The pathogenesis of reflux nephropathy

In an experimental study, the scars of chronic pyelonephritis have been shown to be caused by infected intrarenal reflux. Intrarenal reflux occurs in the presence of vesicoureteric reflux and a renal papilla having special morphological characteristics predisposing to this phenomenon. Such papillae occur predominantly in the polar regions of the kidney where large pyelonephritic scars are most commonly seen. The clinical implications of this pathogenic mechanism are discussed.

The role of post-mortem investigations in determining the cause of sudden unexpected death in infancy

INTRODUCTION

Several autopsy protocols have been suggested for investigating sudden unexpected deaths in infancy (SUDI). The aim of this study is to provide data on the utility of such post-mortem investigations from a large paediatric autopsy series to inform future policy.

METHODS

Retrospective analysis of >1500 consecutive post-mortem examinations carried out by specialist paediatric pathologists at a single centre during a 10-year period according to a common autopsy protocol that included the use of detailed ancillary investigations. SUDI was defined as the sudden unexpected death of an infant aged from 7 to 365 days. All data capture and cause of death classification were carried out according to defined criteria.

RESULTS

Of 1516 paediatric post-mortem examinations, 546 presented as SUDI. In 202 infants (37%), death was explained by the autopsy findings. The other 344 cases (63%) remained unexplained. Of the explained deaths, over half (58%) were infective, most commonly due to pneumonia (22%). The component of the post-mortem examination that primarily determined the final cause of death was histological examination in 92 infants (46%), macroscopic examination in 61 (30%), microbiological investigations in 38 (19%) and clinical history in 10 (5%).

CONCLUSION

This constitutes the largest single-institution autopsy study of SUDI. Ten years on from the Confidential Enquiry into Stillbirths and Deaths in Infancy (CESDI) SUDI studies, the ascertainment of a cause of death at autopsy has improved. However, with almost two thirds of SUDI remaining unexplained, alternative and/or additional diagnostic techniques are required to improve detection rates of identifiable causes of death at autopsy.

Clinicopathological features of paediatric deaths due to myocarditis: an autopsy series

INTRODUCTION

Myocarditis is a recognised cause of cardiac failure in childhood but the frequency of myocarditis as a cause of sudden unexpected death across the paediatric age range is uncertain.

METHODS

A structured review of the results of all autopsies carried out in a single paediatric centre over a 10-year period, including the results of all investigations performed as part of the centre's policy for the post-mortem investigation of paediatric deaths.

RESULTS

During the study period there were 1516 autopsies of children aged 0-18 years. Histologically proven myocarditis was present in 28 cases (1.8%, age range 10 days to 16 years, median age 10 months), of which 16 (57%) presented as sudden death. More than half of all cases (54%) occurred in infants less than 1 year of age, accounting for 2% of infant deaths referred for autopsy, compared with around 5% of childhood deaths over the age of 5 years. In almost 40% of cases there were no macroscopic cardiac abnormalities, the diagnosis being entirely dependent on routine histological examination of the heart, and post-mortem heart weight was normal in the majority of cases. Virus was detected in nine (36%) of the 25 cases in whom virological analyses were performed. The histological features were similar in all cases, with an interstitial inflammatory cell infiltrate, predominantly lymphocytic, with focal myocyte necrosis and interstitial oedema.

CONCLUSIONS

Myocarditis is a rare cause of death in infancy and childhood, and the majority of cases present as sudden unexpected deaths, which require routine histological sampling of the heart for its detection.

Isolated unilateral tuberous sclerosis-associated renal cystic disease in a neonate

We present a male infant with antenatally detected, focal, unilateral apparently isolated renal cystic disease with morphological features of renal involvement in tuberous sclerosis. Only one previous case with similar presentation has been described. Most affected children present with either diffuse bilateral renal cystic disease or extrarenal manifestations. The major genes involved in tuberous sclerosis are now well described, and early onset of severe renal cystic disease in affected children often is related to the presence of a contiguous gene deletion syndrome involving TSC2 and PKD1 on chromosome 16.

Epstein-Barr virus-associated lymphoproliferative disorder presenting as apparently isolated gastrointestinal lesions in childhood

We present an unusual case of post-transplant lymphoproliferative disorder (PTLD) presenting as apparently isolated gastrointestinal lesions in a pediatric renal transplant recipient. The multiple bowel lesions were related to Epstein-Barr virus and demonstrated the appearance of a monomorphic PTLD that was morphologically indistinguishable from diffuse large B-cell lymphoma. The patient responded to therapy with targeted anti-CD20 immunotherapy. PTLD may manifest as apparently isolated gastrointestinal tract lesions in childhood.

