Dr Sarita Bajaj, Associate Professor in medicine, MLN College, (Allahabad)

What is Diabetes?

The disease diabetes whose name is derived from the Greek word meaning "Siphon" was known to ancient physicians. However one of the first recorded references to diabetes is in the papyrus discovered by Ebers in the tomb of Thebes in Egypt in 1862. Said to have been written in about 1500 BC, it was and is, the oldest book of any kind.

Diabetes occurs either because of a lack of insulin or because of the presence of factors that oppose the action of insulin. The result of insufficient action of insulin is an increase in blood glucose concentration (hyperglycemia). Many other metabolic abnormalities occur, notably an increase in ketone bodies in the blood when there is a severe lack of insulin.

Diagnosis

The diagnosis of diabetes must always be established by measuring blood glucose concentration, although glycosuria usually (though not always) indicates disease. Criteria for diagnosis are :

1. Symptoms of diabetes plus casual (ie at any time of day without regard to time since last meal) plasma glucose concentration >/=200 mg /dl

2. Fasting plasma glucose (FPG) >/=126mg/dl

3. 2 hours plasma glucose of >/= 200mg /dl

These criteria should be confirmed by repeat testing on a different day.

Common mistakes in diagnosis

1. Diagnosis and treatment of diabetes on detection of urine glucose alone

2. Diagnosis by one single blood glucose strip alone (Glucometer). This is not reliable enough to make a lifelong diagnosis

3. Requesting a blood test after intake of glucose (glucose tolerance test) when the diagnosis is already confirmed Types of diabetes

The vast majority of cases of diabetics fall into two categories. In one category (type 1 or insulin dependent diabetes) the cause is an absolute deficiency of insulin secretion. Type 1 diabetics need insulin forever. In the other category (type 2 or non insulin dependent diabetes), the cause is a combination of resistance to insulin action and an inadequate compensatory insulin secretory response. In the latter category, a degree of hyperglycemia sufficient to cause pathologic and functional changes in target tissues, but without clinical symptoms may be present for a long period of time (upto 12 years) before diabetes is detected. During this asymptomatic period, it is possible to demonstrate an abnormality in carbohydrate metabolism by measurement of plasma glucose in the fasting state or after a challenge with an oral glucose load. Type 2 diabetics may need insulin for control when oral drugs fail to do so.

Type 1 diabetes is auto immune in origin whereas

type 2 is multifactorial. Two factors stand out distinctly in its causation :

1. Genetic factors

2. Environmental factors

The interaction of the genetic factors with the various environmental factors culminates in the final development of the disease. It is obvious that while the genetic factors cannot be modified after birth, the environmental factors can definitely be influenced to a great extent.


Who should be screened ?

1. Persons with a family history of diabetes
2. Persons who are markedly obese
3. Persons with high blood pressure
4. Persons with an abnormal lipid profile
5. Women with a bad obstetric history - recurrent stillbirths, abortions, delivering malformed babies, elderly women, women with a large parity and those who have delivered large babies.
6. All pregnant women
7. Patients with recurrent genital, urinary tract or skin infections
8. Patients with otherwise unexplained
- Neuropathy
- Atherosclerosis
- Coronary artery disease
- Peripheral vessel disease
- Retinopathy
- Nephropathy
- All pre-operative patients
9. Testing for diabetes should be considered in all individuals at age 45 years and above and, if normal, it should be repeated at 3-year intervals

Presentation, Symptoms and Signs

Thirst, tiredness, genital itching, passing excessive urine, and weight loss despite excessive hunger are the familiar symptoms of diabetes. Why then is the diagnosis so often missed? Patients do not, of course, always describe their symptoms in the clearest possible terms, or else their complaints may occur may only as an indirect consequence of the more common features. Many patients describe dry mouth rather than thirst and are then investigated for dysphagia. Frequency is often treated blindly with antibiotics; previously continent children may start bedwetting and incontinence may be a manifestation in elderly people; and the true diagnosis is overlooked. Complex urological investigations are sometimes performed before the urine is tested. Some diabetic patients present chiefly with weight loss (despite an increased appetite), but even then the diagnosis is sometimes missed. Perhaps weakness, tiredness, and lethargy, which may be the dominant symptoms, are the most commonly misinterpreted. Tonics and vitamins are sometimes given as the symptoms worsen. Deteriorating vision is not uncommon as a presentation, due either to a change of refraction causing myopia or to the early development of retinopathy. Foot ulceration or sepsis in older patients brings them to accident and emergency departments and is nearly always due to diabetes. Occasionally neuritis is the presenting symptom, causing exquisite pain in the feet, thighs or trunk.

