21 mo daughter has been drinking excessively and urinating extremely frequently. what could be cause? should i be concerned about diabetes?

Diabetes: Excessive thirst and urination are often hallmark signs of diabetes mellitus.

Possibly: Drinking a lot would include middle of the night demands for fluid because of high sugars if this is diabetes mellitus. This isn't the only reason, however. It is easy enough to test by checking the toddler's urine. Sticking cotton balls inside diaper before doctor appt so that the cotton ball can be squeezed for urine once at the office. Please see her pediatrician.