The initial early sign is elevated blood glucose levels (hyperglycemia). The most common symptoms of diabetes are those related to hyperglycemia. Signs and symptoms for diabetes, especially type 2 diabetes, may gradually develop over several years without any noticeable symptoms.
More significant hyperglycemia causes glycosuria (increased urine glucose) and thus an osmotic diuresis (increased urination rate), leading to urinary frequency, polyuria (increased production of urine), and polydipsia (increased thirst), that may progress to orthostatic hypotension (decreased blood pressure when standing) and dehydration. Severe dehydration causes weakness, fatigue, and mental status changes. Symptoms may come and go as plasma glucose levels fluctuate. Polyphagia (excessive hunger) may accompany symptoms of hyperglycemia, but is not typically a primary patient concern. Hyperglycemia can also cause weight loss, nausea and vomiting, and blurred vision, and it may predispose to bacterial or fungal infections.
In summary, the main symptoms that may present in diabetes may include one or
more of the following:
- Increased blood glucose levels (hyperglycemia)
- Increased thirst (polydipsia)
- Increased urination rate (osmotic diuresis)
- Increased urine production (polyuria)
- Increased hunger (polyphagia)
- Weakness, fatigue and listlessness
- Nausea, dizziness, and blurred vision
- Weight loss
If extreme hyperglycemia persist, individuals may become confused and drowsy or even lose consciousness (diabetic coma).