“Sweet” Hydrothorax in a Peritoneal Dialysis Patient. A Case Report and Review of the Literature on Novel Diagnostic and Therapeutical Approaches

Abstract

“Sweet” hydrothorax is a rare complication of peritoneal dialysis (PD). It is characterized by the presence of peritoneal fluid in the pleural cavity. We describe the case of a 41-year-old woman who developed this complication three days after starting continuous ambulatory peritoneal dialysis (CAPD). We present the current diagnostic approach and treatment of this rare complication.

Keywords:peritoneal dialysis, “sweet” hydrothorax, pleuroperitoneal leakage, diaphragmatic defect, contrast-enhanced ultrasound, pleurodesis.

INTRODUCTION

Peritoneal dialysis (PD) is one of the renal replacement therapy options currently offered to patients with end-stage renal disease (ESRD). In the concept of integrated nephrological care in ESRD patients, PD plays a special role as a first modality suitable to use in almost all individuals. However, in comparison to hemodialysis (HD), PD seems to be underutilized due to many reasons, including the potential contraindications for PD, inappropriate pre-dialysis education, unplanned acute start of HD, tendency to continue this form of treatment and some barriers in PD catheter insertion (1). Lower costs of treatment and improved patients’ survival rates in the first 2-3 years after dialysis initiation are important advantages of PD (2). However, PD has also some disadvantages such as infectious and non-infectious complications. Hydrothorax (“sweet” hydrothorax) is one of the rare potentially life-threatening complications of PD. It occurs more frequently in women and is regularly localized on the right side of the chest (3). It is usually overlooked because it is mainly asymptomatic or associated with mild dyspnea. However, it can lead to severe dyspnea and acute respiratory distress, which is a life-threatening condition (4). Herein, we present the case of a patient with dyspnea which developed three days after starting continuous ambulatory peritoneal dialysis (CAPD).

CASE REPORT

A 41-year-old woman on PD, with a history of biopsy-proven focal segmental glomerulosclerosis (FSGS), steroid-dependent- and cyclosporine- dependent nephrotic syndrome, hypertension and end-stage kidney disease (ESKD), was admitted to the hospital because of dyspnea, right chest pain and anxiety. There was no fever or cough on admission. Viral infections such as SARS-CoV-2 or influenza were excluded (negative PCR tests). Three days before she started CAPD with three exchanges of 1000 mL of peritoneal fluid (incremental PD). The next day after starting CAPD she noticed mild dyspnea. She decided to continue PD exchanges but she diminished the fill volume of PD fluid to 600-800 mL per exchange. The third day after commencing PD, severe dyspnea appeared and the patient was immediately admitted to the Emergency Room of our hospital and then to our department.

Moreover, her medical history included long-term immunosuppressive treatment based on cyclosporine and prednisolone use (she has been receiving nephrological outpatient care over the last 12 years), renal anemia treated with ESA in the pre-dialysis period, chronic kidney disease and mineral bone disorder (CKD-MBD), moderate regurgitation of the mitral and tricuspid valve, degenerative changes in the right hip joint, scoliosis in the thoracic spine and mild clinical course of COVID-19 disease (March 2021).

In mid-January 2022, during our patient’s hospital stay, evidence of rapidly progressive CKD to stage 5, with an increase of serum creatinine level from 3.7 mg/dL (November 2021) to 4.7 mg/dL (a decrease in eGFR from 14.5 mL/min to 10.8 mL/min), and therefore we decided to offer her PD as a first renal replacement modality (during hospitalization, creatinine level decreased to 4.26 mg/dL). A peritoneal catheter was inserted on the 26th of January 2022 and four weeks later, the patient started the first peritoneal exchanges. Besides dyspnea, she observed an increase in her body weight and a lack of peritoneal ultrafiltration (UF).

Her laboratory tests on admission are summarized in Table 1. Chest X-ray showed a large right-sided pleural effusion with complete shadowing of the right lung, therefore confirming the fluid overload (Figure 1). An immediate thoracentesis was performed and 1700 mL of the pleural fluid were drained. Laboratory analysis of the pleural fluid showed a high concentration of glucose (glucose concentration was 218.4 mg/dL in the fluid vs 95.5 mg/dL in the blood), while the pleural protein concentration and LDH were normal. These results were specific for “sweet” hydrothorax and suggested pleuroperitoneal communication and leakage of the fluid from the peritoneal cavity into the pleural cavity. As a result of thoracentesis, clinical improvement was achieved and dyspnea subsided. A control chest X-ray showed no signs of pneumothorax (Figure 2).

