What are the symptoms of hypoglycemia?
The symptoms of low blood sugar may be mild, moderate, or severe. Mild hypoglycemia can cause nausea, a jittery or nervous feeling, cold and clammy skin, and a rapid heartbeat. Moderate hypoglycemia often makes you feel irritable, anxious, or confused. You may have blurred vision, feel unsteady, and have difficulty walking. Severe hypoglycemia can lead
to loss of consciousness, seizures, and coma and may be fatal. Some medications may mask symptoms of low blood sugar, including beta-blockers, which are often used to treat heart conditions and high blood pressure.
Symptoms related to low levels of sugar supplying the brain including headache, dizziness, blurred vision, difficulty concentrating, poor coordination, confusion, weakness or fainting, tingling sensations in the lips or hands, confused speech, abnormal behavior, convulsions, loss of consciousness, and coma. Symptoms related to epinephrine and norepinephrine including sweating, tremors (feeling shaky), rapid heartbeat, anxiety, and hunger.
The symptoms of hypoglycemia rarely develop until the level of sugar in the blood falls below 60 milligrams per deciliter of blood. Some people develop symptoms at slightly higher levels, especially when blood sugar levels fall quickly, and some do not develop symptoms until the sugar levels in their blood are much lower.
The body first responds to a fall in the level of sugar in the blood by releasing epinephrine (adrenaline) from the adrenal glands. Epinephrine stimulates the release of sugar from body stores but also causes symptoms similar to those of an anxiety attack: sweating, nervousness, shaking, faintness, palpitations, and hunger. More severe hypoglycemia reduces the sugar supply to the brain, causing dizziness, fatigue, weakness, headaches, inability to concentrate, confusion, inappropriate behavior that can be mistaken for drunkenness, slurred speech, blurred vision, seizures, and coma. Prolonged hypoglycemia may permanently damage the brain. Symptoms can begin slowly or suddenly, progressing from mild discomfort to severe confusion or panic within minutes. On the infrequent occasions when people who have well-controlled diabetes develop hypoglycemia, awareness of the symptoms of hypoglycemia may be lost, and faintness or even coma may develop without any other warning.
In a person with an insulin-producing pancreatic tumor, symptoms are likely to occur early in the morning after an overnight fast, especially if the sugar stores in the blood are further depleted by exercise before breakfast. At first, people with a tumor usually have only occasional episodes of hypoglycemia, but over months or years, episodes become more frequent and severe.