Evaluation of a phased pneumococcal conjugate vaccine introduction in Mongolia using enhanced pneumonia surveillance and community carriage surveys: a study protocol for a prospective observational study and lessons learned.

BACKGROUND: Streptococcus pneumoniae causes substantial morbidity and mortality among children. The introduction of pneumococcal conjugate vaccines (PCV) has the potential to dramatically reduce disease burden. As with any vaccine, it is important to evaluate PCV impact, to help guide decision-making and resource-allocation. Measuring PCV impact can be complex, particularly to measure impact on one of the most common and significant diseases caused by the pneumococcus, namely pneumonia. Here we outline the protocol developed to evaluate the impact of 13-valent PCV (PCV13) on childhood pneumonia in Mongolia, and a number of lessons learned in implementing the evaluation that may be helpful to other countries seeking to undertake pneumonia surveillance. METHODS: From 2016 PCV13 was introduced in a phased manner into the routine immunisation programme with some catch-up by the Government of Mongolia. We designed an evaluation to measure vaccine impact in children aged 2-59 months with hospitalised radiological pneumonia as a primary outcome, with secondary objectives to measure impact on clinically-defined pneumonia, nasopharyngeal carriage of S. pneumoniae among pneumonia patients and in the community, and severe respiratory infection associated with RSV and/or influenza. We enhanced an existing hospital-based pneumonia surveillance system by incorporating additional study components (nasopharyngeal swabbing using standard methods, C-reactive protein, risk factor assessment) and strengthening clinical practices, such as radiology as well as monitoring and training. We conducted cross-sectional community carriage surveys to provide data on impact on carriage among healthy children. DISCUSSION: Establishing a robust surveillance system is an important component of monitoring the impact of PCV within a country. The enhanced surveillance system in Mongolia will facilitate assessment of PCV13 impact on pneumonia, with radiological confirmed disease as the primary outcome. Key lessons arising from this evaluation have included the importance of establishing a core group of in-country staff to be responsible for surveillance activities and to work closely with this team; to be aware of external factors that could potentially influence disease burden estimates; to be flexible in data collection processes to respond to changing circumstances and lastly to ensure a consistent application of the pneumonia surveillance case definition throughout the study period.

An evaluation of chest X-ray in the context of community-based screening of child tuberculosis contacts.

BACKGROUND: There are no published data on the critical review of chest X-ray (CXR) findings of children in the context of community-based contact screening. OBJECTIVES: To describe the quality, findings and inter-observer agreement of CXRs in child TB contacts in Indonesia. METHODS: We performed antero-posterior (AP) and lateral CXR in children who had had close contact with a pulmonary TB case. The CXRs were interpreted independently by four reviewers. RESULTS: A total of 530 CXRs of 265 children were reviewed. Most (63%) of the children were asymptomatic at the time of CXR. Only 60% of the CXRs were reported as moderate to good quality by all reviewers, and inter-observer agreement on quality was slight to moderate (weighted κ = 0.16-0.35) for AP view. The majority of the CXRs were reported as normal (range 65-77%), with fair to moderate inter-observer agreement (κ = 0.25-0.46). Hilar lymphadenopathy (6-16%) was the most common CXR abnormality reported with poor inter-observer agreement (κ = -0.03 to 0.25). CONCLUSION: The CXRs of child TB contacts investigated in the community were characterised by low quality, low agreement and low yield. Our findings support guidelines that CXR is not routinely indicated in asymptomatic child TB contacts in this setting.

Stratification of radiological test ordering: its usefulness in reducing unnecessary tests with consequential reduction in costs.