Clinico-pathological findings in diarrhoea-negative haemolytic uraemic syndrome

This is a retrospective, national clinico-pathological study of past and current patients with haemolytic uraemic syndrome not associated with diarrhoea (D- HUS). Thirty-four patients were analysed and notified by members of the British Association for Paediatric Nephrology in 1998-1999. There was a 2:1 excess of males. Ten presented in infancy. The aetiology included 5 patients with complement abnormalities, 2 patients with complications of pneumococcal infection, and 2 with malignancies. Parental consanguinity was noted in 6 patients. Five children died, 9 developed chronic renal failure, and 10 end-stage renal failure. Only 7 made full recoveries. With a single exception, the pathological findings were unlike the previously reported glomerular thrombosis that is characteristic of diarrhoea-associated HUS, or HUS complicating verocytotoxin-producing Escherichia coli infection. Early and late glomerulopathy could be distinguished. Arteriolar and arterial disease was observed in 8 and 7 patients, respectively. Arterial disease correlated with a poor outcome. The pathology of D- HUS is of prognostic value, but this study was not powered to identify specific aetiological/pathological correlations.

Focal or diffuse lesions in persistent hyperinsulinemic hypoglycemia of infancy: concerns about interpretation of intraoperative frozen sections

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) results from defects of regulated insulin release from pancreatic beta cells and is often refractory to medical treatment. Histological changes in the pancreas associated with PHHI may be focal or diffuse, and the intraoperative confirmation and siting of focal lesions would require frozen section diagnosis. The recognition of focal involvement and its distinction from diffuse disease by frozen section depends on the identification and distribution pattern of islet cells with large hyperchromatic nuclei. This study was designed to test the feasibility of using this parameter in PHHI to delineate focal from diffuse diseases prior to the introduction of frozen sections to guide intraoperative management in our institution. A total of 66 coded and randomized paraffin sections (from 18 PHHI and 4 postmortem pancreases) were scored by three independent observers into the following categories: a focal lesion (A), no large endocrine nuclei (B), few large endocrine nuclei (C), and frequent large endocrine nuclei (D). Interobserver concordance was complete in 88%, but there were minor discrepancies in the remaining 12%. When a focal lesion was present in one section no large endocrine nuclei were seen in sections from the rest of the pancreas. In four patients with diffuse PHHI, no or only very scanty large endocrine nuclei were seen. From this finding, and the observation that in other examples of diffuse disease, large endocrine nuclei were sparse even in large paraffin sections, we have reservations about using small frozen sections for reliable diagnosis.

Congenital maxillary sinus cholesteatoma

Cholesteatoma of the paranasal sinuses is a rare condition. The purpose of this paper is to present a child with a congenital maxillary sinus cholesteatoma. An 18-month-old girl presented with a 4-week history of right cheek and intraoral swelling. Examination revealed a smooth swelling of the right hard palate in association with the facial swelling in the maxillary region. An inferior meatal antrostomy revealed pultaceous debris in the right maxillary antrum and biopsy confirmed a maxillary sinus cholesteatoma. The inferior meatal antrostomy was enlarged to allow exteriorisation of the disease. Recurrence of the disease has not presented on follow-up. An exteriorisation procedure as performed, in child of this age, allows normal facial growth. If recurrence develops then further treatment may be instituted in a more mature facial skeleton.

Quantitative 99mTc-DMSA uptake in experimental pyelonephritis

Quantitative 99mTc-dimercaptosuccinic acid (DMSA) renal uptake was studied in unilateral reflux-related pyelonephritis in pigs. The changes to absolute % dose uptake and differential uptake occurring with induction and after treatment of pyelonephritis were correlated with the DMSA images and renal pathology.

METHODS

Quantitative uptake in 53 young pigs was obtained from planar images acquired 6 h after injecting the dose. Baseline studies were made (Q1), and studies were made again after urinary infection was established (Q2), when 8 pigs had normal (no defect) renal images (group A), 23 had photon-deficient (reversible) focal defects (group B) and 22 had photon absent (irreversible) focal defects (group C). Q3 studies were made in 21 animals from groups B and C after 3-wk antimicrobial treatment.

RESULTS

At Q2 the affected kidney differential uptake was unchanged for group A and reduced for groups B and C (respective mean changes -1.7%, P < 0.01; and -5.5%, P < 0.01). The absolute % dose uptake was unchanged in pyelonephritic kidneys, but increased in the contralateral nondiseased kidneys in groups B and C (respective mean increases +1.4%, P < 0.05; and +5.4%, P < 0.01), while remaining unchanged for group A. In group C, global renal accumulation was actually increased above the Q1 values. After treatment (Q3) the reduced pyelonephritic kidney differential uptake persisted in groups B and C. In group C, however, the increased absolute % dose uptake by the contralateral kidney was less marked and not significantly different from Q1 values in this small group.

CONCLUSION

Induction of unilateral pyelonephritis produced a small reduction in diseased kidney differential uptake that was greatest in the group with irreversible imaging defects. The method did not discriminate individuals with reversible and irreversible imaging defects. The decrease in pyelonephritic kidney differential uptake resulted from increased DMSA accumulation (absolute % dose uptake) by the nondiseased contralateral kidney, while that in pyelonephritic kidneys remained unchanged. After treatment, the reduced pyelonephritic kidney differential uptake persisted, but the elevated global DMSA accumulation seen for group C (with irreversible imaging defects) was not sustained and was variable.

