1. Malaria

Multiple laboratory studies exist to confirm the diagnosis of malaria but the best test is still the peripheral smear.  Thick and thin preparations are often utilized in endemic areas.  The thick smear allows a larger quantity of erythrocytes to be screened for the presence of the parasite; however, it lacks the sensitivity of the thin smear.  The thin smear remains the “gold standard” for the diagnosis of malaria and it also has significant treatment implications.  From the thin smear the species of plasmodium can be identified, the percentage of erythrocytes affected can be calculated and response to therapy can be monitored.

The patient’s peripheral smear displayed above reveals a diagnosis of Plasmodium Falcipirum malaria.  The rings shown are characteristic of falciparum.  These rings are composed of double chromatin dots that resemble a “set of headphones” with some RBCs being multiply-infected.  The RBCs are normal in size and shape when compared to other erythrocytes on the smear.   This slide does not show the other stages of P. falciparum, but gametocytes, trophozoites and the rare schizont may be seen. 

The WHO as well as the Centers for Disease Control makes treatment decisions based on the severity of illness and the species of Plasmodium. This patient is presenting with altered mental status, jaundice and increased serum creatinine which classify him as severely infected.

Table 1. WHO Classification of Severe Malaria, 2010

Which of the following drugs have been used to treat P. falcipirum malaria?

  1. Chloroquine
  2. Atovaquone-proguanil (Malarone®)
  3. Quinine
  4. Artesunate
  5. All of the above

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