We decided to stop the PD program and start hemodialysis. After permanent catheter insertion, the first hemodialysis was initiated. There was a good tolerance for hemodialysis treatment. Follow- up evaluation showed neither recurrence of symptoms nor recurrence of pleural effusion on chest X-ray. There was a correct location of the tip of the catheter on the chest X-ray (Figure 2). The patient started an HD program in our HD unit with three HD sessions per week. According to the patient’s wish, we did not restart PD.

DISCUSSION

“Sweet” hydrothorax is a rare complication that occurs in less than 2% of patients with ESKD undergoing PD as a treatment. Common PD complications include peritonitis, exit site infections, peritoneal catheter dysfunction and deterioration of peritoneal membrane status in long-term dialysis. During the last decade, improve- ments in our comprehension of the pathophysiological processes in peritoneal membrane, studies on new more biocompatible dialysis fluids and a new concept of automated peritoneal dialysis (APD) (telemonitoring) have made it possible to provide more appropriate dialysis (5, 6). In the present case report, our patient’s switching to HD resolved the problem of pleuroperitoneal communication and subsequent leakage of fluid from the peritoneal cavity into the pleural cavity. It may be considered as a temporary solution, based on the assumption that the diaphragmatic defect should be diagnosed and resolved. We decided to abandon further diagnostic due to the patient’s wish to start hemodialysis instead of restarting PD. We believe this approach can also be acceptable.

Traditional diagnostic approaches to this clinical problem comprise technetium-99m (Tc-99m) peritoneal scintigraphy or video-assisted thoracic surgery (VATS). The last method facilitates visualization of the diaphragm defect and allows treatment, consisting of either repairing the defect or performing pleurodesis. In the past couple of years, a new non-invasive approach, contrast-enhanced ultrasound (CEUS), was discussed; it is a specialized form of ultrasound (US) using an intravenous injection of microbubble contrast agents (7). Contrast-enhanced ultrasound is a technique that has developed as an adjunct to conventional US. It offers several benefits due to the lack of ionizing radiation. Also, patient’s safety is increased based on the type of contrast agents used (8).

Typically, CEUS is used in biopsy, drainage, percutaneous nephrostomy insertion, biliary intervention, thermal ablation of abdominal tumors, gastrointestinal imaging in pediatric patients, and detection of vascular complications (9), but as a novel approach, it has also applications in the musculoskeletal system. However, CEUS of the musculoskeletal system is used in clinical trials or off-label. Therefore, it is not well established in clinical routine (10). This imaging method has minimal side effects due to several reasons, including the lack of radiation, the rapid elimination of the contrast agent from the body within minutes, and the good visualization of the microcirculation, which could indicate a muscular defect (9, 10). In PD, CEUS is also useful for the evaluation of pleuro-peritoneal leakage, peritoneal catheter malfunction or presence of hernias. Contrast- enhanced ultrasound is a new add-on test to B-mode ultrasound in the peritoneal dialysis field. While the cuff is displayed in the proper position, CEUS allows for the determination of the precise location of the PD catheter leakage between the cuff and the peritoneum. It is possible to rule out a role for the leakage in the development of the initial clinical symptoms because it is usually occurring outside the peritoneal cavity, and vice versa. Also, it seems unlikely that the free air inside the abdominal wall is caused by visceral perforation. This experience leads to the introduction of CEUS as a promising and easy way to identify PD catheter leaks. The CEUS procedure is thought to be accurate, inexpensive, radiation-free, time-saving, and low-effort compared to other radiological imaging techniques such as peritoneography, computed tomography, magnetic resonance or peritoneal scintigraphy (11, 12).

The urgent clinical approach to pleuroperitoneal leakage suspicion is to perform a chest X-ray or chest ultrasound to detect the pleural effusion. High glucose concentration in the clear yellowish pleural fluid is an important clinical clue (3, 4).