Childhood reflux and urinary infection: a follow-up of 10-41 years in 226 adults

To ascertain the outcome of childhood vesicoureteric reflux (VUR), 226 adults (37 males), mean age 27 years, were studied after 10-35 years, extended to 41 years by postal questionnaire in 161. At presentation (mean age 5 years) all had VUR (grade III-V in 68) and urinary tract infection (UTI); there was renal scarring in 85 (acquired before referral in 11 and during follow-up in 1), hypertension in 6 and impaired renal function in 5. They were managed and followed prospectively by one paediatrician; 63% of these children remained free from UTI; VUR persisted in 63 and had resolved in 69% of 193 children managed medically. At follow-up, 61% of adults had remained free from infection; 17 adults had hypertension and/or raised plasma creatinine, 16 with scarred kidneys. Their deterioration was predictable because of scar type, blood pressure or plasma creatinine levels in childhood. No new scars developed after puberty. Renal growth rates were unaffected by initial severity or persistence of VUR. On the later questionnaire, 9 further adults, mean age 38 years, had moderate hypertension. The adults with complications were those with extensive renal scarring and/or at least borderline hypertension in childhood. Those with VUR, but no scarring, and managed carefully in childhood, did not suffer serious consequences as adults. There is a need for early recognition and treatment of children with VUR and UTI to limit scar development.

Five-year study of medical or surgical treatment in children with severe vesico-ureteral reflux dimercaptosuccinic acid findings. International Reflux Study Group in Europe

The results of serial dimercaptosuccinic acid (DMSA) imaging over 5 years are reported in 287 children with severe vesico-ureteral reflux entered into the European Branch of the International Reflux Study in Children. The children were randomly allocated to medical (n=147) or surgical (n=140) management and DMSA studies were performed during the follow up period at least 6 months after any urinary tract infection. Abnormal images were classified into four types: (1) large polar hypodensity with normal renal outline; (2) peripheral photon deficient defect(s) in a non-deformed kidney; (3) small renal image with normal contour; and (4) peripheral defect(s) with resultant irregularity of the renal outline. The DMSA findings were abnormal at entry in 235 (82%) with no difference in incidence or severity between the two treatment groups. During follow up, deterioration was observed in 25 medically and 23 surgically treated patients and comprised image deterioration alone in 17, image deterioration with corresponding reduction in differential function in 16 and reduction in relative function without image change in 15, with similar distribution between the two treatment groups. Deterioration was more frequent in children entering the study under the age of 2 years and in those with grade IV rather than grade III reflux. These findings, showing no difference in outcome between children managed surgically or medically, are consistent with the radiological results already published.

CONCLUSION

In the International Reflux Study the DMSA scintigraphic data showed no difference in outcome between children managed surgically or medically.

Long-term renal function in the posterior urethral valves, unilateral reflux and renal dysplasia syndrome

PURPOSE

The syndrome of posterior urethral valves, persistent unilateral reflux and renal dysplasia (VURD) is said to be protective of the contralateral nonrefluxing kidney and the outcome for renal function is reported to be excellent. We tested this hypothesis in our patients by replicating previous studies but with longer followup and glomerular filtration rate data.

MATERIALS AND METHODS

We retrospectively reviewed the records of 183 boys presenting with posterior urethral valves between 1980 and 1989, including 12 who underwent nephrectomy for ipsilateral nonfunction and fulfilled all criteria for the VURD syndrome. Mean age at the most recent followup was 8.5 years. Serial serum creatinine levels and glomerular filtration rates were analyzed and compared to age matched normal values.

RESULTS

Histological evaluation revealed dysplasia in all kidneys, confirming the VURD syndrome. Followup plasma creatinine was normal 67% of the patients during year 2 of life, 50% between ages 4 and 5 years, and only 30% between ages 8 and 10 years. Glomerular filtration rate was within the normal range in 25% of boys tested in year 2 of life, and between ages 5 and 8 years.

CONCLUSIONS

Our data do not support the protective effect of the VURD syndrome on long-term renal function. All patients with posterior urethral valves require diligent long-term followup.

An evaluation of the role of suction rectal biopsy in the diagnosis of intestinal neuronal dysplasia

BACKGROUND

German pathologists have developed a consensus for histological features of intestinal neuronal dysplasia.

METHODS

A blind reevaluation of ganglionic suction rectal biopsies from infants and children who initially presented with symptoms of intestinal dysmotility was made.

RESULTS

84 of 411 specimens had sufficient depth of submucosa for adequate assessment. Questionnaires or clinical interviews were employed 3-5 years after biopsy in these 84 patients to assess the relationship between histological changes and persistent symptomology. Eighteen children were lost to follow-up, 4 others had Hirschsprung's disease the study biopsy specimen having been taken from the pulled-through bowel after surgical resection of the aganglionic segment. The remaining 62 patients were divided into three groups. There were six patients in group A (both obligatory criteria) and 28 in group B (nonessential, or just one of the obligatory criteria), and 28 in group C (normal appearances). On follow-up, two of the 28 (7%) in group B, and six of the 28 (21%) in group C had persistent dysmotility symptoms.

CONCLUSIONS

Histological criteria of the consensus of German Pathologists for intestinal neuronal dysplasia was unhelpful in predicting the clinical outcome and therefore, should not influence clinical management. As one of the obligatory criteria, hyperplasia of the submucosal plexus was significantly more common in neonates (< 4 weeks), it is concluded that this is an age-related variation.

