Inpatients With 'Unexplained' Leukocytosis

Area of Science:

• Immunology
• Critical Care Medicine
• Infectious Diseases

Background:

• Persistent leukocytosis is a common, complex clinical challenge, often associated with the persistent inflammation-immunosuppression and catabolism syndrome (PICS).
• Patients with unexplained leukocytosis frequently experience prolonged hospitalizations and receive extensive broad-spectrum antibiotics.
• This study aimed to identify clinical features and outcomes of patients with persistent leukocytosis to inform future diagnostic and therapeutic strategies.

Observation:

• A review of infectious disease consultations identified 29 patients with leukocytosis or bandemia.
• Common admission reasons included sepsis, major trauma, and cerebrovascular accidents.
• Patients exhibited elevated white blood cell counts and prolonged leukocytosis, with significant "bandemia" in trauma cases and eosinophilia in 15 patients.

Findings:

• Leukocytosis was primarily driven by tissue damage rather than active infection in most cases, with only one pelvic abscess identified.
• Patients received prolonged broad-spectrum antibiotics without clear clinical benefit, leading to colonization with resistant organisms like Clostridium difficile.
• Hospitalization was prolonged, with many patients discharged to nursing homes or rehabilitation facilities, and a mortality rate of 10.3%.

Implications:

• The findings suggest that persistent leukocytosis may represent PICS, supported by eosinophilia, rather than solely active infection.
• Future research should investigate myeloid suppressor cells and the roles of damage-associated molecular patterns (DAMPs) versus pathogen-associated molecular patterns (PAMPs).
• A more judicious antibiotic approach is warranted, potentially improving patient outcomes and reducing antimicrobial resistance.