Diabetes MellitusBy Malek Abidkhan

M. Luqmaan Jinnah

What is diabetes mellitus?

Diabetes Mellitus is a syndrome of impaired carbohydrate, fat and protein metabolism caused by either lack of insulin secretion or decreased sensitivity of the tissues to insulin.

InsulinO Hormone secreted by β cells of pancreas.

O Binds on enzyme link receptor of target cells.

O Acts as a primary messenger and activates tyrosine kinase

O This promotes glucose transport in the cells.

O It effects CHO, lipid and protein metabolisms and growth and gene expression.

Types of Diabetes Mellitus

O Type I Also called insulin-dependent diabetes mellitus (IDDM), is caused by lack of insulin secretion.

O Type II Also called non-insulin-dependent diabetes mellitus (NIDDM), is caused by decrease sensitivity of target tissue to the metabolic effect of insulin.

SymptomsO The same for types one and two

O excessive secretion of urine, thirst, weight loss, and tiredness

Type 1 Diabetes Mellitus –

lack of insulin production by beta cells of the

pancreas

Injury to beta cells of pancreas or diseases that impair insulin prodution can lead to type I diabetes.

Reason for injury:Viral infectionAutoimmune disordersHereditary tendency for beta cell degenration

The usual onset of diabetes occures at about 14 years of age in USA, and for this reason it is often called juvenile diabetes mellitus.

It develop very abruptly over period of a few days or weeks, with three principle sequelae:increased blood glucoseIncreased utilization of fats for energy and for formation of cholesterol by the liverDepletion of body’s proteins

Increased blood glucose level

O Normal blood glucose level is approximately 80 – 110 mg/ 100 ml.

O In diabetes is increase up to 300 – 1200 mg/100 ml.

O Increased blood glucose causes; (i) Loss of glucose in urine (ii) dehydration (iii) tissue injury

Other effects of type IO Diabetes mellitus causes increased

utilization of fats and “Metabolic acidosis”

NO Insulin in blood

Glucose cannot enter cells

Therefor cells metabolize fats for energy

Release keto acids (acetoacetate)

Metabolic acidosis

O Metabolic acidosis Dehydration (polyuria)

Severe Acidosis

Diabetic COMA

Excess Fat utilization in the liver for long time

Release large amounts of cholesterol in blood

Increased deposition of cholesterol in arterial walls

ARTERIOSCLEROSIS

Type 2 Diabetes Mellitus

O Far more common than type I.O Accounts for ≈ 90% of all cases of

diabetes mellitus.O Onset occurs after age 30, often between

50 and 60 years.O Therefore, syndrome is often referred to

as adult - onset diabetes.O Obesity is the most important risk factor

for type II.

Less sensitivity of receptors for insulin

secretion of insulin by pancreas

plasma insulin – hyperinsulinemia.Due to insulin resistance

Insulin Resistance “Diminished sensitivity of target tissues to the metabolic effects of insulin.”

When cell becomes resistance to insulin

Less glucose uptake/utilization by cells

plasma glucose

Type II Diabetes

Other factors that cause insulin resistance and type II diabetes

OAcquired or genetic conditions that impair insulin signaling in peripheral tissues.

OPolycystic ovary syndrome (PCOS).

OCushing’s syndrome.

DiagnosisO Urinary glucose

O Fasting blood glucose level

O Insulin level

O Glucose tolerance test

O Acetone breath

Fasting blood glucose level

O Normal blood glucose level is 80-90 mg/100 ml.

O 110 mg/100ml is upper limit of normal.

O More than that is diabetic.

Glucose tolerance testO Normal fasting person is given 1g of

glucose per kg of body weight.

O Blood glucose level rises from 90mg/100ml to 120 – 140mg/100ml and falls back to below normal in 2hrs.

O But in diabetics, it is always above 110mg/100ml.

Type I diabetes Administration of insulin.

Treatment

Treatment

Type II diabetesODieting and exercise to reduse weight and to reverse insulin resistance.OIn severe cases, insulin administrationODrugs: To increase insulin sensitivity to cells, thiazolidinediones and metformins. To increase insulin release, sulfonylureas.

ComplicationsO Diabetic retinopathy: a leading cause

of blindness and visual disabilityO Kidney failureO Heart diseaseO Diabetic neuropathyO Diabetic foot disease

Insulin shock High dose of insulin to diabetics

Blood glucose level falls below normal

(50 – 70mg/100ml) (20-50mg/100ml) (below 20)

Hypoglycemia, Clonic seizures HypoglycemicExcites CNS, and loss of comaHallucinations consciousness