Ultrasound of the pelvis and renal tract combined with a plain film of abdomen in young women with urinary tract infection: can it replace intravenous urography? A prospective study

Comparison of the diagnostic yield of routine versus indicated flowmetry, ultrasound and cystoscopy in women with recurrent urinary tract infections

Introduction and hypothesis

To quantify and compare the outcomes of routine vs. urologist-requested diagnostic testing for recurrent urinary tract infections (rUTI).

Methods

A retrospective cohort study of patients with rUTI referred to a large non-academic teaching hospital between 2016 and 2018 (Hospital A) and a university hospital between 2014 and 2016 (Hospital B). Electronic medical records were reviewed for baseline and diagnostic data. Women underwent the following assessments routinely: urinalysis, voiding diary, flowmetry in Hospital A and urinalysis, voiding diary, flowmetry, ultrasound, abdominal x-ray and cystoscopy in Hospital B. All other diagnostics were performed by indication in each hospital.

Results

We included 295 women from Hospital A and 298 from Hospital B, among whom the mean age (57.6 years) and mean UTI frequency (5.6/year) were comparable, though more were postmenopausal in Hospital A. We identified abnormalities by flowmetry or post-void residual volumes in 134 patients (Hospital A: 79; Hospital B: 55), cystoscopy in 14 patients (Hospital A: 6; Hospital B: 8) and ultrasound in 42 patients (Hospital A: 16; Hospital B: 26), but these differences were not significant. Diagnostics altered treatment in 117 patients (e.g., pelvic floor muscle training, referral to another specialist, surgical intervention), mostly due to flowmetry and post-void residual volume measurement. The retrospective design and absence of follow-up data limit these results.

Conclusions

The routine use of cystoscopy and ultrasound in female patients with rUTIs should not be recommended as they yield few abnormalities and lead to additional costs.

Hounsfield unit attenuation value can differentiate pyonephrosis from hydronephrosis and predict septic complications in patients with obstructive uropathy

We aimed to assess the role of computerized tomography attenuation values (Hounsfield unit-HU) for differentiating pyonephrosis from hydronephrosis and for predicting postoperative infectious complications in patients with obstructive uropathy. We analysed data from 122 patients who underwent nephrostomy tube or ureteral catheter placement for obstructive uropathy. A radiologist drew the region of interest for quantitative measurement of the HU values in the hydronephrotic region of the affected kidney. Descriptive statistics and logistic regression models tested the predictive value of HU determination in differentiating pyonephrosis from hydronephrosis and in predicting postoperative sepsis. A HU cut-off value of 6.3 could diagnose the presence of pyonephrosis with 71.6% sensitivity and 71.5% specificity (AUC 0.76; 95%CI: 0.66-0.85). At multivariable logistic regression analysis HU ≥ 6.3 (p ≤ 0.001) was independently associated with pyonephrosis. Patients who developed sepsis had higher HU values (p ≤ 0.001) than those without sepsis. A HU cut-off value of 7.3 could diagnose the presence of sepsis with 76.5% sensitivity and 74.3% specificity (AUC 0.79; 95%CI: 0.71-0.90). At multivariable logistic regression analysis, HU ≥ 7.3 (p ≤ 0.001) was independently associated with sepsis, after accounting for clinical and laboratory parameters. Measuring HU values of the fluid of the dilated collecting system may be useful to differentiate pyonephrosis from hydronephrosis and to predict septic complications in patients with obstructive uropathy.

Computerized tomography attenuation values can be used to differentiate hydronephrosis from pyonephrosis

PURPOSE

To determine the diagnostic value of computerized tomography (CT) in differentiating pyonephrosis from hydronephrosis on the basis of attenuation values (Hounsfield unit-HU).

METHODS

Data of the patients with grades 1-3 hydronephrosis on abdominopelvic CT, who underwent nephrostomy tube placement for decompression of the collecting system, were retrospectively analyzed. Patient demographics and CT findings were recorded along with the first access urine culture results. Three physicians calculated the surface areas and the attenuation values of the dilated collecting systems using the system software. Mean HU of pyonephrosis and hydronephrosis cases was compared.

RESULTS

A total of 105 patients with the mean age of 47.7 ± 15.5 (range 20-80) were included. The interclass correlation coefficient of three physicians was 0.981 for HU measurement and 0.999 for calculation of collecting system surface area. Of the patients, 47 (44.8 %) had pyonephrosis. Mean surface areas of the collecting system were similar in patients with pyonephrosis and hydronephrosis (1481.13 ± 1562.94 vs. 1612.94 ± 2261.4 mm², p = 0.735). Urine cultures were positive in all patients with pyonephrosis, whereas 12.7 % of hydronephrosis cases had bacterial in first access urine culture. The HU of the patients with pyonephrosis was significantly higher that that of patients with hydronephrosis (13.51 ± 13.29 vs. 4.67 ± 5.37, p = 0.0001). Having a HU of 9.21 or over diagnosed pyonephrosis accurately with 65.96 % sensitivity and 87.93 % specificity.

