Low blood sugar

Alternative names
Insulin shock; Hypoglycemia

Definition
Hypoglycemia occurs when your body’s blood sugar, or glucose, is abnormally low. The term insulin shock is used to describe severe hypoglycemia that results in unconsciousness.

Causes, incidence, and risk factors

Hypoglycemia results when your body’s glucose is used up too rapidly, when glucose is released into the bloodstream more slowly than is needed by your body, or when excessive insulin is released into the bloodstream. Insulin is a hormone that reduces blood glucose. It is produced by the pancreas in response to increased glucose levels in the blood.

Hypoglycemia is relatively common in diabetics. It occurs when too much insulin or oral antidiabetic medication is taken, not enough food is eaten, or from a sudden increase in the amount of exercise without an increase in food intake.

Relative hypoglycemia, where a newborn’s blood glucose is low, is fairly common. Severe hypoglycemia may occur in an infant born to a woman with Diabetes or gestational diabetes. In these cases, the child is referred to as an IDM for “infant of diabetic mother.”

If, during the pregnancy, the mother’s blood sugar is persistently high, the fetus’ pancreas assists in controlling the excess blood sugar by producing extra insulin. When the infant is born, it no longer gets the mother’s glucose, but still produces increased insulin, and the increased insulin drives the infant’s blood sugar down to dangerous levels. This is a medical emergency that may result in seizures and damage to the baby’s nervous system if not treated.

Sometimes the cause of hypoglycemia is unknown (idiopathic). In these cases, people who are not diabetic and who do not have another known causes of hypoglycemia experience these symptoms.

Hypoglycemia can occur because of an insulin-secreting tumor of the pancreas, liver disease, or as a response to the ingestion of alcohol. It can occur in adults, infants, and children, and affects approximately 1 out of every 1,000 people.

Symptoms

     
  • Fatigue  
  • General discomfort, uneasiness, or ill feeling (malaise)  
  • Nervousness  
  • Irritability, or even aggression  
  • Trembling  
  • headache  
  • Hunger  
  • Cold sweats  
  • Rapid heart rate  
  • Blurry or double vision  
  • Confusion  
  • Convulsions  
  • Coma

Additional symptoms that may be associated with this disease:

     
  • Excessive sweating  
  • Sleeping difficulty  
  • Paleness  
  • Muscle pain  
  • Memory loss  
  • Palpitations, or feeling your heartbeat (heartbeat sensations)  
  • Hallucinations  
  • Fainting  
  • Different size pupils  
  • Dizziness  
  • Decreased consciousness

Signs and tests

     
  • Serum glucose, or sugar level in the blood, is low.  
  • If the person is monitoring his/her own blood glucose levels, readings will be low (less than 50 mg/dl).

This disease may also alter the results of the following tests:

     
  • Glucose tolerance test  
  • CSF collection  
  • Blood glucose monitoring

Treatment
A snack or drink containing sugar will raise the blood-glucose level, and you should see an immediate improvement in symptoms.

Infants of diabetic mothers that develop low blood sugars are treated with glucose solutions given into the vein to maintain the blood sugar at normal levels. The glucose is slowly reduced over the next 24-48 hours while the infant begins to regulate its blood sugar at normal levels.

If the person’s blood-sugar levels are so low that he/she becomes unconscious or unable to swallow, this is called insulin shock, and emergency medical treatment is needed. An injection of glucose solution or the hormone glucagon will be given immediately.

In the longer term, you may need to modify your diet so that you get glucose into your body more evenly throughout the day. This may prevent further hypoglycemic episodes. Small, frequent meals with complex carbohydrates, fiber, and fat; and avoiding simple sugars, alcohol, and fruit juice are the type of dietary modifications that may be recommended. You should also eat meals at regular intervals, and balance extra exercise with extra food.

If hypoglycemia is caused by an insulinoma (insulin-secreting tumor), surgery to remove the tumor is the best treatment.

Expectations (prognosis)
Severe hypoglycemia can often be avoided by recognizing the early warning signs of the condition and treating yourself rapidly and appropriately. Untreated hypoglycemia can progress to unconsciousness and if the brain is exposed to reduced glucose for a long period of time, there may be permanent damage.

Complications

     
  • Loss of consciousness  
  • Coma

In the infant

     
  • Seizure  
  • Permanent damage to the nervous system

Calling your health care provider
Go to the emergency room immediately or call a local emergency number, such as 911, if early signs of hypoglycemia do not improve after you’ve eaten a snack containing sugar. If a diabetic, or other person known to experience hypoglycemia, becomes unresponsive or you can’t wake them, you should also call an emergency number.

Prevention
Diabetics should follow their doctors’ advice regarding diet, medications, and exercise.

Pregnant diabetic women should maintain careful control of their blood sugar. Gestational diabetes, or diabetes that occurs during pregnancy, is diagnosed by repeat testing of expectant mothers. Upon delivery, routine blood sugar levels are taken from the infant until he/she no longer has low blood sugar.

People who are known to experience hypoglycemia should keep a snack or drink containing sugar available at all times to take as soon as symptoms appear. If symptoms do not improve in 15 minutes, additional food should be eaten. A glucagon kit is available by prescription for episodes of hypoglycemia that respond poorly to other types of treatment.

Johns Hopkins patient information

Last revised: December 6, 2012
by Simon D. Mitin, M.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.