title: Changes in full blood count parameters in leptospirosis: a prospective study.
abstract: BACKGROUND
  Leptospirosis presents diagnostic challenges to clinicians, in settings where other acute febrile illness are prevalent. The patterns of serial changes in haematological parameters in leptospirosis has not been evaluated previously.
  
  
  METHODS
  Clinical and laboratory data were collected prospectively from patients with leptospirosis in two hospitals in Sri Lanka. Leptospirosis was diagnosed based on WHO clinical criteria with confirmation using Microscopic Agglutination Test titre > 400 or 4 fold rise between acute and convalescent samples. Full blood count parameters were analysed up to the 14(th) day of illness.
  
  
  RESULTS
  Data from 201 patients with leptospirosis were available. Leukocyte counts and absolute neutrophil counts showed a decline over the first 5 days of illness, then rose until the end of the second week. On day 3 of fever, the majority (75%) had normal leukocyte counts, and by day 5, leukocytosis was seen only in 38.1%; leucopenia was an uncommon finding. Lymphopenia was seen in over half on day 5, declining to just under a quarter of patients by day 10. Platelets declined over the first 6 days and then gradually rose. Thrombocytopenia was seen in nearly three-fourths of patients by day 5. Haemoglobin and haematocrit levels declined over the course of illness. Total white cell and neutrophil counts were higher, and haemoglobin and haematorcrit were significantly lower, in patients with severe disease.
  
  
  CONCLUSIONS
  Neither leukocytosis nor lymphopenia were prominent features, while thrombocytopenia was seen during the 3(rd) to 5(th) day of illness, with dropping haemoglobin levels. Neutrophilia and low haemoglobin levels appear to predict severe disease. These findings may be of use to clinicians in differentiating leptospirosis from other acute infections like dengue, and could help in predicting severe leptospirosis.
authors.affiliation: Tropical Medicine Research Unit, Faculty of Medicine, University of Colombo, 25 Kynsey Road, Colombo 08, Sri Lanka.
authors.forename: Nipun Lakshitha
authors.initials: NL
authors.lastname: De Silva
authors.affiliation: Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
authors.forename: Mjr
authors.initials: M
authors.lastname: Niloofa
authors.affiliation: Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
authors.forename: Narmada
authors.initials: N
authors.lastname: Fernando
authors.affiliation: Medical Research Institute, Colombo, Sri Lanka.
authors.forename: Lilani
authors.initials: L
authors.lastname: Karunanayake
authors.affiliation: Tropical Medicine Research Unit, Faculty of Medicine, University of Colombo, 25 Kynsey Road, Colombo 08, Sri Lanka.
authors.forename: Chaturaka
authors.initials: C
authors.lastname: Rodrigo
authors.affiliation: Faculty of Medicine, University of Kelaniya, Kelaniya, Sri Lanka.
authors.forename: H Janaka
authors.initials: HJ
authors.lastname: De Silva
authors.affiliation: Faculty of Science, University of Colombo, Colombo, Sri Lanka.
authors.forename: Sunil
authors.initials: S
authors.lastname: Premawansa
authors.affiliation: Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
authors.forename: Shiroma M
authors.initials: SM
authors.lastname: Handunnetti
authors.affiliation: Tropical Medicine Research Unit, Faculty of Medicine, University of Colombo, 25 Kynsey Road, Colombo 08, Sri Lanka.
authors.forename: Senaka
authors.initials: S
authors.lastname: Rajapakse
keywords: Leptospirosis; Lymphocytes; Neutrophils; Platelets