CONCLUSION

Measuring attenuation values of the collecting system may be useful to differentiate pyonephrosis from hydronephrosis. Diagnosing pyonephrosis accurately may avoid septic complications.

Investigation of uncomplicated recurrent urinary tract infections in women

Background:

Recurrent urinary tract infections (UTIs) in women are common despite anatomically normal urinary tracts and are frequently referred to secondary care for further assessment.

Patients and methods:

Clinic letters and pathology reports of 244 women referred to our centre over a 2-year period with uncomplicated recurrent UTIs were reviewed to determine the investigations they underwent in both primary and secondary care.

Results:

A significant proportion of women do not meet the criteria for recurrent UTIs as their infections are not proven on culture. The majority of women undergo both renal tract ultrasound scan (USS) and flexible cystoscopy. Though USS was found to demonstrate relevant pathology, flexible cystoscopy, however, did not reveal any relevant pathology.

Conclusion:

Investigation of women with recurrent uncomplicated UTIs should be done with adequate cultures and renal tract USS.

Contemporary Management of recurrent UTI in adult females

The management of recurrent UTI is subject to significant variation and patients may fall under the care of a variety of specialties. We review the pathogenesis, investigation and management of this group of patients. Accurate diagnosis of UTI is the cornerstone of successful management, and careful interpretation of MSU results is needed. Although prophylactic antibiotic regimes are often successful, the emergence of antibiotic resistance mandates the cautious use of antibiotics and consideration of other initial therapies where possible.

Evaluation of the diagnostic workup in young women referred for recurrent lower urinary tract infections

OBJECTIVES

To evaluate the current practice of the diagnostic workup in The Netherlands and the clinical relevancy of the outcome of various diagnostic procedures in young women referred for recurrent lower urinary tract infections (UTIs).

METHODS

A questionnaire was sent to all urologic departments in The Netherlands (n = 104) inquiring about the diagnostic procedures used for recurrent lower UTIs. Furthermore, we performed a prospective study in 100 consecutive young female patients (18 to 40 years old) referred for evaluation of recurrent lower UTIs. All patients underwent a standardized workup: questionnaire, voiding diary, physical examination, urinalysis and culture, abdominal x-ray with ultrasound or intravenous urography, and cystoscopy.

RESULTS

The response rate to the questionnaires was 92%. The standard procedures were laboratory blood tests in 56%, cystoscopy in 69%, plain abdominal x-ray in 91%, and abdominal ultrasound in 59%. Only 18% of the urologists asked every patient to make a voided urine frequency volume chart. In our group of patients, the radiologic procedures revealed only one relevant abnormality. Cystoscopy confirmed cystitis in 22 patients, but never revealed relevant findings. None of these diagnostic procedures ever contributed to the diagnosis. The 24-hour urine output was less than 1.5 L in 43 patients, which was considered insufficient. The individual self-reports of fluid intake were unreliable.

CONCLUSIONS

Many Dutch urologists perform an extensive routine workup in patients referred for recurrent lower UTIs. The results of our study revealed that the yield of most diagnostic procedures in these patients is low. The focus in evaluating these patients should be directed toward the behavioral aspects. Thus, the routine workup can be restricted to a voiding diary, urinalysis, and urine culture.

Ultrasonography and abdominal radiography versus intravenous urography in investigation of urinary tract infection in men: prospective incident cohort study

OBJECTIVES

To compare ultrasonography and abdominal radiography with intravenous urography in the investigation of urinary tract infection in men.

DESIGN

Prospective study in two hospital departments. Radiological procedures and urological assessments performed on different days by different clinicians

SETTING

District general hospital.

PARTICIPANTS

Consecutive series of men (n=114) referred to the department of urology for investigation of proved urinary tract infection.

INTERVENTIONS

Ultrasonography and intravenous urography of renal tract and assessment of urinary flow rate. Clinical assessment, cystoscopy, urodynamic studies, and transrectal ultrasonography with biopsy.

MAIN OUTCOME MEASURES

Sensitivity and specificity of ultrasonography and abdominal radiography compared with intravenous urography.

RESULTS

Important abnormalities were seen in 53 of 100 fully evaluated patients, the most common being a poorly emptying bladder (34). The combination of plain radiographs of kidneys, ureter, and bladder and ultrasonography detected more abnormalities than intravenous urography alone. No important abnormality was missed by this combination (sensitivity 100% and specificity 93%).

CONCLUSIONS

Ultrasonography with abdominal radiography is as accurate as intravenous urography in detecting important urological abnormalities in men presenting with urinary tract infection. This combination is safer than intravenous urography and should be the initial investigation for such patients. Additional determination of urinary flow rate is useful for the assessment of an incompletely emptying bladder.

