DIABETIC FOOT : CORRELATION BETWEEN CLINICAL ABNORMALITIES AND ELECTROPHYSIOLOGICAL STUDIES

Diabetic foot ulceration is a serious and expensive complication with considerable morbidity that affects up to 15% of diabetic patients during their lifetime and 80-85% of amputations are preceded by foot ulcers. The aim of this work is to study the correlation between severity of clinical abnormalities and electrophysiological studies in diabetic foot ulcers. This study was a cross sectional evaluation of 44 patients with diabetic foot ulcers seen in 2 hospitals in Basrah (Al-Faiha General and Basrah Teaching) from October 2003 to July 2004. All patients were type 2 diabetes mellitus. The sensitivity of numbness, burning feeling, pricking feeling and worse symptom at night was 84.6%, 69.2%, 61.5% and 51.5% respectively. While sensitivity of decreased pin prick sensation, absent vibration sense, absent ankle jerk, decreased temperature sensations and absent position sense was 100%, 87.2%, 71.8%, 56.5% and 12.8% respectively. Sensitivity of combined clinical symptoms was 66.6%, with specificity of 40%, and predictive value of 89.6% while that of clinical signs 48.7% and 60% respectively and predictive value of 90.4 %. There was no significant difference in severity of electrophysiological abnormalities in the affected and non-affected feet. Clinical findings was correlated well with the severity of electrophysiological changes in patients with diabetic foot ulcers.


Introduction
europathy is present in 80% of patients with foot ulcers; it promotes ulcer formation by decreasing pain sensation and perception of pressure, by causing muscle imbalance that can lead to anatomic deformities and by impairing the microcirculation and the integrity of the skin [1][2][3][4][5] .Even in the face of non-obstructed vessels, impaired micro vascular reactivity diminishes blood supply to the ulcerated areas.About 20% of diabetic patients with foot ulcers will primarily have inade-quate arterial blood flow, about 50% will primarily have diabetic neuropathy and about 30% will be afflicted with both conditions 6 .
Diabetic foot ulceration is a serious and expensive complication with considerable morbidity that affects up to 15% of diabetic patients during their lifetime and 80-85% of amputations are preceded by non-healing foot ulcers [7][8][9][10] .
There is increasing evidence that measures of neuropathy, such as electrophysiology (including motor nerve conduction velocity) and quantitative tests, are predictors of not only end points, including foot ulceration, but also of mortality 11 .
In Iraq, diabetic foot ulcers were reported in 17% of diabetics in a small N series from Baghdad 12 .The aim of this work is to study the correlation between severity of clinical abnormalities and electrophysiological studies in diabetic foot ulcer.

Methods
This was a cross sectional study of patients with diabetic foot ulcer seen in 2 hospitals in Basrah (Al-Faiha general and Basrah Teaching) from October 2003 to July 2004.Patients from outpatient and inpatient clinics were included.All patients were type 2 diabetes mellitus (DM), they were 44.

Definitions
DM was diagnosed according to the American Diabetic Association recommendations in 2002 13 .Patient who were currently on drug treatment for diabetes and hypertension were considered hypertensive and diabetic respectively.For blood pressure, the average of second and third blood pressure measurements in the office were considered.Two blood pressure recordings were obtained from the right arm of patients in a sitting position after 30 min of rest at 5-min intervals and their mean value was calculated.Hypertension was considered if blood pressure is equal to 140/90 mmHg or above.Nephropathy was diagnosed on the basis of persistent frank proteinuria without erythrocytes or white blood cells in urine.Microalbuminuria detection was not feasible.An Ophthalmologist diagnosed retinopathy.Body mass index was calculated according to the formula: wt (kg)/ht 2 (m 2 ) 14 .The women were non pregnant.Autonomic function tests were not done because they were final-consuming and add nothing to our context.Diabetic foot ulcer was defined as any fullthickness skin lesion distal to the ankle that required treatment in hospital, excluding minor abrasions or blisters and/or the presence of any other cause of diffuse peripheral neuropathy (malignancy, alcohol abuse, drug abuse, anemia, known vitamin B12 deficiency, or untreated hypothyroidism).Vibration sensation was measured on the plantar hallux using a 128-Hz tuning fork and was graded as absent if the subject reported no vibration while the examiner could still sense vibration.Achilles tendon reflex was elicited with the subject in a seated position.Neuropathy screening instruction questionnaire was done for all (appendix -1) 15 .
Quantitative assessment of the clinical findings was done by the same examiner according to general practice protocols (appendix-2) 1 .Nerve conduction studies were performed using standard protocols 16 .Nerve conduction abnormalities were classified into normal and abnormal according to the common peroneal nerve conduction of each leg separately (normal >44.4ml/ second, mild 40-44.3ml/second,moderate 36-39.9ml/secondand severe <36 ml/second).Using electrophysiological study as gold standard for the neuropathy, we calculated measures of validity, namely sensitivity and specificity.The results were expressed as percent.For statistical analysis, Chisquare test was used as appropriate.Level of significance was set to be <0.05throughout analysis.Sensitivity of combined clinical symptoms was 66.6%, with specificity of 40%, and predictive value of 89.6% while that of clinical signs was 48.7% and 60% respectively with predictive value of 90.4 % (table IV).No significant difference in severity of electrophysiological abnormalities between the affected and non-affected foot was abscond (table V).Twenty five percent of those with optimal diabetes control had severe electrophysiological changes versus 63.6% in those with non-optimal control (table VI).

