Diabetes can have both short and long term complications. It is these complications that are responsible for the premature death and disability of the disease. Some complications can arise very quickly while others take years to decades to develop. Long term complications are unfortunately irreversible and progressive thus the drive to limit their severity and delay their appearance through comprehensive diabetes management.

Short term complications of diabetes can include:

• Diabetic ketoacidosis (DKA) - Caused by high blood sugar (hyperglycemia) and considered a medical emergency requiring prompt attention at a hospital. DKA may be accompanied by serious dehydration which by itself can lead to cardiac irregularities. In DKA the body produces ketones that can alter the pH of the blood stream. A narrow and normal blood pH is essential to the maintenance of life. Since the patient may be unconscious or confused, some diabetics wear ID bracelets or carry some form of identification indicating they are diabetic. DKA is easily treated in the hospital when properly diagnosed. Patients are rehydrated and often given IV insulin. An extreme form of DKA is termed "hyperosmal ketoacidosis". In this form patients build up ammonia in the blood and must have blood chemistry restored to normal values or face imminent coma and death.
• Hypoglycemia - or low blood sugar. When blood glucose falls below 60 the result can be very dangerous including tremors, confusion, and coma. Hypoglycemia is easily reversed with the administration of oral glucose (orange juice or glucose tablets) or in extreme cases by injection of the glucose producing hormone glucagon and/or IV administration of a sugar solution. People are often confused about just how someone who doesn’t metabolize glucose well ends up with low blood sugar. The answer is simple. In order to maintain strict glucose control, patients are advised to use oral medications and/or insulin in sufficient quantity and frequency as to occasionally result in hypoglycemic episodes. Usually, diabetics are alert to the symptoms of approaching hypoglycemia but not always, particularly when it occurs at night while patients are sleeping. Normally, during waking hours patients notice an increased anxiety, sweating, and rapid pulse as blood sugar precipitously drops.

Long term complications of diabetes include:

• Neuropathy - or nerve damage. Damage can be peripheral (usually the lower legs and feet) or autonomic (bladder, sex organs, and GI tract). Over 40% of diabetics will develop some form of neuropathy. Symptoms of neuropathy can include a burning or tingling sensation, numbness, pain, and cramping in the extremities and in autonomic neuropathy, abdominal cramps, nausea, incontinence, constipation, diarrhea, and impotence. The majority of diabetics over the age of 40 suffer from some degree of sexual dysfunction.
• Retinopathy/Glaucoma/cataracts - or damage to the nerves and blood vessels of the eye. Diabetes is the major cause of blindness. Diabetics also experience markedly higher rates of both narrow and wide angle glaucoma. All diabetics are recommended to have an annual opthomological examination. Hourly fluctuations of blood sugar may also change the osmolarity of fluid in the eye causing blurred vision. This normally passes as blood sugar stabilizes but cataracts can develop. When one combines the factors of declining vision with numbness or insensitivity in the hands and feet it is obvious that these patients are at high risk of injury through falls, mishaps, and burns.
• Nephropathy - or damage to the filtering cells of the kidney. Diabetes is the leading cause of End Stage Renal Disease (ESRD). Nephropathy can contribute to high blood pressure which makes other diabetic complications more aggravated. The progression of ESRD can be delayed for many years with proper management including the use of ACE inhibitors to reduce blood pressure and help protect the kidney. ESRD progresses through five stages which are monitored by measuring albumin in the urine (dipstick method) along with kidney function tests like creatine levels. In ESRD the kidneys are increasingly unable to filter the blood. Protein is carried into the urine and toxic wastes can build up in the bloodstream. In severe cases kidney dialysis is necessary to maintain life.
• Heart disease - or damage/deposits in the blood vessels that supply the heart. Coronary artery disease (CAD) is a major threat to the lives of diabetics who develop serious heart problems at 200-400% the rate of normal individuals. Heart muscle disease (cardiomyopathy) is the leading cause of death in diabetics. Narrowing of the arteries and arterial inflammation can also occur in the periphery particularly the legs.
• Peripheral artery disease - (PAD) When peripheral circulation is effected it is called "claudication". This can be both painful and lead to serious circulation problems in the legs and feet. Diabetics are cautioned to never go barefoot as injury and infection in the feet are difficult to notice and hard to treat where impaired circulation is present. PAD is most likely to occur in the arteries of the legs but can effect arms as well.
• Cerebrovascular disease - or damage to the tiny blood vessels in the brain that can result in stroke. High blood pressure common in diabetes contributes to the higher incidence of stroke. Some patients with persistent high blood pressure who are obese and have continuously high levels of sugar may have to be placed on dangerous anti-coagulants to help prevent strokes.
• Chronic infection - diabetics have a markedly reduced ability to fight even common infections. Reduced blood circulation in the extremities and compromised immune function contribute to infections that can be persistent and sometimes dangerous. Diabetics are at high risk for amputation of extremities and developing complications such as pneumonia. During the course of an infection, diabetics develop increased hyperglycemia and may require increased doses of insulin and/or oral medications. Infection can easily occur in diabetics whose hands and/or feet have developed insensitivity. Infections can also occur at insulin injection sites and on areas used to provide blood samples for blood glucose monitoring (usually the finger tips).
• Chronic Pain - Many of the complications listed above can involve chronic pain syndromes of various types from neuropathic pain to organ pain (see article and links on chronic pain).