Hi, After going through your case I want to know- 1) Current medicine for diabetes. Control of blood sugar level (recent blood sugar level test, HbA1c level) if available. 2) Any associated fever, back or abdominal pain. 3) What was the reason for non functioning left kidney? (If you are aware of) 4) Any history of kidney stones. 5) Urine volume, urinary stream. Urinary infections may be the cause of your symptoms. Diabetic patients are more prone for infections mainly urinary. Chances increased with uncontrolled blood sugar level. In the age of 64yrs there may be prostate problem which increases the chances of infection. Also there may be possibility of kidney stone. Elevated serum creatinine may be part of Chronic kidney disease (CKD) due to diabetic nephropathy or cause that may result in left kidney failure in past or it may be due to overlying Acute kidney injury (AKI) which may be due to infection or kidney stone. Following investigations may be helpful in management- 1) Complete blood count, Urine examination for pus cells and culture sensitivity. 2) Ultrasound of abdomen and pelvis which help in knowing condition of kidneys, urinary bladder, prostate. There is need for strict blood sugar control for that use of insulin is a better option. There might be need for intravenous antibiotics. I hope this may be helpful to you. If so do vote.