapy is not sufficient and invasive procedures such as bypass or angioplasty cannot be applied. Yet, more information is needed, for example, about the fibrinogen concentration that has to be reached to get the maximal improvement of micro- and/or macrocirculation.

Complications of ankle fractures in diabetic patients

Ankle fracture in patients with DM mandates a stepwise protocol to minimize the potential complications of delayed fracture healing, wound complications, and development of Charcot arthropathy. For nondisplaced ankle fracture, a nonoperative approach with increased duration of immobilization seems successful based on experience of the limited series. A displaced ankle fracture in a patient with DM requires a surgical intervention. The authors advocate tight glucose control in both groups to improve the fracture milieu and to ameliorate the potential complications. Appropriate stable fixation with adequate length of immobilization is crucial for successful fracture resolution.

Factors associated with ulceration and amputation in the neuropathic foot

The purpose of this paper is to review selected literature on the relationship of neuropathy and other related factors in foot ulceration and lower extremity amputation. There is strong evidence that sensory loss and mechanical stress are the primary cause of foot ulceration and common factors in the pathway to lower extremity amputation. Foot stress results from extrinsic factors such as footwear and intrinsic factors such as deformity and limited joint mobility. Understanding the interplay of these factors is valuable in identifying persons whose feet are at risk, effectively preventing and treating foot ulcerations and ultimately preventing lower extremity amputation.

Adjunct low intensity ultrasound in Charcot neuroarthropathy

Neuropathic arthropathy or Charcot joint is a disease process that results in progressive destruction of bone and soft tissue secondary to the loss of protective sensation. The disease is most common among patients suffering from diabetes mellitus. Although there is no known definitive cure for the progressive destruction of a Charcot joint, it is possible to slow and in some cases arrest the destruction of the bone and soft tissue. The Charcot joint will be addressed with a review of the literature and use of a new technology as adjunct treatment.

Evaluation of microangiopathy of the skin in patients with non-insulin-dependent diabetes mellitus by laser Doppler flowmetry; microvasodilatory responses to beraprost sodium

To determine the relationship of skin microangiopathy and other diabetic microvascular complications, we measured changes in skin blood flow after the administration of the prostacyclin (PGI2) analogue, beraprost sodium (BPS), in 82 patients with non-insulin-dependent diabetes mellitus and 20 healthy subjects. The diabetic patients had various degrees of retinopathy and nephropathy. Using laser Doppler flowmetry we measured skin blood flow at the dorsum of the right big toe at various times after the administration of 40 micrograms BPS and calculated the blood flow change (delta flux = peak flux--basal flux). We also determined the ankle pressure index (API), an ankle/brachial systolic pressure ratio. The basal blood flow was higher in healthy subjects than in diabetic patients (P < 0.001). BPS significantly increased blood flow in both diabetic patients and healthy subjects (P < 0.001). In all 102 subjects delta flux was positively correlated with the API (R = 0.40, P < 0.001). Despite no differences in API among the diabetic retinopathy and nephropathy subgroups, the delta flux in diabetic patients with progressive retinopathy and macroalbuminuria was significantly lower than in healthy subjects or in diabetic patients with less severe retinopathy and nephropathy (P < 0.05). The results suggested that BPS increases skin blood flow and the flow increase induced by BPS is related partly to the levels of API. The effect of BPS on skin blood flow decreased with an increases in the severity of retinopathy and nephropathy. Diabetic skin microangiopathy appears to coexist with other microvascular diabetic complications and may be proportional to their severity.

[Mutilating acrodystrophic neuropathy of alcoholic origin in the French West Indies]

Among principal causes of acrodystrophic neuropathy-ie, leprosy, diabetes, amyloid neuropathy, hereditary sensory neuropathies-alcoholism is controversial since first descriptions (Bureau et al, 1957) incriminating heavy drinking. This retrospective review of 38 cases occurring in West-Indian rhum abusers, tends however to confirm its etiologic role. Patients present with three non specific signs or symptoms of the lower extremities: anaesthetic foot, plantar ulcers, and chronic, indolent, mutilating arthropathies. Motor function is spared. Male gender, massive (> or = 150 g pure alcohol daily) and prolonged (> or = 12 years) rhum intake, hygiene deficiency, poverty and social distress, exposition to repeated foot microtrauma and a protracted, non fatal, but disabling course leading to amputation, are the main features of this syndrome. The pathophysiology is poorly documented, and many questions remain unanswered including a genetic predisposition or a particular neuro-toxicity of West Indian rhum. However, the clinical and epidemiologic data presented here favour the concept of an "alcoholic foot" or true alcoholic acrodystrophic neuropathy, quite different from the most common sensory-motor form.