Discussion
It is generally agreed that diabetic neuropathy should not be diagnosed on the basis of one symptom, sign or test alone: a minimum of two abnormalities (symptoms, signs, nerve conduction abnormalities, quantitative sensory tests or quantitative autonomic tests) is recommended (Dyck) 17 .In our study, the sensitivity of clinical symptoms in predicting severe electrophysiological changes in patients with diabetic foot ulcer was 66.6% and that of clinical signs 48.7%.In some other studies the prevalence of diabetic neuropathy has been estimated to be as high as 62% of diabetic based on subjective complaints, 55% by signs and 100% by nerve conduction studies 18 .Of our patients 22.7% were smoker, 38.6% hypertensive, 63.6 % having non-optimal control of diabetes and most of them were with low education level.In univariate analyses, diabetic foot problems were characterized by older age, male preponderance, longer duration of diabetes, smoking, poorer glycemic control, more insulin users, hypertension, hyperlipidemia, higher diastolic and systolic blood pressure, lower education level and living in rural areas 19 .
Retinopathy was seen in 63.6%, nephropathy in 45.4%, and absent pulsation of the feet in 13.6%.Only 34.1% used insulin with or without oral hyperglycemic agents.Theories of ulcer development other than the roles for neuropathy include diminished vascular perfusion, foot deformity and higher foot pressure, diabetes severity (reflected by type of treatment) and preexisting diabetic complications 20 .
This study showed muscle atrophy in 75% with pes cavus in 50%.Motor neuropathy is commonly believed to lead to weakness in the intrinsic muscles of the foot, thus upsetting the delicate balance between flexors and extensors of the toes.Atrophy of the small muscles responsible for metatarsophalangeal plantar flexion is thought to lead to the development of hammer toes, claw toes, prominent metatarsal heads and pes cavus 21 .Decreased pinprick sensation was observed in all patients (100%), absent ankle reflex in 70.4% and decreased vibration in 84.1% in this study.In prospective studies, the three main independent predictors for foot ulceration has been shown to be absent Achilles tendon reflex, impaired mono-filament pressure sensation and impaired vibration sensation 22 .Most of our patients had low educational level, nevertheless, high incidence of foot ulceration has been reported in a population of diabetic patients with established peripheral neuropathy, despite the patients receiving a high level of education 23 .
In conclusion clinical findings correlated with the severity of electrophysiological changes in patients with diabetic foot ulcers.

Appendix-1-
Neuropathy screening instruction questionnaire (yes or no) 15 Are your leg or feet numb?( ) Do you ever have any burning pain in your legs and/or feet?( ) Are you feet too sensitive to touch? ( ) Do you get muscle cramp in your legs and/or feet?( ) Any pricking feeling in your legs and/or feet?( ) Does it hurt when the bed covers touch your skin?( ) Can you tell in the bathroom the cold from hot water?( ) Any ever seen open sore in the feet?( ) Any doctor told patients that he is having diabetic neuropathy?( ) Do you feel weak all over most of time?( ) Are you symptoms worse at night?( ) Do your legs hurt when you walk?( ) Are you able to sense your feet hen you walk?( ) Is the skin on your feet so dry that it cracks open?( ) Have you ever had amputation?( ) are present in table I and feet findings in table II.Fifty percent of ulcers were from Wagner grade one.

Table - V: Correlation between electrophysiological study in the affected and non-affected foot. Each lower limb was considered a subject in the analysis. Electrophysiological study Affected foot no. (%) Non-affected foot No. (%)
*7

patients have both feet affected and we took foot with higher Wagner grade as the affected.
**Non-severe includes moderate and mild.***NS denote non-significant.

Table - VI-correlation between severity of electrophysiological study and degree of diabetic control.
*Non-