Saturday 7 November 2015

DIABETES MELLITUS (DM)

By Sam Maondu

According to WHO, DM is a metabolic condition characterized by elevated blood glucose level as a result of defects in insulin secretion, insulin action or both. [12]

Types of Diabetes Mellitus


Type 1 diabetes
Although it is common in children and adolescents, type 1 diabetes may also occur in adults. It is characterized by absolute deficiency of insulin and individual will require long term insulin for survival. [12]

Type 2 Diabetes
 Formerly called adult-onset diabetes mellitus or non-insulin dependent diabetes mellitus (NIDDM) is a metabolic condition characterized by chronically elevated blood glucose levels as a result of decreased responsiveness of cells to insulin (insulin resistance) and relative deficiency to insulin. [1]

Gestational Diabetes
The etiology of gestational  diabetes mellitus is not clear but it is thought that pregnancy hormones are the ones which interfere with insulin action.[12]

Insulin is an hormone produced by the Islets of Langerhans in the endocrine pancreas which functions to control blood glucose level[2].

WHAT HAPPENS AFTER A MEAL?

After a meal, the blood glucose level rises gradually and the beta cells in pancreas release insulin. Insulin then diffuses into the blood where it attaches to the insulin receptors on the surface of cell membrane where it enables transport of glucose into the cell for production of energy. [3]

Insulin resistance in type 2 diabetes mellitus is characterized by the liver, muscle cells and fat tissue not responding appropriately to insulin. [4]

Harvard Health Publications in their article on Type 2 DM noted that the pancreas will keep on producing more insulin as a result of increasing blood glucose level in people with insulin resistance. Insulin resistance continues to worsen and and more insulin continues to be produced until it reaches a point whereby the pancreas gets 'burn outs' and can't keep up with the body's insulin demand. As a result blood glucose level remain high. [7]
 
 Overweight and obese individual have some degree of insulin resistance and their progression from non-diabetic to diabetic is dictated by the ability of the beta cells in the endocrine pancreas to keep up with their increasing demand for insulin. [4]

According to Wikipedia, when insulin sensitive tissues like the liver, fat tissue and muscle cells becomes resistant to insulin, there is a reduced uptake of glucose in the respective tissue. Obese individuals have certain degree of insulin resistance. In insulin resistance the body goes into a compensated mode and the beta cells produce more insulin to lower the rising level of blood glucose. If this compensated state fails then the individual progresses to developing type 2 diabetes mellitus. [5]

People who progress into type 2 diabetes mellitus usually exhibit signs and symptoms like:-
  • Frequent urination
  • Constant hunger.
  • Excess thirst.
  • Unexplained loss of weight.
  • Dry mouth
  • Blurring of vision. [6]

Risk factor for type 2 Diabetes Mellitus includes:-


Genetic factors- having a blood relative with type 2 DM puts one at risk of being diabetic. [8]

Overweight and obesity- when the body is over-nourished with nutrients, the cells in the body are overworked as the need to process all those nutrients supplied to the body through diet rises. The overworked cell starts to complain because it handling too much nutrients. Therefore, it signals the cell membrane to dampen some insulin receptors on its surface so that less glucose is brought into the cell for metabolism. This sequelae leads to glucose accumulating in the blood causing elevated blood glucose level hence DM. [9]

Age- people over 40 years of age are at risk of being diabetic.[8]

Poor diet- according to everyday health, eating too much of food that are calorie-dense and refined may put one at risk of developing type 2 DM. [10]

Criterion for the diagnosis ofdiabetes mellitus.