Treatment of diabetic polyneuropathy with the neurotrophic peptide ORG 2766

The efficacy of the neurotrophic peptide ORG 2766 in diabetic patients with polyneuropathy was evaluated in a double-blind, placebo-controlled, multicentre trial. One hundred and twenty four patients were randomised in five groups to receive 0.1, 0.4, 2 or 5 mg ORG 2766 or placebo, once daily, administered subcutaneously 52 weeks. Thermal discrimination thresholds (TDT) and vibration perception thresholds (VPT), motor and sensory nerve conduction velocity, Hoffmann reflex, heart rate variation during deep breathing and heart rate response after standing up, neurological examination score and neuropathic symptom score were determined at baseline and after 17, 34 and 52 weeks of treatment. Of the nerve function indices studied, at week 52 the TDTwarmth of the hand in the ORG 2766 0.1, 0.4 and 5 mg groups and the TDTcold of the foot in the ORG 2766 0.1 and 0.4 mg groups significantly improved compared with placebo. Further significant improvement as compared with placebo was observed in the paraesthesia score at week 34 and week 52 in the ORG 2766 2 mg group. Only at week 34 had both the heartbeat variation during deep breathing and the VPT of the foot in the ORG 2766 0.1 mg group improved significantly, compared with placebo. No further statistically significant differences were observed at time for the other measures. No adverse reactions were observed. The only recorded drug-induced side effect was pain at the injection site. Taking all measures of efficacy into account, the statistically significant results observed did not show consistency within each measure. Therefore, it is concluded that ORG 2766, in contrast to earlier reports, is not effective in treating diabetic polyneuropathy.

The use of orthotic devices to correct plantar callus in people with diabetes

Foot problems are a major cause of morbidity in people with diabetes. Plantar callus is common and is a sign of abnormal foot pressures. Shear stresses at these areas of high foot pressures may ultimately result in ulcer formation. This study compared the effect on plantar callus of the use of rigid orthotic devices and conventional podiatric care. Twenty diabetic subjects participated in the study and were randomly allocated to conventional treatment (n = 11) or orthotic device treatment (n = 9). After 12 months the patients in the orthotic group showed a significant reduction in callus grade, whereas the conventionally treated group showed no significant change. There were no adverse effects from wearing the orthotic device. Rigid orthoses have a beneficial effect on plantar callus presumably through the lowering and redistribution of abnormal foot pressures.

The Semmes-Weinstein monofilament as a potential predictor of foot ulceration in patients with noninsulin-dependent diabetes

The objective was to evaluate the Semmes-Weinstein monofilament as a potential predictor of foot ulceration. A case-control study was carried out in a teaching hospital clinic specializing in diabetes and hyperlipidemic disorders. Two groups of patients with noninsulin-dependent diabetes mellitus were studied: 168 with no history of foot lesions (No-Ulcer group, aged 58.1 +/- 9.7 years, duration 11.5 +/- 7.8 years) and 14 who had at least one foot ulceration during the last year (foot ulcer group, aged 60.8 +/- 7.8 years', duration 17.1 +/- 10.5 years). The authors defined and measured a "monofilament index" using a size 5.07 Semmes-Weinstein monofilament on three locations on each foot and then measured peroneal nerve current perception thresholds using the Neurometer at three frequencies: 5 Hz, 250 Hz, and 2,000 Hz. The monofilament index score was lower in patients in the foot ulcer group than in patients in the No-Ulcer group (1.71 +/- 2.36 vs 5.21 +/- 1.81, P < 0.001). A cutoff point at an index of 5 out of 6 yielded a sensitivity rate of 85.71% and a false-positive rate of 16.07%. The peroneal nerve current perception threshold was higher (P < 0.005) in patients in the foot ulcer group than in patients in the No-Ulcer group for all frequencies (605.8 +/- 414.6 vs 181.5 +/- 272.3 for 5 Hz; 743.2 +/- 361.7 vs 251.6 +/- 283.7 for 250 Hz; 859.4 +/- 220.2 vs 423.3 +/- 252.6 for 2,000 Hz). (ABSTRACT TRUNCATED AT 250 WORDS)

