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Introduction

The cloudy bag in peritoneal dialysis consists of the loss of clarity usually observed in the dialytic effluent, a circumstance generally associated with infectious peritonitis, although it can also be caused by non-infectious etiologies [1].

It should be noted that a cloudy but aseptic peritoneal effluent (negative culture) may have a high cytological count (greater than 100 cells) or a normal count [1]. Additionally, peritoneal effluent with increased cellularity may be due to infectious or non-infectious causes (e.g., atopic or neoplastic) [2]. In the case of a cloudy peritoneal bag with a low cell count, the concomitant detection of fibrin or fat can provide guidance on its etiology [3, 4].

The cloudy peritoneal bag with a whitish appearance is usually due to its high fat content (chyloperitoneum), and may be generated by pharmacological, traumatic or inflammatory causes [2]. The type of elevated fat in its lymphatic component, triglyceride or cholesterol, classifies chyloperitoneum as chylous or pseudochylous, respectively [5].

In the following report we present the case of an adult patient with stage 5 chronic kidney disease (CKD) who began continuous ambulatory peritoneal dialysis and, since the beginning of the procedure, presented cloudy but acellular peritoneal effluent with a chylous appearance. The patient was asymptomatic, with repeated negative peritoneal fluid cultures and low levels of triglycerides and cholesterol on physicochemical evaluation.

 

Case report

A 72-year-old patient with a history of heart transplant in 2015, high blood pressure, and chronic kidney disease (CKD) secondary to prolonged use of calcineurin inhibitors, diagnosed in 2023, which progressed to the need for dialysis treatment. The usual medication is presented in Table 1.

Medication	Dose
– Tacrolimus – Everolimus – Meprednisone – Rosuvastatin – Folic acid – Calcium citrate – Cholecalciferol – Hydralazine – Amlodipine – Carvedilol – Erythropoietin – Iron Sucrose	1 mg every 12 hours (8 AM and 8 PM) 2 mg every 12 hours (8 AM and 8 PM) 12 mg every day (8 AM) 5 mg every day (8 AM) 5 mg every day (8 AM) 1905 mg, 2 tablets every day (10 AM) 4000 UI every day (4 PM) 50 mg every 12 hours (8 AM and 8 PM) 5 mg every day (8 AM) 6.25mg every 12 hours (8 AM and 8 PM) 4000 UI, three times a week 100 mg every 15 days

Table 1. Usual patient´s medication and dose.

Tenckhoff cannula placement by laparoscopic technique was performed without complication (medications used during the procedure are listed in Figure 1), and from the first peritoneal effluent, the fluid had a chylous appearance.

On physical examination, the patient had no relevant findings, with a normal-appearing catheter insertion site and the aforementioned peritoneal effluent, which appeared chylous (Figure 2). The patient was receiving amlodipine as part of his antihypertensive treatment, and given the association of this drug with the appearance of chylous fluid, we decided to switch it to methyldopa. However, the whitish-looking effluent persisted even 4 months later during follow-up.

In the complementary studies, blood tests did not yield relevant findings. The physicochemical analysis of the peritoneal effluent showed a low triglyceride level (15 mg/dl) and a normal cytological profile: leukocytes less than 5/mm³ and red blood cells less than 10/mm³ (Table 2). Similar parameters were found in control samples with clear dialysis fluid, both in blood and peritoneal effluent analyses.

Peritoneal fluid analysis in Chylous like effluent	Blood analysis in Chylous like effluent	Peritoneal fluid analysis in normal effluent	Blood analysis in normal effluent
-Leukocytes <5/mm³ -Red blood cells <10/mm³ -Amylase <10 IU/l -Albumin <1.5 g/d -Glucose 791 mg/dl -Proteins <1 g/dl -LDH <25 IU/l -Triglycerides 19 mg/dl – Cholesterol < 30 mg/dl	-Triglycerides 139 mg/dl -Total cholesterol 226 mg/dl – LDL 130 mg/dl – HDL 61 mg/dl Amylase 85 IU/l -Lipase 32 IU/l -Proteins 7.2 g/dl -Albumin 3.77 g/dl -CPK 52 IU/l -Lactic acid 1.56 mmol/l	-Leukocytes <15/mm³ -Red blood cells 0 /mm³ -Amylase <10 IU/l -Albumin <1.5 g/d -Glucose 531 mg/dl -Proteins <1 g/dl -LDH <25 IU/ -Triglycerides 19 mg/dl – Cholesterol< 30 mg/dl	-Triglyceridemia 285 mg/dl – Total cholesterol 289 mg/dl – LDL 130 mg/dl – HDL 61 mg/dl – Amylase 73 IU/l – Lipase 36 IU/l – Proteins 8.2 g/dl – Albumin 4.2 g/dl – CPK 64 IU/l – Lactic acid 1.81 mmol/l

Table 2. Comparative studies in blood and peritoneal fluid during periods with chylous-like effluent and normal effluent.

