Diabetes Mellitus
From Ask Dr Wiki
By Nadia Ali M.D, M.B.B.S
Contents |
Introduction
Diabetes Mellitus is a metabolic disorder characterized by hyperglycemia. This hyperglycemia is secondary to an absolute or relative deficiency of Insulin. Insulin is a hormone secreted by the beta islet cells of the pancreas, which plays a critical role in glucose uptake by the peripheral tissues, hepatic gluneogenesis and antilipolysis.
Classification of Diabetes Mellitus
There are two main types of Diabetes Mellitus
Type 1 Diabetes Mellitus
It was previously known as Juvenile diabetes since the age of onset is usually less than 25 years. It is characterized by lack of insulin. The etiology is immune mediated and those affected may have antibodies against the islet cells of the pancreas. These patients often have other immune mediated disorders such as thyroiditis and vitiligo. These patients need insulin for control of diabetes.
Type 2 Diabetes Mellitus
This is the most common form of Diabetes Mellitus. It is often associated with either a insulin secretory defect of the beta cells of the pancreas or a resistance to the action of insulin in the peripheral tissues. The risk factors associated with type 2 diabetes are obesity and physical inactivity. These patients can be initially treated with oral medications but may eventually need insulin therapy.
Gestational Diabetes
It is the new onset of hyperglycemia diagnosed in pregnant women. It can be either the initial recognition of a previously present diabetes or it could be secondary to the various hormones such as ‘Human Placental Lactogen’ produced by the placenta. These hormones lead to insulin resistance causing elevated blood sugar levels.
Secondary Diabetes
It is characterized by hyperglycemia secondary to the presence of other diseases or drugs. These diseases include those that directly cause the destruction of the exocrine pancreas such as chronic pancreatitis as well as diseases that lead to an excessive production of hormones that counteract the effect of insulin such as Cushing’s Disease and Glucagonoma. Medications such as steroids can also impair insulin secretion leading to secondary diabetes.
MODY [Maturity onset diabetes of the young]
It is a hereditary form of diabetes type 2 that is diagnosed usually in the early age. Unlike Diabetes type 1 which also occurs in this age group, it is responsive to oral hypoglycemics. It is different from type 2 Diabetes as the patients may not necessarily have the risk factors associated with it.
LADA [Latent Autoimmune Diabetes in Adults]
It is an autoimmune form of Diabetes which unlike Type 1 diabetes has a late onset. It is managed with insulin.
Presentation of Diabetes Mellitus
Patients may be found to have diabetes on routine blood testing. On the other hand, they may present with an acute complication of Diabetes such as diabetic ketoacidosis as an initial presentation. The other symptoms indicating the possibility of diabetes are polydipsia, polyuria, polyphagia, weakness, fatigue, nausea, vomiting, blurred vision, frequent urinary tract infections and vaginal candidiasis.
Diagnosis
According to the American Diabetic Association, the criteria for diagnosis of diabetes is as follows
- Symptomatic patient with a random blood glucose level of ≥ 200mg/dl or
- Asymptomatic patient with a fasting blood glucose level of ≥ 126mg/dl or
- A blood glucose of ≥ 200mg/dl after a 2 hour Oral Glucose tolerance test with 75gm of glucose
In asymptomatic patients the diagnostic criteria need to be repeated to confirm the values.
Impaired Glucose Tolerance
Impaired glucose tolerance is the term used when the patient has ‘Pre diabetes’. A pre-diabetic patient does not fulfill the criteria for diabetes but has higher blood sugar levels than normal. These individuals are at higher risk for developing diabetes. The criteria for impaired glucose intolerance is as follows
- Asymptomatic patient with a fasting blood glucose level of <126 but ≥ 100 or
- A blood glucose level of < 200mg/dl but ≥ 140 after a 2 hour Oral Glucose tolerance test with 75gm of glucose.
Treatment
It is very important to strictly control blood sugar in diabetics in order to prevent long term complications. All patients diagnosed with diabetes should be trained to check their blood sugars via glucometer on a daily basis. In addition to self monitoring of blood sugars, the physician should assess the degree of glycemic control by measuring Hemoglobin A1C or glycosylated hemoglobin. According to the American Diabetic Association, the goal is to keep the A1C ≤ 7. It correlates with the mean blood glucose levels over a period of 120 days.
Non Pharmalogical intervention
Diet
It is recommended that a diabetic diet be low in carbohydrates and saturated fats and rich in fiber containing foods such as cereals, Legumes, fruits and vegetables.
Weight loss
A moderate weight loss in obese individuals by means of diet and exercise improves insulin resistance.
Exercise
Physical activity and exercise decrease insulin resistance independent of weight loss.
Pharmacological intervention
For Treatment options for Diabetes see Diabetes Mellitus Pharmalogic Treatment
Complications of Diabetes Mellitus
Acute complications of Diabetes Mellitus
Chronic complications of Diabetes Mellitus
Macrovascular complications
- Cardiovascular disease
- Cerebrovascular disease
- Peripheral vascular disease
- Diabetic Foot Ulcers
Microvascular
Other complications related to Diabetes
- Cataracts
- Dyslipidemia
