Glycemia or the concentration of glucose in the blood is strictly regulated in the body through several mechanisms.

Several health conditions can cause the blood glucose level to become too high or fall too low. For example, stress, injury, heart attack or stroke can cause temporary increases in blood glucose, while drugs such as alcohol, acetaminophen, gemfibrozil or clofibrate can cause the level to fall. Diabetes is the most common cause of a raised blood sugar level but some drugs that can increase blood glucose include corticosteroids, estrogens, lithium, antidepressants and phenothiazine.

Raised blood glucose or hyperglycemia

Hyperglycemia can cause several complications if it is left untreated. Long-term hyperglycemia can cause damage to the nerves, the vessels and several organs including the eyes, heart and the kidneys. A very high blood sugar level can lead to a life threatening complication called diabetes ketoacidosis, which can cause coma in severe cases.

Some of the causes of hyperglycemia include over-eating, a low level of physical activity, stress, and major injury or surgery. Symptoms of hyperglycemia include increased thirst, a frequent need to urinate, fatigue, excessive hunger, nausea, dry and itchy skin, blurred vision, shallow breathing, and delayed healing of skin infections and wounds.

Low blood sugar or hypoglycemia

Hypoglycemia can be caused by skipped meals or long periods of fasting, blood sugar lowering medications and excessive exercise. Symptoms include tiredness, shortness of breath, palpitations, dizziness, and nausea. In severe cases, hypoglycemia can lead to a seizure, coma and even death.