Management of Postpartum Colitis with Leukopenia and Lymphopenia
In a postpartum patient with colitis, leukopenia, and a lymphocyte count of 15%, you must immediately rule out Clostridioides difficile infection (CDI) and consider surgical consultation if severe disease markers are present, as leukopenia (particularly lymphopenia <1.5 × 10³ cells/μL) is associated with high mortality in fulminant colitis. 1, 2
Immediate Diagnostic Workup
Obtain stool testing for C. difficile toxins using a two-step protocol (GDH/toxin EIA or molecular test for TcdB, followed by free fecal toxin detection) as this is the most common cause of postpartum colitis with these laboratory findings. 3 The postpartum period increases risk for CDI due to peripartum antibiotic exposure and physiological stress. 1
Check complete blood count with differential, serum creatinine, lactate, and C-reactive protein to assess disease severity. 1, 3 Your patient's lymphocyte count of 15% requires calculation of absolute lymphocyte count—if this is <1.5 × 10³ cells/μL, mortality risk increases significantly in toxic colitis. 2
Obtain CT abdomen/pelvis with contrast urgently to evaluate for colonic wall thickening, pericolonic fat stranding, colonic distension, or perforation. 1, 3 Up to 84% of CDI patients show colonic wall thickening on CT, with 50% having pancolitis. 1
Severity Assessment
Your patient meets criteria for severe colitis based on leukopenia with lymphopenia. 1 Additional markers of severe disease to assess include:
- Fever >38.5°C, hemodynamic instability, or signs of peritonitis (decreased bowel sounds, abdominal tenderness, rebound, guarding) 1, 3
- Serum creatinine >50% above baseline 1, 3
- Elevated serum lactate 1, 3
- Imaging showing colonic distension, wall thickening, or ascites 1, 3
Leukopenia (WBC <4,000/μL) or severe leukocytosis (WBC ≥35,000/μL) are both predictors of mortality in CDI requiring surgical intervention. 1
Treatment Algorithm
If C. difficile Confirmed or Highly Suspected:
Start oral vancomycin 125 mg four times daily immediately while awaiting test results if clinical suspicion is high. 1 Do not delay treatment for test results in severe disease.
Obtain early surgical consultation within 24 hours if any of the following are present: 1
- Leukopenia (WBC <4,000/μL) or severe leukocytosis (≥35,000/μL)
- Hemodynamic instability or shock
- Signs of peritonitis or ileus
- Lactate elevation
- Failure to improve within 3-5 days of medical therapy
Subtotal colectomy is the procedure of choice if surgery is required, as it is superior to partial colectomy. 1 Diverting loop ileostomy with antegrade vancomycin lavage is an alternative colon-preserving option. 1
If C. difficile Negative:
Proceed with colonoscopy and biopsy to evaluate for:
- Pseudomembranous colitis (can occur with CDI despite negative initial testing) 1, 3
- Lymphocytic colitis (increased intraepithelial lymphocytes, median 30 per 100 epithelial cells) 4, 5
- CMV colitis (check CMV IgM serology and CMV antigenemia, look for CMV-positive cells on biopsy) 6
- Ischemic colitis (postpartum risk due to hemodynamic changes)
Do not empirically start corticosteroids before excluding infectious causes, particularly CMV, as immunosuppression can worsen outcomes. 7
Critical Pitfalls to Avoid
Do not dismiss leukopenia as "just postpartum"—lymphopenia <1.5 × 10³ cells/μL combined with colitis carries high mortality risk and requires aggressive management. 2
Do not delay surgical consultation beyond 24-48 hours if the patient is not improving with medical therapy, as timing of surgical intervention is the most important factor influencing survival in fulminant colitis. 1
Do not confuse postpartum physiological changes with pathological findings—while postpartum patients normally have elevated neutrophils and CRP, leukopenia with lymphopenia is never normal and indicates severe disease. 1
Evaluate treatment response only after at least 3 days of appropriate therapy, as metronidazole (if used) may take 3-5 days to show clinical response. 1, 3 However, if the patient is clinically worsening at any point, escalate care immediately.