What causes frequent urination?

Q: I am a 29 year old female suffering from excessive urination. Two months ago, I had a urine infection, which got cured with medication. But the problem of frequent urination has emerged again now, even though I don't drink much water. I am overweight and do smoke. What is the cause of frequent urination? Is it because of some kidney-related problem?

A:Basic causes of frequent urination are excessive urine formation or small bladder capacity. Excessive urination may occur with high fluid intake, uncontrolled diabetes, and some kinds of renal failure, apart from many other causes. Small bladder capacity could be due to a sensitive bladder, as in urinary tract infection or overactive bladder. A very common cause of urinary frequency is anxiety. Bladder may contract due to chronic infections like tuberculosis. One may have functionally small bladder capacity if bladder is not emptied completely with each void and there is significant residual urine. Proper history, physical examination and investigations are thus a must before reaching a correct cause, before giving any fruitful advice.