TLS Online TPP Program

#Question id: 11946


A 3-week-old infant is brought to the emergency room in a comatose condition. The history reveals that her parents have been feeding her concentrated, undiluted formula for 5 days. (Infant formula preparations are often sold in concentrated forms that must be properly diluted with water before feeding.) The infant’s plasma osmolality is 352 mOsm/L (normal is 280 to 300 mOsm/L), and the osmolality of the urine is 497 mOsm/L. What is the explanation for the hyperosmotic condition of the plasma?

#Unit 7. System Physiology – Animal
  1. The infant has inappropriate antidiuretic hormone regulation
  2. The infant has excessive secretion of aldosterone
  3. The infant is unable to form urine sufficiently concentrated to excrete the solute load from the formula without losing more water than required to maintain normal plasma osmolality
  4. The infant has a renal collecting duct abnormality that prevents it from forming concentrated urine