Extreme hypoglycemia is a medical emergency and should be treated immediately.

Patients with diabetes who take insulin are susceptible to hypoglycemia (low blood glucose) when they administer too much insulin, delay or miss a meal, exercise without first eating a snack, or drink alcohol on an empty stomach. But insulin treatment isn’t the only cause of hypoglycemia. Hypoglycemia can also result from treatment with the oral sulfonylureas, repaglinade and nateglinide. Unfortunately, unexplained “lows” frequently occur even in people who carefully control their medications and regularly monitor their blood sugar levels. That’s why it’s important to recognize the early signs of hypoglycemia, and know what to do when hypoglycemia occurs.

There are two types of hypoglycemic symptoms, adrenergic and neurologic:

• Adrenergic hypoglycemia symptoms. Sweating, heart palpitations, nervousness, hunger, faintness, and weakness are the earliest signs that you have hypoglycemia and that your blood sugar has dropped below about 60 mg/dL. When your blood glucose is this low, a hormone called epinephrine is released into the bloodstream, triggering the liver to increase its glucose production and the pancreas to release glucagon, another hormone that increases blood glucose. These unpleasant adrenergic symptoms are actually advantageous, because they warn you that you must immediately eat or drink something with sugar to raise your blood glucose level. The best choices are sugars that are rapidly absorbed into the bloodstream, such as 4 oz. of orange juice, 6 oz. of non-diet soda, 5–7 hard candies, or 2–5 glucose tablets.

• Neurologic hypoglycemia symptoms. If your blood sugar drops to below 40 mg/dL, you may develop severe neurological symptoms such as headache, lack of coordination, double vision, slurred speech, confusion and numbness in your fingers and around your mouth. This can happen if you are taking beta-blocking drugs (heart medication) or have diabetes-related nerve damage. It can also happen if you have had diabetes for 5–10 years, because the body’s response to hypoglycemia, particularly the release of glucagon, may no longer occur.

Without treatment, extreme hypoglycemia can cause seizures, coma, and, in rare cases, permanent brain damage and death. If you are taking insulin or an oral diabetes drug that can cause hypoglycemia, your doctor or diabetes educator will train you (and family members or friends who would be available to help you) on how to give a glucagon injection, which can rapidly raise your blood glucose level and prevent disaster. It’s easy to do, because you can inject glucagon almost anywhere (abdomen, thigh, buttocks, upper arm), and it’s nearly impossible to take an overdose. You’ll need a prescription to buy a pre-filled glucagon syringe to keep on hand at all times. It should be kept cool, but need not be refrigerated, and should be replaced on the expiration date. If glucagon is unavailable or its use does not achieve consciousness, an ambulance must be called immediately.