West African trypanosomiasis stage 2 — DTM&H MCQ

Correct answer: C — Eflornithine intravenously

The correct answer is C, eflornithine intravenously. The clinical picture (a painless trypanosomal chancre, subsequent haemolymphatic stage features including posterior cervical lymphadenopathy, Winterbottom's sign) in a traveller to South Sudan, followed by CSF pleocytosis and raised protein, indicates second-stage (meningoencephalitic) infection with Trypanosoma brucei gambiense, the West African form of human sleeping sickness endemic in that region. Drugs used in stage 1 disease do not cross the blood-brain barrier adequately, so once CNS invasion is confirmed (as here, by CSF changes) a CNS-penetrant regimen is mandatory. WHO interim guidelines identify eflornithine, usually as part of nifurtimox-eflornithine combination therapy (NECT), as the recommended first-line treatment for late-stage gambiense HAT, with cure rates of 95-98% and far lower mortality than melarsoprol. Why the other options are wrong: B. Suramin intravenously: this is used for stage 1 (haemolymphatic) T. b. rhodesiense infection and does not adequately cross the blood-brain barrier, so it is ineffective once CNS disease has developed. D. Pentamidine intramuscularly: this is first-line only for stage 1 gambiense disease; it has poor CNS penetration and is not used once CSF changes indicate second-stage disease. A. Melarsoprol intravenously: this arsenical agent is reserved for second-stage T. b. rhodesiense (East African) disease because it causes a fatal reactive encephalopathy in 5-10% of patients, a risk not justified when effective, safer eflornithine-based therapy is available for gambiense infection. E. Nifurtimox orally: nifurtimox alone is not adequate monotherapy for HAT; it is only used in combination with eflornithine (NECT), not as a single agent. Key point: CSF pleocytosis and raised protein confirm second-stage gambiense sleeping sickness, which requires CNS-penetrant eflornithine (NECT), not the stage 1 drugs suramin or pentamidine, nor melarsoprol which is reserved for rhodesiense CNS disease.

Reference: WHO, Guidelines for the treatment of human African trypanosomiasis, 2019 (interim guidelines incorporated 2024), section on eflornithine and NECT for second-stage gambiense HAT, https://www.who.int/publications/i/item/9789240096035