Post-artesunate delayed haemolysis — DTM&H MCQ

Correct answer: D — Post-artesunate delayed haemolysis

The correct answer is D, post-artesunate delayed haemolysis (PADH). This occurs 1 to 3 weeks after intravenous artesunate for severe malaria, driven by splenic pitting of once-parasitised erythrocytes, which re-enter circulation as rigid spherocytes and are subsequently haemolysed once the spleen clears them synchronously. A positive direct antiglobulin test is now well recognised in a substantial subset of PADH cases and does not exclude the diagnosis. The negative blood film rules out recrudescent parasitaemia as the cause of the falling haemoglobin, and the temporal pattern (day 14, after successful parasite clearance and completion of oral ACT) is classic for PADH rather than an acute infective process. Why the other options are wrong: C. Recrudescent falciparum malaria: excluded because the blood film is negative; recrudescence requires demonstrable parasitaemia on film or PCR, which is absent here. E. G6PD deficiency triggered by artemether: G6PD-related haemolysis is typically oxidant-drug triggered, occurs earlier and is associated with a negative DAT and film evidence of oxidative red cell damage (Heinz bodies, bite cells), not a positive DAT. B. Blackwater fever from quinine hypersensitivity: this patient received artesunate, not quinine; blackwater fever is a historic quinine-associated immune haemolysis, mechanistically distinct and not supported by the drug history here. A. Autoimmune haemolytic anaemia unrelated to malaria: the clear temporal relationship to artesunate treatment and the known association of PADH with positive DAT make an unrelated autoimmune process far less likely than the recognised drug-related syndrome. Key point: a positive DAT with a negative film 1 to 3 weeks after IV artesunate for severe malaria is characteristic of post-artesunate delayed haemolysis, not recrudescence or unrelated autoimmune disease.

Reference: Lalloo DG, Shingadia D, Bell DJ, Beeching NJ, Whitty CJM, Chiodini PL; PHE Advisory Committee on Malaria Prevention in UK Travellers. UK malaria treatment guidelines 2016. J Infect. 2016;72(6):635-649. Notes delayed haemolysis 7-21 days post IV artesunate in approximately 10-15% of patients, especially with high parasitaemia. https://www.journalofinfection.com/article/S0163-4453(16)00047-5/fulltext