What is the treatment for an infected cyst in polycystic kidney disease (PKD)?

From the Guidelines

The treatment for an infected cyst in polycystic kidney disease (PKD) should prioritize the use of lipid-soluble antibiotics, such as trimethoprim-sulfamethoxazole or fluoroquinolones, due to their better penetration into the cysts, as recommended by the KDIGO 2025 clinical practice guideline 1. When managing an infected cyst in PKD, it's crucial to consider the potential benefits and risks of different treatment approaches. The use of fluoroquinolones, for example, has been associated with an increased risk for tendinopathies and aortic aneurysms and dissections 1.

Key Considerations

• The choice of antibiotic should be guided by the severity of the infection and the potential for antibiotic resistance.
• In cases where the infection is severe or not responding to antibiotics alone, percutaneous drainage of the infected cyst may be necessary, performed under ultrasound or CT guidance.
• Patients should be closely monitored for signs of worsening infection, such as fever, flank pain, or sepsis, and should maintain adequate hydration throughout the treatment period.
• The KDIGO 2025 guideline also recommends the use of 18FDG PET-CT scan for confirmation of infected cysts when additional imaging is required 1.

Treatment Approach

• Initially, broad-spectrum antibiotics are administered intravenously, with treatment lasting 2-4 weeks depending on clinical response.
• Once the patient shows improvement, they may transition to oral antibiotics to complete the course.
• The duration of antibiotic therapy should be at least 4 weeks for liver cyst infection, and longer treatment periods may be required based on the response to therapy, as suggested by the KDIGO 2025 guideline for polycystic liver disease, which may have similar implications for PKD 1.
• In rare cases where infection persists despite these measures, surgical intervention such as nephrectomy might be considered.

From the Research

Treatment for Infected Cyst in Polycystic Kidney Disease (PKD)

• The treatment for an infected cyst in PKD often involves the use of antibiotics that can effectively penetrate the cyst fluid, as most antibiotics fail to do so 2, 3, 4.
• Ciprofloxacin, a quinolone antibiotic, has been shown to possess in vitro activity against most pathogens likely to be encountered in renal cyst infection and can accumulate in gradient cysts, exceeding serum levels by more than fourfold 2.
• High-dose ciprofloxacin has been successfully used to treat a renal cyst infection, with the patient's clinical condition rapidly improving on the antibiotic therapy 3.
• Chloramphenicol, a lipid-soluble antibiotic, has also been effective in treating infected cysts in ADPKD, but its use requires caution due to the risk of selecting resistant organisms 5.
• Other antibiotics, such as ampicillin, trimethoprim-sulfamethoxazole, erythromycin, vancomycin, and cefotaxime, may also be effective in treating cyst infections, but their concentrations in cyst fluid can vary 4.
• A study found that clinical efficacy of initial antibiotic treatment was noted in 71% of episodes, and antibiotic treatment modification was more frequently required for patients who were receiving initial monotherapy compared with those who were receiving bitherapy 6.
• Large (diameter >5 cm) infected cysts frequently require drainage, and positron emission tomography scan can be useful in detecting infected cysts 6.
• The use of antibiotic association, including a fluoroquinolone, and the drainage of large infected cysts remain the main treatment for cyst infections 6.