This study examines the effectiveness of an automated, stratified system of radiological test ordering, known as 'Traffic Lights', in reducing the number of unnecessary tests and their associated costs. The system involves stratification of radiological tests into three groups, denoted by red, amber and green colours. 'Red' tests must be authorized by a consultant. 'Amber' tests must be signed by a registrar or authorized by a consultant. 'Green' tests can be ordered directly by residents or interns. In the 4 months after the introduction of 'Traffic Lights', each radiological method showed a reduction in both the number of tests and their associated costs. The reduction was consistent across both medical and surgical groups. Analysis of data 20 months immediately after the introduction of 'Traffic Lights' also showed a consistent reduction in the total number of tests, suggesting that the changes are sustainable and unlikely to be due to seasonal variation. Combined with evidence-based medicine protocols, this stratified system of radiological test ordering should ensure the safety, quality and appropriateness of imaging tests and minimize overall patient radiation dose.

Is informed consent necessary for paediatric computed tomography?

Computed tomography (CT) is a valuable examination in children, but the lifetime cancer mortality attributed to CT radiation in children is an order of magnitude higher than in adults. Therefore, it is important that radiologists and referring clinicians ensure that parents are fully informed of the radiation risks, the appropriateness of the examination is considered and imaging protocols are tailored to reduce the radiation burden.

Sonographic measurement of renal enlargement in children with acute pyelonephritis and time needed for resolution: implications for renal growth assessment.

OBJECTIVE: Failure of a kidney to grow satisfactorily in childhood is evidence of renal disease. Because kidneys may enlarge during an episode of acute pyelonephritis, concomitant renal length measurements cannot be used as baselines for growth assessment. This study was designed to determine the degree of renal enlargement in children with acute pyelonephritis and the time the enlargement takes to resolve after treatment is started to find the optimum time for obtaining baseline measurements. SUBJECTS AND METHODS: In a cohort study, 180 children younger than 5 years old with their first proven acute urinary tract infection, with or without pyelonephritis, had renal scintigraphy and sonography within 15 days of starting treatment. The presence of cortical defects on scintigrams indicated pyelonephritis. The lengths of kidneys with and without scintigraphic defects (i.e., with and without pyelonephritis) were compared, adjusting for age and sex, and the length of kidneys with defects was related to time elapsed between the start of treatment and sonography. RESULTS: Ninety-nine kidneys (28%) in 77 children (43%) had scintigraphic defects. Kidneys with defects were an average of 3.2 mm longer than kidneys without defects. Length and time interval between treatment and sonography in kidneys with defects correlated negatively, with mean length approaching that of kidneys without defects by 10-11 days. CONCLUSION: Kidneys with acute pyelonephritis initially increase in length but return to normal on average by the 11th day of treatment. If poor renal growth is used as an indication of renal disease, sonography should be delayed or repeated at least 2 weeks after the start of treatment to determine the length of the uninflamed kidney.

Voiding cystourethrography in boys: does the presence of the catheter obscure the diagnosis of posterior urethral valves?

OBJECTIVE: In voiding cystourethrography, the urethral catheter may or may not be left in place during voiding. The main argument for removing the catheter is that the diagnosis of posterior urethral valves may be missed because the catheter can hold open the valve, efface it, and render it invisible. However, if the catheter does not prevent the diagnosis of urethral disease, it is preferable to leave it in place. The catheter makes it possible to repeat the procedure easily if necessary, and using it to drain the bladder provides information about ureteric obstruction in the presence of vesicoureteric reflux. Accordingly, the purpose of this study was to determine whether leaving the urethral catheter in place throughout voiding cystourethrography affects the efficacy of the procedure for the diagnosis of posterior urethral valves. MATERIALS AND METHODS: Three radiologists reviewed the preoperative voiding cystourethrograms obtained in 48 boys who ranged in age from 1 day to 10 years old (mean, 1.5 years). All patients had a diagnosis of posterior urethral valves made at cystoscopy, which was used as the gold standard. The voiding cystourethrogram was obtained with a catheter in place during voiding in 28 (58%) of the 48 boys, without a catheter in 17 (35%), and with and then without a urethral catheter during the voiding phase of the study in three (6%). RESULTS: Posterior urethral valves were detected on 25 (89%) of the 28 voiding cystourethrograms obtained with a urethral catheter in place and in 15 (88%) of the 17 voiding cystourethrograms done without a urethral catheter. The five children in whom posterior urethral valves had been diagnosed by cystoscopy but were not detected on voiding cystourethrography had no dilatation of the posterior urethra nor any other evidence of obstruction; these were possibly false-positive cystoscopic diagnoses. CONCLUSION: Our results show that a urethral catheter does not obscure posterior urethral valves in boys and need not be removed routinely during the voiding phase of voiding cystourethrography.

