Treatment of E. coli Cyst Infection in ADPKD

Diagnostic Confirmation

The Kidney International guideline recommends confirming the diagnosis using criteria that include CRP ≥50 mg/L OR WBC >11 × 10⁹/L, PLUS at least 2 items from at least 2 clinical categories (fever, flank pain, tenderness) 1, 2
Blood cultures should be obtained if upper UTI or cyst infection is suspected, as recommended by the Kidney International guideline 1
Imaging such as ultrasound, CT, or MRI should be used to exclude other sources of infection, according to the Kidney International guideline 2
If confirmation is needed, a ¹⁸FDG PET-CT scan is superior to conventional imaging for localizing infected cysts, as stated in the Kidney International guideline 2

Lipid-soluble antibiotics are essential because they achieve superior cyst penetration compared to standard agents, as recommended by the Kidney International guideline 1, 3
The Kidney International guideline suggests that fluoroquinolones achieve good cyst penetration and are effective alternatives, but carry significant risks such as tendinopathies, aortic aneurysms, and dissections 1, 3

The Kidney International guideline recommends 4-6 weeks of antibiotic therapy for kidney cyst infections 1, 2

The Kidney International guideline advises against treating asymptomatic bacteriuria, as this is not cyst infection 1, 2
The Kidney International guideline recommends not using nitrofurantoin or fosfomycin for cyst infections, as these do not penetrate cysts adequately 1
The Kidney International guideline suggests differentiating from cyst hemorrhage or kidney stones, as these can present similarly but require different management 1, 2