Diabetes mellitus is a chronic disease characterized by the body's inability to produce or respond to the hormone insulin, resulting in impaired metabolism of glucose and high blood glucose levels. There are four main types of diabetes: prediabetes, type 1 diabetes caused by an absolute insulin deficiency, type 2 diabetes caused by defects in insulin secretion and effectiveness accounting for 90% of cases, and gestational diabetes during pregnancy. Treatment depends on the type and includes insulin therapy, oral hypoglycemic drugs, diet, exercise and managing complications which can include cardiovascular, kidney and nerve damage if not controlled.

1. Diabetes mellitus
Written by: Ikram ullah

2. Definition:
A chronic disease characterized by the body inability to produce or respond to the hormone
insulin this results in impaired metabolism of glucose, carbohydrate and protein with
persistent high blood glucose level.
Diabetes mellitus is a chronic systemic disease that alters carbohydrate, fat, and protein
metabolism; it’s the most common endocrine disorder and the third leading cause of death in the
United States. Four general classifications are recognized:
◆ Prediabetes can occur when the fasting blood glucose is greater than 100 mg/dL and less than
126 mg/dL or postprandial blood glucose is greater than 140 mg/dL and less than 200 mg/dL
◆ Type 1 diabetes mellitus is an absolute deficiency of insulin secretion and may be hereditary;
it’s associated with histocompatibility antigens, some viruses, abnormal antibodies that attack the
islet of Langerhans cells, and toxic chemicals; it causes symptoms when 90% of the pancreatic
beta cells have been destroyed
◆ Type 2 diabetes mellitus may be hereditary, is associated with obesity, and results from
different causes than type 1 diabetes; it’s caused by defects in insulin secretion and decreased
insulin effectiveness; it accounts for 90% of diabetic patients
◆ Gestational diabetes mellitus causes glucose intolerance during pregnancy; it usually
disappears after delivery but may develop into type 1 or type 2 diabetes
Other types of diabetes mellitus can be linked to either a disorder (such as an endocrinopathy, a
genetic syndrome, an insulin receptor disorder, or an infection) or to the use of a drug or a
chemical (such as a corticosteroid, epinephrine, furosemide, glucagon, lithium, or phenytoin)
◆ Impaired glucose tolerance occurs when glucose levels are outside the normal range
following a glucose tolerance test but the patient doesn’t meet the criteria for diabetes mellitus
◆ Many complication are associated with diabetes mellitus
 Microvascular and macrovascular changes can increase the risk of heart disease,
accelerate atherosclerotic disease, and cause cerebrovascular accidents, hypertension, and
peripheral vascular disease
 Microvascular changes can thicken capillary basement membranes and cause changes in
the vessels of the kidneys and eyes
 Motor and sensory neuropathies may result in weakness, hyperesthesia, hypoesthesia, and
pain; autonomic neuropathy generally occurs after many years and may cause cardiac
abnormalities, diabetic diarrhea, gastroparesis, impotence, and urine retention
 Infections can result from accumulation of serum glucose in the skin and poorly
functioning white blood cells

3. Signs and symptoms: Following are the classical signs and symptoms of diabetes
mellitus
 Polyuria is one of the common symptoms of diabetes mellitus because large
amount of urine is excreted in urine and water follows the excretion of urine.
 Polyphagia occurs due to excessive amount of glucose excreted in urine.
 Polydipsia occurs because large amount of water is excreted following glucose.
Above are the most common signs and symptoms of diabetes mellitus. Diabetes mellitus
may be characterized by other signs and symptoms these include fatigue, weight loss in
type 2 diabetes mellitus, diabetic ketoacidosis etc. The patient may have impaired vitamin
profile because large amount of B complex is excreted in urine. This vitamin deficiency
may cause disturbance in sleep, visual and auditory problem. For example vitamin B6 is a
precursor for GABA (an inhibitory neurotransmitter).This leads to the balance between
excitatory and inhibitory neurotransmitters and the patient suffers from insomnia.
Treatment: Treatment of diabetes mellitus depends on the type and the condition of the
patient. Patient with type 2 diabetes mellitus may be put on oral hypoglycemic agent therapy
because they have the problem of peripheral insulin resistance. Patients with type 1 diabetes
mellitus are put on insulin therapy because they have absolute deficiency of insulin and
subcutaneous insulin administration is the treatment of choice in these patients. Along with
insulin and oral hypoglycemic agents the patient should be provided with B complexes therapy
because low level of B complexes is a serious problem faced by diabetic patient. These problems
may include retinopathy, neuropathy, very poor healings of wounds, insomnia etc.
Along with pharmacological therapy the patient is advised to perform daily exercise because
exercise lowers blood glucose levels, maintains normal cholesterol levels, helps blood vessels
perform more effectively, and may reduce the amount of insulin needed. Therefore, the patient
should follow a consistent exercise program, engaging in activity when glucose levels are high.
(Carbohydrate intake must be increased if the patient exercises when glucose levels are low).
Balance diet also helps patient to keep the blood
glucose level within the normal range and prevent
them from rapid increase.

4. Pathophysiology: Pancrease is a double gland organ that serves both as exocrine and
endocrine gland. The islet of Langerhans serves the endocrine function. The beta cells of islet of
Langerhans release the pancreatic insulin in response to high blood glucose level which then
brings glucose to normal. Insulin acts on insulin receptors presents on the surface of and
transport glucose inside the cell which is then used for the production of ATP. The altered
physiology is associated with either absolute deficiency of insulin or due to peripheral resistance
to insulin.
Type 1 : Type 1 diabetes is characterized by the absolute deficiency of insulin due the
destruction of insulin producing beta cells that may have auto immune bases. This type of
diabetes most commonly occur in the young age. These individuals are totally dependent on
exogenous insulin to avoid life threatening hyperglycemia and ketoacidosis due t absolute
deficiency of insulin. Type 1 diabetes is very rare and account for about 5% of the total diabetes
cases.
Type 2: This is the most common form of diabetes and accounts for 90-95% of the total
diabetes. There are a lot of factors that influence type 2 diabetes such genetic factor, obesity,
aging, and peripheral insulin resistance. It is thought that obesity impaired the functioning of the
insulin receptors and these individuals may have peripheral insulin resistance that leads to
hyperglycemia. In type 2 diabetes some of the beta cells of pancreas may retain their function but
due to persistent insulin resistance these cells may also loss their function. In contrast to type 1
diabetes, type 2 patient are commonly obese which is the major contributing factor of insulin
resistance. These individuals are treated with oral hypoglycemic agent that either stimulate
pancreatic beta cells to release insulin (e.g. sulfonylureas) or decrease the peripheral insulin
resistance (e.g. biguanides).
Gestational diabetes: Gestational diabetes occurs due to glucose intolerance that
develops during pregnancy. During pregnancy the steroid hormone level increase which are
diabetogenic in nature that leads to the hyperglycemia. Gestational diabetes resolve on their own
after pregnancy but some cases may
develop into type 2 diabetes.

5. Prognosis: Prognosis is good if the case is diagnosed early and immediate treatment is
started with regular monitoring of blood glucose, electrolyte and fluid balance. Majority of the
cases are diagnosed when the typical symptoms has arises. In these cases the prognosis are very
poor and patient may develop life threatening complication.
Complications: Diabetes mellitus is a very life threatening condition that may leads to
severe complication.
 Cardiovascular complication may involve hypertension and micro and macro vascular
injuries.
 Nephropathy is the most common complication of diabetes mellitus.
 Neuropathy
 Diabetic foot (gangrene)
 Retinopathy
 Auditory problem
 Sleep disturbances