Types of coma in DM:

1. Diabetic ketoacidosis (DKA):

 Is an acute and dangerous complication that is always a medical emergency. Lack of insulin causes the liver to turn fat into ketone bodies, a fuel mainly used by the brain. Elevated levels of ketone bodies in the blood decrease the blood's pH, leading to most of the symptoms of DKA. On presentation at hospital, the patient in DKA is typically dehydrated and is breathing rapidly and deeply. Abdominal pain is common and may be severe. The level of consciousness is typically normal until late in the process, when lethargy may progress to coma. Ketoacidosis can become severe enough to cause hypotension, shock, and death. Prompt proper treatment usually results in full recovery, though death can result from inadequate or delayed treatment, or from complications. Ketoacidosis is much more common in type 1 diabetes than type 2.

1. Nonketotic hyperosmolar coma:

The hyperosmolar nonketotic state (HNS) is an acute complication with many symptoms in common with DKA, but an entirely different cause and different treatment. In a person with very high blood glucose levels (usually considered to be above 300 mg/dl (16 mmol/l)), water is drawn out of cells into the blood by osmosis and the kidneys dump glucose into the urine. This results in loss of water and an increase in blood osmolality. 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 dangerous. As with DKA, urgent medical treatment is necessary, especially volume replacement. Lethargy may ultimately progress to a coma, which is more common in type 2 diabetes than type 1.

Diagnosis:

Diagnosis of diabetes is suspected based on symptoms and confirmed by blood tests that measure the level of glucose in blood plasma.

1. Urine Glucose test.
2. Blood tests :

• Fasting Blood Sugar or Glucose test (FBS)
• Two-hr Postprandial Blood Sugar Test (2-h PPBS)
• Oral Glucose Tolerance test (OGTT)
• Intravenous Glucose Tolerance test (IVGTT)
• Glycosylated Hemoglobin (HbA_1C)
• Divide the mg/dL by 18 to get mmol/Lor multiply by 0.055.

Urine tests and blood tests can be used to confirm a diagnosis of diabetes based on the amount of glucose in the urine and blood.

1- Urine Tests:

Urine tests also can detect ketones and protein in the urine which may help diagnose diabetes and assess how well the kidneys are functioning. These tests also can be used to monitor the disease once the patient is under treatment.

Clinistix and Diastix are paper strips or dipsticks that change color when dipped in urine. The test strip is compared to a chart that shows the amount of glucose in the urine based on the change in color. The level of glucose in the urine lags behind the level of glucose in the blood. Testing the urine with a test stick, paper strip, or tablet is not as accurate as blood testing, however it can give a fast and simple reading.

2- Blood Tests

  a) Fasting glucose test.

  b) Postprandial glucose test. Blood is taken right after the patient has eaten a meal.

  c) Oral glucose tolerance test.

  d) Other tests

Blood tests can help to differentiate between type 1 and type 2 when the diagnosis is unclear. One of these is an assessment of c-peptide levels, a protein released along with insulin that can help a physician determine whether or not a patient is producing sufficient amounts of insulin. The other is a GAD (Glutamic Acid Decarboxylase) autoantibody test. The presence of GAD autoantibodies may indicate the beginning of the autoimmune process that destroys pancreatic beta cells.