An audit of RCP guidelines on DMSA scanning after urinary tract infection

Imaging in urinary tract infections: current strategies and new trends

The aim of imaging in a child with urinary tract infection (UTI) is to detect abnormalities that require appropriate treatment or findings that can be acted on to prevent development of complications (hypertension, chronic renal failure or pregnancy-related complications). Imaging protocols in pediatric urinary tract infections are evolving. From strategies based on extensive investigations in all children younger than 7 years of age, we are slowly moving to imaging strategies focused on children at risk of developing renal damage and possibly long-term complications. The article provides an overview on urinary tract infections, their complications and the use of imaging in their management. The different imaging strategies in children with UTIs (including the recommendation of excluding from imaging certain groups of patients) still needs full evaluation. It is interesting to note, however, a slow move from wide use of cystography in all children with UTI, which has been standard practice for many years but was probably not based on solid scientific evidence, toward a more focused use of cystograms in specific groups of children.

The role of imaging in urinary tract infections

The aim of imaging in urinary tract infections (UTI) is to detect conditions that must be corrected to avoid imminent deterioration of kidney function, or to prevent recurrent infections and long-term kidney damage. The most threatening conditions are obstruction of an infected upper tract and abscesses of the genitourinary system. An image-guided percutaneous drainage can be lifesaving. The role of imaging in small children with UTI is controversial in terms of the importance of anatomical and functional disorders in relation to the preventive measures to be taken. In newborns identified with hydronephrosis during pregnancy or by neonatal screening, vesicoureteral reflux (VUR) and renal scarring are congenital and not caused by infection. Most of these patients are males and the VUR is of a higher grade than VUR detected in girls after the first UTI. Imaging in children with UTI should only be ordered after a thorough evaluation of the risk of renal damage and the benefits of preventive measures. In adult females, no imaging is necessary in cystitis, while ultrasonography and plain films are recommended in acute pyelonephritis. Since uncomplicated UTI in men is rare, diagnostic imaging should be started early to rule out complicating factors in the urinary tract. In prostatitis, vesiculitis, epididymitis and orchitis the role of imaging is to rule out abscess formation and testicular malignancies.

Vesicoureteric reflux and reflux nephropathy

Reflux nephropathy i.e. renal scarring associated with vesico-ureteric reflux (VUR) and urinary tract infection (UTI) was originally considered an acquired disease. The renal scarring seems to get worse with recurrent urine infections especially in the young. Therefore, in the past much effort was undertaken to correct the VUR surgically and minimize the number of recurrent urinary tract infections by antibiotic prophylaxis with the hope of reducing if not arresting the onset of complications that follow i.e. hypertension and renal failure. However, it is now becoming clear that reflux nephropathy encompass at least two major categories of disease; "acquired" renal scarring secondary to UTI and VUR predominantly affecting females and "congenital" scarring with dysplastic features associated with prenatal VUR but with no infection and predominantly affecting boys. The latter is much less common but is disproportionately represented in the group of patients with reflux nephropathy that go on to develop renal failure. Unfortunately, the susceptibility to renal scarring, the onset of hypertension and progression to renal failure seems to be significantly influenced by genetic factors and hence measures undertaken to prevent recurrence of UTI may not change the ultimate outcome although it will certainly improve the comfort of the individual. Therefore, the extensive investigation and management routines adopted today in these children may not be cost-effective in preventing end stage renal disease in VUR. The progression to renal failure, however, can be delayed but not halted with adequate control of high blood pressure and hence the need for life long follow-up.

Diagnosis and imaging in urinary tract infections

The aim of imaging in urinary tract infection is to detect conditions that must be treated in order to avoid immediate deterioration or recurrences, and probable long-term kidney damage. In newborns identified with hydronephrosis during pregnancy or by neonatal screening, vesicoureteral reflux and renal scarring are congenital and not caused by infection. Most of these patients are male and the vesicoureteral reflux is of a higher grade than that detected in girls having had urinary tract infection. In children with urinary tract infection, several authors advocate a more selective policy and recommend imaging only in those children who are at risk for developing renal damage. In adult females no imaging is necessary in cystitis, whereas ultrasonography and plain films are recommended in acute pyelonephritis. Because uncomplicated urinary tract infection in men is rare, diagnostic evaluation including imaging should be started early in order to rule out complicating factors within the urinary tract. The role of imaging in prostatitis, vesiculitis, epididymitis and orchitis is primarily to rule out abscess formation, but also to exclude testicular malignancies.

Renal function in congenital anomalies of the kidney and urinary tract

Congenital anomalies of the kidneys and urinary tract are a major cause of chronic and end-stage renal failure in children. The molecular mechanisms having been elaborated, there is now growing evidence that kidney function is to a large extent determined genetically at an early stage. Assessment of kidney function is an important tool in clinical medicine and is feasible in utero. Postnatally, determination of absolute glomerular filtration rate and also of split and excretory renal function play an important role in the determination of treatment and prognosis. This is supplemented by other biochemical, molecular and interventional prognostic factors, which are of help in preservation of kidney survival by minimizing modulating factors. If chronic or terminal renal failure ensues in childhood or even in early infancy, however, improved medical care has led to encouraging results, ultimately influencing the motivation in the care of children with congenital anomalies of the kidney and urinary tract.

An evidence and consensus based guideline for acute diarrhoea management

OBJECTIVE

To develop an evidence and consensus based guideline for the management of the child who presents to hospital with diarrhoea (with or without vomiting), a common problem representing 16% of all paediatric medical attenders at an accident and emergency department. Clinical assessment, investigations (biochemistry and stool culture in particular), admission, and treatment are addressed. The guideline aims to aid junior doctors in recognising children who need admission for observation and treatment and those who may safely go home.

EVIDENCE

A systematic review of the literature was performed. Selected articles were appraised, graded, and synthesised qualitatively. Statements on recommendation were generated.

CONSENSUS

An anonymous, postal Delphi consensus process was used. A panel of 39 selected medical and nursing staff were asked to grade their agreement with the generated statements. They were sent the papers, appraisals, and literature review. On the second and third rounds they were asked to re-grade their agreement in the light of other panelists' responses. Consensus was predefined as 83% of panelists agreeing with the statement.

RECOMMENDATIONS

Clinical signs useful in assessment of level of dehydration were agreed. Admission to a paediatric facility is advised for children who show signs of dehydration. For those with mild to moderate dehydration, estimated deficit is replaced over four hours with oral rehydration solution (glucose based, 200-250 mOsm/l) given "little and often". A nasogastric tube should be used if fluid is refused and normal feeds started following rehydration. Children at high risk of dehydration should be observed to ensure at least maintenance fluid is tolerated. Management of more severe dehydration is detailed. Antidiarrhoeal medication is not indicated.

VALIDATION

The guideline has been successfully implemented and evaluated in a paediatric accident and emergency department.