Encrustations of the urinary catheter and prevention strategies: a literature review

Abstract

Patients with an indwelling urinary catheter are at risk of developing urinary tract infection: for each day of the catheter remaining in situ, there is an increasing risk from 3% to 7% for infection to appear. One of the main complications of catheterization is the onset of encrustations, frequently resulting in obstruction of the catheter. Aim of this study is to describe the problem of indwelling urinary catheter encrustation and prevention strategies. A narrative review of the literature was conducted. Indwelling urinary catheter encrustations originate more easily when urine contains high concentrations of poorly soluble constituents and when the state of the urinary tract enables their precipitation as an alkaline urinary pH, often associated with the presence of bacteria urease-producers, for instance Proteus mirabilis. Urease can generate crystals and this process keeps going until the accumulation of crystalline deposits block the urine flow within the catheter lumen. The literature suggests that there are manifold pharmacological and non-pharmacological strategies to prevent encrustations. The literature analysis suggests that the permanence of the catheter could potentially be one of the most relevant causes of encrustation. The catheterization duration is the most important risk factor for bacteriuria, essential for the process of encrustation to start off. There are many prevention strategies, among which promotion of nucleation pH (pHn) supplementation in the daily diet with liquids containing citrate; this is the most simple and suitable for all patients being inexpensive and effective.