According to World Health Organization and International Diabetes Federation meeting held in Geneva 2006, specific plasma glucose cut offs for the diagnosis of diabetes mellitus are as follows:-
  1. A fasting plasma glucose of 7.0mmol/l {126mg/dl} or more.
  2. A 2-hour plasma glucose of 11.1mmol/l {200mg/dl} or more.
An individual with intermediate hyperglycemia or plasma glucose levels which don't meet the criteria for diagnosis of diabetes mellitus but the values are above the normal cut off, an oral glucose tolerance test (OGTT) is done to rule out an impaired glucose tolerance (IGT)

For diabetics, a glycated hemoglobin A1C is used to establish an average glucose level for the previous 2-3 months. A joint force by WHO/IDF declared HbA1C not a suitable tool for diagnosis of DM and intermediate hyperglycemia. Anemia, hemoglobin abnormalities, uremic syndrome and pregnancy are some of the factors to be put into consideration if a physician wants to do HbA1C for a patient. [11]

An elevated plasma glucose level done at random requires further test or a repeat of the same test at a different date to confirm the diagnosis of diabetes mellitus. This is to exclude other causes of elevated plasma glucose which may occur when the body is under stress like during infections.[12]

In pregnancy, an Oral Glucose Tolerance Test is done at 24-28 weeks of gestation if there is any suspicion of gestational DM. This is done after 8 hours of fasting after which a fasting plasma glucose is taken and 75g of oral glucose solution is given orally. If after 2 hours plasma glucose concentration is 7.8 Mmol/l and above shows that the pregnant woman has gestational diabetic mellitus.[12]

Prevention is always better than cure. Type 2 DM can be prevented by:-
  • Diet- eating healthy diet.
  • Avoiding stress
  • Exercise- doing exercise regularly.
  • Maintaining a healthy body weight i.e not overweight or obese. [7]

references
1. Medicine, Second edition, 2004
Diabetes Mellitus, Lipoprotein Disorders and other Metabolic Diseases.
By John S. Axford and Chris A. O'Callaghan.
2. The Digestive System, Pancreas -Anatomy and Physiology Ross and Wilson
in health and illness. Tenth Edition,2006 by Anne Waugh and Allison Grant
3. What is insulin? Endocrine Web,
Diabetes >> Type 1 diabetes. Written by: Amy Hess-Fischi MS, RD, LDN, BC-ADM,CDE.
Viewed at: http://www.endocrineweb.com/conditions/type-1-diabetes/what-insulin. On 13/04/2015
4. Diabetes Mellitus type 2 -Wikipedia, The Free Encyclopedia
Viewed at: http://www.en.wikipedia.org/wiki/diabetes_mellitus_type_2. Viewed on 1/04/2015.
5.Insulin resistance -Wikipedia, The Free Encyclopedia
Last modified: 9th, April 2015 @05:16. Viewed at: http://en.m.wikipedia.org/wiki/Insulin_resistance. On 13/04/2015
6,Symptoms of type 2 DiabetesWebMD, Diabetes Health Center.
Viewed at: http://www.webmd.com/diabetes/guide/diabetes-warning-signs. Viewed on 14/4/15.
7. Type 2 diabetes mellitusDrugs.com, Havard health publication
Viewed at: http://www.drugs.com/health-guide/type-2-diabetes-mellitus.html. viewed on 16/04/2015
8.National Health Service, Type 2 diabetes- causes
Viewed at: http://www.nhs.uk/conditions/diabetes-type-2/pages/causes.aspx. Viewed on 16/04/2015
9. Why does obesity cause Diabetes?-MedicineNet.com. Viewed at: http://www.medicinenet.com/sript/main/art.asp?articlekey=39840. Viewed on 16/04/2015
10. What causes type 2 diaetes mellitus?-Everyday Health. Viewed at: http://www.everydayhealth.com/type-2-diabetes/causes/
Viewed on 16/04/2015. Last updated on: 13/10/2014
11. Definition and diagnosis of diabetes mellitus and intermediate hyperglycaemia report of WHO/IDF consultation. Viewed at (PDF): http://www.who.int/diabetes/publications/diagnosis_diabetes2006/en/
Virwed on 24/04/2015.
12.Diabetic Programme, about diabetes. World Health Organization, Viewed at: http://www.who.int/diabetes/action_online/basics/en/. On 28/03/2015