Diagnosis of pediatric urinary tract infections

Urinary tract infection (UTI) is the second common infection in children. The diagnosis of UTI in infants and children can be difficult. Good history taking and physical examination are corner stones of good care of UTI. In addition, this article reviewed current evident on the methods of urine specimen collection and various diagnostic criteria to reach the diagnosis of UTI. Asian Guideline for UTI in children is highlighted to increase consensus of the diagnosis of UTI.     

Evaluation and management of pediatric urinary tract infections

Urinary tract infections (UTIs) are relatively common in children. We describe the evaluation and management of children with UTIs, as well as the risks and consequences related to the UTI. This article describes a rational approach to the evaluation and management of childhood UTIs with the relation to the natural history and risk factors.     

L-forms and urinary tract infections

Bacteria may be transformed into L-forms as a result of stress. They could theoretically persist in the host as commensals and produce disease when they revert to their parent pathogenic bacterial form. Even though L-forms have been reported to occur in 20 per cent of patients with chronic bacteriuria, our current knowledge does not allow us to directly implicate them in the production of disease.     

Stones and urinary tract infections

The term infection stones refers to calculi that occur following urinary tract infections (UTIs) caused by urease-producing gram-negative organisms. They consist of magnesium ammonium phosphate, carbonate apatite and monoammonium urate. Alkaline urine is most favorable to their formation. Urinary tract obstruction, neurogenic bladder, voiding dysfunction, temporary or indwelling urinary catheters, distal renal tubular acidosis and medullary sponge kidney are considered the main risk factors for developing infection stones. Urinalysis and urine culture are essential for diagnosis. A typical finding on imaging is a moderately radiopaque, staghorn or branched stone. Curative treatment is possible only by eliminating all of the stone fragments and by eradicating UTI. A variety of operative and pharmaceutical approaches is available. Metaphylactic treatment is mandatory to prevent recurrences. The relationship between urinary stones and UTIs is well known and shows two different clinical pictures: (1) stones that develop following UTIs (infection stones) which play a key role in stone pathogenesis, and (2) stones complicated by UTIs (stones with infection) which are metabolic stones that passively trap bacteria from coexistent UTIs and may consist of calcium or non-calcium. This article presents an overview of infection stones, analyzing the epidemiology, composition, pathogenesis, diagnosis, treatment and prevention of this type of calculi.     

Managing urinary tract infections

Urinary tract infections (UTI) are common in childhood. Presence of pyuria and bacteriuria in an appropriately collected urine sample are diagnostic of UTI. The risk of UTI is increased with an underlying urological abnormality such as vesicoureteral reflux, constipation, and voiding dysfunction. Patients with acute pyelonephritis are at risk of renal scarring and subsequent complications such as hypertension, proteinuria with and without FSGS, pregnancy-related complications and even end-stage renal failure. The relevance and the sequence of the renal imaging following initial UTI, and the role of antimicrobial prophylaxis and surgical intervention are currently undergoing an intense debate. Prompt treatment of UTI and appropriate follow-up of those at increased risk of recurrence and/or renal scarring are important.     

Complicated urinary tract infections

A complicated urinary tract infection is that which occurs in a patient with an anatomically abnormal urinary tract or significant medical or surgical comorbidities. Whereas this definition may not cover each and every situation, it does serve to encompass the great majority of these patients and guide their care. The definition is necessarily broad, to assure that these potentially complex patients are appropriately managed. Thus, complicated urinary tract infection describes a group of patients that usually need a prolonged course of antimicrobial therapy, with all its attendant morbidities, costs, and outcome differences.     

Catheter-associated urinary tract infections

In the past few years it has been clearly demonstrated that the concept of bacterial biofilm production permits an understanding and provides some explanation of the pathogenesis, diagnosis and treatment of catheter-associated urinary tract infections. This concept describes the colonization of catheter surfaces and the movement of bacteria against the urinary flow. It explains the antibacterial resistance of these matrix-enclosed sessile populations of bacteria. The catheter encrustation can be observed as mineralizing bacterial biofilm. The differentiation in swarming cells exposing a much higher activity of the enzyme urease is responsible for the predominant role of Proteus mirabilis in obstructing encrustations. The guidelines for the prevention of catheter-associated urinary tract infections were developed over the past decades by clinicians and are still valid. They can now be better understood taking into consideration these new theories. As overuse of urethral catheters and non-compliance of their recommended use are still apparent, educational and surveillance programmes are needed to help maintain good standards of care.     

