Hypoglycemia, also called low blood sugar, occurs when the blood glucose (blood sugar) level drops too low to provide enough energy for the body's activities. In adults or children older than 10 years, hypoglycemia is uncommon except as a side effect of diabetes treatment, but it can result from other medications or diseases, hormone or enzyme deficiencies, or tumors.
Two types of hypoglycemia can occur in individuals who do not have diabetes: reactive (postprandial, or after meals) and fasting (post-absorptive). Reactive hypoglycemia is not usually related to any underlying disease; fasting hypoglycemia often is related to an underlying disease. Reactive hypoglycemia describes recurrent episodes of hypoglycemia occurring two to four hours after a high carbohydrate meal (or taking glucose by mouth). Reactive hypoglycemia is due to an excessive insulin release triggered by the carbohydrate meal that continues past the digestion and disposal of the glucose derived from the meal.
Normally, the body makes insulin when it is needed. Right after meals, the body produces enough insulin to process the blood sugar from that meal, moving it out of the blood and into the cells. Between meals, the level of insulin drops before it drives blood sugar levels too low.
If there is not enough insulin to let glucose enter the cells, too much glucose remains in the blood. This can cause symptoms of diabetes, including fatigue, frequent urination, thirst, and a risk of ketoacidosis (a dangerous condition with warning signs that include rapid deep breathing and sweet-smelling breath. Hypoglycemia can occur if the individual has more insulin than usual, has eaten too little food, or has been extra active (exercise helps insulin work more efficiently).
Many conditions besides diabetes may lead to low blood sugar levels in individuals who do not have diabetes. For instance, some types of cancer, critical illnesses (such as kidney, heart, or liver failure), and some medications (such as aspirin and sulfa antibiotics) may lead to hypoglycemia. Individuals who drink excessive amounts of alcohol without food may develop hypoglycemia. Individuals with anorexia nervosa or those who do not eat enough food may develop hypoglycemia. Tumors of the pancreas may stimulate the pancreas to release too much insulin, which may then lead to hypoglycemia.
Common symptoms include confusion, abnormal behavior, impaired vision (such as blurred or double vision), irregular heartbeat, tremors, anxiety, sweating, and hunger. In rare cases, patients may develop seizures or lose consciousness.
Treatment of hypoglycemia involves short-term steps to increase the individual's blood sugar level. It also involves long-term steps to identify and treat the underlying cause of hypoglycemia. Individuals with hypoglycemia will first receive treatment to reduce symptoms. They may receive glucose tablets or eat foods high in sugar (such as candy) to increase blood sugar levels. In severe cases, individuals may require intravenous glucose or an injection of the glucagon hormone.
Once initial symptoms are treated, healthcare providers will work with the individual to determine the underlying cause of symptoms. Treating the underlying cause reduces the chances of hypoglycemia occurring in the future. If a tumor in the pancreas is causing symptoms, individuals may need to have it surgically removed. If a medication is causing the condition, an alternative drug or dose may be recommended.
Medications, including some used to treat diabetes, are the most common cause of hypoglycemia.
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