Risk Factors and Characterization of Plasmodium Vivax-Associated Admissions to Pediatric Intensive Care Units in the Brazilian Amazon

BACKGROUND: Plasmodium vivax is responsible for a significant proportion of malaria cases worldwide and is increasingly reported as a cause of severe disease. The objective of this study was to characterize severe vivax disease among children hospitalized in intensive care units (ICUs) in the Western Brazilian Amazon, and to identify risk factors associated with disease severity. METHODS AND FINDINGS: In this retrospective study, clinical records of 34 children, 0-14 years of age hospitalized in the 11 public pediatric and neonatal ICUs of the Manaus area, were reviewed. P. falciparum monoinfection or P. falciparum/P. vivax mixed infection was diagnosed by microscopy in 10 cases, while P. vivax monoinfection was confirmed in the remaining 24 cases. Two of the 24 patients with P. vivax monoinfection died. Respiratory distress, shock and severe anemia were the most frequent complications associated with P. vivax infection. Ninety-one children hospitalized with P. vivax monoinfections but not requiring ICU were consecutively recruited in a tertiary care hospital for infectious diseases to serve as a reference population (comparators). Male sex (p = 0.039), age less than five years (p = 0.028), parasitemia greater than 500/mm(3) (p = 0.018), and the presence of any acute (p = 0.023) or chronic (p = 0.017) co-morbidity were independently associated with ICU admission. At least one of the WHO severity criteria for malaria (formerly validated for P. falciparum) was present in 23/24 (95.8%) of the patients admitted to the ICU and in 17/91 (18.7%) of controls, making these criteria a good predictor of ICU admission (p = 0.001). The only investigated criterion not associated with ICU admission was hyperbilirubinemia (p = 0.513)]. CONCLUSIONS: Our study points to the importance of P. vivax-associated severe disease in children, causing 72.5% of the malaria admissions to pediatric ICUs. WHO severity criteria demonstrated good sensitivity in predicting severe P. vivax infection in this small case series

The reality of using primaquine.

BACKGROUND: Primaquine is currently the only medication used for radical cure of Plasmodium vivax infection. Unfortunately, its use is not without risk. Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency have an increased susceptibility to haemolysis when given primaquine. This potentially fatal clinical syndrome can be avoided if patients are tested for G6PD deficiency and adequately informed before being treated. CASE PRESENTATION: A 35-year old male presented to our clinic on the Thai-Burmese border with a history and clinical examination consistent with intravascular haemolysis. The patient had been prescribed primaquine and chloroquine four days earlier for a P. vivax infection. The medication instructions had not been given in a language understood by the patient and he had not been tested for G6PD deficiency. The patient was not only G6PD deficient but misunderstood the instructions and took all his primaquine tablets together. With appropriate treatment the patient recovered and was discharged home a week later. CONCLUSIONS: Whilst primaquine remains the drug of choice to eradicate hypnozoites and control P. vivax transmission, the risks associated with its use must be minimized during its deployment. In areas where P. vivax exists, patients should be tested for G6PD deficiency and adequately informed before administration of primaquine