Weakening of small blood vessels called capillaries causes blood to leak from the vessel.

Eyes: Damage to the retina, the part of the eye that captures images

• Impaired vision and, in severe cases, blindness

Kidneys: Impaired functioning of the kidneys, and, in severe cases, kidney failure

• Fatigue
• Muscle cramping
• Inability to think clearly
• Swelling from retention of body fluids

Nerves: Decreased sensation, especially common in the feet and hands; weakness; abnormal functioning of some organ systems

• Numbness, tingling, weakness in the feet and hands
• Swings in heart rate and blood pressure
• Nausea and vomiting from abnormal functioning of the digestive tract
• Impotence in men
• Double vision

Increased plaque in large blood vessels throughout the body can cause heart attacks, strokes, and compromised circulation.

Heart disease: Problems with the circulatory system that weaken the heart

• Chest pain and shortness of breath
• Decreased tolerance for physical activity
• Chronic fatigue
• Swelling of the legs and ankles
• Palpitations (feeling like the heart is racing or pounding)

Strokes: Blood supply to the brain is cut off, usually caused by a blood clot in an artery.

• Impaired speech
• Inability to see
• Inability to walk
• Paralysis on one side of the body, numbness, or tingling

Peripheral arterial disease: Blood has trouble reaching the extremities, such as the hands and feet.

• Pain in the calves when walking
• Coolness of the lower extremities
• Loss of hair on the legs
• Ulcers that do not heal promptly, on the legs

Frequent infections, sometimes with unusual types of bacteria and fungus

• Symptoms associated with a variety of infectious diseases, including fever, abscesses, and redness