Introduction

Dialysis is a treatment typically used for patients with kidney failure, replicating the kidney’s ability to clean waste out of the blood. There are two kinds of dialysis: haemodialysis and peritoneal dialysis (PD). Haemodialysis requires blood to be pumped outside the body into an artificial machine which acts as a kidney, returning the blood to the body once it has been cleaned. PD uses the lining of the abdominal cavity, called the peritoneum, to filter the blood naturally, and waste is removed by washing the abdomen using a cleansing fluid called dialysate inserted through a catheter. PD eliminates the need for using a machine in dialysis, whilst maintaining limited invasiveness.¹

Peritonitis is a serious and potentially life-threatening infection of the peritoneum, with 0.3 episodes globally per patient per year in patients undergoing PD.² This article aims to explore peritonitis, how it is diagnosed and how to manage the infection.

Etiology and Risk Factors

Common causes of peritonitis in PD

Bacterial infections

Bacterial infections are the leading cause of peritonitis in PD patients. The infection typically occurs when bacteria enter the peritoneal cavity through the dialysis catheter, a tube that’s used to introduce and remove dialysate from the abdomen. Bacteria enter the abdomen due to:³

• Poor hygiene: If the area around the catheter is not cleaned properly, harmless bacteria which reside on the skin can invade the peritoneal cavity, an environment where they are not usually found, and elicit an immune response.
• Contamination: When dialysis fluid is exchanged, there’s a risk of contamination if the fluid itself or the equipment used during the exchange is not sterile.
• Touch contamination: This occurs when the person performing the exchange accidentally touches the catheter or connection sites with unclean hands or equipment.

Staphylococcus aureus and Staphylococcus epidermidis are most commonly associated with PD-related peritonitis. These bacteria make up part of the skin microbiome, which is a population of diverse bacteria helping the body to stay healthy and fight infection but can cause serious infections if they enter parts of the body, such as the abdomen, where they are not needed to aid health.

Fungal Infections

While less common than bacterial infections, fungal infections can also lead to peritonitis in PD patients. These infections are typically more severe and harder to treat. Fungal peritonitis often arises after repeated or prolonged antibiotic treatment for bacterial infections, which can disrupt the normal balance of microorganisms in the body and allow fungi to overgrow.

The fungi most commonly responsible for peritonitis belong to the Candida species, such as Candida albicans, which are normally harmless, but they can cause infection if they enter the peritoneal cavity.

Patient-related risk factors

Specific patient characteristics can significantly increase the risk of developing peritonitis:

• Age: Older adults may have a higher risk due to a weakened immune system and potential difficulties in performing the dialysis procedure correctly since their veins are more fragile.
• Diabetes: Patients with diabetes are more prone to infections, including peritonitis, since high blood sugar levels weaken the immune system and impact wound healing.
• Poor nutritional status: Malnutrition can weaken the body’s ability to fight off infections, making it easier for peritonitis to develop.
• Previous peritonitis episodes: Having had peritonitis before increases the likelihood of it happening again, especially if the underlying issues still exist.
• Impaired immune system: Patients with weakened immune systems, due to infections such as HIV, autoimmune conditions or certain medications, are at greater risk of infection.
• Improper technique: Difficulty in handling the dialysis process correctly, such as not following hygiene protocols, increases the risk of bacteria entering the peritoneal cavity.
• Prolonged PD use: The longer a patient is on PD, the higher the chance of complications like peritonitis.

Catheter-related risk factors

Catheter-related factors that increase the risk of peritonitis in peritoneal dialysis (PD) include:

• Improper insertion: If the catheter isn’t placed correctly, it can lead to infections.
• Poor hygiene: Not cleaning the catheter site properly allows bacteria to enter the body.
• Catheter damage: A damaged or cracked catheter can let germs in, increasing infection risk.
• Improper handling: Touching the catheter or its connections with unclean hands during exchanges can introduce bacteria.
• Frequent disconnections: Repeatedly disconnecting and reconnecting the catheter increases the chance of contamination.

Clinical Presentation and Diagnosis

Signs and symptoms

Common symptoms of peritonitis include:⁴

• Pain in the stomach
• High temperature
• Noticeably increased heartbeat, often feeling like the heart is beating out of your chest
• Decreased passing of urine or inability to urinate

Other signs of peritonitis include reduced appetite, feeling and being sick and a swollen abdomen.

Diagnosis

Peritonitis is diagnosed during a physical exam by a medical professional, assessing presence of signs and symptoms. If the medical professional suspects peritonitis, usually due to tenderness or bloating in the abdominal region, blood tests, x-rays or CT scans may be carried out to further investigate. Additionally, fluid may be withdrawn for laboratory testing to look for telltale signs of infections.⁵ 

Management of Peritonitis

Due to the serious nature of peritonitis, most patients are admitted to the hospital where they receive antibiotic treatment through intravenous (IV) injection directly into their veins. This allows quick and effective delivery of the antibiotic into the site of infection, reducing chances of complications and the infection worsening. Additionally, patients may be given IV fluids and other medications to maintain a healthy blood pressure and reduce the likelihood of sepsis. All of these fluids, including antibiotics, are given alongside PD-fluid however haemodialysis may need to be used temporarily to treat the underlying kidney condition to prevent further infection. After treatment for peritonitis is completed, patients can resume PD unless infections become regular and recurring. In these circumstances, a permanent switch to haemodialysis is advised.

Summary

• Peritonitis is a serious infection of the peritoneum, commonly affecting patients undergoing peritoneal dialysis (PD) and is primarily caused by bacterial infections, with a global incidence of 0.3 episodes per patient per year.
• The main causes include bacterial contamination from poor hygiene, improper catheter handling, and fungal infections, especially after prolonged antibiotic use. Risk factors include older age, diabetes, poor nutrition, prior peritonitis episodes, and prolonged PD use.
• Improper catheter insertion, poor hygiene at the catheter site, catheter damage, and frequent disconnections can increase the risk of infection.
• Peritonitis symptoms include abdominal pain, fever, rapid heartbeat, and reduced urine output. Diagnosis involves a physical exam, lab tests, and imaging like X-rays or CT scans.
• Peritonitis is typically treated with intravenous antibiotics and fluids in a hospital setting. Patients may temporarily switch to haemodialysis during treatment, with a permanent switch recommended if infections are recurrent.