The nurse knows that the best test to differentiate between ...

[torybrooks]

The nurse knows that the best test to differentiate between central and nephrogenic DI is
 
  a. the water deprivation test.
  b. serum osmolality.
  c. computed tomography scan.
  d. the ADH test.

Question 2

A patient with renal failure reports all of the following during the medical history. Which is most likely to have precipitated the patient's renal failure?
 
  a. Recent computed tomography of the brain with and without contrast
  b. A recent bout of congestive heart failure after an acute myocardial infarction
  c. Twice-daily prescription of Lasix 40 mg by mouth
  d. A recent bout of benign prostatic hypertrophy and transurethral resection of the prostate

[wfdfwc23]

Answer to Question 1

D
The antidiuretic hormone test is used to differentiate between neurogenic diabetes insipidus (DI) (central) and nephrogenic (kidney) DI. In severe central DI, in which the pituitary is affected, the urine osmolality shows a significant increase (becomes more concentrated), which indicates that the cell receptor sites on the kidney tubules are responsive to vasopressin. Test results in which urine osmolality remains unchanged indicate nephrogenic DI, suggesting kidney dysfunction because the kidneys are no longer responsive to ADH.

Answer to Question 2

A
Intravenous contrast media can be nephrotoxic, especially with the patient's pre-existing cardiac disease. The other choices, although possible causes, are less likely than the intravenous contrast media.