Other possibilities are diabetes, glomerulonephritis, pyelonephritis(inflammation of the kidneys),
urinary tract infection, hypercalcemia, hypokalemia(low potassium),hyperthyroidism, hyperparathyroidism, diuretic drugs.
In my opinion, investigations like kidney functions, blood sugar levels, ultrasound lower abdomen ,intravenous pyelography , pregnancy blood test, thyroid function tests and cystoscopy may be needed to confirm a diagnosis.
I hope it helps. Take care and regards.