The History Of Diabetes Mellitus

Published Date: 02 Nov 2017

CHAPTER VI:

DISCUSSION

Diabetes mellitus is a group of metabolic disorders characterized by hyperglycemia due to relative insulin deficiency, resistance or both. Its late complications result in reduced life expectancy and major health costs. [ 178] These include macro vascular diseases leading to an increased prevalence of coronary artery disease, peripheral vascular disease, stroke and micro vascular damage leading to diabetic retinopathy and nephropathy. Neuropathy is another micro vascular complication which results in peripheral nerve dysfunction in diabetes. [178]

Diabetic neuropathy in turn can give rise to a number of serious complications and it is important to uncover diabetic peripheral neuropathy early in the course of its development because the progressive loss of nerve function in neuropathy is clearly related to glycemic control in both type 1 and type 2 diabetes; an early intervention with tight, stable glycemic control may both provide the needed symptomatic relief and also slow the progression of peripheral neuropathy. Otherwise electro physiologic abnormalities in the lower limb of a patient with type 2 diabetes who has chronic neuropathy will gradually increase over the years.

Moreover early screening and diagnosis is critical because patients at all stages of neuropathy are at a greater risk of developing insensitive foot ulcerations. These patients must be properly identified, and at the earliest possible time in the course of their disease, provided with appropriate education on regular self-foot care and medical management if appropriate in order to decrease their relative risk of foot ulcerations.

Evidence of early neuropathy, especially small fiber neuropathy, has been reported even in pre diabetic patients who have impaired glucose tolerance. Thus these patients should be screened for diabetes. It is important to take a careful history, asking the patient for any symptoms of neuropathy he/ she has experienced. Since many patients do not experience positive symptoms, it is also important to ask if there are any negative symptoms. The evidence of loss of sensation should be sought through various testing modalities such as pain, vibration, pressure, pinprick, light touch, joint position sensation, and ankle reflexes. Various simple and cost effective clinical tests and scoring systems have been proposed and used for the detection of early neuropathy in diabetic patients. One such test is Semmes-Weinstein monofilament test, which has been recommended by International Diabetic Federation and World Health Organization as a simple and inexpensive tool for the detection of peripheral neuropathy in a primary care setting. [43,180] Patients who have insensate feet, cannot detect application of monofilament to designated sites on the plantar surface of their feet. [74] Among various scoring systems and instruments proposed for assessment of diabetic poly neuropathy the accuracy of Michigan Neuropathy Screening Instrument scoring makes it a useful screening test for diabetic neuropathy in taking a decision regarding which patients should be referred to a neurologist for electrophysiological studies. High specificity and a moderate to good post-test probability give a high diagnostic impact for MNSI scoring. [144] The Michigan Neuropathy Screening Instrument is included in our research and has already been discussed in review of literature.

Our study reported that 31.3 % of asymptomatic diabetes mellitus with type 2 diabetes mellitus had peripheral distal symmetrical sensory motor neuropathy; 21.8 % had reduced sensation and 9.5 % had absent sensation upon testing with Semmes-Weinstein monofilament.

Different studies from all over the globe, have shown that the prevalence of distal symmetric poly neuropathy in diabetes mellitus varies from 5% to 60% and sometimes 100% if patients with asymptomatic abnormalities of nerve conduction are also included. [178]

The variation in results of research work is due to wide variety of methods and procedures used for the evaluation, screening and diagnosis of distal symmetric polyneuropathy. [179]

In America, several studies have been conducted on this subject. Pirart, in a study of 4,400 diabetes type 2 patients found that the prevalence of diabetic neuropathy is 7.5% at the time of diagnosis, 20% to 30% after 10 to 15 years from diagnosis and this prevalence rises linearly to 50% after 25 years.[42]

Rochester Diabetic Neuropathy Study in 1986 , stated that among 64,573 inhabitants in Rochester, 1.3% had clinically recognized diabetes mellitus and of these, two thirds had objective evidence for some variety of neuropathy, but only about 20% had symptoms. [4]

Boulton et al. research showed that up to 50% of diabetic peripheral neuropathies may be asymptomatic and these asymptomatic neuropathies lead to insensate ulcers or injuries, thereby, contributing to amputations of feet. [64,114]

American Diabetes Association, in 2009 also said that as 50% of patients with distal symmetric poly neuropathy may be asymptomatic. These are at risk for insensate foot injury. [180]

A multicentre study in the United Kingdom hospital in 1993, including 6487 diabetic patients, found that the prevalence of diabetic peripheral neuropathy was 28.5% and this prevalence increased with age; from 5% in the 20-29 year age group to 44.2% in the 70-79 year age group. Neuropathy was also related with duration of diabetes, i.e., it was found to be present in 20.8% of patients with diabetes duration less than 5 years and in 36.8% of those with diabetes duration greater than 10 years. [43]

In 1996, the EURODIAB IDDM Complications Study, conducted on 3250 insulin-dependent diabetic patients, from 31 centers in 16 European countries, showed that the prevalence of diabetic neuropathy across Europe was 28%. There were no significant geographical differences observed in the study. [74]

Neurodiab Executive Committee stated in their guidelines that diabetic peripheral neuropathy affects 30% of patients with diabetes mellitus. [120]

In the UKPDS study, damage to the peripheral nerves from prolonged hyperglycaemia and its metabolic consequences was found to be present in 12.3% at diagnosis and in 30% after 12 years of diabetes. [181]

