title: Direct in vivo assessment of microcirculatory dysfunction in severe falciparum malaria.
abstract: BACKGROUND
  This study sought to describe and quantify microcirculatory changes in the mucosal surfaces of patients with severe malaria, by direct in vivo observation using orthogonal polarization spectral (OPS) imaging.
  
  
  METHODS
  The microcirculation in the rectal mucosa of adult patients with severe malaria was assessed by use of OPS imaging, at admission and then daily. Comparison groups comprised patients with uncomplicated falciparum malaria, patients with bacterial sepsis, and healthy individuals.
  
  
  RESULTS
  Erythrocyte velocities were measured directly in 43 adult patients with severe falciparum malaria, of whom 20 died. Microcirculatory blood flow was markedly disturbed, with heterogeneous obstruction that was proportional to severity of disease. Blocked capillaries were found in 29 patients (67%) and were associated with concurrent hyperdynamic blood flow (erythrocyte velocity, >750 mm/s) in adjacent vessels in 27 patients (93%). The proportion of blocked capillaries correlated with the base deficit in plasma and with the concentration of lactate. Abnormalities disappeared when the patients recovered. In healthy individuals and in patients with uncomplicated malaria or sepsis, no stagnant erythrocytes were detected, and, in patients with sepsis, hyperdynamic blood flow was prominent.
  
  
  CONCLUSIONS
  Patients with severe falciparum malaria show extensive microvascular obstruction that is proportional to the severity of the disease. This finding underscores the prominent role that microvascular obstruction plays in the pathophysiology of severe malaria and illustrates the fundamental difference between the microvascular pathophysiology of malaria and that of bacterial sepsis.
authors.affiliation: Department of Physiology, Academic Medical Centre, Amsterdam, The Netherlands. arjen@tropmedres.ac
authors.forename: A M
authors.initials: AM
authors.lastname: Dondorp
authors.forename: C
authors.initials: C
authors.lastname: Ince
authors.forename: P
authors.initials: P
authors.lastname: Charunwatthana
authors.forename: J
authors.initials: J
authors.lastname: Hanson
authors.forename: A
authors.initials: A
authors.lastname: van Kuijen
authors.forename: M A
authors.initials: MA
authors.lastname: Faiz
authors.forename: M R
authors.initials: MR
authors.lastname: Rahman
authors.forename: M
authors.initials: M
authors.lastname: Hasan
authors.forename: E
authors.initials: E
authors.lastname: Bin Yunus
authors.forename: A
authors.initials: A
authors.lastname: Ghose
authors.forename: R
authors.initials: R
authors.lastname: Ruangveerayut
authors.forename: D
authors.initials: D
authors.lastname: Limmathurotsakul
authors.forename: K
authors.initials: K
authors.lastname: Mathura
authors.forename: N J
authors.initials: NJ
authors.lastname: White
authors.forename: N P J
authors.initials: NP
authors.lastname: Day
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001783:Blood Flow Velocity; D005260:Female; D018056:Hemorheology / Q000379:methods; D006801:Humans; D007413:Intestinal Mucosa / Q000098:blood supply* / Q000503:physiopathology; D016778:Malaria, Falciparum / Q000503:physiopathology*; D008297:Male; D008833:Microcirculation / Q000503:physiopathology*; D020678:Microscopic Angioscopy / Q000379:methods; D008859:Microscopy, Polarization; D008875:Middle Aged; D009061:Mouth Mucosa / Q000098:blood supply* / Q000503:physiopathology; D012007:Rectum / Q000098:blood supply* / Q000503:physiopathology