The diagnostic yield of intravenous urography

BACKGROUND

Intravenous urography (IVU) is considered an integral imaging component of the nephro-urological work-up in a wide array of clinical settings. At our institution there is an open-access policy with regard to requesting IVU studies.

METHODS

In a prospective, blinded observational study we undertook to assess the diagnostic yield of IVU with respect to the source of referral (i.e. Urology, Nephrology, GP, A & E, other speciality) and the presenting features, such as renal colic, haematuria, bladder outflow obstruction, recurrent urinary tract infection (UTI) etc. Two hundred consecutive patients were evaluated.

RESULTS

Overall, 23% of tests were positive. There was a highly significant difference in diagnostic yield between the groups (P<0.001 for both referral source and test indication). A positive result was most likely after referral by a kidney specialist (37.1%) and when the test indication was renal colic (42%) or haematuria (32%). The yield was <15% in all other circumstances, with 94.9% and 92.1% of GP- and other hospital speciality-initiated IVUs being negative. When investigating recurrent UTI, 91.7% of tests were negative and 86.2% were negative when the indication was bladder outflow obstruction.

CONCLUSIONS

It is suggested that an open access policy for IVU is not justified, especially when cost and the risk associated with contrast media and radiation exposure are taken into account. Our study supports the abandonment of routine IVU in the investigation of UTI and bladder outflow obstruction.

Bacterial urinary tract infections in diabetes

Diabetes mellitus has a number of long-term effects on the genitourinary system. These effects predispose to bacterial urinary tract infections in the patient with diabetes mellitus. Bacteriuria is more common in diabetic women than in nondiabetic women because of a combination of host and local risk factors. Upper tract infection complications are also more common in this group. Diabetic patients are at higher risk for intrarenal abscess, with a spectrum of disease ranging from acute focal bacterial pyelonephritis to renal corticomedullary abscess, to the renal carbuncle. A number of uncommon complicated urinary tract infection complications occur more frequently in diabetics, such as emphysematous pyelonephritis and emphysematous pyelitis. Because of the frequency and severity of urinary tract infection in diabetic patients, prompt diagnosis and early therapy is warranted. A plain abdominal radiograph is recommended as a minimum radiographic screening tool in the patient with diabetes presenting with systemic signs of urinary tract infection. Ultrasonography or further radiographic studies such as CT scanning may also be warranted, depending on the clinical picture, to identify upper urinary tract complications early for appropriate intervention.

The use of standard imaging techniques and their diagnostic value in the workup of renal colic in the setting of intractable flank pain

OBJECTIVES

This study reviews the rate at which diagnostic imaging techniques are used in patients with intractable flank pain attributed to renal colic who are admitted to the hospital through the emergency room and determines the diagnostic values of plain film of the abdomen {kidney, ureter, bladder [KUB]} and of ultrasonography (US) of the urinary tract, using intravenous urography (IVU) as the gold standard for establishing the presence of a calculus.

METHODS

We reviewed the medical records of 288 patients who were admitted to our medical center over a period of 5 consecutive years for intractable flank pain, the admission and working diagnosis in all cases being that of renal colic, and we retrieved all data pertaining to their diagnostic evaluation.

RESULTS

A total of 265 patients (92%) were subjected to KUB, 158 (55%) to IVU, and 135 (45%) to US of the renal-urinary tract. Two diagnostic imaging techniques were used in the same patient in the following combinations: KUB and IVU in 146 patients (51%), KUB and US in 110 (38%), and IVU and US in 60 (21%). Three imaging techniques (IVU, KUB, and US) were utilized in 54 patients (19%). The sensitivity and specificity of KUB alone were 95% and 65%, respectively, and the positive and negative predictive values were 82% and 88%. The sensitivity of US alone was 93%, its specificity 83%, the positive predictive value 93%, and the negative predictive value 83%. The sensitivity of combined KUB and US (requiring both tests to be positive for diagnosing the presence of a calculus) was 89%, the specificity 100%, the positive predictive value 100%, and the negative predictive value 81%.

CONCLUSIONS

Our data indicate that combining US with KUB provides the best diagnostic algorithm that approaches the yield of IVU in excluding the presence of a calculus in the renal-urinary tract in patients who present with intractable flank pain.

London after Tomlinson. Care in the capital: what needs to be done

One of the aims of the Tomlinson report is to shift more care from the secondary to the primary sector in London. But the primary sector is already underresourced and overloaded. The capital has a heterogeneous population which often makes inappropriate demands on general practitioners. Many premises are inadequate and there are insufficient support staff. David Metcalfe emphasises that London is special and that the shift will not become a reality unless these problems are tackled. He suggests the establishment of different models of practice centres which could treat some of the patients who now go to accident and emergency departments. Some would be the night emergency service base, some would have primary care beds, and each would have a different mix of specialist support.

Diagnosis and management of urinary tract infection in adults

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