#578 Calcium-channel blockers chyloperitoneum: an underrated complication in peritoneal dialysis
Authors: Albrizio Paolo , Foschi Annalisa , Milani Ivo Angelo Antonio , Muciaccia Silvia , Rindi Stefano , Zucchi Manuela , Milanesi Fabio 
Published: May 2024

Abstract

Background and Aims
Bacterial peritonitis is the most feared complication for peritoneal dialysis (PD) patients. Together with abdominal pain and elevated white cell count in peritoneal effluent, the presence of a cloudy peritoneal effluent represents the main diagnostic criteria. The appearance of this last sign, even in an asymptomatic patient, always represents cause for concern and raises suspicion of an already subclinical peritonitis but can also represent other causes.
Among acellular aetiologies for a cloudy peritoneal effluent, there is the presence of triglycerides, usually above 200 mg/dl, called chyloperitoneum, secondary to pancreatitis or concomitant calcium- channel blockers (CCBs) therapy.
Most of dialysis patients are affected by hypertension. Considering the frequent necessity of limiting dosage of angiotensin 2 receptors blockers (ARB) and ACE inhibitors (ACE-I) for the risk of hyperkalaemia, CCBs frequently represent one of the most common prescribed antihypertensive drugs. Usually well tolerated and with limited adverse effects, literature demonstrates how they can induce, for not fully understood reasons (research supposed a role for the lipophilicity of these drugs, an impaired lymphatic absorption, an increased lympho-vascular dilatation or lymphatic hydrostatic pression) the presence of triglycerides in peritoneal effluent to levels causing chyloperitoneum. Frequently reported as anecdotical cases, especially in Asian studies, only limited information are available about influence of drug dosage or other concomitant therapies but is evident a higher frequency with lercanidipine assumption.

Method
We evaluated all patients undergoing peritoneal dialysis in our Centre in 2023. Chyloperitoneum (Fig. 1) diagnosis was obtained in cases of cloudy peritoneal effluent in asymptomatic patients with normal inflammatory indexes, normal white cell count on peritoneal effluent and negative cultural samples on peritoneal effluent associated with complete remission after fast peritoneal washes and reduction or discontinuation of CCBs.

Results
16 patients underwent PD in our Centre during 2023: 4 automated (APD) and 12 ambulatory (CAPD). All of them were affected by hypertension and 10 of 16 (2 APD and 8 CAPD) were already in chronic therapy with CCBs (5 with lercanidipine, 4 with lacidipine and 1 with barnidipine), all at maximum accepted dosage.
4 patients presented during 2023 one or more episodes of cloudy peritoneal effluent without any sign or symptom of infection. All these patients were in CAPD and in therapy with lercanidipine and underwent to full remission after fast peritoneal washes; for 2 of them was necessary to discontinue CCBs therapy while for the other 2 dose reduction was fair. In 1 patient was recently associated oral anticoagulant therapy and in another 1 was recently associated dual antiplatelet therapy. None of these patients presented more episodes and all of them are still in PD.
Among the other 8 patients in CCBs therapy without episodes of chyloperitoneum, only 1 was already in therapy with single antiplatelet therapy and none of them with double one or with oral anticoagulant.

Conclusion
cloudy peritoneal effluent is always cause for concern for Nephrologists since that it could represent, event without any other sign or symptom of infection, an already subclinical bacterial peritonitis. Most of dialysis patients are also affected by hypertension. Since usage of ARB and ACE-I is limited by risk of hyperkalaemia, CCBs represents one of the most prescribed antihypertensive drugs. For PD patients, however, the risk of chyloperitoneum must be considered since, even if it can be easily corrected, it could also affect therapy and patient management. Described in literature as only an anecdotical complication, our study shows that the incidence could be much higher and appears to be linked a specific molecule, lercanidipine, taken at higher dosage and to CAPD. Concomitant therapies as dual antiplatelet or oral anticoagulant therapy could represent a stimulating factor but other studies, with more numerous patients, are needed for further considerations.