Paper II
2024 August (Supplementary) (2010 Scheme)

Question

A 24year old lady comes to the OPD with complaints of high fever with chills and rigors for the past 3 days. She also complains of headache, body ache and weakness. The fever lasts for 4 to 6 hours and subsides after sweating. You make a diagnosis of malaria based on blood smear which showed P. vivax parasites.

  • (a) Prescribe for this patient, if there is no drug resistance 2 mark(s)
  • (b) Briefly describe the erythrocytic schizonticide you prescribed 3 mark(s)
  • (c) Write two drugs given for Chemoprophylaxis 1 mark(s)
Q26 marksEssays

Answer

a) Prescription (no drug resistance) Chloroquine (blood schizonticide, for the acute attack) plus Primaquine (tissue schizonticide, added after acute treatment for radical cure of the hepatic hypnozoites specific to P. vivax).

b) The erythrocytic schizonticide — Chloroquine Mechanism: chloroquine accumulates in the parasite’s acidic food vacuole (ion-trapped as a weak base) and inhibits haem polymerase, the enzyme that normally converts toxic free haem (released as the parasite digests hemoglobin) into inert haemozoin. Without polymerization, toxic free haem accumulates and kills the parasite. It is a rapidly acting blood schizonticide, clearing the parasitemia responsible for this patient’s clinical symptoms (the classic vivax pattern of fever with chills/rigors every 48 hours, subsiding with sweating). Adverse effects include retinopathy with prolonged use, pruritus, and QT prolongation at high doses.

c) Chemoprophylaxis Chloroquine and Doxycycline (or Mefloquine).

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