A woman taking weekly methotrexate develops mouth ulcers, fever, diarrhoea, neutrophils 0.3 × 10^9/L and platelets 28 × 10^9/L ten days after

Question

A woman taking weekly methotrexate develops mouth ulcers, fever, diarrhoea, neutrophils 0.3 × 10^9/L and platelets 28 × 10^9/L ten days after trimethoprim. Her eGFR has fallen to 24 mL/min/1.73 m². Which interpretation should drive urgent management?

Accepted Answer

Antifolate toxicity with impaired methotrexate clearance and severe marrow suppression

Answer

Heparin-induced thrombocytopenia because the platelet fall exceeds 50%

Answer

Felty syndrome because any neutropenia in rheumatoid arthritis is splenic sequestration

Answer

Vitamin B12 deficiency because macrocytosis is obligatory in low-dose methotrexate toxicity

Answer

Immune thrombocytopenia caused by trimethoprim with unrelated neutropenia

Methotrexate toxicity — SCE Acute Medicine MCQ

A woman taking weekly methotrexate develops mouth ulcers, fever, diarrhoea, neutrophils 0.3 × 10^9/L and platelets 28 × 10^9/L ten days after trimethoprim. Her eGFR has fallen to 24 mL/min/1.73 m². Which interpretation should drive urgent management?