Complications of diabetes mellitus - B. Pharma 2nd Semester Pathophysiology notes pdf

Complications of diabetes mellitus


       Complications of diabetes mellitus

       Pathogenesis of complications of DM

       Oral Glucose Tolerance Test (OGTT)


At the end of this PDF Notes, student will be able to

         List the complications associated with DM

         Describe the pathophysiology involved in the development of diabetic complications

         Describe Oral Glucose Tolerance Test

Clinical features of DM

Type I DM

       Low plasma insulin levels

       Poly uria




       Hypoglycemic episodes

Type II DM



       Unexplained weakness

       Plasma insulin normal to high 

       Hyperosmolar non-ketotic coma

Pathophysiological basis of common signs and symptoms due to uncontrolled hyperglycaemia in diabetes mellitus

Complication of DM – Pathogenesis

       Consequence of hyperglycemia

       Effects all most all the tissue

       Complications can either be acute or chronic

       2 possible mechanism involved in development of complications

      Non-enzymatic protein glycosylation

      Polyol pathway mechanism

Non-enzymatic protein glycosylation

       Free amino group binds reversible to glucose

       Non enzymatic mechanism

       E.g. Hb with glucose (glycated Hb)

       Accumulates on collagen

       Irreversible advanced glycosylation end products (AGE)

       AGEs bind to receptors

       Biological & chemical changes

Polyol pathway mechanism

       Intracellular accumulation of sorbitol & fructose

       Entry of water inside cell

       Cellular swelling & damage

       Deficiency of myo inositol

       Harmful to retina

Acute metabolic complications

Diabetic ketoacidosis

       Complication of type I DM

       Due to shortage of insulin along with glucagon excess

       Failure to take insulin

       Lipolysis of adipose tissue

       Free fatty acids formed taken up by liver

       Converted ultimately to ketone bodies

       Excreted in urine

Hype osmolar non-ketotic coma

       Complication of Type II DM

       Due to sustained hyperglycemic diuresis

       Loss of glucose in urine

       Difficult to substitute the fluids lost of diuresis

       High viscosity of blood

       Bleeding complications

       Results in death 

Hypoglycemic episodes

       Complication of type I & II DM

       Results from excess administration of insulin or oral hypoglycemic drugs

       May lead to permanent brain damage

       Worsening of diabetic control

Late systemic complications


       Diabetic microangiopathy

       Diabetic nephropathy

       Diabetic neuropathy

       Diabetic retinopathy


Oral Glucose Tolerance Test (OGTT)

       Oral GTT is performed principally for patients with borderline fasting plasma glucose value (i.e. between 100-140 mg/dl)

       High carbohydrate diet for at least 3 days prior to the test

       overnight fast on the day of the test

       fasting blood sugar sample is first drawn

       75 gm of glucose dissolved in 300 ml of water is given

       Blood and urine specimen are collected at half-hourly intervals for at least 2 hours

       Normal cut off value for fasting blood glucose level -100 mg/dl.

       Fasting blood glucose value in range of 100- 125 mg/dl - impaired fasting glucose tolerance (IGT)

       Fasting value of plasma glucose higher than 126 mg/dl

        2-hour value after 75 gm oral glucose

       Higher than 200 mg/dl - diabetics


       Persistent hyperglycemia is associated with diabetic complications

       Non-enzymatic glycation and polyol pathway mechanism are the two main mechanisms involved in the development of complications of DM

       Acute metabolic complication and late systemic complication are major complications of DM

       Oral GTT is performed principally for patients with borderline fasting plasma glucose value (i.e. between 100-140 mg/dl)

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