Computed tomography peritoneography: one-stop diagnosis and treatment reference for multiple combined complications in peritoneal dialysis patients

Introduction

Peritoneal dialysis (PD) is an important alternative renal replacement therapy for patients with end-stage renal disease (ESRD) (1). Its flexible administration mode brings great convenience to ESRD patients, and in many countries, the economic cost of PD is lower than that of hemodialysis (HD) (2).

However, continuous ambulatory peritoneal dialysis (CAPD) may have to be discontinued in clinical practice due to various complications. Common complications include peritonitis, catheter-related infections, hernias, peritoneal dialysate leakage, thoracoabdominal fistulas, etc. The incidence of peritoneal dialysate leakage is reported to range from 5% to 9.6% (3). The integrity of the peritoneal cavity is impaired due to increased intra-abdominal pressure (IAP) or catheter structural defects, thus leading to dialysate leakage. Therefore, early diagnosis and standardized management of combined and occult PD-related complications can minimize the rate of dialysis modality conversion in ESRD patients (4).

Case presentation

A 33-year-old male patient diagnosed with ESRD has been treated with CAPD for 5 years. Over the past month, he was found to have a palpable mass in the right lower abdominal quadrant during routine CAPD sessions and was subsequently admitted to the hospital for further evaluation. His past medical history included hypertension and lymph node tuberculosis, both of which were controlled with long-term oral medications.

Physical examination on admission identified the palpable right lower abdominal mass as the key clinical sign. Laboratory examinations showed hypocythemia with a red blood cell count of 2.4×10¹²/L (normal reference range, 4.3–5.8×10¹²/L), hemoglobin level of 78 g/L (normal reference range, 130–175 g/L), and platelet count (PLT) of 76×10⁹/L (normal reference range, 125–350×10⁹/L). Pre-dialysis biochemical tests (serum sample) demonstrated elevated serum urea (22.95 mmol/L, normal reference range, 3.1–8.0 mmol/L), serum creatinine (1,793.33 µmol/L, normal reference range, 57–97 µmol/L), and uric acid (515.56 µmol/L). Considering the patient’s long-term CAPD history combined with the newly detected abdominal mass, clinical suspicions were raised for peritoneal dialysate leakage or abdominal wall hernia, and a comprehensive imaging assessment was planned for definitive diagnosis.

The patient first underwent a fasting non-contrast abdominal computed tomography (CT) scan with the scanning range covering the abdominal visceral area, which failed to show obvious specific findings, only revealing flocculent soft tissue shadows with ill-defined borders around both atrophic kidneys, mild exudative changes in the retroperitoneum and perirectal region, and suspicious exudative alterations in the abdominal wall (Figure 1). For further definitive diagnosis of the suspected complications, computed tomography peritoneography (CTP) was subsequently performed with an IQON CT scanner (Philips Medical Systems). Under strict aseptic conditions, 50 mL of iodixanol was mixed with 2 L of 1.5% glucose-containing PD fluid, and the mixture was infused intraperitoneally through the PD catheter. The patient was advised to perform ambulatory activities for 40 minutes (5) to increase IAP and ensure thorough mixing of the intra-abdominal solution, followed by a repeated non-contrast abdominal CT scan of the same anatomical field of view and subsequent multiplanar reconstruction (MPR).

Figure 1 Axial plain scan images (A,B) and sagittal plain scan image (C). The areas marked by circles indicate exudative lesions, and the arrow-pointed regions represent magnified images of the lesions.

CTP imaging findings revealed clear pathological features of multiple complications: An oblique axial image (Figure 2A,2B) clearly demonstrated an abdominal wall hernia and right inguinal hernia with the hernial sac filled with PD fluid. The above-mentioned abdominal wall hernia and right inguinal hernia were also clearly visualized on the sagittal image (Figure 2C). Figure 3 accurately shows the localized the fistula orifice of the retroperitoneal fistula by virtue of the multi-modal imaging advantages of 120 kV mixed energy images (Figure 3A), non-iodine images (Figure 3B) and effective atomic number images (Figure 3C). Meanwhile, minimal contrast medium extravasation in the abdominal wall was observed on these images, which further supported the diagnosis of abdominal wall fistula. Figure 4 clearly displays the location and course features of the peritoneal-mesorectal fistula, providing definite imaging evidence for the comprehensive clinical evaluation of the patient’s condition. Based on the definitive diagnosis by CTP, PD was immediately discontinued upon confirmation. Meanwhile, an individualized HD regimen was formulated for the patient to rapidly replace renal excretory function. After therapeutic intervention, the patient achieved significant improvement in clinical symptoms, the right lower abdominal mass disappeared, and the patient’s condition was confirmed to be stable following comprehensive evaluation, with discharge approved thereafter.

Figure 2 Conventional 120 kV mixed-energy images: an oblique axial view (processed with CPR technique) (A), an axial view (B), and a sagittal view (C). The areas circled indicate the tract of the peritoneal-abdominal wall fistula and a portion of the peritoneal-mesorectal fistula. Scanning parameters: collimation 64 mm × 0.625 mm, tube voltage 100 kV, tube current 350 mA, matrix 512×512, and reconstructed section thickness 0.5 mm. CPR, curved planar reconstruction.

