Two patients with pneumatosis intestinalis with distinct risk profiles managed conservatively

Pneumatosis intestinalis (PI) is a radiological and pathological finding characterized by gas within the gastrointestinal wall.^[1] Although its true incidence is uncertain, autopsy series suggest an overall incidence of approximately 0.03%. While PI ranges from benign incidental findings to life-threatening bowel ischemia, prognosis depends more on the underlying disease process than on the PI itself.^[2] Historically, PI has been frequently managed surgically; however, advances in imaging and recognition of benign etiologies have shifted management toward conservative treatment in clinically stable patients.^[3] Herein, we report two cases of PI with different etiologies and radiologic severities who were managed conservatively.

Patient 1. A 59-year-old man with a history of atrial fibrillation, hypertension, diabetes mellitus, myocardial infarction with ischemic cardiomyopathy, and end-stage renal disease (ESRD) on hemodialysis presented to the emergency department (ED) with one day of epigastric pain. The patient was taking apixaban and clopidogrel for cardiovascular disease. On presentation, vital signs were stable, and physical examination revealed mild epigastric tenderness without signs of peritonitis. C-reactive protein (CRP) and lactate levels were normal. Contrast-enhanced abdominal computed tomography (CT) revealed intramural air densities in the small bowel with extension into the mesenteric and portal venous systems, which was consistent with PI with portal venous gas (PVG) (Figure 1). Given the absence of peritoneal signs, stable vital signs, and preserved bowel perfusion on imaging, conservative management was selected after surgical consultation. The patient was admitted to the Department of Internal Medicine and treated with bowel rest, intravenous (IV) crystalloid fluids, and IV antibiotics, including ceftriaxone (2 g/d) and metronidazole (500 mg every 8 h). Because of prominent ileus, nasogastric tube drainage was performed. Apixaban and clopidogrel were temporarily discontinued due to hematochezia. Follow-up abdominal radiography demonstrated improvement in the PI, and the patient was discharged on hospital day 8. No PI-related complications or readmissions were observed during follow-up.

Figure 1. Contrast-enhanced abdominal CT image at the time of presentation in patient 1. A: axial view of the intestines demonstrating intramural gas within the bowel wall (white arrows); B: axial view of the liver demonstrating portal venous gas (white arrows); C: coronal view demonstrating air densities in the mesenteric venous system (white arrows). CT: computed tomography.

Patient 2. A 77-year-old man with a history of hypertension, diabetes mellitus, dyslipidemia, ischemic heart disease, adrenal insufficiency on chronic steroid therapy, and cholangiocarcinoma under chemotherapy presented to the ED with 10 d of diarrhea and intermittent abdominal pain. His vital signs were stable, and physical examination revealed no abdominal tenderness. Laboratory tests revealed elevated lactate (4.1 mmol/L) with normal CRP levels. Contrast-enhanced abdominal CT revealed newly developed intramural gas in the ascending colon, which was consistent with PI, with preserved bowel wall enhancement suggesting adequate bowel perfusion (Figure 2). In the absence of peritoneal signs or hemodynamic instability and with preserved bowel perfusion on imaging, conservative management was selected after surgical consultation, and the patient was admitted to the Department of Internal Medicine. The patient was treated with bowel rest, IV crystalloid fluids, and IV ceftriaxone (2 g/d) combined with metronidazole (500 mg every 8 h). Because ileus was not prominent, nasogastric tube drainage was not needed. Lactate levels normalized prior to discharge, and follow-up CT performed 10 days later demonstrated improvement in the PI. The patient was discharged on hospital day 14 without PI-related complications or readmissions during follow-up.

Figure 2. Contrast-enhanced abdominal CT image at the time of presentation in patient 2. A: coronal view showing pneumatosis intestinalis in the ascending colon (white arrows); B: intramural gas is more clearly visualized on lung window images (black arrows), as this window setting enhances the contrast between gas and the bowel wall.

