The onset of diabetes mellitus causes many symptoms that range from the subtle to the more severe:
Excessive and frequent urination (as often as every hour or so). Nighttime awakening to urinate is also common.
Unintentional weight loss.
Fatigue and weakness.
Recurring or persistent infections of the bladder, skin, or gums.
Numbness and tingling in feet and hands.
Symptoms of hypoglycemia (low blood sugar).
Emergency symptoms of hyperosmolar nonketotic states: extreme thirst, lethargy, weakness, mental confusion, coma.
Emergency symptoms of diabetic ketoacidosis: nausea and vomiting, labored breathing, mental confusion, coma.
Some people who have type 2 diabetes exhibit no symptoms. Symptoms may be mild and almost unnoticeable, or easy to confuse with signs of aging. Half of all Americans who have diabetes do not know it.