Diabetes mellitus type 2 natural history, complications, and prognosis

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]

Overview

If diabetes mellitus type 2 left untreated, it may result in hyperosmolar hyperglycemic state (HHS) and in rare circumstances diabetic ketoacidosis (DKA).

Natural History

Type 2 diabetes may go unnoticed for years because symptoms are typically mild, non-existent or sporadic, and usually there are no ketoacidotic episodes. However, severe long-term complications can result from unnoticed type 2 diabetes, including renal failure due to diabetic nephropathy, vascular disease (including coronary artery disease), visual changes due to diabetic retinopathy, loss of sensation or pain due to diabetic neuropathy, and liver damage from non-alcoholic steatohepatitis secondary to metabolic syndrome.
If diabetes mellitus type 2 left untreated it may result in hyperosmolar hyperglycemic state (HHS) and in rare circumstances diabetic ketoacidosis (DKA).

Complications

Complications of Diabetes
Acute complications due to hyperglycemia	Diabetes ketoacidosis Hyperglycemic hyperosmolar state
Microvascular complications	Eye disease Retinopathy (nonproliferative/proliferative) Macular edema Neuropathy  Sensory and motor (mono- and polyneuropathy) and Autonomic neuropathy Nephropathy (albuminuria and declining renal function)
Macrovascular complications	Coronary heart disease Peripheral arterial disease Cerebrovascular disease
Other	Gastrointestinal (gastroparesis, diarrhea) Genitourinary (uropathy/sexual dysfunction) Dermatological complications Infectious complications Cataracts Glaucoma Cheiroarthropathya(thickened skin and reduced joint mobility) Periodontal disease Hearing loss Depression, Obstructive sleep apnea, Fatty liver disease, Hip fracture Osteoporosis (in type 1 diabetes), Cognitive impairment Dementia Low testosterone in men

Unlike Type 1 diabetes, there is little tendency toward ketoacidosis in Type 2 diabetes, though it is not unknown. One effect that can occur is nonketonic hyperglycemia. Complex and multifactorial metabolic changes lead to damage and function impairment of many organs, most importantly the cardiovascular system in both types. This leads to substantially increased morbidity and mortality in both Type 1 and Type 2 patients, but the two have quite different origins and treatments despite the similarity in complications.

Heart Disease and Stroke

People with diabetes have extra reason to be mindful of heart and blood vessel disease. Diabetes carries an increased risk for heart attack, stroke, and complications related to poor circulation. 2 out of 3 people with diabetes die from heart disease or stroke. Diabetes management is more than control of blood glucose. People with diabetes must also manage blood pressure and cholesterol and talk to their health provider to learn about other ways to reduce their chance for heart attacks and stroke. Again, lifestyle changes, such as choosing foods wisely and being physically active, as well as taking medication can help. Many people find that changing what they eat can make a big difference in their blood glucose, blood pressure, and cholesterol levels.

Kidney Disease

Diabetes can damage the kidneys, which not only can cause them to fail, but can also make them lose their ability to filter out waste products. Diabetes can damage the filtering ability of kidneys. High levels of blood sugar make the kidneys filter too much blood. All this extra work is hard on the filters. After many years, they start to leak. Useful protein is lost in the urine. Having small amounts of protein in the urine is called microalbuminuria. When kidney disease is diagnosed early, (during microalbuminuria), several treatments may keep kidney disease from getting worse. Having larger amounts is called macroalbuminuria. When kidney disease is caught later (during macroalbuminuria), end-stage renal disease, or ESRD, usually follows. In time, the stress of overwork causes the kidneys to lose their filtering ability. Waste products then start to build up in the blood. Finally, the kidneys fail. This failure, ESRD, is very serious. A person with ESRD needs to have a kidney transplant or to have the blood filtered by machine (dialysis). Diabetic kidney disease can be prevented by keeping blood sugar in your target range.

Eye Complications

People with diabetes are 40% more likely to suffer from glaucoma than people without diabetes. The longer someone has had diabetes, the more common glaucoma is. Risk also increases with age. Glaucoma occurs when pressure builds up in the eye, and vision is gradually lost because the retina and nerve are damaged. Many people without diabetes get cataracts, but people with diabetes are 60% more likely to develop this eye condition. People with diabetes also tend to get cataracts at a younger age and have them progress faster. With cataracts, the eye's clear lens clouds, blocking light. Diabetic retinopathy is a general term for all disorders of the retina caused by diabetes. In nonproliferative retinopathy, capillaries in the back of the eye balloon and form pouches. Nonproliferative retinopathy can move through three stages (mild, moderate, and severe), as more and more blood vessels become blocked. In some people, retinopathy progresses after several years to a more serious form called proliferative retinopathy which can lead to blindness caused by retinal detachment. People who keep their blood sugar levels closer to normal are less likely to have retinopathy or to have milder forms.

