Which combination would cause the greatest immediate concern for a child with cancer?

• A. Nausea and vomiting with potassium 3.3 mEq/L
• B. Nosebleed with platelet count 100,000/mm3
• C. Fever with absolute neutrophil count 450/mm3
• D. Fatigue with hemoglobin 8 g/dL

Answer: (C)

The most urgent concept is febrile neutropenia in a child with cancer. When someone is severely neutropenic, their ability to fight off infection is greatly reduced. A fever in this state signals a potential life-threatening infection, so it requires immediate evaluation and treatment. With an absolute neutrophil count of 450/mm3 and a fever, this child has febrile neutropenia, which carries a high risk of rapid deterioration and sepsis. The best action is to hospitalize and start IV broad-spectrum antibiotics right away, along with blood cultures and other infection workup. Timing matters—antibiotics should be given promptly to improve outcomes.

The other scenarios, while they need attention, do not pose the same immediate, high-risk threat. Nausea and vomiting with a low potassium is important to correct, but it’s an electrolyte issue rather than an imminent life-threatening infection. A nosebleed with platelets at 100,000/mm3 indicates some bleeding risk but is not typically emergent unless bleeding is active or worsening. Fatigue with a hemoglobin of 8 g/dL is a common chemo-related symptom; it may require transfusion or supportive care, but it doesn’t carry the same immediate danger as febrile neutropenia.