The PAX2 tanscription factor is expressed in cystic and hyperproliferative dysplastic epithelia in human kidney malformations

Human dysplastic kidneys are developmental aberrations which are responsible for many of the very young children with chronic renal failure. They contain poorly differentiated metanephric cells in addition to metaplastic elements. We recently demonstrated that apoptosis was prominent in undifferentiated cells around dysplastic tubules (Winyard, P.J.D., J. Nauta, D.S. Lirenman, P. Hardman, V.R. Sams, R.A. Risdon, and A.S. Woolf. 1996. Kidney Int. 49:135-146), perhaps explaining the tendency of some of these organs to regress. In contrast, apoptosis was rare in dysplastic epithelia which are thought to be ureteric bud malformations. On occasion, these tubules form cysts which distend the abdominal cavity (the multicystic dysplastic kidney) and dysplastic kidneys may rarely become malignant. We now demonstrate that dysplastic tubules maintain a high rate of proliferation postnatally and that PAX2, a potentially oncogenic transcription factor, is expressed in these epithelia. In contrast, both cell proliferation and PAX2 are downregulated during normal maturation of human collecting ducts. We demonstrate that BCL2, a protein which prevents apoptosis in renal mesenchymal to epithelia] conversion, is expressed ectopically in dysplastic kidney epithelia. We propose that dysplastic cyst formation may be understood in terms of aberrant temporal and spatial expression of master genes which are tightly regulated in the normal program of human nephrogenesis.

Congenital enterocyte heparan sulphate deficiency with massive albumin loss, secretory diarrhoea, and malnutrition

BACKGROUND

The molecular basis of protein-losing enteropathy is unknown. However it has been shown that sulphated glycosaminoglycans may be important in regulating vascular and renal albumin loss.

METHODS

We describe three baby boys who presented within the first weeks of life with massive enteric protein loss, secretory diarrhoea, and intolerance of enteral feeds. All required total parenteral nutrition and repeated albumin infusions. No cause could be found in any case despite extensive investigations, including small intestinal biopsy sampling, which were repeatedly normal.

FINDINGS

By specific histochemistry, we detected gross abnormality in the distribution of small intestinal glycosaminoglycans in all three infants, with complete absence of enterocyte heparan sulphate. The distribution of vascular and lamina propria glycosaminoglycans was, however, normal.

INTERPRETATION

The presentation of these infants suggests that enterocyte heparan sulphate is important in normal small intestinal function.

Deregulation of cell survival in cystic and dysplastic renal development

Various aberrations of cell biology have been reported in polycystic kidney diseases and in cystic renal dysplasias. A common theme in these disorders is failure of maturation of renal cells which superficially resemble embryonic tissue. Apoptosis is a feature of normal murine nephrogenesis, where it has been implicated in morphogenesis, and fulminant apoptosis occurs in the small, cystic kidneys which develop in mice with null mutations of bcl-2. Therefore, we examined the location and extent of apoptosis in pre- and postnatal samples of human polycystic and dysplastic kidney diseases using propidium iodide staining, in situ end-labeling and electron microscopy. In dysplastic kidneys cell death was prominent in undifferentiated cells around dysplastic tubules and was occasionally found in cystic epithelia. The incidence of apoptosis was significantly greater than in normal controls of comparable age both pre- and postnatally. In the polycystic kidneys there was widespread apoptosis in the interstitium around undilated tubules distant from cysts, in undilated tubules between cysts and in cystic epithelia. The level of apoptosis compared to controls was significantly increased postnatally. A similar increase of cell death was also noted in the early and late stages of renal disease in the polycystic cpk/cpk mouse model. We speculate that deregulation of cell survival in these kidneys may reflect incomplete tissue maturation, and may contribute to the progressive destruction of functional kidney tissue in polycystic kidneys and the spontaneous involution reported in cystic dysplastic kidneys.

Endocrine cells of the human gastrointestinal tract have no proliferative capacity

There is compelling evidence that the epithelial cell lineage of the gastrointestinal tract are derived from a common stem cell precursor, but the details of the subsequent cellular hierarchies remain uncertain. In this context, it is important to know the arrangement of cell proliferation that gives rise to the final cell populations. In rodents, a number of studies have been performed examining the possible proliferative capacity of endocrine cells, but a wide range of technical problems makes interpretation of these data difficult. Continuous labelling studies suggest there is potential for proliferation in endocrine cells but flash labelling studies have not been conclusive. In man there are no data on this issue. We have taken advantage of the ability to perform double immunostaining for operational markers of proliferation (Ki67 antigen) and endocrine cell phenotype (chromogranin expression). We demonstrate that there are no double-labelled cells in the normal stomach, small intestine or colon of fetal, neonatal or adult humans. Moreover, no double-labelled cells are found in pathological states associated with endocrine cell hyperplasia (gastritis, ulcerative colitis). These data indicate that the normal endocrine cells of the human gut have no proliferative capacity and that, in this cell lineage, population expansion precedes differentiation.