Figure 3 Abdominal CT images demonstrating the location of the retroperitoneal fistula ostium and contrast-agent leakage. (A) Axial conventional 120 kV mixed energy image; (B) iodine-no-water map; (C) sagittal effective atomic number image. The fistula ostium, marked by circles, is clearly visualized in all images; boxed insets show magnified views of the lesions. CT, computed tomography.

Figure 4 Sagittal images showing a mesorectal fistula. The fistula orifice is indicated by circles, and boxes show magnified views of the lesions: (A) conventional 120 kV mixed-energy image; (B) iodine-no-water map; (C) effective atomic-number image.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. The need for patient consent for the publication of this article and accompanying images was waived according to the Ethics Committee of Gansu Provincial Hospital. All patient identifiable information is fully excluded from the manuscript to ensure privacy protection.

Discussion

In this case, a young adult patient with long-term CAPD was diagnosed with multiple complications including abdominal wall fistula, multiple retroperitoneal fistulas, abdominal wall hernia, right inguinal hernia and peritoneal-mesorectal fistula based on the integrated analysis of CTP imaging findings, clinical manifestations and medical history. It is noteworthy that the palpable mass in the right lower abdominal quadrant was caused by the right inguinal hernia with PD fluid filling the hernial sac, rather than a direct pathological consequence of fistulous tracts. Initially, tuberculous peritonitis was the primary clinical diagnostic consideration due to the patient’s past medical history of lymph node tuberculosis and palpable abdominal mass, which required differential diagnosis with abdominal wall hernias and localized peritonitis. The typical imaging features of tuberculous peritonitis include free or loculated ascites with slightly increased density in the abdominal cavity, smooth and uniform thickening of the peritoneum complicated with abdominal adhesions in most cases, and significant enhancement of the peritoneum on contrast-enhanced scans (6). On imaging, abdominal wall hernias are characterized by definite defects or continuity interruptions of the abdominal wall, with low-density or soft tissue shadows in the defective areas and clear perilesional fat spaces without abnormal density shadows or exudative changes (7). Although localized peritonitis may also present with peritoneal thickening (either uniform or non-uniform) with mild enhancement on contrast-enhanced scans, most patients with this condition are accompanied by typical clinical symptoms such as fever and abdominal pain, which can serve as important differential diagnostic criteria (8). Combined with the patient’s negative history of abdominal surgery, the possibility of primary abdominal wall hernia was further analyzed and differentiated in this case, and CTP imaging provided key evidence for the final differential diagnosis.

As one of the core renal replacement therapy options for ESRD patients, CAPD has been widely applied in clinical practice due to its advantages such as preservation of residual renal function, hemodynamic stability and improvement of patients’ quality of life. However, during long-term maintenance PD, patients are susceptible to various structural abnormalities of the peritoneal cavity due to peritoneal structural damage, recurrent peritoneal infections, chronic elevation of IAP or surgery-related traumatic factors (9). These complications include fistula formation, abdominal wall hernia, encapsulating peritoneal sclerosis and other pathological changes. In clinical practice (10), typical inguinal hernias and superficial dialysate leakage can be suspected early based on signs such as abdominal masses and abnormal dialysate drainage. However, when complicated by deep retroperitoneal fistulas, these conditions are easily overlooked during routine examinations. These combined lesions often present with subtle clinical symptoms, typically manifesting only as mild abdominal distension, unexplained decrease in ultrafiltration volume, or abnormal dialysate drainage, thereby complicating the early comprehensive diagnosis and treatment decision-making for coexisting conditions.

Traditional imaging modalities such as abdominal plain X-ray, ultrasonography or conventional non-contrast abdominal CT scans have inherent limitations including insufficient contrast resolution, inadequate spatial resolution or poor display of deep anatomical structures (5). As a result, they are unable to clearly identify subtle fistulous tracts, accurately locate fistula orifices and delineate the course of fistulous tracts, nor can they comprehensively evaluate the scope of lesion involvement. This often leads to clinical misdiagnosis or missed diagnosis, thus delaying the optimal timing of clinical intervention. In contrast, CTP achieves high-contrast visualization of intra-abdominal anatomical structures and pathological tissues through the precise intraperitoneal injection of non-ionic iodine contrast agent combined with high-resolution CT scanning technology. This technical advantage not only can confirm the presence of fistula formation, dialysate leakage or abdominal wall hernia, but also can accurately delineate key anatomical details, including the exact location of fistula orifices, the pathway and branching characteristics of fistulous tracts, the size and anatomical location of hernias, the scope of peritoneal involvement, and the anatomical relationship between abnormal communicating structures and adjacent organs, thereby providing clinicians with comprehensive and intuitive imaging evidence.

