3. Foot problems

What they are: People with diabetes are prone to a host of foot ailments including calluses, ulcers, and poor blood flow or circulation. These conditions are more likely if the patient also has loss of feeling in her feet due to nerve damage.

What they do: Left unchecked, even the most mundane foot ailments -- like an ingrown toenail -- can get worse and lead to serious infections and other complications.

How to prevent them: Make sure the person you're caring for examines her feet on a daily basis for any cuts, sores, patches of redness, swelling, or hot spots, which should be promptly reported to her doctor. She should also remove her shoes and socks and have her doctor check her feet at every routine doctor's visit. Exercise can help poor circulation. However, infections, ulcers, or foot injuries require her to stay off her feet until the problem heals.

4. Nerve damage

What it is: The most common form of nerve damage in people with diabetes is known as peripheral neuropathy, which mainly affects the lower legs and feet. Nerve damage that affects the stomach is called gastroparesis.

What it does: Neuropathy causes pain, numbness, weakness, or an uncomfortable tingling sensation, which can increase the chance of foot injuries. Gastroparesis may delay or otherwise affect digestion, resulting in nausea, vomiting, or bloating; this can make blood glucose control difficult.

How to prevent it: Lowering blood pressure, losing excess weight if necessary, and -- of course -- managing blood glucose levels can all help ward off neuropathy.

5. Amputation

What it is: The removal of a limb or extremity. The most common amputations for people with diabetes involve the lower legs or feet.

Why it happens: Many people with diabetes have artery damage, which can result in less blood flow to the feet. Many people with diabetes also have nerve disease, which can reduce feeling in the feet. Together, these predicaments make it easy for ulcers or infections to take hold -- and, if left untreated, they may lead to amputation.

How to prevent it: Fortunately, most amputations are preventable with routine self-care, proper footwear, and regular foot checks from a healthcare provider.