In most cases, the diaphragmatic defect is treated with video-assisted thoracic surgery, which enables the patient to continue PD after recovery (4, 5). Open thoracic surgery is not recommended because of its invasive nature and possible complication. Video-assisted thoracic surgery is a minimally invasive technique that shortens the length of hospital stay, improves recovery, implies fewer perioperative complications and indicates a better long-term survival for selected patients. However, there are some limitations of this procedure, including a steep learning curve, difficult hand–eye coordination or lack of instrument flexibility (13).

Sometimes, pleurodesis might be selected as a substitute technique. It is a surgical procedure that eliminates the pleural space by uniting the visceral and parietal pleura to prevent recurrent pneumothorax or hydrothorax. It is most commonly used in patients with malignant conditions who have also developed pleural effusion (14). The symphysis between the pleura can be obtained using chemical or mechanical agents, but the last one requires surgical intervention. Pleurodesis can be achieved via either the introduction of a sclerosant agent through a chest tube into the pleural space, medical thoracoscopy, surgical thoracoscopy or thoracotomy (15). While pleurodesis does not have any particular contraindications, it is not an optimal approach for patients with high oxygen requirements because they may not tolerate the systemic inflammatory response or the presence of impaired gas exchange induced by chemical pleurodesis (16). Our preference for chemical-induced pleurodesis is explained by the fact that it enables administration of chemical agents in the pleural cavity resulting in fibrosis that creates a symphysis between the two pleurae (17). In the more than a century-long history of pleurodesis, numerous techniques have been suggested and put to the test to achieve successful pleural symphysis. These include mechanical abrasion, which was invented by the American surgeon Edward Delos Churchill in 1941, as well as various chemical sclerosants antibiotics (tetracycline, erythromycin, minocycline, doxycycline), cytostatic agents (mitomycin C, bleomycin, cytarabine), antiseptics (silver nitrate, iodopovidone), radioactive colloidal gold, quinacrine, transforming growth factor β (TGF-β), lipoteichoic acid-T, autologous blood or even bacteria (Corynebacterium parvum, Streptococcus pyogenes A3 (OK-432). The search for the perfect sclerosing agent is (17). Tetracycline derivatives are frequently used in chemical pleurodesis, and numerous studies have demonstrated their efficacy. Recently, chemical pleurodesis employed a plant extract of Viscum album. Chemical pleurodesis was performed using doxycycline in 40 patients and V. album extract in 37 patients. There was no statistically significant difference in the results of treatment with doxycycline and V. album extract. Chest pain was the most typical complication in both study groups. Severe chest pain was reported by more patients in the doxycycline group. Some of the patients in the V. album extract group needed a chest tube to drain their pleural effusion. After pleural effusion drainage, all patients were discharged from hospital without experiencing any problems. The authors of the above-mentioned study concluded that V. album may be a viable option for chemical pleurodesis with less discomfort during treatment (18). It has been reported that using talc as a chemical agent in pleurodesis had a high success rate. However, there are growing safety concerns and no solid data to support its use over alternative tactics. Povidone-iodine is a low-cost option that induces a potent inflammatory response in pleural sclerosis, while having few side effects and 90% efficacy. Guerra-Torres XE et al has recently described the successful use of this agent for chemical pleurodesis in pleuroperitoneal leakage in a PD patient. However, there is still little information available on which strategy of treatment is the best option in this rare PD complication (19).

In the present case report, we used a very simple strategy aiming just to transfer the patient to hemodialysis with no resumption of PD treatment. Spontaneous formation of pleural adhesions on the side of the leakage may be considered the optimal treatment option in the presented case. In 2005, in our PD center there was a previous case of “sweet” hydrothorax: a 65-year-old female patient on APD (pleural effusion appeared seven days after urgent start of PD) in whom hydrothorax appeared on the same side after she had been transferred by us to HD for three weeks, followed by restarting of PD. Therefore, we decided to perform VATS and chemical pleurodesis with tetracycline. As we achieved good treatment results, APD was successfully resumed.

CONCLUSIONS

“Sweet” hydrothorax should always be taken into account in the differential diagnosis of pleural effusion in PD patients. Non-invasive diagnostic techniques such as CEUS and non-surgical treatment should be recommended for these patients. Individualization of the therapeutic approach is necessary for each patient.

Conflict of interests: none declared.

Financial support: none declared.

TABLE 1.

Laboratory parameters at hospital admission

FIGURE 1.

Chest X-ray performed at hospital admission. Right-sided hydrothorax

FIGURE 2.

Chest X-ray after thoracentesis and permanent catheter insertion