Micturating cystourethrogram as a tool for investigating UTI in children - An institutional audit

BACKGROUND

Micturating cystourethrograms (MCUG) are the gold standard for evaluating vesicoureteric reflux (VUR). There is a growing consensus for increasing the threshold for performing MCUGs following urinary tract infections (UTI) in children. There are several varying guidelines. It is important to detect high-grade reflux in the setting of an UTI because of potential long-term complications.

OBJECTIVE

This audit aimed to retrospectively: (1) identify the conformance rate of local guidelines at the Women's and Children's Hospital (WCH); (2) assess predictors for an abnormal MCUG; and (3) compare local guidelines against the Royal Children's Hospital, Melbourne (RCH), National Institute for Healthcare and Excellence (NICE), and American Academy of Pediatrics (AAP) guidelines for selectively detecting high-grade reflux.

METHOD

The number of MCUGs performed from 2008 to 2012 at the WCH radiology department was collected. Patients undergoing MCUG during the 2012 calendar year were identified. Only children having an initial MCUG as part of an UTI investigation with prerequisite imaging as per guidelines were included. Each child's age, sex, referral source, reason, renal ultrasound (RUS) prior to the MCUG, MCUG result and VUR grade were recorded. The WCH guidelines were applied to determine conformance, to evaluate predictors for an abnormal MCUG, and compared against other retrospectively applied guidelines (RCH, NICE, AAP).

RESULTS/DISCUSSION

There was complete data for 168 children who underwent MCUG as part of an UTI investigation (median age 0.79 years, range 0.12-8.74, male:female 67:101). There were 67/168 abnormal MCUGs (62 children with VUR, five bladder diverticulum), and 97 refluxing renal units (43 high-grade VUR units). No posterior urethral valves (PUV) were identified as part of the UTI investigation. A total of 143/168 patients had prior RUS (normal:abnormal 67:76). The WCH guidelines had 82% conformance. There was no statistically significant association between an abnormal MCUG and age, sex, referral source, reason, or prior RUS result. The WCH guidelines may have missed five children with high-grade VUR (four children had surgery), compared with RCH, APP and NICE, with 8, 15, and 17 children, respectively, having high-grade VUR (two, five, and five children had surgery, respectively) show in the Summary Table. The retrospective study had limitations and possible selection bias (children with UTI without a MCUG). There were no standard treatment approaches for VUR; hence establishing a MCUG guideline is difficult. An alternative is the top-down approach.

CONCLUSION

Current institutional guidelines for considering MCUG following UTI in children vary considerably. The MCUG guidelines at any institution must take into account the local management guidelines for high-grade VUR.

Efficacy of once-daily tobramycin monotherapy for acute pulmonary exacerbations of cystic fibrosis: a preliminary study

Our objective was to compare the efficacy, safety, and microbiology of once-daily intravenous (IV) tobramycin with conventional 8-hourly tobramycin/ceftazidime IV therapy for acute Pseudomonas aeruginosa (PA) pulmonary exacerbations in cystic fibrosis (CF). CF patients with PA-induced pulmonary exacerbations were allocated to receive either once-daily tobramycin (Mono) or conventional therapy with tobramycin/ceftazidime given 8-hourly (Conv). The two longitudinal groups received therapy in a double-blind, randomized manner over a period of 2 years. Tobramycin doses were adjusted to achieve a daily area under the time-concentration curve of 100 mg x hr/L in both groups. Results were assessed for both short-term changes (efficacy and safety after 10 days of IV antibiotics during acute exacerbations) and long-term changes (efficacy, safety, and sputum microbiology between study entry and exit). Pulmonary function tests (PFTs) on admission were similar in both groups. After 10 days of IV antibiotics, absolute mean improvements in percent of predicted PFTs were 12.8, 12.1, and 13.7 for forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), and forced expired flow between 25--75% of FVC (FEF(25--75%)) in the Conv group (n = 51 admissions) compared to 10.6, 9.9, and 10.6 in the Mono group (n = 47)(P<0.05 for all). Sixteen percent in the Conv group and 15% of patients in the Mono group did not respond to therapy by day 10. Long-term PFT patterns were similar for the Conv and Mono groups. The time between admissions did not differ. The Mono group showed a significant increase in tobramycin minimum inhibitory concentrations (MICs) against PA from study entry to study exit (P = 0.02, n = 27 strains); this failed to reach significance in the Conv group (P = 0.08, n = 25). There was no significant increase in the number of isolates, with MIC> or =8 mg/L in both groups. No short- or long-term changes in audiology or serum creatinine were found in either group. After 10 days of IV therapy, the urinary enzyme N-acetyl-beta-d-glucosaminidase/creatinine ratios increased in both groups (P0.05). This increase was greater in the Conv compared to the Mono group (P < 0.05). We conclude that this pilot study indicates once-daily tobramycin therapy to be as effective and safe as conventional 8-hourly tobramycin/ceftazidime therapy. Combination antibacterial therapy appears to offer no clinical advantage over once-daily tobramycin monotherapy. Tobramycin once-daily monotherapy is a potential alternative to conventional IV antibacterial therapy which deserves further investigation, including the impact on susceptibility of PA to tobramycin.