Diabetic Neuropathy and Nerve Damage

One of the most common complications of diabetes is diabetic neuropathy. Neuropathy means damage to the nerves that run throughout the body, connecting the spinal cord to muscles, skin, blood vessels, and other organs. There are two common types of nerve damage. The first is sensorimotor neuropathy, also known as peripheral neuropathy. This can cause tingling, pain, numbness, or weakness in your feet and hands. The second is called autonomic neuropathy. This type can lead to:

• Digestive problems such as feeling full, nausea,
• Vomiting, diarrhea, or constipation
• Problems with how well your bladder works
• Problems having sex
• Dizziness or faintness
• Loss of the typical warning signs of a heart attack
• Loss of the warning signs of low blood glucose
• Increased or decreased sweating
• Changes in how your eyes react to light and dark

People with diabetes can also have what is called focal neuropathy. In this kind of nerve damage, a nerve or a group of nerves is affected, causing sudden weakness or pain. It can lead to double vision, a paralysis on one side of the face called Bell's palsy, or pain in the front of the thigh or other parts of the body. People with diabetes also are at risk for compressed nerves. Something in the body presses against a nerve preventing it from sending a signal. Carpal tunnel syndrome is a common cause of numbness and tingling in the fingers and can lead to muscle pain and weakness as well. Keeping your blood glucose levels in the target range can prevent or delay further damage and may lessen your symptoms.

Foot Complications

Although it can hurt, diabetic nerve damage can also lessen your ability to feel pain, heat, and cold. Loss of feeling often means you may not feel a foot injury. You might not notice a foot injury until the skin breaks down and becomes infected. Nerve damage can also lead to changes in the shape of your feet and toes. Ulcers occur most often on the ball of the foot or on the bottom of the big toe. Neglecting ulcers can result in infections, which in turn can lead to loss of a limb. Poor circulation (blood flow) can make your foot less able to fight infection and to heal. Diabetes causes blood vessels of the foot and leg to narrow and harden. You can control some of the things that cause poor blood flow. Don't smoke - smoking makes arteries harden faster. People with diabetes are far more likely to have a foot or leg amputated than other people. The problem? Many people with diabetes have artery disease, which reduces blood flow to the feet. Also, many people with diabetes have nerve disease, which reduces sensation. Together, these problems make it easy to get ulcers and infections that may lead to amputation. One of the biggest threats to your feet is smoking. Smoking affects small blood vessels. It can cause decreased blood flow to the feet and make wounds heal slowly. A lot of people with diabetes who need amputations are smokers.

Gastroparesis

Gastroparesis is a disorder affecting people with both type 1 and type 2 diabetes, where the stomach takes too long to empty its contents. It happens when nerves to the stomach are damaged or stop working. The vagus nerve controls the movement of food through the digestive tract. If the vagus nerve is damaged, the muscles of the stomach and intestines do not work normally, and the movement of food is slowed or stopped. Gastroparesis can make diabetes worse by making it more difficult to manage blood glucose. When food that has been delayed in the stomach finally enters the small intestine and is absorbed, blood glucose levels rise. If food stays too long in the stomach, it can cause problems like bacterial overgrowth because the food has fermented. Also, the food can harden into solid masses called bezoars that may cause nausea, vomiting, and obstruction in the stomach. Bezoars can be dangerous if they block the passage of food into the small intestine.

Prognosis

Hypoglycemia, Hyperglycemia, and a High Risk for Diabetic Comas

Hypoglycemia, low blood glucose (sugar), sometimes called an insulin reaction, can happen even during those times when you're doing all you can to manage your diabetes. So, although many times you can't prevent it from happening, hypoglycemia can be treated before it gets worse. The symptoms of hypoglycemia include:

• Shakiness
• Dizziness
• Sweating
• Hunger
• Headache
• Pale skin color
• Sudden moodiness or behavior changes, such as crying for no apparent reason
• Clumsy or jerky movements
• Seizure
• Difficulty paying attention, or confusion
• Tingling sensations around the mouth

The quickest way to raise your blood glucose and treat hypoglycemia is with some form of sugar, such as 3 glucose tablets (you can buy these at the drug store), 1/2 cup of fruit juice, or 5-6 pieces of hard candy. Ask your health care professional or dietitian to list foods that you can use to treat low blood glucose. Good diabetes control is the best way we know to prevent hypoglycemia. Hyperglycemia is the technical term for high blood glucose (sugar). High blood glucose happens when the body has too little, or not enough, insulin or when the body can't use insulin properly. If you have type 2 diabetes, your body may have enough insulin, but it is not as effective as it should be. The problem could be that you ate more than planned or exercised less than planned. The stress of an illness, such as a cold or flu, could also be the cause. Other stresses, such as family conflicts or school or dating problems, could also cause hyperglycemia. The signs and symptoms include: high blood glucose, high levels of sugar in the urine, frequent urination, and increased thirst. It's important to treat hyperglycemia as soon as you detect it. If you fail to treat hyperglycemia, a condition called ketoacidosis (diabetic coma) could occur. Ketoacidosis develops when your body doesn't have enough insulin. Often, you can lower your blood glucose level by exercising. Cutting down on the amount of food you eat might also help. Your best bet to prevent hyperglycemia is to practice good diabetes management. Ketoacidosis is life-threatening and needs immediate treatment. It can occur when a case of hyperglycemia gets out of control. Symptoms include:

• Shortness of breath
• Breath that smells fruity
• Nausea and vomiting
• Very dry mouth

References

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