ABSTRACT

Background

Symptomatic peripheral neuropathy in a diabetic patient may be associated with the presence of other foot complications, which may otherwise be overlooked.

Objective

We conducted this study to determine the prevalence of symptomatic peripheral neuropathy among diabetic patients attending the diabetes outpatient clinic of our hospital as well as document the presence of other foot complications/problems in patients with symptomatic peripheral neuropathy.

Methods

A cross-sectional survey of foot complications was conducted over a 6-month period in diabetic patients symptomatic for peripheral neuropathy and compared with age/sex matched diabetics without peripheral neuropathy and apparently healthy individuals.

Results

Of 322 diabetic patients studied, 64(19%) had symptomatic peripheral neuropathy. The most frequent symptoms of peripheral neuropathy were numbness or tingling sensation in (65.6%), cramps, aches and fatigue (14.1%) respectively, and burning sensation (10.9%). Dry skin, hyperpigmentation, corns and callosities, cracked skin
and fungal infections were the most frequent lesions seen in diabetic patients symptomatic for peripheral neuropathy. These lesions occurred more frequently in them than in patients without neuropathy and healthy subjects. While (34.7%) symptomatic patients had foot ulcers, none was recorded in the asymptomatic or healthy population.

Conclusion

Foot complications other than foot ulcers may occur in diabetic patients with symptomatic peripheral neuropathy. Awareness of these skin and foot lesions and their sequelae with prompt initiation of measures to limit disability may prevent limb losses/foot deformities and should be emphasised. Proper education on foot care and frequent limb inspection can never be over emphasised. Moreover, these foot lesions may also serve as markers for the presence as well as severity of peripheral neuropathy.

RESUME

Introduction

Les neuropathies diabétiques symptomatiques s’accompagnent de complications au niveau des pieds qui risquent d’être négligées.

But

Le but de l’étude est de déterminer la prévalence des neuropathies périphériques ainsi que les complications au niveau des pieds chez des diabétiques suivis dans notre département, en ambulatoire.

Méthode

Une étude transversale a été menée pendant six mois chez des diabétiques atteints d’une neuropathie périphérique symptomatique et des individus apparemment sains.

Résultats

Sur les 322 patients étudiés, 64 (19%) présentaient une neuropathie périphérique symptomatique. Les symptômes les plus souvent rencontrés sont : les engourdissements ou picotements (65,6%), les crampes, des douleurs continues, une fatigabilité (14,1%) et une impression de brûlure (10,9%). Une peau sèche et craquelée, une hyperpigmentation, des callosities ainsi que des signes de mycoses étaient les lésions les plus souvent observées chez les patients diabétiques ayant une neuropathie périphérique. Aucun ulcère n’a été noté chez les individus sains contrairement à la population diabétique ( 34,7%).

Conclusion

L’attention est portée sur la nécessité de surveiller et de diagnostiquer au plus tôt les lésions cutanées chez les patients diabétiques. Par ailleurs, les lésions cutanées sont l’expression de la sévérité de la neuropathie périphérique sous-jacente, chez ce type de patients.

Keywords : Diabetes mellitus, foot complications, peripheral neuropathy, Afrique, diabete, complications, neuropathie peripherique, pied diabetique

INTRODUCTION

Peripheral neuropathy, which commonly manifests as loss of sensation in the feet is an important factor in the pathogenesis of foot ulcers. There is a complex inter play between this abnormality and a number of other contributing factors such as peripheral vascular disease, altered foot pressure, limited joint mobility, glycaemic control, ethnicity and cardiovascular parameters.(1,13,15) Some published data suggest that in addition to foot ulcers, some other foot lesions may be associated with the presence of peripheral neuropathy in diabetics .(6,13)

We have therefore conducted this study to determine the prevalence of symptomatic peripheral neuropathy among diabetic patients attending the diabetes outpatient clinic of the Obafemi Awolowo University Teaching Hospital Complex (OAUTHC), Ile-Ife, Nigeria as well as document the presence of other foot complications/problems in patients with symptomatic peripheral neuropathy.

METHODS

All patients who attended the diabetes clinic of the OAUTHC, Ile Ife between July and December 2000 were recruited into the study. A comprehensive history was taken from each patient followed by a thorough physical examination. The history included data on demography, type and duration of diabetes, symptoms associated with peripheral neuropathy, use of footwear, alcohol and cigarette use, occupation, and literacy level.

Physical examination included objective evaluation for signs of peripheral neuropathy, peripheral vascular disease, and the presence of other foot lesions/complications. Symptoms and signs of peripheral neuropathy were assessed using the scoring system proposed by Young et al(15) (Appendix). Scores of 3 or more implied the presence of peripheral neuropathy. The presence of other foot lesions were also determined in age-sex matched diabetics who were not symptomatic for peripheral neuropathy as well as apparently healthy controls recruited from hospital staff and members of public. The frequency of such complications was then compared across the three groups. Peripheral vascular disease was defined by an ankle/arm blood pressure ratio greater than 0.9.
Data are presented as mean (SD) and percentages as appropriate.

RESULTS

During the six-month study period 322 diabetic patients were seen. 64(19%) had symptomatic peripheral neuropathy and are further described (Table 1). There were equal number of males and females, their ages ranged between 36 -80 years, mean 58.1 ± 8.1 years. 56 (87.5%) were non-insulin dependent diabetics, 2(3.1%) were insulin dependent while 6(9.4%) were non-insulin dependent now requiring insulin. The mean duration of disease was 8.41 ± 7.1 years, range 2 to 29 years. The type of out door footwear used by patients varied from covered shoes 8 (12.5%), flat heeled slippers 50 (78.1%), to both slippers and covered shoes 16 (25%). No one walked outdoors without footwear though 10 patients admitted to not using footwear a times when indoor. None of the patients smoked nor took alcohol.

