DIABETES  

A worldwide epidemic

 

Diabetes Mellitus is a group of derangements of normal body metabolism, induced by an excess of sugar (glucose) in the blood (hyperglycaemia).  The normal level in blood, when fasting in the early morning, is in the range of 70 to 110 milligrams per decilitre (mg/dl). Being that the kidneys filter blood and its constituents all the time, it can reabsorb glucose up to the level of 180 mg/dl: above that figure, glucose is spilled into the urine. This induces extra water in the urine to maintain an adequate concentration. Thomas Willis in 1675 tasted the urine of one of these patients, and noticed the sweet taste. Later, in 1776, Mathew Dobson of Liverpool evaporated a sample of urine, and was left with a brownish residue which looked and tasted like brown sugar.  Hence DIABETES from the Greek “running through” and MELLITUS from the Greek “honey”: in other words, large volumes of sweet urine.  This large volume of urine (polyuria) induces thirst (polydipsia) and the loss of sugar induces hunger (polyphagia) accompanied by weight loss.

In 1889 the role of the pancreas in this illness was confirmed, when Minkowski and von Mehring found that the surgical removal of the pancreas in dogs induced very severe diabetes. In 1893, Laguesse suggested that the pancreas produced a hormone which controlled carbohydrate metabolism, and that the source of this was a curious group of cells of the pancreas described in 1869 by Paul Langerhans, which he called islets of Langerhans. It was only in 1921 when the antidiabetic hormone, insulin, was isolated by Frederick Banting and Charles Best, in Toronto. The former was awarded the Nobel Prize, which he shared with Dr. Best.  A year earlier, the physiologist Nicholas Paulesco in Rumania, published a paper describing that he had extracted a pancreatic extract, though he never cured a patient with it.

By the following year insulin was being produced in commercial quantities. The most dramatic effect was seen in young people who were miraculously “resurrected” with these injections of insulin.  It was soon seen that insulin was not a cure, but a necessity to prolong life; patients had to inject themselves daily for the rest of their lives, and a number of complications of the illness became apparent. In other words, insulin converted an acute fatal disease into a chronic one with long term complications. These are lesions in the retina of the eyes, damage to the peripheral nerves, damage to arteries in general and in particular the small arteries of the kidneys followed by progressive kidney failure, susceptibility to have frequent infections and ulcers on the sole of the feet, are the most frequent problems. There was a longstanding controversy of the role of diabetes regarding atherosclerosis and high blood pressure: the Diabetes Control and Complications Trial in 1933 showed that in a follow-up of over 10 years, those with the best sugar control had a 50-70% lower rate of complications.

There are various forms of Diabetes:

  • Type 1 autoimmune Diabetes Mellitus (DM). Known previously as Juvenile Onset or Insulin Dependent DM, it affects mostly children, adolescents or young adults, who have next to no production of insulin, as the Langerhans islets have been destroyed by auto antibodies.

  • Type 2 Diabetes Mellitus. This the commonest form of DM, accounting for a 90% over all, and appears in maturity or accompanying obesity, and is due to a dual mechanism. On the one hand there is a lesser production of insulin by the pancreas, and on the other there is a deficient utilization or uptake of glucose by the tissues. This is known as Insulin Resistance, where the tissue receptors for glucose are damaged, and the intake of glucose to the cells is impaired. Both of these Types are transmitted genetically, though in a differing fashion.

  • Gestational Diabetes Mellitus. Diabetes can appear in up to 14% of pregnancies, usually between the 14th and the 28th week of pregnancy. This can bring on problems for the mother (high blood pressure, infections, premature delivery) or for the unborn baby, which has a tendency to be very large (with its associated problems) and with a higher incidence of pre-term death.

  • There are other Types of Diabetes, either due to illnesses that damage the pancreas, other hormonal illnesses, or due to chemical compounds or drugs.

 

The World Health Organization established in 1999 the following criteria to diagnose Diabetes:

  • Classical symptoms of DM, such as polyuria, polydypsia, polyphagia and unexplained weight loss, with a blood glucose level of 200 mg/dl  or more;

  • An 8-hour fasting blood glucose of 126 mg/dl or more;

  • After the intake of 75 gm of glucose in 30 ml of water, the blood glucose level is 200mg/dl or more.
The incidence of Diabetes worldwide is increasing at an alarming rate, in both Types, with heredity, population explosion, increased high carbohydrate and fatty diets and lack of exercise as the leading causes. So much so that leading health workers and physicians have rated it as an epidemic, and should be addressed as such by governments, health care institutions and individual physicians.

A relatively new and popular diagnosis, the “Metabolic Syndrome”, groups the following conditions: Type 2 Diabetes, high blood pressure, central obesity (either defined as a waist circumference of more than 102 cm or a Body Mass Index of over 30), lack of exercise, decreased HDL cholesterol and raised triglycerides.   There is some controversy as to whether these risk factors joined or clustered together are more than a sum of the parts, though each on is a definite risk on its own.  The last word is not in yet on this condition.

 

Treatment

The object of treatment, reducing the levels of blood glucose between 70 to 105 mg/dl, is to avoid or delay the onset of the chronic complications.  In all Types, an adequate low carbohydrate diet (basically sugars and starches) is paramount, associated to weight control and a regular exercise programme. In Type 1 regular use of insulin is indispensable, whereas in Type 2 there are a number of medicines which help gain adequate control.  Either they enhance the production of insulin by the pancreas, or they increase the uptake of glucose by the tissues, or they block the absorption of glucose in the intestines.

It is absolutely indispensable to assume that this is programme for life, and the sooner one adopts the changes in life style, the better the possibilities to avoid the dreaded complications. It is also useful to know that the damage to the arteries that lead to heart attacks and strokes, caused by high blood pressure, high cholesterol, and smoking cigarettes, are enhanced by diabetes, so that attention must be paid to these other factors.

Having diabetes implies that you must see your physician regularly, to make sure that the diet you are following is the correct one for you, that the medications prescribed should be continued or changed over time, and to test your blood, eyes, nerves and kidneys periodically. According to each individual case, he might seek the help of a specialist in diabetes, or other specialists as necessary.  Remember that your attitude and changes of life style are determinants of how well the illness is controlled, and how free of complications your life will be.

 

Author:
Dr. John Emery 
Buenos Aires British Hospital

 

References:

Fauci, Braunwald, Kasper, Hauser, Longo, Jameson & Loscalzo (2007): “The Principles of Internal Medicine” 17th Edition. The Mc Graw-Hill Companies.

Lock S, Last JM & Dunes G (Editors) The Oxford Illustrated Companion to Medicine”, Oxford University Press, 2001.

September 2009