Diabetic Coma: Causes, Signs and Nursing Management

Definition of Diabetic Coma:

A diabetic coma is a life-threatening diabetes complication that causes unconsciousness. If a person have diabetes, dangerously high blood sugar (hyperglycemia) or dangerously low blood sugar (hypoglycemia) can lead to a diabetic coma.

Diabetic Coma
Fig: Diabetic Coma

A diabetic coma could happen when the blood sugar gets too high — 600 milligrams per deciliter (mg/dL) or more causing to become very dehydrated. It usually affects people with type 2 diabetes that isn’t well-controlled. It’s common among those who are elderly, chronically ill, and disabled.

Causes of Diabetic Coma:

The main causes of coma occurring in people with diabetes are as a result of very low or very high blood glucose levels.

  1. Severe hypoglycemia,
  2. Diabetic ketoacidosis,
  3. Hyperglycaemic hyperosmolar state.

Severe hypoglycemia and coma:

Coma is more likely to occur from low blood glucose levels if;

  • A large insulin overdose is taken,
  • Alcohol is in the body during hypoglycemia,
  • Exercise has depleted the body’s glycogen supply.

Diabetic ketoacidosis and coma:

Diabetic ketoacidosis is a dangerous state of having very high blood glucose levels (typically above 17 mmol/L) in combination with high ketone levels.

Ketoacidosis is able to occur if the body runs out of insulin and is therefore a factor for people with type I diabetes to be aware of. Insulin can prevent ketone levels rising and this is the key reason why people with diabetes are advised never to miss their long term (basal) insulin injections.

Sign and Symptoms of Diabetic Coma:

Before developing a diabetic coma one will usually experience signs and symptoms of high blood sugar or low blood sugar.

High blood sugar (hyperglycemia):

  • Increased thirst,
  • Frequent urination,
  • Fatigue,
  • Nausea and vomiting,
  • Shortness of breath,
  • Stomach pain,
  • Fruity breath odor,
  • A very dry mouth,
  • A rapid heartbeat.

Low blood sugar (hypoglycemia):

  • Shakiness or nervousness,
  • Anxiety,
  • Fatigue,
  • Weakness,
  • Sweating,
  • Hunger,
  • Nausea,
  • Dizziness or light-headedness,
  • Difficulty speaking,
  • Confusion

Difference between Diabetic Coma and Hypoglycemic Coma:


Diabetic Coma

Hypoglycemic Coma


Infection, too little
or no insulin digestive disturbance

Missed meal, Insulin
over dose


Over hours or days

In a minute


Abdominal pain and


Skin and tongue




Weak and rapid pulse

Fully bounding



Normal or raised


Deep sighing

Slow breathing




Planter response

Normal or equivocal

Normal and extensor



No glycosuria


Hypoglycemia reduced
plasma bicarbonate

Normal plasma bi

Nursing Management of Diabetic Coma:

  1. Patient should keep in rail cot bed to prevent him falling down.
  2. The patient should be kept lying flat with the head torned to one side unless other instruction given.
  3. Monitor vital signs.
  4. Assess peripheral pulses, capillary refill, skin turgor, and mucous membranes.
  5. Airway must be kept clear by suction so that patient can breathe easily.
  6. Oxygen inhalation is given if necessary.
  7. Constant day & night attention & observation.
  8. A naso-gastric tube may be passed & liquid feeding can be given. E.g. milk, Horlicks, glucose, soup, fruit, juice etc.
  9. Change of position every 2 hourly by day & by night.
  10. Take care oral hygiene is very important especially if patient is being tube feeding.
  11. Care of the bowels and bladder.
  12. Monitor input and output; record the specific gravity of urine.
  13. Provide fluid therapy as indicated.
  14. Give regular insulin treatment as indicated.
  15. Observed signs of infection and inflammation.
  16. Improve efforts to prevention by good hand washing for all people in contact with patients including the patients themselves.
  17. Maintain aseptic technique in invasive procedures.

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