Written by Ann Pietrangelo, Medically Reviewed by George Krucik, MD, MBA
Diabetes is a group of diseases that affect the body’s ability to produce or use insulin, a hormone that allows your body to turn glucose into energy. Diabetes can be effectively managed, but potential complications include heart disease, stroke, and kidney damage.
After you eat or drink, your body breaks down the sugars in your blood and turns it into glucose. The glucose travels through your bloodstream and provides your body with energy. To accomplish this, your pancreas needs to produce a hormone called insulin. In a person with diabetes (diabetes mellitus), the pancreas either produces too little insulin or none at all, or the insulin can’t be used effectively. This allows blood glucose levels to rise while the rest of your cells are deprived of much needed energy. This can lead to a wide variety of problems affecting nearly every part of your body.
There are two main types of diabetes. Type 1, also known as juvenile diabetes or insulin-dependent diabetes, is an immune system disorder. In Type 1 diabetes, the patient’s own immune system attacks the insulin-producing cells in the pancreas, destroying the ability to manufacture insulin. People with Type 1 diabetes must take insulin to live. Most people with Type 1 diabetes are diagnosed as children or young adults.
The main problem in Type 2 diabetes is the presence of what is called insulin resistance. In this sort of diabetes, the pancreas starts off robust in its production of insulin. However, cells that need energy don’t respond normally to the usual amounts of insulin. The pancreas has to produce much higher levels of the hormone in order to manage blood glucose levels. Over time, the insulin-producing cells in the pancreas can burn themselves out due to this overproduction. At this point a person with Type 2 diabetes begins to require insulin medication. However, in earlier phases of this more common type of diabetes, the illness can be effectively managed with diet, exercise, and careful monitoring of blood sugars. Some people with Type 2 diabetes may require a variety of oral medications and eventually, as described above, some will eventually need insulin.
Gestational diabetes is high blood sugar that develops during pregnancy. Most of the time, gestational diabetes can be controlled through diet and exercise, and it typically resolves after the baby is delivered.
Common symptoms of diabetes include excessive thirst, frequent urination, and sluggishness. Blood tests will reveal high sugar levels.
Endocrine, Excretory, and Digestive Systems
Your pancreas produces and releases insulin to help make energy out of sugars. If your pancreas produces little or no insulin, or if your body can’t use it, alternate hormones are used to turn fat into energy. This can create high levels of toxic chemicals, including acids and ketone bodies, which may lead to a condition called diabetic ketoacidosis. This is a serious complication of the disease. Symptoms include extreme thirst, excessive urination, and fatigue. Your breath may have a sweet scent that is caused by the elevated levels of ketone bodies in the blood. High blood sugar levels and excess ketones in your urine can confirm diabetic ketoacidosis. Untreated, the condition can lead to loss of consciousness or even death.
Diabetes can damage your kidneys, affecting their ability to filter waste products from your blood. Elevated amounts of protein in your urine (microalbuminuria) may be a sign that your kidneys aren’t functioning properly. Kidney disease related to diabetes is called diabetic nephropathy. This condition doesn’t show symptoms until it advances to later stages. People with diabetes should be evaluated for nephropathy in order to avoid irreversible kidney damage and kidney failure.
Diabetic hyperglycemic hyperosmolar syndrome (HHS) occurs in Type 2 diabetes. It involves very high blood glucose levels but without ketones. Symptoms also include dehydration and loss of consciousness. It usually happens to people whose diabetes is undiagnosed or who have not been able to control their diabetes. It can also be caused by heart attack, stroke, or infection.
High blood glucose levels can make it hard for your stomach to completely empty (gastroparesis). In turn, the delay causes blood glucose levels to rise. Diabetes is the leading cause of gastroparesis. Symptoms include nausea, vomiting, bloating, and heartburn.
High blood glucose levels can contribute to the formation of fatty deposits in blood vessel walls. Over time, that can restrict blood flow and increase the risk of hardening of the blood vessels (atherosclerosis).
Lack of blood flow can affect your hands and feet. Poor circulation can cause pain in the calves while you’re walking (intermittent claudication). People with diabetes are particularly prone to foot problems due to narrowed blood vessels in the leg and foot. Your feet may feel cold, and you may be unable to feel heat due to lack of sensation. A condition called diabetic neuropathy causes decreased sensation in the extremities, which may prevent you from noticing an injury or infection. Diabetes increases your risk of developing infections or ulcers of the foot. Poor blood flow and nerve damage increase the likelihood of having a foot or leg amputated. If you have diabetes, it is critical that you take good care of your feet and inspect them often.
Diabetes raises your risk of developing high blood pressure, putting strain on the heart. According to the National Diabetes Information Clearinghouse, people with diabetes have double the risk of heart disease or stroke than people without diabetes. Monitoring and controlling your blood glucose, blood pressure, and cholesterol can lower that risk. So can good eating habits and exercise.
Diabetes and smoking are a very bad mix, increasing risk of cardiovascular problems and restricted blood flow.
Diabetes can affect your skin. Lack of moisture can cause the skin on your feet to dry and crack. It is important to completely dry your feet after bathing or swimming. You can use petroleum jelly or gentle creams, but be careful: creams or oils left between your toes can become so moist that it can lead to infection.
High-pressure spots under your foot can lead to calluses. If you don’t take good care of them, they can become infected or develop ulcers. If you get an ulcer, see your doctor immediately to lower your risk of losing your foot.
You may also be more prone to boils, infection of the hair follicles (folliculitis), sties, and infected nails. People with diabetes have a higher incidence of bacterial infections, including staph (Staphylococcus), than the general population.
Moist, warm folds in the skin are susceptible to fungal or yeast infections. You’re most likely to develop this type of infection between fingers and toes, the groin, armpits, or in the corners of your mouth. Symptoms include redness, blistering, and itchiness.
A condition called diabetic dermopathy can cause brown patches on the skin. There’s no cause for concern and no treatment is necessary. Eruptive xanthomatosis causes hard yellow bumps with a red ring. Digital sclerosis causes thick skin, most often on the hands or feet. Both of these skin conditions are signs of unmanaged diabetes. They usually clear up when you get your blood sugar under control.
Central Nervous System
Diabetes causes damage to the nerves (peripheral neuropathy), which can affect your perception of heat, cold, and pain, making you more susceptible to injury. This also makes it more likely that you’ll ignore an injury, especially if it’s in a difficult place to see, such as between your toes, on your heels, or the bottoms of your feet.
Swollen, leaky blood vessels in the eye (diabetic retinopathy) can damage your vision and even lead to blindness. Symptoms include floaters or spots in your field of vision. People with diabetes tend to develop cataracts at an earlier age than other people. They are also more likely to develop glaucoma. Symptoms of eye trouble can be mild at first, so it’s important to see your eye doctor regularly.
The hormones of pregnancy can cause gestational diabetes. This also increases the risk of high blood pressure (preeclampsia or ecclampsia). In most cases, gestational diabetes is easily controlled, and glucose levels return to normal after the baby is born. Symptoms are the same as other types of diabetes, but may also include repeated infections affecting the vagina and bladder. Women with gestational diabetes may have babies with higher birth weight, making delivery more complicated. Women who have had gestational diabetes should be monitored, as there’s an increased risk of developing diabetes within ten years.