From the Guidelines
Ischemic bowel disease with lactic acidosis can indeed present with normal CT abdomen findings, particularly in the early stages of the disease. This is because CT scans may not capture the initial functional changes in bowel perfusion that precede structural changes visible on imaging 1. The guidelines from the World Society of Emergency Surgery emphasize that no laboratory parameters, including lactate levels, are sufficiently accurate to conclusively identify the presence or absence of ischemic or necrotic bowel, although they may assist in corroborating clinical suspicion 1.
Key points to consider in the diagnosis of ischemic bowel disease include:
- Elevated l-lactate, leukocytosis, and D-dimer may assist in diagnosis, but are not definitive 1.
- Metabolic acidosis with elevated lactate level occurs in 88% of patients, but differentiation of early ischemia versus irreversible bowel injury based on lactate level alone is not reliable unless accompanied by other clinical evidence 1.
- The presence of lactic acidosis in combination with abdominal pain should lead to consideration of early CTA, even if the patient does not otherwise appear clinically ill 1.
- D-dimer may be useful in the early assessment, with a specificity, sensitivity, and accuracy of 82%, 60%, and 79%, respectively, for intestinal ischemia when D-dimer is > 0.9 mg/L 1.
In cases where clinical suspicion is high despite normal imaging, additional diagnostic approaches should be considered, including laboratory markers, mesenteric angiography, or diagnostic laparoscopy. The combination of abdominal pain out of proportion to physical examination findings, elevated lactate levels, and risk factors for vascular disease should raise suspicion for bowel ischemia even when imaging appears normal.
From the Research
Ischemic Bowel Disease with Lactic Acidosis and Normal CT Abdomen Findings
- Ischemic bowel disease (IBD) can present with various symptoms, including abdominal pain, bowel urgency, and passage of bloody diarrhea 2.
- The diagnosis of IBD is often made using a combination of clinical suspicion, imaging studies, and colonoscopy with biopsy 3.
- Computed Tomography (CT) scan of the abdomen and pelvis with oral and IV contrast is a common diagnostic tool used to evaluate patients with suspected IBD 2, 4.
- However, it is possible for patients with ischemic bowel disease to have normal CT abdomen findings, especially in the early stages of the disease or in cases of isolated right colon ischemia 2, 4.
- Elevated serum lactate levels can be an indicator of bowel ischemia, but the correlation between lactate levels and the extent of ischemic bowel is not always straightforward 5, 6.
- Serial serum lactate measurements may be useful in predicting the extent of ischemic bowel and outcome of patients with acute mesenteric ischemia, but the value of this measurement is limited 6.
- Lactic acidosis can occur in patients with ischemic bowel disease, and it is often associated with a poor outcome 5, 6.