Furthermore, CTP delivers precise anatomical data to tailor personalized treatment for CAPD-related complications. Uncomplicated inguinal hernias without deep fistulae are prioritized for surgical repair with subsequent CAPD resumption, while mild superficial dialysate leakage generally responds to conservative management. Retroperitoneal fistulae sit deep; conservative therapy succeeds in under 30% of cases, and surgery carries high recurrence risk. For this patient with concurrent inguinal hernia and multiple retroperitoneal fistulae, sustained intraperitoneal dialysate pressure worsens both lesions, triggering impaired ultrafiltration and solute clearance. Combined simultaneous repair inflicts major trauma with over 50% recurrence, making HD conversion optimal. CTP eliminates blind exploration for complex lesions to confirm dialysis switching necessity, and guides surgical planning for operable cases to cut trauma and complications. Early CTP diagnosis also prevents leakage-induced peritoneal infection, malnutrition and peritoneal dysfunction, boosting patient outcomes and life quality.

In summary, CTP serves as a highly efficient and non-invasive imaging modality that holds irreplaceable value in the diagnosis of PD-related combined and occult complications. It is particularly endowed with precise diagnostic and differential diagnostic significance for clinically challenging conditions such as multiple occult fistula formation, dialysate leakage and combined abdominal wall hernias. As illustrated in this case, CTP clearly depicted the location and course of multiple fistulous tracts as well as the morphological features of abdominal wall hernia and inguinal hernia, and accurately identified the pathological cause of the abdominal mass, and guided the reasonable switch to HD based on comprehensive assessment of combined lesions, finally achieving a favorable clinical outcome for the patient. Therefore, CTP should be recognized as one of the preferred imaging modalities in the diagnostic and therapeutic process of complications in patients with long-term PD, and it is worthy of further clinical promotion and standardized application in clinical practice.

Acknowledgments

None.

Footnote

Funding: This study was supported by 2025 Central Government Guidance Funds for Local Science (No. 25ZYJA017), Technology Development Program and Natural Science Fund Program (No. 20JR5RA143) and Gansu University of Traditional Chinese Medicine Postgraduate Innovation and Entrepreneurship Fund (No. 2026CXCY‑070).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2026-0557/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. The need for patient consent for the publication of this article and accompanying images was waived according to the Ethics Committee of Gansu Provincial Hospital. All patient identifiable information is fully excluded from the manuscript to ensure privacy protection.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Li PK, Chow KM, Van de Luijtgaarden MW, Johnson DW, Jager KJ, Mehrotra R, Naicker S, Pecoits-Filho R, Yu XQ, Lameire N. Changes in the worldwide epidemiology of peritoneal dialysis. Nat Rev Nephrol 2017;13:90-103. [Crossref] [PubMed]
2. Vachharajani TJ, Taliercio JJ, Anvari E. New Devices and Technologies for Hemodialysis Vascular Access: A Review. Am J Kidney Dis 2021;78:116-24. [Crossref] [PubMed]
3. Cheng XBJ, Bargman J. Complications of Peritoneal Dialysis Part II: Nonmechanical Complications. Clin J Am Soc Nephrol 2024;19:791-9. [Crossref] [PubMed]
4. Szeto CC, Li PK. Peritoneal Dialysis-Associated Peritonitis. Clin J Am Soc Nephrol 2019;14:1100-5. [Crossref] [PubMed]
5. Scanziani R, Pozzi M, Pisano L, Santagostino Barbone G, Dozio B, Rovere G, Gabella P, Magrì F. Imaging work-up for peritoneal access care and peritoneal dialysis complications. Int J Artif Organs 2006;29:142-52. [Crossref] [PubMed]
6. Ogah I, Milne F, Zevin B. Peritoneal tuberculosis. CMAJ 2021;193:E1664. [Crossref] [PubMed]
7. Ghafoor S, Hoppe AT, Lange M, Tognella A, Bueter M, Lehmann K, Alkadhi H, Stocker D. Computed tomography for evaluation of abdominal wall hernias-what is the value of the Valsalva maneuver? Hernia 2024;28:1709-18. [Crossref] [PubMed]
8. Ling CW, Sud K, Castelino RL, Johnson DW, Tan THY, Lee VW. Systematic Review on Treatment and Outcomes of Tuberculous Peritonitis in Patients on Peritoneal Dialysis. Kidney Int Rep 2024;9:277-86. [Crossref] [PubMed]
9. Chung MC, Yu TM, Wu MJ, Chuang YW, Muo CH, Chen CH, Huang ST, Li CY, Shieh JJ, Hung PH, Chung CJ. Impact of peritoneal dialysis-related peritonitis on PD discontinuation and mortality: A population-based national cohort study. Perit Dial Int 2022;42:194-203. [Crossref] [PubMed]
10. Li PK, Chow KM, Cho Y, Fan S, Figueiredo AE, Harris T, Kanjanabuch T, Kim YL, Madero M, Malyszko J, Mehrotra R, Okpechi IG, Perl J, Piraino B, Runnegar N, Teitelbaum I, Wong JK, Yu X, Johnson DW. ISPD peritonitis guideline recommendations: 2022 update on prevention and treatment. Perit Dial Int 2022;42:110-53. [Crossref] [PubMed]