Diabetes Complications: Know the Symptoms

Take note of these red flags and learn what to do.

Medically Reviewed by Brunilda Nazario, MD on March 24, 2016
From the WebMD Archives

As careful as you may be to keep your blood sugar under control, related health problems called complications can happen.

Don’t ignore these symptoms, says Sethu K. Reddy, MD, chief of the adult diabetes section at Joslin Diabetes Center.

Sweating, nervousness, or lightheadedness: If you suddenly feel shaky and your heart is racing, your blood sugar may have dropped below 70 mg/dL.

That can also cause hunger, headaches, irritability, and fatigue.

"If the blood sugar goes down further, people are more likely to get changes in personality or they might lose consciousness," Reddy says.

You should have a handy source of about 15 to 20 grams of simple carbohydrates, such as a glucose tablet or gel, 2 tablespoons of raisins, or 4 ounces of juice or soda, to raise your blood sugar quickly.

Thirst and peeing often: These are symptoms of high blood sugar. You might also have a dry mouth, unexplained weight loss, fatigue, and slow-healing sores.

Those symptoms also can be warning signs of a serious condition called diabetic ketoacidosis, or DKA, which is related to high blood sugar. When you don’t have enough insulin, your body burns fat for energy instead of sugar, and ketones build up in your blood.

High levels of ketones may cause you to feel tired or confused, have trouble breathing, vomit or have belly pain, and have dry or flushed skin. Use an at-home urine test or a blood sugar meter (if yours has this capability) to measure your ketones. Call your doctor if the level is high.

Numbness, tingling, or pain: Even when high blood sugar doesn't cause symptoms, it can lead to nerve damage, or neuropathy. You may first notice numbness or tingling in your hands or feet. If you lose the ability to feel cold, heat, or pain in your feet, you could get a sore or infection without knowing it.

Constipation, heartburn, or nausea: These could be warning signs of gastroparesis, when the stomach empties slowly because of nerve damage.

"Constipation is probably the earliest sign that something is going on with the nervous system and the GI [gastrointestinal] system," Reddy says.

Gastroparesis can lead to gastroesophageal reflux, when some food or stomach acid leaks back into the esophagus, causing a burning feeling.

Blurry vision: When blood sugars fluctuate, as they often do with type 1 diabetes, fluid buildup can blur your vision. Getting your sugar level under control clears up the problem.

Still, be aware that serious eye damage can happen from other conditions, such as diabetic retinopathy, without early symptoms.

Ask Your Doctor

What is the level of protein in my urine?

What should I do if my blood sugar is high or low?

How often should I have a medical or eye exam?

What symptoms signal a medical emergency?

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Sethu Reddy, MD, MBA, Chief, Adult Diabetes Section, Joslin Diabetes Center, Boston, MA.

American Diabetes Association: “Diabetes Symptoms,” “DKA (Ketoacidosis) and Ketones,” “Eye Complications,” “Foot Complications,” “Gastroparesis,” “Hypoglycemia (Low Blood Sugar).”

Joslin Diabetes Center: “Diseases of the Eye,” “High Blood Glucose: What It Means and How to Treat It.”

Centers for Disease Control and Prevention: “Prevent Complications.”

McCulloch DK., December 2015.

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