Wilms' tumor: a rational use of preoperative imaging.

OBJECTIVE: To determine whether a preoperative imaging protocol relying predominantly on a chest X-ray film (CXR) and ultrasound in patients with Wilms' tumor is adequate for patient management and to determine the frequency more sophisticated imaging, in particular, computed tomography (CT), is required. DESIGN AND SETTING: Historical cohort study at a tertiary pediatric hospital. SUBJECTS: 60 consecutive patients with Wilms' tumor treated at our institution between 1980 and 1990. MAIN OUTCOME MEASURE: The preoperative imaging was recorded and 2- and 4-year survival were compared with the National Wilms' Tumor Study. RESULTS: 100% of patients had a preoperative CXR, 95% abdominal ultrasound, 5% abdominal CT, 13% chest CT, 47% abdominal X-ray, 2% aortography, 5% cavography, and 35% intravenous urography. The overall 2- and 4-year survivals of 92% and 90%, respectively, did not statistically differ from the National Wilms' Tumor Study 2- and 4-year survivals of 94% and 91%. CONCLUSIONS: A preoperative imaging protocol relying predominantly on a CXR and abdominal ultrasound does not reduce survival. Other more sophisticated imaging, in particular, CT, is not required in the majority of cases and is warranted only when a CXR or ultrasound is unable to resolve relevant management problems.

Risk factors in the development of early renal cortical defects in children with urinary tract infection.

OBJECTIVE: Defects seen on early cortical scintigrams of the renal cortex in children with urinary tract infection may represent acute inflammatory change or established scar. The purpose of this study was to determine the relationship between these defects and age, sex, the presence and grade of vesicoureteral reflux, and infective organism in a cohort of children examined after their first proved urinary tract infection. SUBJECTS AND METHODS: We prospectively examined 193 consecutive patients less than 5 years old who were seen at the ambulatory pediatric department during a 3-year period and had a first proved urinary tract infection. Children with obstructed or solitary kidneys were excluded. All patients were imaged with scintigraphy of the renal cortex and radiographic voiding cystourethrography within 15 days of diagnosis. The association of age, sex, the presence and grade of vesicoureteral reflux, and infective organism with a defect (acute pyelonephritis or a renal scar) seen on a cortical renal scan was studied. RESULTS: The prevalence of cortical defects was greater in the kidneys of patients less than 2 years old (96/290, 33%) than in older children (16/96, 17%) and greater in those with vesicoureteral reflux (41/92, 45%) than in those without it (71/294, 24%). Vesicoureteral reflux was absent in 63% (71/112) of kidneys with a cortical defect. No association with sex or infective organism was established. As well as having a greater prevalence of cortical defects, 145 (75%) of the 193 urinary tract infections included in the study were in children less than 2 years old. The kidneys of these younger patients also had a greater severity and prevalence of vesicoureteral reflux (74/290, 26%) than did those of older children (18/96, 19%). CONCLUSION: Early cortical defects are associated with an age less than 2 years and vesicoureteral reflux. However, the association of early defects with the presence and grade of vesicoureteral reflux is confounded by the declining prevalence and severity of reflux with age. A significant proportion of cortical defects occur in the absence of vesicoureteral reflux, and the contribution of reflux to scar formation might be less than previously considered.