Some older men are first aware of diabetes when they notice white spots on their trousers. In hot climates drops of sugary urine attract an interested population of ants.

Symptoms are similar in the two types of diabetes (type 1 & 2), but they vary in their intensity. The presentation is most typical and the symptoms develop most rapidly is patients with type 1 diabetes. Symptomatic type 2 diabetics represent the tip of an iceberg, the majority being asymptomatic. It is common to disbelieve a raised blood glucose report in the absence of symptoms, but it must be confirmed by a repeat test on a subsequent day and if still abnormal be appropriately treated irrespective of symptoms. The diagnosis of diabetes should no longer be missed. New patients attending their doctor, whether their family doctor or at a hospital outpatient clinic, should have a blood glucose measurement or at the very least a urine test especially if their symptoms are unexplained.

Prevalence

Type 1 diabetes constitutes only 2% of diabetes. The remaining (98%) have type 2 diabetes. The prevalence of diabetes differs widely for different ethnic groups and countries. For example, it can range from < 3% among rural communities in developing countries to almost 50% in Pima Indians in the USA. Though the incidence of diabetes is increasing worldwide, the dubious distinction of being the country with the largest number of diabetic individuals and the greatest predicted increase in the prevalence of diabetes (200% between 1995 and 2005), lies with India.

While the prevalence of diabetes in rural Indians remains low (2-5%), in urban areas it has risen to 10-20%. Type 2 diabetes affects Indians at a younger age than in the west. Thus it affects patients during their most productive years and also increases the chances that chronic complications may ensue. Indian type 2 patients are in general far less obese than their western counterparts. Type 2 diabetes has reached epidemic proportions in Indians. An interplay of environmental factors as well as genetic predisposition is probably responsible. Increasing urbanization and adoption of a westernized life-style with changes in diet as well as reduced physical activity are likely causes. A genetic predisposition is evident from the strong familal aggregation. The predisposing genes are, however not yet known.

Complications of diabetes

Patients with longstanding diabetes may develop complications affecting the eyes, kidneys, nerves, heart, and blood vessels. Long term complications of diabetes include : retinopathy with potential loss of vision, nephropathy leading to renal failure, peripheral neuropathy with risk of foot ulcers and amputation and autonomic neuropathy causing gastrointestinal, genitourinary, and cardiovascular symptoms and sexual dysfunction. Patients with diabetes have an increased incidence of atherosclerotic cardiovascular peripheral vascular, and cerebrovascular disease. Hypertension, abnormalities of lipoprotein metabolism, and periodontal disease are often found in people with diabetes. The emotional and social impact of therapy may cause significant psychosocial dysfunction in patients and their families. Coronary artery disease (angina, myocardial infarction) and stroke are commoner in diabetics.

Investigations to be performed at regular intervals

1) Fasting and Post Prandial blood glucose
2) Kidney tests : Microalbuminuria
: Complete urine examination
: Serum urea and creatinine
3) Eye examination : Ophthalmoscopy
4) Electrocardiogram
5) Complete lipid profile
6) Glycosylated hemoglobin (HbA1c)

Treatment and Prevention

There is no cure for diabetes in any science, today. The aims of treatment are, first, to save life and alleviate symptoms, and secondly, to achieve the best possible control of diabetes with blood glucose concentrations as near normal as possible to minimize long term complications. Control is achieved by :

1) Diet and exercise alone

2) Diet, exercise and oral drugs

3) Diet, exercise and insulin

Diet and exercise are the cornerstones on which the management of diabetes rests. There is no substitute. Decision regarding drug, insulin therapy should be taken by the consultant endocrinologist. Other important aims in management include control of weight and elimination of risk factors, notably hypertension, smoking, and hazards to the feet.

Primary prevention can be achieved by identifying high risk subjects at an early stage and imparting appropriate health education to them and the community. Fasting hyperglycemia can be prevented in 90% of individuals who are at risk of developing it by maintaining ideal body weight throughout a lifetime or losing excess body weight. All it takes is a 30 minute walk a day! Secondary prevention aims at early diagnosis and appropriate treatment of the disease to reduce morbidity and mortality and rehabilitation of those physically handicapped due to the disease.

There are currently 20 million type 2 diabetics in India, and these will increase to 57 million in the next 25 years. There is an urgent need to put into place programmes which will prevent the development of diabetes in susceptible individuals, provide diabetes education to health care professionals, and improve patient care so that chronic complications of diabetes are reduced. Such a diabetes prevention and control programme has, unfortunately, not yet been formulated at the national level.

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