title: Risk factors and characterization of Plasmodium vivax-associated admissions to pediatric intensive care units in the Brazilian Amazon.
abstract: 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.
  
  
  RESULTS
  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.
authors.affiliation: Universidade do Estado do Amazonas, Manaus, Amazonas, Brazil.
authors.forename: Ellen Fátima Caetano
authors.initials: EF
authors.lastname: Lança
authors.forename: Belisa Maria Lopes
authors.initials: BM
authors.lastname: Magalhães
authors.forename: Sheila
authors.initials: S
authors.lastname: Vitor-Silva
authors.forename: André Machado
authors.initials: AM
authors.lastname: Siqueira
authors.forename: Silvana Gomes
authors.initials: SG
authors.lastname: Benzecry
authors.forename: Márcia Almeida Araújo
authors.initials: MA
authors.lastname: Alexandre
authors.forename: Connor
authors.initials: C
authors.lastname: O'Brien
authors.forename: Quique
authors.initials: Q
authors.lastname: Bassat
authors.forename: Marcus Vinícius Guimarães
authors.initials: MV
authors.lastname: Lacerda
mesh_terms: D000293:Adolescent; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D015278:Intensive Care Units, Pediatric; D016778:Malaria, Falciparum / Q000150:complications / Q000453:epidemiology / Q000401:mortality; D016780:Malaria, Vivax / Q000150:complications* / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D018512:Parasitemia / Q000453:epidemiology; D010966:Plasmodium vivax; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index