Vesicoureteral reflux: an accurate predictor of acute pyelonephritis in childhood urinary tract infection?

PURPOSE: To determine the association between vesicoureteral reflux (VUR) and the presence of acute pyelonephritis in children with urinary tract infections. MATERIALS AND METHODS: The authors studied 150 consecutive patients less than 5 years of age with their first proved urinary tract infection. All patients underwent renal cortical scintigraphy (with technetium-99m dimercaptosuccinic acid or Tc-99m gluconate) and voiding cystourethrography (VCUG) to identify the presence of cortical defects and VUR, respectively. RESULTS: Of 300 kidneys, 88 (29.3%) had a cortical defect at scintigraphy. Fifty-four of the 88 patients (61%) did not have VUR demonstrated at VCUG. Conversely, 72 of the 300 kidneys (24%) had VUR; of these, 38 (53%) had no cortical defect. The sensitivity of VCUG in helping predict a defect was 38.6%, and the specificity was 82.1%. CONCLUSION: VUR (as shown by VCUG) and renal cortical scintigraphic defects frequently occur independently of each other. Renal cortical scintigraphy may be a more accurate predictor of patients at risk for scarring.

Cerebral herniation during bacterial meningitis in children.

OBJECTIVE: To see whether the incidence of cerebral herniation is increased immediately after lumbar puncture in children with bacterial meningitis and whether any children with herniation have normal results on cranial computed tomography. DESIGN: Retrospective review of case notes; computed tomograms were read again. SETTING: Large paediatric teaching hospital. SUBJECTS: 445 children over 30 days old admitted to hospital with bacterial meningitis. MAIN OUTCOME MEASURES: Timing of herniation in relation to lumbar puncture; findings on computed tomography in children with herniation. RESULTS: Cerebral herniation was detected in 19 (4.3%) of the 445 children (21 episodes; herniation occurred twice in two children). Herniation occurred in 14 (45%) of the 31 children who died. Nineteen episodes of herniation occurred in the 17 children who had a lumbar puncture; 12 of the episodes occurred in the first 12 hours after the lumbar puncture and seven over six other 12 hour periods (odds ratio 32.6 (95% confidence interval 8.5 to 117.3); p < 0.001). The results of cranial computed tomography were normal in five (36%) of the 14 episodes of herniation in which scanning was performed at about the time of herniation. CONCLUSIONS: The temporal relation between lumbar puncture and herniation strongly suggests that a lumbar puncture may cause herniation in some patients, and normal results on computed tomography do not mean that it is safe to do a lumbar puncture in a child with bacterial meningitis.

Is the preliminary film necessary prior to the micturating cystourethrogram in children?

The aim of the study was to determine the value of the preliminary film in children undergoing a micturating cystourethrogram (MCU). The coded computer reports of 806 children undergoing MCUs in a 12-month period were retrospectively reviewed for abnormalities of the lumbar spine, hips, or for calcifications. Vesicoureteric reflux was present in 185 patients (23%). Four patients had renal calculi (0.5%), and in all cases the abnormality was evident on preceding imaging of the upper urinary tract. Spinal anomalies (other than known meningomyelocele) were present in four patients. The clinically obvious abnormalities present in these were a sacral teratoma, a sacral lipoma, scoliosis with tracheo-oesophageal fistula, and a cutaneous angioma with a sacral pit. No patients (other than those with known meningomyelocele) had dislocated hips diagnosed. If the preliminary film had not been performed in 806 patients, neither spinal anomaly, renal calculus, nor congenital dislocated hip would have been missed. The low incidence of plain film anomalies indicates that in our population a plain film is not justified routinely.

Clinical signs of pneumonia in children.