Influence of antenatal ultrasound on the management of fetal exomphalos

OBJECTIVE

To determine the influence of antenatal ultrasound on the management of exomphalos.

METHODS

Retrospective case note review of 23 fetuses and infants referred to our institution with either a pre- or postnatal diagnosis of exomphalos over a 7-year period.

RESULTS

There were 21 cases of exomphalos of which 18 were correctly diagnosed on antenatal ultrasound by 18 weeks' gestation. There were 2 false-positives and 3 false-negatives, including 1 case of amniotic band syndrome with an abdominal wall defect and 1 morphologically normal fetus. Associated anomalies were correctly identified in 12 but incorrectly reported in 8. Maternal serum alpha-fetoprotein levels were abnormal in 61% of cases of abdominal wall defects in this series. Amniocentesis was performed in 12 and cordocentesis in 1. There were 13 terminations, including 2 trisomy 18s and 1 trisomy 13. Two fetal deaths followed amniocentesis. Of the 10 live births, 9 had their exomphalos repaired with a 1-year survival rate of 89%. Prenatal diagnosis did not appear to influence outcome.

CONCLUSIONS

Antenatal ultrasound diagnosed 86% of cases of exomphalos and correctly reported 67% of associated anomalies. Amniocentesis may have led to the death of 1 morphologically normal fetus.

Colour duplex ultrasound: a screening modality for femoropopliteal disease in patients with intermittent claudication

In patients presenting with intermittent claudication, Colour Duplex Ultrasound (CDU) examination of the femoro-popliteal segment has been proposed as a screening modality. Those patients with atheromatous lesions suitable for percutaneous transluminal angioplasty (PTA) could proceed to diagnostic angiography. Patients with long segment occlusive disease demonstrated by CDU, who were not considered suitable candidates for surgery, would not require angiographic examination. This prospective study was performed on 46 limbs in 25 consecutive patients who presented for investigation of claudication. There was close correlation between the two methods in the demonstration of high-grade stenoses and occluded segments. Using angiography as the 'gold standard' this study indicated a diagnostic accuracy for CDU of 93% with a sensitivity of 89% and a specificity of 95%. Angiography tended to show longer occluded segments than CDU. Colour Duplex Ultrasound shows promise as a screening investigation in patients with intermittent claudication to detect lesions that may be suitable for PTA.

Retrograde esophageal balloon dilatation: salvage treatment of caustic-induced stricture

A 14-month-old boy with severe esophageal strictures following ingestion of potassium hydroxide is described. Initially, treatment was by surgical bougienage but following esophageal perforation, 65 balloon dilatations were performed over an 8-month period using a retrograde approach via a feeding gastrostomy without anesthesia or sedation. A further nine dilatations in the following 6 months were performed using a per-oral approach after establishment of full oral nutrition and removal of the gastrostomy. The main advantage of the retrograde approach was the large number of dilatations that could be performed without anesthesia in an infant. This has allowed nonoperative treatment of a high grade caustic esophageal stricture which would otherwise have required esophageal replacement.

Radiological assessment of duodenal calibre in congenital duodenal obstruction

A review of barium meal studies in 32 cases of congenital intrinsic duodenal obstruction (CDO) from the Adelaide Children's Hospital was performed to assess and measure pre and post operative duodenal dilatation. Comparisons were made with a group of 153 normal barium studies from the same Hospital with a view to quantifying normal and abnormal proximal duodenal calibre. Duodenal size was expressed as a ratio D1/L1, (diameter of 1st part of duodenum/height of first lumbar vertebra). In this study a normal range of duodenal diameter was found to be 0.90 to 1.62 (+/- 2 SD from mean), with a mean of 1.26. The CDO patients recorded a range of postoperative ratios on first follow-up barium studies of between 1.2 and 4.5 with a mean of 2.28. Where serial studies had been performed, duodenal diameter was found to show some decrease in size postoperatively. In patients who underwent surgery for membrane obstruction there was a trend towards normalisation of duodenal diameter over time, compared with the atresia group. However, this difference did not reach statistical significance.