Changes in full blood count parameters in leptospirosis: a prospective study

Abstract

BackgroundLeptospirosis 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.MethodsClinical 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 14th day of illness.ResultsData 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.ConclusionsNeither leukocytosis nor lymphopenia were prominent features, while thrombocytopenia was seen during the 3rd to 5th 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.

Leptospiraspecies promote a pro‐inflammatory phenotype in human neutrophils

“…promoted the formation of mixed platelet–neutrophil aggregates. Thrombocytopenia is a common feature of leptospirosis, but its origin is still not clear (Adiga, Mittal, Venugopal, & Mittal, ; de Silva et al, ; Goeijenbier et al, ; Raffray et al, ; Tunjungputri et al, ). In this regard, the formation of circulating mixed aggregates could represent a possible mechanism that accounts for the clearance of platelets and the consequent thrombocytopenia.…”

“…IL-6 is upregulated not only in response to a variety of signals, including bacterial components, but also by IL-1β and other cytokines, suggesting a complex activation network (Moon et al, 2000;Tuyt et al, 1999). Moreover, acting synergistically, they could also be responsible for the neutrophilia (Chiba et al, 2017) observed during acute leptospirosis in humans (de Silva et al, 2014;Lindow et al, 2016;Raffray et al, 2016).…”

Leptospirosis presenting as acute acalculous cholecystitis

“…Thrombocytopenia is observed in approximately 75% of patients at day five of illness. In tropical regions, this can provide further diagnostic uncertainty in the undifferentiated febrile patient, in that it can mimic arboviruses such as dengue fever . A marked lymphopenia represents a common early finding yet a decreased total white cell as demonstrated as in this case is unusual.…”

A comparative study of hematological profile on presentation in confirmed cases of malaria, dengue and leptospirosis

“…26 Neutrophilia and low haemoglobin predicted severe disease in this study. Mortality was 50% in patients with total leucocyte count of 4000-11000/cmm and 41.6% in those with total leucocyte count of >11,000/cmm.…”