Clinical and chest radiographic findings were recorded prospectively in 185 children with cough who attended an outpatient clinic in Papua New Guinea. Children were studied if they were between 8 weeks and 6 years of age; patients with wheeze, stridor, measles, or pertussis were excluded. 56 children (30%) had radiological evidence of pneumonia. The presence of either a respiratory rate greater than or equal to 50/min or chest indrawing, or of both signs, was a good indication of pneumonia, with a predictive power of 46% for a positive test and 83% for a negative test. A more complex definition of tachypnoea, as a respiratory rate greater than or equal to 40/min in children over 12 months old and greater than or equal to 50/min in infants, showed little additional diagnostic benefit.

Computed tomographic assessment of vertebral bone mineral in childhood.

Quantitative computed tomography (QCT) was used to assess trabecular bone mineral concentration in the vertebrae of 132 children, 45 with suspected disorder of bone mineralisation, 54 with thalassaemia and 37 controls. The range for bone mineral concentration in controls, expressed as equivalent K2HPO4 concentrations, was 90-190 mg cm-3. Abnormally low values were seen in all untreated children with idiopathic juvenile osteoporosis, 3/9 steroid recipients, and three patients with osteogenesis imperfecta. Abnormally high values were seen in 10/14 chronic renal failure patients. Comparison of the single and dual-energy methods showed that the single energy method, which has a lower radiation dose and is less prone to error from movement artifact, is satisfactory in most paediatric applications.

Volume related configurational changes in the aetiology of pelvi-ureteric junction obstruction.

The aetiology of pelivi-ureteric junction (PUJ) obstruction is controversial. We present four patients who had normal or equivocal intravenous pyelograms and non-obstructive Whitaker tests in whom complete pelvi-ureteric obstruction was precipitated by more rapid distension of the renal pelvis. We speculate that in vivo physiological urine flow rates and temporary kinking of PUJ produces a critical increase in pelvic volume and subsequent valvular kinking of the upper ureter, which cannot be usually achieved by maximal urine flow rates alone. Co-existence of vesico-ureteric reflux (VUR) may be a contributory factor to critical pelvic distension and tortuous PUJ. Volume related configurational changes of this type are probably a more frequent cause of PUJ obstruction than is generally recognised.

Allergic reaction following micturating cystourethrography.

Adverse reactions associated with the parenteral use of contrast agents are widely recognized, but reactions to contrast agents used in micturating cystourethrography (MCU) are much less common, although absorption of contrast media through intact bladder mucosa has been documented. A significant adverse reaction to ionic contrast material used for MCU in which neither reflux nor traumatic urethral catheterization could be implicated is presented. This case illustrates that significant reactions can occur during MCU and appropriate resuscitation facilities must be available. In a patient with a history of reaction to IV contrast media, the need for MCU should be reviewed and consideration given to nuclear medicine MCU. If a radiologic MCU is needed, consideration should be given to performing it in the hospital, with nonionic contrast media and steroid premedication.

Gas reduction of intussusception.

Efforts to improve the non-surgical management of childhood intussusception centre around (a) reassessment of selection criteria used to ensure as many children as possible have the advantage of hydrostatic reduction, and (b) improvements and modifications of enema technique to ensure successful and safe reductions without increased morbidity. Reports that pneumatic reduction was highly successful in treating childhood intussusception prompted the authors to evaluate this technique over an 18 month period using our previously reported technique of oxygen at 2 litres/minute and a pressure of 80 mm Hg. Pneumatic reduction was attempted in 114 of 129 consecutive cases of intussusception, and was successful in 85 (75%). Fifteen patients (8.6%) were considered unacceptable risks for gas reduction using our current selection criteria and had primary surgery. The overall success rate considering all cases of intussusception managed at our institution over this period was 66% (85/129). As with any form of hydrostatic reduction, pneumatic reduction of intussusception requires careful selection of patients, meticulous technique, and awareness of complications and their appropriate management. Because of its simplicity and improved success rate, pneumatic reduction has replaced traditional barium reduction at our institution. It may be that with further evaluation of selection criteria, higher pressures, and prolonged attempts that results will improve further.