Abnormal digital pressure measurements in diabetic neuropathic foot ulceration

The diabetic neuropathic ulcer is typically slow to heal and recurrent. Macrovascular insufficiency is usually excluded as foot pulses are present and ankle:brachial pressure ratios are not decreased. These assessments cannot however exclude more distal vascular disease. Digital pressure measurements enable a reliable assessment of the distal peripheral vascular status to be made. The aim of this study was therefore to use toe pressures to assess the contribution of distal ischaemia in the pathogenesis of the neuropathic ulcer. Sixteen diabetic patients with recurrent neuropathic foot ulceration had their toe pressures compared to 10 neuropathic patients without a history of foot ulceration, 10 diabetic control subjects, and 11 normal subjects. Four non-diabetic patients with neuropathy and foot ulceration were also assessed. All subjects had ankle:brachial pressure indices > or = 1. Toe pressure was assessed using laser Doppler flowmetry to record the return of skin blood flow. The toe:brachial pressure index (TBI) was then calculated. The diabetic patients with a history of recurrent neuropathic ulceration, had the lowest mean TBI, 0.63 +/- 0.14 (SD), compared to the non-ulcerated diabetic neuropathy patients, the diabetic control subjects, and the normal subjects. 0.84 +/- 0.11, 0.82 +/- 0.1, and 0.81 +/- 0.07, p < 0.01, respectively. Three of the four non-diabetic patients with neuropathic foot ulceration also had an abnormally low TBI. Reduced toe pressure measurements are thus found to be associated with neuropathic foot ulceration. The contribution of distal ischaemia in the pathogenesis of the diabetic neuropathic foot ulcer needs to be evaluated.

Skin microcirculation in diabetic and non-diabetic patients at different stages of lower limb ischaemia

One hundred and one non-diabetic and 54 diabetic patients suffering from lower limb ischaemia were divided into (i) asymptomatic subjects, (ii) claudicants, (iii) critically ischaemic patients, i.e. Fontaine III or IV patients with either an ankle pressure < 51 mmHg or a toe pressure < 31 mmHg, and (iv) Fontaine III or IV patients in whom ankle and toe pressures could not be assessed due to vessel wall sclerosis or skin ulceration. Skin microcirculation was investigated to assess (a) the compounding effect of diabetes in leg ischaemia and (b) the additive value of microcirculatory investigation in the appreciation of the severity of the ischaemic disease. The techniques used included capillary microscopy, transcutaneous oximetry and laser Doppler fluxmetry. The severity of ischaemia was readily discernable using microcirculatory techniques. The presence of diabetes appeared to change skin microcirculatory perfusion, but especially in critically ischaemic patients, the microcirculation was no more compromised than non-diabetics. Using skin oxygen tension measurements, a positive predictive value of 77% was obtained in the detection of critical ischaemia, when a cut-off value of 30 mmHg was applied. Seventy per cent of patients, in whom the severity of ischaemia could not be classified using blood pressure measurements, could be classified as critically ischaemic on the basis of microcirculatory investigation. In conclusion, the influence of diabetes on the microcirculation is outweighed by the effects of atherosclerosis when vascular disease becomes severe. Techniques to investigate skin microcirculation are a useful way of assessing the severity of lower limb ischaemia in the presence of diabetes mellitus or if peripheral blood pressures cannot be obtained.