Renal pathology and the 99mTc-DMSA image before and after treatment of the evolving pyelonephritic scar: an experimental study

This study reports the effects of 3-weeks' antimicrobial treatment on the pathology and appearance of the 99mTc-DMSA renal image in piglets with pyelonephritis induced by a combination of vesicoureteral reflux (VUR) and urinary infection. Before treatment, either photon-deficient (B1, B2) or photon-absent (C) scintigraphic abnormalities were present in the refluxing kidney in all 22 animals examined. All (100%) of the initially B1 and the majority (71%) of B2 photon deficient defects resolved with treatment, leaving only insignificant residual pathologic lesions. Conversely almost all (93%) of the C photon-absent scintigraphic abnormalities persisted after treatment and were always associated with significant scarred or cratered pathologic lesions in the refluxing kidney at sacrifice.

Renal pathology and the 99mTc-DMSA image during the evolution of the early pyelonephritic scar: an experimental study

This study describes the pathologic changes underlying the appearances of the 99mTc-DMSA renal image during acute pyelonephritis induced in piglets by a combination of vesicoureteral reflux (VUR) and urinary infection. In a total of 42 animals examined, pathologic lesions were identified in 36 of the 46 kidneys subjected to VUR and urinary infection, but no lesions developed in the remaining 10 refluxing kidneys. While scintigraphic defects were invariably associated with pyelonephritic lesions (specificity 100%), some small lesions were not identified (sensitivity 80%). There was a significant association (p = < 0.001) between the degree of photon deficiency seen scintigraphically and the histologic changes (early and late lesions). However, the scintigraphic appearance of individual lesions was also influenced by factors such as their extent and density, so that consideration of the macroscopic characteristics was also important for precise correlation.

Reflux nephropathy in children submitted to unilateral nephrectomy: a clinicopathological study

The clinical findings and renal histopathology have been reviewed in children with gross primary vesicoureteric reflux (VUR) submitted to unilateral nephrectomy. Of the 42 children reviewed, sections of the nephrectomy specimens were available in 36. In this series, 34 patients were male and eight were female. The boys included seven in which hydronephrosis was identified by fetal ultrasound. The male patients tended to present earlier and had nephrectomies younger than the females. Segmental scarring was frequent in both males and females, but evidence of dysplastic renal development was confined to the male patients and occurred in the majority (63%). Acquired mechanisms for the induction of segmental renal scarring, involving VUR, intrarenal reflux (IRR) and urinary infection, shown to be important in older children, clearly operate in infancy. However, this study emphasizes that congenital malformation of the kidney is a crucial factor in the development of reflux nephropathy (RN) in this younger age group, particularly in males. Speculation on the significance of the association between renal dysplasia and RN is discussed in relation to observations on the embryological development of the male lower urinary tract.

The small scarred kidney in childhood

Reflux nephropathy is now a generally accepted term to describe small scarred kidneys discovered during childhood; it recognises the close association between this renal lesion and vesicoureteric reflux (VUR). This paper briefly reviews the pathogenic factors involved in reflux nephropathy and suggests that at least two main mechanisms operate: acquired segmental scarring due to intrarenal reflux and congenital maldevelopment (renal dysplasia). The spectrum of renal changes associated with VUR can be usefully divided on this basis and the opportunity to recognise by fetal ultrasound those renal lesions acquired in utero may further enhance our understanding of the congenital maldevelopment group.

Mesangiocapillary glomerulonephritis associated with meningococcal meningitis, C3 nephritic factor and persistently low complement C3 and C5

We report two unusual cases in which mesangiocapillary glomerulonephritis occurred in association with meningococcal infection. C3 nephritic factor, an autoantibody to alternate pathway C3 convertase, was present. Low serum complement C3 and C5 levels were also noted. The depressed complement levels, in conjunction with terminal complement complexes at the upper limit of normal, suggest activation of the early and late complement cascade. We suggest that children presenting with meningococcal infection should have a regular urine examination, as well as full complement measurements performed, in view of the association with hypocomplementaemic mesangiocapillary glomerulonephritis. Similarly, prophylactic penicillin should be prescribed for patients with mesangiocapillary glomerulonephritis and persistently low C5 levels to prevent meningococcal complications.