In a study conducted on 1000 diabetic patients in Saudi Arabia, peripheral neuropathy was reported in 35.9% of the patients. [182]

A prospective conducted at Abdul-Aziz University Hospital outpatient from January 1998 until April 1999; also showed subclinical neuropathy was present in 57% of asymptomatic diabetic patients. [129]

Southern Brazil cross-sectional study conducted on 340 patients with type 2 diabetes mellitus showed that seventy-five patients (22.1%) had peripheral diabetic neuropathy. Tests performed in the study were tuning fork test, monofilament test, test for temperature and pain sensations, as well as ankle reflexes and heel walking. [183]

Osuntokun and colleagues reported a prevalence of 48% of peripheral neuropathy in Nigerian diabetics in their study on 832 patients; while a prevalence of 75% was noted in another study in Jos University Teaching Hospital (JUTH), Jos, Nigeria. [184-185]

In 2008, African journal of medicine and medical sciences stated that asymptomatic peripheral neuropathy is present among Nigerian diabetic subjects and the absence of alarm symptoms of peripheral neuropathy does not exclude the presence of genuine peripheral neuropathy. They found in a study that among 120 diabetic participants, 37 (30.8%) are asymptomatic cases, having no symptoms of peripheral neuropathy. [186]

China city hospitals have also reported a prevalence of 17.2% in diabetic peripheral neuropathy in type 2 diabetic outpatients. [187]

Italian Diabetic Neuropathy Committee, in their study found that among 8,757 diabetic patients visiting 109 outpatient diabetes clinics in Italy, peripheral neuropathy was present in 32.3% of the patients. [188]

San Antonio consensus reports have agreed upon the importance of symptom scoring as a diagnostic and prognostic tool [191] .Several scoring systems have been developed for evaluation of diabetic distal symmetric poly neuropathy.

Dyck PJ and his coworkers described, Neuropathy Symptom Score, Neuropathy Symptom Profile, Neuropathy Disability Score, Neuropathy Impairment Score Lower limbs NIS LL, NIS LL +4, NIS LL +5, NIS LL +7 and Neuropathy Symptom Change Score.[192-194]

Valk et al proposed Clinical Neuropathy Examination[134-135]; Cornblath et al, Total Neuropathy Score[195]; EDIC Research Group, Michigan Diabetic Neuropathy Instrument[196]; Meijer et al proposed Diabetic Neuropathy Examination Score[141]; Bril et al, Toronto Clinical Scoring System [142]; Zeigler et al, Total Symptom Score[143]; Bastyr et al, Neuropathy Total Symptom Score- 6[197]; And Graham and Hughes described Overall Neuropathy Limitations Scale (ONLS), a slight modification of the Overall Disability Sum Score (ODSS)[198]

In our study, Michigan Diabetic Neuropathy Score was used to separate asymptomatic diabetic patients from symptomatic diabetic patients. It was developed by Eva Feldman in 1989. [ 190] We used this scoring system due to its simplicity and accuracy regarding which patients should be referred to a neurologist for electrophysiological studies. High specificity and a moderate to good post-test probability give a high diagnostic impact for MNSI scoring. [190]

We used 10g Semmes-Weinstein monofilament for clinical examination of asymptomatic diabetic patients to look for evidence of diabetic neuropathy. Monofilament testing as a screening tool for detection of peripheral neuropathy has been recommended in guide lines by International Diabetic Federation, World Health Organization [7-8], American Diabetes Association,[199] Dutch Association of Neurology, NHS National Institute for Clinical Excellence (NICE) and Canadian Diabetes Association. [200-202] Therefore, Semmes Weinstein monofilament test is being used and can be used as a simple screening method to detect diabetic neuropathy. It is a simple, inexpensive, portable [167] and rapid method of detecting neuropathy in diabetes mellitus. It requires minimal training. Both the medical and non medical staff can use it easily. [219] The need is to define a standard method of using it.

Various clinical trials have used and validated the efficacy of 10g Semmes- Weinstein monofilament for screening and diagnosing of peripheral neuropathy in diabetes mellitus. Some of these are by the following research workers: Wilasrusmee C et al (2010) [203], Vatankhah N et al (2010)[204], Perkins BA et al (2010) [205] , Dros J et al (2009 )[206], Feng Y et al (2009)[153], Martini J (2008) [207], Nather A (2008) [208], Tres GS (2007) [209], Armstrong DG et al (2005) [152], Lee S et al (2003) [7], Abbott CA et al (2002)[210], Olaleye D et al (2001)[168], McGill M et al ( 1999 )[211], Cheng WY et al ( 1999 )[214], Boyko EJ et al ( 1999 )[119], Smieja M et al ( 1999 )[118], Frykberg RG (1998) [213] and Mueller MJ et al (1996)[218], etc.

Peripheral neuropathy in diabetes mellitus is a big health hazard. Not only it is troublesome for the patient in terms of that it can leads to ulceration and even worse amputations; it is also produces financial burden on government. Efforts have always been in process for early diagnosis of peripheral neuropathy in diabetes mellitus. Simple 5.07/ 10 g Semmes Weinstein monofilament test is also one such procedure. The only need is to standardize a method for using it, so that it can be of more usefulness in diagnosis and patient education and diabetes control.