High prevalence of diabetes in chronic leg ulcer patients: a cross-sectional population study

In a cross-sectional survey, designed to detect all patients with current chronic leg ulcers, 27% of the patients had diabetes mellitus. The outcome for the 104 examined diabetic patients has been evaluated and compared with the 278 nondiabetic patients. The purpose was to establish the prevalence of leg ulcers among diabetic patients and to assess potential causes. The point prevalence was calculated by extrapolating the leg ulcer frequency to the total diabetic population in the studied area. The point prevalence for active leg ulcers (including foot ulcers) in diabetic patients was 3.5% (95% CI 2.8-4.2). Ulcers above the malleoli were almost as common as foot ulcers. Peripheral vascular disease was present in 67% of all ulcerated legs in patients with diabetes compared to 42% in nondiabetic patients (p < 0.001). In 72% of foot ulcers in diabetic patients arterial impairment was judged to be a contributing aetiological factor and in nondiabetic patients 45% (p < 0.001). Ulcers solely attributed to possible neuropathy were less common (15%). Ulcers with multifactorial causes were common above the malleoli. This survey has given the size of the problem and indicates macroangiopathy to be the dominating factor responsible for slow or nonhealing ulcers in diabetic patients. Objective assessment of arterial circulation is mandatory and signs of arterial impairment require consultation with a vascular surgeon.

The association between clinical risk factors and outcome of diabetic foot ulcers

OBJECTIVE

The aim of the study was to describe the association between clinical risk factors in diabetic patients with food ulcers in relation to outcome.

DESIGN

A prospective study of 314 consecutively presenting diabetic patients with foot ulcers referred to the Department of Internal Medicine between July 1, 1983 and June 30, 1987. All patients were followed to final outcome.

SETTING

All patients were treated by the same multi-disciplinary foot care team at the Department of Medicine, both as in- and out-patients. Healing was defined as intact skin for at least 6 months.

RESULTS

One hundred and ninety-seven patients healed primarily, 77 after amputation, and 40 died unhealed. Signs of macroangiopathy were more common among patients who healed after amputation. The outcome was strongly related to age, though 43% of the patients with an age over 80 years healed primarily. There was no difference in smoking habits between patients who healed primarily and those who required amputation to heal. Diabetic nephropathy was found in 26% of the patients and was strongly associated with amputation. Presence of retinopathy was found in 54% of the patients, but this finding was not related to the outcome. There were no differences in short-term metabolic control as assessed by hemoglobin A1c levels between patients who healed primarily and those who healed after amputation.

CONCLUSION

The presence of diabetic foot ulcers was strongly associated with age and diabetic complications such as multiple cardiovascular disease and nephropathy, which were important factors related to amputation.

Lower limb arterio-venous shunts, autonomic neuropathy and diabetic foot

We have quantitatively assessed the percentage of lower limb arterio-venous (a-v) shunting using a radioisotopic technique and correlated it with autonomic neuropathy evaluated by cardiovascular tests. We have studied three groups of diabetic patients: Group A, 12 non-neuropathic subjects without foot lesions; Group B, 12 neuropathic subjects without foot lesions; Group C, 12 neuropathic subjects with recurrent foot ulcers. Shunting was higher in Group C (10.4 +/- 2.7%) than in Group B (6.8 +/- 2.3%, P less than 0.01) and Group A (3.8 +/- 1.2%, P less than 0.001). Shunts in Group B were higher than in Group A (P less than 0.05). All the tests exploring autonomic function were more impaired in Groups B and C than in Group A, with no difference between Groups B and C. A direct correlation was found between a-v shunting and the following cardiovascular tests: postural hypotension (PH) (r = 0.41, P less than 0.02), sustained handgrip (SH) (r = 0.56, P less than 0.001), deep breathing (DB) (r = 0.40, P less than 0.005) and lying to standing (LS) (r = 0.44, P less than 0.01). A positive correlation was also found between a-v shunts and duration of the disease (r = 0.62, P less than 0.001). Arterio-venous shunting was found to be directly related to autonomic neuropathy even if the higher shunting found in the patients with foot ulcers was not related to a higher degree of autonomic involvement; in addition, this group of patients was characterized by having a more advanced sensory and motor neuropathy. In conclusion, autonomic neuropathy, through its influence on a-v shunts, may play a role in the pathogenesis of diabetic foot, but peripheral neuropathy probably plays a key role in conditioning the development of the overt clinical manifestations of diabetic foot.