Crescentic glomerulonephritis in children

Data on patients with crescentic glomerulonephritis (greater than 50% glomeruli with crescents), referred to the Hospital for Sick Children during the past 13 years, were reviewed. Thirty patients (13 male, 17 female) aged 3.7-15.7 years (mean 9.5) were evaluated. Initial clinical features included: oedema (24/30), hypertension (19/30), gross haematuria (15/30), oliguria (15/30) and a decreased glomerular filtration rate (GFR less than 30 ml/min per 1.73 m2) (22/30). Henoch-Schönlein purpura was present in 9 patients, microscopic polyarteritis in 3, polyarteritis nodosa in 1, Wegener's granulomatosis in 1, systemic lupus erythematosus in 1, post-streptococcal glomerulonephritis in 2, mesangiocapillary glomerulonephritis in 7, anti-glomerular basement membrane glomerulonephritis in 2, and 4 were idiopathic. In 10 patients 50%-79% of glomeruli were affected by crescentic changes (group 1) and in the remaining 20, 80% or more (group 2). The crescents were cellular, fibrocellular or fibrous, and the degree of sclerosis was assessed. Patients in both groups were treated with plasma exchange, corticosteroids, anticoagulants, cyclophosphamide and azathioprine in different combinations. On follow-up, 3 patients were dead, 1 was lost to follow-up, 12 were on dialysis/transplant programmes, 4 had a GFR of less than 30 and 10 a GFR of more than 30 ml/min per 1.73 m2. In our experience, 50% progressed to end-stage renal failure. The interval between disease onset and start of treatment was a prognostic factor for outcome. Fibrous crescents were associated with a worse outcome than fibrocellular crescents (P less than 0.05). Outcome was not, however, related to the percentage of glomeruli affected (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary endothelin (ET1) in complete ureteric obstruction in the miniature pig

Segmental renal scarring occurs in experimental obstructive uropathy in the multipapillary porcine kidney, and segmental abnormalities in renal perfusion are likely to be responsible. This preliminary study examines the urinary excretion of the potent locally active vasoconstrictor endothelin 1 (ET 1) in a pig model of renal obstruction and subsequent relief. Significant urinary excretion of ET 1 from the postobstructive kidney was found to occur after longstanding obstruction. Preglomerular arteriolar stenosis may be the cause of the renal ischaemia in obstruction that is at first reversible but later becomes irreversible if the stimulus persists. ET 1 may be implicated in the pathogenesis of this injury.

Cystic renal neoplasms of infancy and childhood: a light microscopical, lectin histochemical and immunohistochemical study

Cystic renal neoplasms of infancy and childhood, represented largely by cystic variants of nephroblastoma, form a spectrum of clinicopathological entities with differing behaviours. Cystic nephroma and cystic partially differentiated nephroblastoma occupy the benign end of the tumour spectrum, while polycystic Wilms' tumour forms the malignant end. A wide variety of names, reflecting different theories on aetiology, has been applied to the lesions comprising this spectrum, and this has undoubtedly caused confusion in their recognition and classification. We examined five cases of cystic renal tumours in young children which illustrate the entire spectrum, and lectin histochemical and immunohistochemical analysis of these cases showed a close similarity in the pattern of staining of the three variants of cystic tumours. This finding, which has not previously been reported to our knowledge, supports the concept of a close pathogenetic relationship between these tumours.

Risks and benefits of percutaneous biopsy and primary chemotherapy in advanced Wilms' tumour

Between 1982 and 1988, 36 children with advanced Wilms' tumour underwent percutaneous trucut needle biopsy followed by chemotherapy before definitive surgery. Nephrectomy was performed after a median of 14 weeks of chemotherapy. Substantial reduction in tumour bulk was achieved in 94% of patients. Biopsy morbidity was low and complete concordance between the histological assessment of the tumour in the biopsy specimen and at subsequent nephrectomy was confirmed in 26 of 28 (93%) patients. The overall clinical value of trucut biopsy was 83% (30/36 patients). Survival rates in this high-risk group were comparable to those of children with less advanced disease. Chemotherapy may be the primary treatment of choice for patients with Wilms' tumour. Percutaneous biopsy allows definition of histology in most patients without increasing morbidity.

Interpretation of biopsies of "normal" urothelium in patients with superficial bladder cancer. MRC Superficial Bladder Cancer Sub Group

In the course of a Medical Research Council trial of intravesical chemotherapy, biopsies were taken from apparently normal bladder urothelium near to newly diagnosed superficial bladder cancers in 417 patients. Differences were noted in the rates at which histological features were described in different centres. To gain more information about the reproducibility of the pathological findings, a group of 6 pathologists (5 from the UK and 1 from the USA), all having a special interest in urological pathology, were asked to examine a representative sample of 92 slides. They were then asked to re-examine 30 of them after an interval of at least 6 months. At first examination and at re-examination the slides were assessed using a standard proforma. However, the definitions of the categories were left unspecified for the pathologists to use their own criteria. The 5 UK pathologists then met to establish a consensus view of each slide. The results indicated that: (1) The reporting of non-dysplastic changes varied so much between pathologists as to render it of little value to clinical practice. (2) There were wide variations between different pathologists in the reported incidence of dysplastic change. (3) On a second review the pathologists reproduced their own assessment on only 62% of occasions. (4) Even after discussion between pathologists there was no consensus on the diagnosis of mild as opposed to moderate dysplasia. Consensus was reached on all biopsies which showed either severe dysplasia or carcinoma in situ. (5) In adopting a policy of taking urothelial biopsies, urologists should be aware of the imprecision and lack of reproducibility in the interpretation of such biopsies. (6) Biopsies of cystoscopically normal urothelium may not be a useful guide in defining therapy.

