Ileus and Leukocytosis: Clinical Guidelines and Evidence

Pathophysiological Mechanisms and Clinical Evidence

Ileus is associated with systemic inflammatory responses that include leukocytosis, as described in sepsis criteria, where it's listed as a sign of organ dysfunction with "absent bowel sounds" 1
The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines recognize ileus as a sign of severe colitis, often accompanied by marked leukocytosis (leukocyte count >15 × 10^9/L) 2
The Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) guidelines note that patients with C. difficile infection may present with ileus and leukocytosis without diarrhea 3
In fulminant C. difficile infection, ileus can be present alongside hypotension, shock, or megacolon, and is often associated with significant leukocytosis 3

Elevated C-reactive protein and procalcitonin may accompany ileus with leukocytosis 5, 6
Increased serum lactate (indicating tissue hypoperfusion) may be present in patients with ileus and leukocytosis 2
Electrolyte disturbances may also occur in patients with ileus and leukocytosis 5

The presence of both ileus and leukocytosis should prompt consideration of severe disease requiring more aggressive management 7, 3
In C. difficile infection with ileus and leukocytosis, more aggressive treatment is recommended, including vancomycin and potentially intravenous metronidazole 3
Leukocytosis >15,000 cells/mL in the setting of ileus is considered an unfavorable prognostic factor in C. difficile infection 7