title: Value of Plasmodium falciparum histidine-rich protein 2 level and malaria retinopathy in distinguishing cerebral malaria from other acute encephalopathies in Kenyan children.
abstract: BACKGROUND
  The diagnosis of cerebral malaria is problematic in malaria-endemic areas because encephalopathy in patients with parasitemia may have another cause. Abnormal retinal findings are thought to increase the specificity of the diagnosis, and the level of histidine-rich protein 2 (HRP2) may reflect the parasite biomass.
  
  
  METHODS
  We examined the retina and measured plasma HRP2 levels in children with acute nontraumatic encephalopathy in Kenya. Logistic regression, with HRP2 level as an independent variable and World Health Organization-defined cerebral malaria and/or retinopathy as the outcome, was used to calculate malaria-attributable fractions (MAFs) and retinopathy-attributable fractions (RAFs).
  
  
  RESULTS
  Of 270 children, 140 (52%) had peripheral parasitemia, 80 (30%) had malaria retinopathy, and 164 (61%) had an HRP2 level of >0 U/mL. During 2006-2011, the incidence of HRP2 positivity among admitted children declined by 49 cases per 100 000 per year (a 78% reduction). An HRP2 level of >0 U/mL had a MAF of 93% for cerebral malaria, with a MAF of 97% observed for HRP2 levels of ≥ 10 U/mL (the level of the best combined sensitivity and specificity). HRP2 levels of >0 U/mL had a RAF of 77% for features of retinopathy combined, with the highest RAFs for macular whitening (99%), peripheral whitening (98%), and hemorrhages (90%).
  
  
  CONCLUSIONS
  HRP2 has a high attributable fraction for features of malarial retinopathy, supporting its use in the diagnosis of cerebral malaria. HRP2 thresholds improve the specificity of the definition.
authors.affiliation: Center for Geographic Medicine Research Coast, Kenya Research Institute, Kilifi.
authors.forename: Symon M
authors.initials: SM
authors.lastname: Kariuki
authors.forename: Evelyn
authors.initials: E
authors.lastname: Gitau
authors.forename: Samson
authors.initials: S
authors.lastname: Gwer
authors.forename: Henry K
authors.initials: HK
authors.lastname: Karanja
authors.forename: Eddie
authors.initials: E
authors.lastname: Chengo
authors.forename: Michael
authors.initials: M
authors.lastname: Kazungu
authors.forename: Britta C
authors.initials: BC
authors.lastname: Urban
authors.forename: Charles R J C
authors.initials: CR
authors.lastname: Newton
mesh_terms: D000953:Antigens, Protozoan / Q000097:blood*; D016009:Chi-Square Distribution; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D016779:Malaria, Cerebral / Q000097:blood* / Q000175:diagnosis; D016778:Malaria, Falciparum / Q000097:blood* / Q000175:diagnosis; D008297:Male; D011446:Prospective Studies; D015800:Protozoan Proteins / Q000097:blood*; D012164:Retinal Diseases / Q000097:blood* / Q000453:epidemiology
chemical_list: D000953:Antigens, Protozoan; C514457:HRP-2 antigen, Plasmodium falciparum; D015800:Protozoan Proteins
keywords: attributable fractions; cerebral malaria; children; histidine-rich protein-2; malaria retinopathy
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