Imaging studies confirmed the correct positioning of the catheter and the absence of local or systemic inflammatory or infectious conditions. Peritoneal fluid cultures for common and atypical organisms (fungi and mycobacteria) were negative. Oncological causes were ruled out based on imaging findings. The cardiac evaluation revealed mild chronic ventricular dysfunction without hemodynamic compromise (Figure 3).

At the start of peritoneal dialysis (45 days after cannulation), the fluid cleared, although chylous effluent reappeared temporarily on two more occasions.

The condition was ultimately interpreted as a cloudy bag with chylous appearance due to multifactorial causes, including the recent placement of a peritoneal catheter and the use of everolimus, which may delay surgical wound healing.

 

Discussion

Chyloperitoneum in peritoneal dialysis is a rare condition with a wide variety of etiologies, characterized by the presence of milky-looking fluid with high lipid content [2, 5]. In many cases, it is a secondary complication of percutaneous catheter insertion or abdominal trauma [5], which causes injury to lymphatic structures. Even though chyloperitoneum can be associated with infectious peritonitis, it is characteristically an aseptic condition. However, chyloperitoneum is frequently misinterpreted as infectious peritonitis and treated with antibiotics until the lack of clinical response and negative fluid cultures lead to its correct diagnosis.

In this condition, the physicochemical analysis of peritoneal fluid usually reveals a key characteristic: the presence of lipids, mainly triglycerides (greater than 110 mg/dl), a finding referred to as chylous peritoneal fluid. However, cases associated with low triglycerides but with high cholesterol (greater than 200 mg/dl) have been reported in studies of samples with a chylous appearance, called pseudochylous peritoneal fluid [2, 3].

Our patient presented chylous-looking effluent with low triglycerides and cholesterol content, which is why it did not meet the strict criteria to be considered chylous or pseudo chyloperitoneum, respectively. For this reason we originally propose to call this type of peritoneal effluent with a whitish or milky appearance but lacking high triglycerides and cholesterol content as lymphoid peritoneal fluid, given its lymphatic origin (Table 3).

 

Conclusion

The present case is, to our knowledge, the first in the literature to report an aseptic and acellular peritoneal fluid with a chylous appearance but free of triglycerides and cholesterol, which is why it cannot be called chylous (rich in triglycerides) nor pseudochylous (rich in cholesterol). The term “lymphoid fluid” is originally proposed for its designation due to the relationship with the coloration of the lymphatic fluid (Table 3).

	Chylous	Pseudochylous	Lymphoid
Triglycerides	>110 mg/dl	≤110 mg/dl	≤110 mg/dl
Cholesterol	≤200 mg/dl	> 200 mg/dl	≤ 200 mg/dl

Table 3. Subtypes of chylous like effluent.

 

Bibliography

1. Rocklin MA, Teitelbaum I. Cloudy dialysate as a presenting feature of superior vena cava syndrome. Nephrol Dial Transplant 15:1455–1457, 2000. https://doi.org/10.1093/ndt/15.9.1455.
2. Rocklin MA, Teitelbaum I. Noninfectious causes of cloudy peritoneal dialysate. Semin Dial. 2001 Jan-Feb;14(1):37-40. https://doi.org/10.1046/j.1525-139x.2001.00012.x. PMID: 11208038.
3. Brunzel, Fundamentals of Urine and Fluid Analysis. Chapter 15, Elsevier – Health Sciences Division, p. 347-359.
4. Yi-Ting Chen, Yung-Ming Chen. A rare cause of chylous ascites, Clinical Kidney Journal, Volume 7, Issue 1, February 2014, Pages 71–72, https://doi.org/10.1093/ckj/sft153.
5. Rodríguez-Sánchez MP, Hurtado-Uriarte M, Díaz-Ruiz JEA, Vergara C, Cuestas JA, Margarita Otálora-Esteban MO-E, Castañeda-Cardona C, Rosselli D. Chyloperitoneum in peritoneal dialysis: case report and systematic review of the literature. Rev Nefrol Dial Transpl. [Internet]. 2019-07-16 [cited 2024-5-30];39(2):115-9. Available at: https://www.revistarenal.org.ar/index.php/rndt/article/view/435.