Intractable ulcerating enterocolitis of infancy

Five children (three boys, two girls) presenting in the first year of life with intractable diarrhoea had a number of features in common. All had ulcerating stomatitis, four had partial villous atrophy on small intestinal biopsy, all had colitis characterised by large ulcers with overhanging edges, and four had severe perianal disease; no stool pathogens were detected. Treatment with steroids, sulphasalazine, and azathioprine was unsuccessful. All five required subtotal colectomy. Four were children of consanguinous marriages, two were siblings of Pakistani origin, two were cousins of Arab origin, and the fifth was Portuguese. Although the diagnoses of Behçet's disease and Crohn's disease were considered, it appears that these children represent a distinct inherited condition affecting the whole gastrointestinal tract, particularly the colon.

Clinicopathologic review of twelve children with nephropathy, Wilms tumor, and genital abnormalities (Drash syndrome)

The clinicopathologic and radiologic features of 12 children with complete and incomplete forms of Drash syndrome are reported. Their common denominator was a nephropathy. Four had the full triad, consisting of nephropathy, Wilms tumor, and genital abnormalities; five had nephropathy and genital abnormalities, and three had nephropathy and Wilms tumor. Of the 11 children who had proteinuria, eight had the nephrotic syndrome. Of the 10 whose condition progressed to end-stage renal failure, seven were less than 3 years of age. The histologic features of Wilms tumor were favorable in all seven children, and the tumor was bilateral in three. Of the nine patients who had genital abnormalities, eight had 46,XY karyotype and either ambiguous genitalia (six patients) or normal female phenotype (two). One other patient had a normal 46,XX female karyotype and phenotype but had both müllerian and wolffian structures and a streak ovary. Nine patients had a distinct pelvicaliceal abnormality not previously reported as a feature of this syndrome. Other congenital abnormalities were aniridia, mental retardation, deafness, nystagmus, and cleft palate. This syndrome must be considered in any infant with unexplained nephropathy, particularly in young phenotypic female infants and in those children with ambiguous genitalia or Wilms tumor with an early presentation.

A further family with congenital renal proximal tubular dysgenesis

A new syndrome of oligohydramnios, Potter's syndrome, and anuric renal failure leading to stillbirth or neonatal death from respiratory failure has recently been described. Histologically, there is renal tubular dysgenesis, especially of the proximal tubules, and apparent glomerular crowding. To date, five families have been reported, in four of which there have been affected sibs and in two parental consanguinity. The disorder is, therefore, thought to be inherited in an autosomal recessive manner.

Thin basement membrane nephropathy as a cause of recurrent haematuria in childhood

A survey of 69 children presenting with recurrent or persistent haematuria and submitted to percutaneous renal biopsy at this hospital over a 17-year period, was performed to establish the incidence of thin basement membrane nephropathy (TBMN). A diagnosis of primary glomerular disease was established in 44 (IgA nephropathy in 16, Alport's syndrome in 13 and other varieties of glomerulonephritis in 15). Of the remaining 25 patients in whom light microscopical and immunochemical examination revealed no abnormalities, material for electron microscopy was available in 11. In eight of these (five of whom had a family history), TBMN was diagnosed on the basis of ultrastructural morphometric evaluation of glomerular basement membrane thickness. Assuming a similar proportion of the remaining 14 patients with renal biopsy specimens normal by light microscopy had TBMN, the probable frequency of this abnormality in the whole series would be 26%, very similar to that of IgA nephropathy. In the eight TBMN patients the mean glomerular basement membrane thickness ranged between 181 and 236 nm, whilst in 'control' biopsies from children with 'minimal change' nephrotic syndrome or IgA nephropathy, the mean thickness ranged between 242 and 333 nm.

Malignant mesenchymoma associated with a congenital lung cyst in a child: case report and review of the literature

Primary lung tumors are uncommon in children, and malignant mesenchymal tumors form only a small proportion of these. Leiomyosarcomas occur more commonly than rhabdomyosarcomas, whereas malignant mesenchymomas are exceedingly rare. Of the total number of primary pulmonary rhabdomyosarcomas and malignant mesenchymomas of lung reported in children, 50% have occurred in association with congenital lung cysts. The relationship between abnormal morphogenesis and neoplasia is well documented in the kidney. A similar relationship may exist in the lung between cystic parenchymal maldevelopment and embryonal mesenchymal tumors. We report a 4-year-old boy with a malignant mesenchymoma of lung arising within a congenital lung cyst; one similar case has previously been reported to our knowledge.

Renin messenger RNA localization in congenital mesoblastic nephroma using in situ hybridization

Renin messenger (m) RNA distribution was studied in congenital mesoblastic nephroma, a usually benign renal tumour of early infancy which may be associated with excess renin production and hypertension. Using in situ hybridization with synthetic radiolabelled oligonucleotide probes combined with immunohistochemical studies, renin expression was found in areas of tumours containing recognizable cortical structures including glomeruli and tubules. Renin mRNA was also detected in vessels and larger vascular spaces within the tumour not associated with cortical structures. Cells in the tumour vessel walls and sinusoids which expressed renin also stained positively for vascular smooth muscle-specific alpha actin.