Nosocomial urinary tract infections

Hospital-acquired urinary tract infections, which account for approximately 40 percent of all nosocomial infections, often result in serious complications and ultimately lead to rising hospital costs. To combat the high incidence of nosocomial urinary tract infections, surveillance and control programs must be developed and carefully maintained by hospitals. When urinary tract infections cannot be prevented, empiric therapy with broad-spectrum antibiotics effective against beta-lactamase-producing bacteria should begin immediately.     

Nosocomial urinary tract infections

Convenience to the hospital staff is certainly not an acceptable reason for the use of a potentially dangerous drainage tube. An indwelling urinary drainage catheter should be used only in patients who need multiple straight urinary catheterizations, develop urinary obstruction or incontinence, or are comatose and require frequent urinary output measurements. An indwelling catheter may also be needed for drainage or stenting during or following genitourinary surgery. Once it has been determined that urinary catheterization is necessary, a closed urinary drainage system catheter must be carefully and aseptically inserted by experienced hospital personnel after careful preparation. The closed drainage system must be meticulously maintained throughout the patient's hospitalization and catheterization. After the catheter is removed, a urinary culture should be performed to identify any postcatheter infection. If there is infection, the patient must be treated with antibiotics. If symptoms of a urinary tract infection, bacteremia, or sepsis ensue, treatment must be rapidly begun with antibiotics as appropriate on the basis of drug sensitivity testing. These techniques will not eliminate bacteriuria associated with urinary drainage catheters. However, they will reduce the incidence, morbidity, and mortality associated with urinary catheterization.     

Pediatric urinary tract infections

Urinary tract infection is a frequent diagnosis in infants and children who are referred to a urologist. Infections in children are often benign, yet the potential for significant renal damage in this age group makes adequate urinary tract evaluation mandatory. Urinary obstruction, vesicoureteral reflux, periurethral bacterial colonization, and voiding dysfunction are important in the pathogenesis of pediatric infections. Adequate therapy requires detection and control of these conditions in order to prevent pyelonephritic renal scarring and its sequelae.     

Imaging in upper urinary tract infections

Most infections of the upper urinary tract are straightforward and do not require any emergency radiological investigations. A sonogram carried out within 48 hours will in most cases be sufficient to eliminate obstructed pyelonephritis requiring emergency drainage of urine. In complicated cases, or those affecting already weakened areas, an urgent CT scan is necessary, preferably after injection of iodinated contrast medium if renal function permits. CT scanning is far better at diagnosis than sonography as well as at investigating whether there are complications. Furthermore, it is essential that the radiologist is aware of unusual and rare forms of pyelonephritis, especially pseudotumoural forms, so that clinicians can be pointed towards the appropriate treatment, avoiding unnecessary and invasive interventions.     

Imaging in lower urinary tract infections

In epididymo-orchitis, a sonogram shows a non-homogenous and hypertrophied epididymis and testis, with increased vascularisation seen on a Doppler sonogram. Abscesses must be investigated using sonography so that a necrotic tumour is not misdiagnosed. In prostatitis, sonography is indicated to investigate urine retention and where treatment has failed (to look for a blockage, an abscess, or pyelonephritis). Endorectal sonography is the best imaging modality for analysing the parenchyma, but otherwise has limited value. Chronic prostatitis is the main differential diagnosis from prostate cancer; the two may be distinguished using diffusion MRI. In cases of cystitis, imaging is indicated when a patient has recurrent cystitis (to investigate what the causative factors might be), or an infection with a less common bacterium (to look for calcifications, emphysema, any involvement of the upper urinary tract), and in cases of cystitis with pseudotumour.     

Uncomplicated urinary tract infections in women

Uncomplicated urinary tract infections, such as acute uncomplicated cystitis and pyelonephritis, are common infections in otherwise healthy women. Although severe complications are rare, the high prevalence of these infections contributes to significant costs to health care systems. The present review addresses recent publications that concern the epidemiology, pathogenesis, aetiology, diagnosis, treatment and prevention of uncomplicated urinary tract infections and recurrent urinary tract infections in women.     

Vesicoureteral reflux and urinary tract infections

Urinary tract infection is a common problem in children. The combination of vesico-ureteric reflux (VUR) and urinary tract infection may predispose children to pyelonephritis and subsequent complications. This review outlines the modifications suggested in the recent literature in the protocol for investigations and diagnosing VUR. Recent interest has been expressed in studying certain molecular markers to measure non-invasively renal damage in children with VUR. Long term results of comparative trials between medical and surgical management have been published recently.