Diabetes Mellitus

Diabetes Mellitus

Diabetes mellitus is a group of metabolic diseases in which the person has high blood glucose (blood sugar) either due to inadequate insulin production or because the body’s cells do not respond properly to insulin or both. The term “diabetes mellitus” describes a metabolic disorder of multiple etiology characterized by chronic hyperglycemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both. The main symptoms are: –
1. Polyuria (frequent urination)
2. Polydipsia (increased thirst)
3. Polyphagia (increased hunger)
The main types of diabetes are:
Type 1 diabetes: It is due to the body’s malfunction to produce insulin in the body, and requires the person to inject insulin. This form was previously referred to as “insulin-dependent diabetes mellitus” (IDDM) or “juvenile diabetes”.
Type 2 diabetes: It is due to insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with an absolute insulin deficiency. This form was previously referred to as non insulin-dependent diabetes mellitus (NIDDM) or “adult-onset diabetes”.
The third main form, Gestational diabetes occurs when pregnant women without a previous diagnosis of diabetes develop a high blood glucose level. It may lead to type 2 DM
Other types of diabetes include those caused by
4. Genetic defects of the beta cell the part of the pancreas that makes insulin such as maturity-onset diabetes of the young (MODY) or neonatal diabetes mellitus (NDM)
5. Diseases of the pancreas or conditions that damage the pancreas, such as pancreatitis and cystic fibrosis
6. Excess amounts of certain hormones resulting from some medical conditions such as cortisol in Cushing’s syndrome that work against the action of insulin
7. Medications that reduce insulin action, such as glucocorticoids, or chemicals that destroy beta cells


The main symptoms of diabetes are:
• Poly uria: urinating frequently (particularly at night)
• Poly dipsia: feeling very thirsty
• Poly phagia: feeling hungry frequently
• Weakness
• Weight loss and loss of muscle bulk
Type 1 diabetes can develop quickly, over weeks or even days. Many people have type 2 diabetes for years without realizing because early symptoms tend to be common.


Type 1 Diabetes: The immune system of body attacks and destroys the cells that produce insulin. As no insulin is produced, glucose levels further increase, which can seriously damage the body's organs. Type 1 diabetes is often known as insulin-dependent diabetes. It is also sometimes known as juvenile diabetes or early-onset diabetes because it usually develops before the age of 40, often during the teenage years. Type 1 diabetes is less common than type 2 diabetes.
Type 2 Diabetes: Type 2 diabetes is where the body does not produce enough insulin or the body's cells do not respond to insulin. This is known as insulin resistance. Type 2 diabetes is far more common than type 1 diabetes.
Gestational Diabetes: During pregnancy, some women tend to experience high levels of blood glucose as a result their body is unable to produce enough insulin to absorb it altogether.


The clinical diagnosis of diabetics is often prompted by symptoms such as
Increased thirst and urine
Recurrent infections
Blood glucose estimation is generally done to know blood glucose levels.


Diabetes mellitus is a chronic disease and as such there is no known cure except management that assists in keeping blood glucose levels as close to normal ("euglycemia") without causing hypoglycemia. This can usually be accomplished with diet, exercise, and use of appropriate medications (insulin in the case of type 1 diabetes; oral medications as well as insulin (if required), in type 2 diabetes.
• Oral biguanides: Metformin is an oral anti diabetic drug in the biguanide class. It is the first-line drug of choice for the treatment of type 2 diabetes, especially for overweight and obese people and those with normal kidney function .
• Insulin: Type 1 diabetes is generally treated with a combinations of regular and NPH (neutral protamine Hagedorn) insulin or synthetic insulin analogs. When insulin is used in type 2 diabetes, a long-acting formulation is usually added initially while continuing oral medications.
• Regular exercise
• Proper diet
• No smoking
• No alcohol
These goals helps in keeping both short-term and long-term blood glucose levels within acceptable bounds.


The complications of diabetes mellitus are less common and less severe in people who have well-controlled blood sugar levels. Its complications are:


Diabetic ketoacidosis: It is an intense and dangerous complication that can always result in a medical emergency. It is generally seen due to low insulin levels may cause the liver to turn fatty acid to ketone for fuel as ketone bodies are intermediate substrates in that metabolic sequence. This is a normal condition if occurs periodically, but can become a serious problem if sustained. Elevated levels of ketone bodies in the blood decrease the blood's pH leading to DKA. The patient with DKA is typically dehydrated and breathing rapidly and deeply. Abdominal pain is common and may be severe.
Hyper glycemia: Hyper glycemia is another acute complication. If a person has very high (usually considered to be above 300 mg/dl (16 mmol/L)) blood glucose levels water is osmotically drawn out of cells into the blood and the kidneys eventually begin to dump glucose into the urine. This results in loss of water and an increase in blood osmolarity. If fluid is not replaced (by mouth or intravenously) the osmotic effect of high glucose levels combined with the loss of water will eventually lead to dehydration. The body's cells become progressively dehydrated as water is taken from them and excreted. Electrolyte imbalances are also common and can be very dangerous.
Hypo glycemia: Hypoglycemia or abnormally low blood glucose is an acute complication of several diabetes treatments. It is rare otherwise, either in diabetic or non-diabetic patients. The patient may become agitated, sweaty, weak, and have many symptoms of sympathetic activation of the autonomic nervous system resulting in feelings akin to dread and immobilized panic.
Diabetic Coma: Diabetic coma is a medical emergency in which a person with diabetes mellitus is unconscious as of one of the acute complications of diabetes:
Severe diabetic hypoglycemia
Diabetic ketoacidosis advanced enough to result in unconsciousness from a combination of severe hyperglycemia, dehydration and shock and exhaustion
Hyperosmolar nonketotic coma in which extreme hyperglycemia and dehydration alone are sufficient to cause unconsciousness.

Diabetic cardiomyopathy: It may damage to the heart, which can lead to diastolic dysfunction and then can eventually lead to heart failure .
Diabetic nephropathy: It may damage to the kidney which can lead to chronic renal failure, eventually requiring dialysis. Diabetes mellitus is the most common cause of adult kidney failure.
Diabetic neuropathy: Anomalous and reduced sensation, usually in a 'glove and stocking' distribution starting with the feet but potentially in other nerves, later often fingers and hands. When combined with damaged blood vessels this can lead to diabetic foot. Other forms of diabetic neuropathy may present as mononeuritis or autonomic neuropathy. Diabetic amyotrophy is muscle weakness due to neuropathy.
Diabetic retinopathy: Growth of friable and poor-quality new blood vessels in the retina as well as macular edema (swelling of the macula), which can lead to serious vision loss or blindness. Retinal damage (from microangiopathy) makes it the most common cause of blindness.

National Institute of Diabetes and Digestive and Kidney Diseases