Congenital mesoblastic nephroma, renin production, and hypertension

Between 1964 and 1987, 12 patients with mesoblastic nephroma were treated. The BP was measured preoperatively in five patients, four of whom were hypertensive. Following nephrectomy, the BP returned to normal. Plasma renin levels were measured in one patient; they were markedly elevated pre-operatively, but returned to normal following tumour excision. Immunoreactive renin staining, using a polyclonal antibody to human renin, was performed in the 12 patients. Staining was positive in ten patients. The most intense staining was noted in the areas of cortex entrapped within the tumour, and in perivascular spaces not associated with entrapped cortex. These findings suggest that hypertension secondary to increased tumour associated renin production is a feature of congenital mesoblastic nephroma.

Effect of unilateral vesicoureteric reflux on renal growth and the uptake of 99mTc DMSA by the kidney. An experimental study in the minipig

The influence of unilateral vesicoureteric reflux (VUR) on renal growth and the uptake of 99mTc DMSA by the kidney has been investigated in a 2-kidney model in the growing minipig over a period of approximately 5 months. Animals with reflux in association with low voiding pressures and normal bladder function (n = 5), as well as those with raised voiding pressures and abnormal bladder function (n = 7), were investigated with appropriate non-refluxing controls (n = 12). Urinary infection and renal scarring were avoided since these factors may affect kidney function and growth independently. Statistical tests of difference failed to demonstrate any effect of VUR on renal growth or renal uptake of 99mTc DMSA even in the presence of elevated voiding pressures and abnormal detrusor function.

Peripheral T-cell lymphoma in childhood. A clinicopathological study of six cases

A review of the pathological material from 42 children with non-Hodgkin's lymphoma seen over a 44 month period revealed 10 large cell tumours. Of these, six were classified as peripheral T-cell lymphoma, an entity rarely reported in childhood. Three patients were boys and three girls (median age 9.5 years), and extranodal presentation was a feature of two patients. Five had high-grade tumours; of these, three were classified as large cell anaplastic, Ki-1 positive and two as pleomorphic large cell. The remaining patient had a low-grade tumour of angioimmunoblastic type. T-cell subsets were examined in three cases and showed the following phenotypes: CD4-, CD8-; CD4+, CD8-; CD4-, CD8+. Three of the patients with high-grade tumours died, with a mean survival of 22 weeks. The remaining patients are alive and clinically disease-free for between 10 and 24 months after treatment.

Renal imaging with 99Tcm-labelled DMSA in the detection of acute pyelonephritis: an experimental study in the pig

Serial renal 99Tcm-labelled dimercaptosuccinic acid (DMSA) scintigrams were acquired 2-58 days after the introduction of urinary tract infection in 33 pigs with experimentally induced vesicoureteric reflux (VUR). In 29 animals VUR was unilateral and in four bilateral, a total of 37 refluxing systems. Animals were killed either at varying intervals after a scintigraphic defect was noted (24 refluxing kidneys) or after a period when sequential scintigrams were normal (13 refluxing kidneys). The appearance of the scintigram acquired on the day prior to death was compared with the renal pathology, each kidney and renal image being divided into three zones (upper, middle, lower) for separate consideration. Of the 37 refluxing systems pyelonephritic lesions were seen in 27, in a total of 61 zones. In the remaining ten kidneys no scintigraphic defect was detected and no pathological lesions were identified either macroscopically or microscopically. Where an abnormality was detected on the scintigram a lesion was always identified in the kidney (sensitivity 100%). Small pyelonephritic lesions in a total of 12 zones in six kidneys were not detected on the scintigram (specificity 82%). Of the lesions undetected by scintigraphy only one occurred in the upper pole.

Renin in mesoblastic nephroma: an immunohistochemical study

Congenital mesoblastic nephroma (CMN) is the most common renal tumor of early infancy. It is usually evident at birth as an abdominal mass and is composed of spindle-shaped cells resembling smooth muscle cells and fibroblasts. There is macroscopic and microscopic infiltration of the surrounding kidney and entrapped tubules and glomeruli are common at the edge of the tumor. In this report, we describe a case of CMN associated with hyperreninaemia and hypertension. We examined the tumor from this case and 11 other cases for the presence of renin using a polyclonal antibody to human kidney renin. Hypertension was present in three of four additional cases for which records were available. Immunoreactive renin was present in ten of the 12 cases studied. In all of these cases, intense staining was present in vessels within the areas of the trapped cortex. In seven cases, renin was identified in the walls of vessels within the tumor itself without identifiable adjacent cortical structures. These findings indicate that CMN may often be associated with primary reninism in early infancy.

Travellers' diarrhoea among children returning to the United Kingdom from visits abroad

Between January 1984 and March 1986, 10 children aged between 7 and 56 months were admitted to Queen Elizabeth Hospital for Children in London with chronic travellers' diarrhoea, after visiting the Indian subcontinent, France or Morocco. All the children were born in the United Kingdom and had been in good health before their journey abroad. On return to England most of these children were malnourished and two of them (twins) had a post-infective, tropical malabsorption-like syndrome. There was a high incidence of positive stool cultures and, on small intestinal biopsy, histological abnormalities were present in six. Children from the United Kingdom travelling abroad are at risk of developing severe travellers' diarrhoea, with serious consequences to their health and nutrition. There is a need for intensive parental education before travelling and this could be achieved through community health workers.