PIs are broadly classified into two categories: primary (idiopathic) and secondary PIs. Primary PIs account for approximately 15% of cases and are typically asymptomatic and are often discovered incidentally by imaging. In contrast, secondary PI is associated with various conditions, such as bowel ischemia, inflammatory or infectious diseases, medications (e.g., corticosteroids, chemotherapy), and systemic illnesses, including chronic renal failure and malignancy.^[4] This distinction is clinically important, as secondary PI may indicate serious underlying pathology and warrants careful clinical and radiologic assessment. In this report, both patients exhibited secondary PIs with distinct etiologies: one with ESRD on hemodialysis and the other underwent chemotherapy with long-term corticosteroid therapy.

Although precise incidence data for PI in specific subgroups are limited, patients with ESRD on hemodialysis and those receiving chemotherapy are increasingly recognized as high-risk populations, often without progression to transmural bowel ischemia. ESRD requiring hemodialysis has been recognized as an important predisposing factor for PI, mainly through its association with nonocclusive mesenteric ischemia (NOMI). In patients with ESRD, hemodialysis-associated hypotension may precipitate NOMI, leading to impaired intestinal perfusion and subsequent mucosal injury with intramural gas formation.^[5] Additionally, increased intestinal permeability with altered gut microbiota promotes bacterial translocation and gas production.^[6] Despite concerns regarding IV contrast use in patients with impaired renal function, contrast-enhanced CT is crucial for assessing bowel wall enhancement and mesenteric perfusion, thereby supporting the exclusion of transmural bowel ischemia. These findings are pivotal in guiding the decision toward conservative management. In patient 1, despite the PVG and extensive PI raising concern for mesenteric ischemia, the absence of peritoneal signs and clinical stability supported conservative management. This highlights that PVG, although radiologically alarming, should be interpreted within the overall clinical context.^[7]

Patient 2 reflects a more benign course of PI in an immunocompromised patient undergoing combination chemotherapy with pembrolizumab and lenvatinib. Immune checkpoint inhibitors such as pembrolizumab may contribute to PI through immune-mediated enterocolitis with secondary mucosal injury.^[8] In addition, lenvatinib, an antiangiogenic multikinase inhibitor, may impair intestinal microvascular perfusion, increasing susceptibility to ischemic or mucosal injury-related PIs.^[9] Although this patient demonstrated an elevated lactate level of 4.1 mmol/L, a factor previously associated with poor outcomes, he responded well to conservative management without complications.^[3] These findings suggest that elevated lactate levels should be interpreted in the context of overall clinical stability. The absence of peritoneal signs and a favorable clinical course further support nonoperative management, which is consistent with emerging evidence on chemotherapy-associated PI.^[9]

In both cases, radiologic findings alone were insufficient to determine the need for surgery. Although PVG in patient 1 and elevated lactate level in patient 2 are traditionally associated with bowel ischemia and poor outcomes, conservative management was chosen on the basis of the absence of peritoneal signs, lack of metabolic acidosis, hemodynamic stability, and preserved bowel wall enhancement on imaging. Because no widely accepted validated scoring system exists for risk stratification in the PI, management decisions should rely on an integrated assessment of clinical stability and radiologic evidence of preserved bowel perfusion, with close monitoring when conservative management is selected.^[10]

The PI presents a diagnostic and management challenge because of its diverse etiologies and variable prognosis. These two cases demonstrate that conservative management may be safe and effective, even in the presence of significant radiologic findings, provided that the patient is clinically stable. Careful clinical judgment is paramount in determining the appropriate therapeutic approach.

Funding: None.

Ethical approval: The study was approved by the Institutional Review Board of the Chungbuk National University Hospital (IRB No. 2025-07-026).

Conflicts of interest: The authors declare that there are no conflicts of interest.

Contributors: Conceptualization: HSC, GJP. Methodology: GJP. Formal analysis: HSC, GJP. Investigation: HSC. Writing - original draft preparation: HSC, GJP. Writing - reviewing and editing: GJP, YMK, HSC, SCK, HK, SWL.