The most frequent symptoms of peripheral neuropathy were numbness or tingling sensation in (65.6%), cramps, aches and fatigue (14.1%) respectively, and burning sensation (10.9%). 27(42.19%) patients had moderate and severe neuropathy symptoms scores respectively, while 8(12.5%) were mild. Neuropathy sign scores were mild in 36 (56.3%) patients; moderate 26(40.6%), and severe in none. 2(3.1%) had no severity score. The commonest signs elicited were impaired vibration sense in 39(60.9%) and loss of ankle reflex in 33 (51.7%). Peripheral vascular disease was present in 3 (4.7%) patients.

Table 2 compares foot lesions seen in patients with and without symptomatic peripheral neuropathy and apparently healthy non-diabetic subjects. Dry skin, hyperpigmentation, corns and callosities, cracked skin and fungal infections were the most frequent lesions seen in diabetic patients symptomatic for peripheral neuropathy. These lesions occurred more frequently in them than in patients without neuropathy and healthy subjects. While 3 (4.7%) symptomatic patients had foot ulcers, none was recorded in the asymptomatic or healthy population.

DISCUSSION

This study assessed foot problems associated with peripheral neuropathy. The prevalence rate of symptomatic peripheral neuropathy was 19%. The commonest symptoms/signs of peripheral neuropathy numbness, cramps and burning sensation in the feet, impaired vibration sense and loss of ankle jerk.
Our PN prevalence rate of 19% is lower than those reported from previous studies.(4-7,9,12) This difference may be accounted for by variations in methodology, diagnostic criteria and intrinsic differences in the study populations. Qualitative sensory tests and/or electrophysiological studies, if employed, may have detected the presence of PN in our apparently asymptomatic patients. Our data, like in previous studies show that numbness, burning feet and posterior column tract signs with a depressed ankle jerk remain the commonest presenting features of peripheral neuropathy. It should be noted however that the severity of some of these features are influenced a great deal by shoe wearing habits. Many rural Nigerians still walk barefoot. Osuntokun(10) had observed attenuation of the plantar response in apparently healthy rural Africans who walk without their shoes on. He had attributed this to the thickening of the soles observed in these individuals as well as possible subclinical malnutrition.

Patients with symptomatic peripheral neuropathy also presented with a myriad of additional foot/skin lesions such as dry skin, callosity, fungal infection, paronychia, hyperpigmentation, yellow nails, cracked skin, ulcers, corns etc. Dry skin, paronychia (both bacteria and candida), corns and hallux valgus were commoner in symptomatic patients than in the asymptomatic or healthy population. Similar foot/skin problems have been previously described among European diabetic patients(2) and in indigenous Tanzanians.(14) All forms of peripheral neuropathy including autonomic, sensory and motor neuropathy each contribute to skin lesions in the diabetic foot. Autonomic neuropathy can be associated with both absence of sweating as well as compensatory over sweating and perspiration in other areas.(8) Dry skin, resulting from absence of sweating, predisposes to puritus a known presenting symptom of diabetes. Dry skin also cracks easily especially when scratched (pruritus) encouraging bacterial invasion and superimposed bacterial infections. Use of emollient in these patients prevents dry skin and itching. Fungal infections are often associated with poor glyceamic control, which is itself a risk factor for peripheral neuropathy.(11) Hyperhydrosis of autonomic neuropathy make the feet conducive for fungal infections in the diabetic as fungi thrives best in moist areas. Sesori-motor neuropathy, which may result in imbalance of internal musculature and poor standing posture coupled with ill-fitting shoes can cause callosities and neuropathic ulcers.(3)
Foot complications other than foot ulcers may occur in diabetic patients with symptomatic peripheral neuropathy. Awareness of these skin and foot lesions and their sequelae with prompt initiation of measures to limit disability may prevent limb losses/foot deformities and should be emphasised. Proper education on foot care and frequent limb inspection can never be over emphasised. Moreover, these foot lesions may also serve as markers for the presence as well as severity of peripheral neuropathy.

TABLE I: CLINICAL CHARACTERISTICS OF STUDY PATIENTS (mean ± SD)

TABLE II: FREQUENCY OF FOOT LESIONS IN SYMPTOMATIC PATIENTS, ASYMPTOMATIC PATIENTS AND HEALTHY SUBJECTS.

APPENDIX

1 – Assessment Of symptoms of P Neuropathy

• Description of symptoms:
  Fatigue(1pt), cramps(1pt) or aches (1pt),
  Burning (2pt), Numbness (2pt) or Tingling (2pt),
• Site of discomfort :
  Calf muscles (1pt),
  Feet or soles (2pt)
• Time of worst symptoms:
  Day (0pt),
  Night (2pt)
  Both Day and Night (1pt)
• Night time insomnia for symptoms :
  No (0pt),
  Yes (1pt)
• Factors that alleviate symptoms:
  Standing (1pt),
  Walking (2pt)

2 – Assessment of signs of P Neuropathy

• Pain, temperature and vibration
  If impaired or absent (1pt)
• Ankle reflex
  If only present with reinforcement (1pt),
  If absent (2pt)

3 – Assessment of peripheral vascular diseases
Peripheral vascular diseases is defined by an ankle / arm blood pressure ratio <0.9 (1 - 1.4 in normal subjects)