Hyperkalemia with a normal total body potassium can be caused by:

Correct Answer: C

Rationale: In major trauma, cell lysis releases intracellular potassium into the blood, leading to hyperkalemia without an actual increase in total body potassium.

Correct Answer: B

Rationale: Medullary relapse, or recurrence of leukemia in the bone marrow, is the most common form of relapse in acute leukemia, requiring additional chemotherapy.

Correct Answer: B

Rationale: Mosquitoes are not a common cause of insect sting anaphylaxis, unlike honeybees, yellow jackets, wasps, and fire ants.

Correct Answer: D

Rationale: At mg/dL, phototherapy is generally not required unless there are risk factors The infant is healthy and breastfed, so no intervention may be necessary

Correct Answer: C

Rationale: Congenital pneumonia with sepsis is likely given the low WBC count, prematurity, and need for ventilation