Answer 42

42.  Choice D is the correct answer.  In the case of nephrogenic diabetes insipidus, the posterior pituitary gland produces ADH but the kidney is resistant to it so there is excessive urinary output. So the patients ADH is normal.  With central diabetes insipidus, this would be a similar picture but the major difference is that the ADH would actually be low.  SIADH would show a high ADH and a low plasma sodium.  Addison Disease sodium would be low and ADH is not really affected.