Congenital renal tubular dysfunction associated with maternal sniffing of organic solvents

Two cases of neonatal renal tubular dysfunction and metabolic acidosis due to maternal sniffing of a product containing toluene are reported. Both mothers had been sniffing regularly throughout their pregnancies. The infants were dysmature and had some dysmorphic features. They had hyperchloraemic acidosis and exhibited amino-aciduria. The metabolic changes were however transient. It is suggested that the sniffing of toluene containing solvents during pregnancy may change membrane permeability in both the proximal as well as distal renal tubules and may also enhance liver enzyme activity in the foetus.

Renal obstructive dysplasia: ultrasound diagnosis and therapeutic implications

57 cases of renal obstructive dysplasia (defined as the abnormal development of nephronic and ductal structures due to in utero obstruction of the urinary tract) were evaluated in terms of sonographic findings, renal and other associated anomalies, and current status of the child. More than one-third of the cases had bilateral disease and although not uniformly fatal bilateral involvement was associated with significant morbidity and mortality. In 12 of the 33 cases with unilateral dysplasia there was an association with contralateral renal problems including uretero-pelvic junction obstruction, vesicoureteral reflux and aplasia. Almost one-half of the cases had congenital anomalies, these included VACTERL association, congenital heart disease, cranial abnormalities and gastrointestinal malformations. Fifteen stillborns and 12 of the patients with bilateral involvement and four with unilateral involvement have died. Four patients are on dialysis (two with bilateral involvement and two with unilateral renal obstructive dysplasia). Only one-quarter are otherwise normal. More serious problems are reported in this mixed age population of patients with obstructive renal dysplasia than has been identified in previous studies. Management decisions of the fetus and child must be based on this new age-expanded population.

Hypoplasia of one kidney in a Sprague-Dawley rat

Pathological examination of a 4-week-old male Sprague-Dawley rat revealed hypoplasia of the left kidney. Grossly, the left kidney exhibited hypoplasia associated with absence of the ureter on the same side. Histologically, components of the cortex and medulla were mingled in the tissue, and the glomeruli and convoluted tubules were scattered in disorder, and connective tissue proliferation was also observed. The papilla and pelvis could not be identified.

The unsuspected double collecting system on imaging studies and at cystoscopy

Five children (three girls and two boys) who had a duplex collecting system with an ectopic ureter or a ureterocele that was not detected with either imaging or cystoscopy were seen during a 10-year period. Four had urinary tract infection. The fifth was noted to have hydronephrosis when CT scanning of the abdomen was done for trauma. In each case, voiding cystourethrography showed reflux into what was thought to be a single (nonduplex) collecting system, but was found during surgery to be the lower pole of a duplex system. Excretory urography in four patients, sonography in two, and CT scanning in one did not show signs of duplication on the affected side. In each case cystoscopy failed to show a duplex system on the affected side. The diagnosis of duplication of the collecting system with ectopic ureter or ureterocele was made in each case only when the bladder was opened to reimplant the ureter. Direct opacification of the previously unsuspected upper pole ureter in each case showed it to be bind-ending and terminating at the level of the kidney. Radiologists and surgeons should be aware that duplex systems may not always be visible on urography and sonography.

Oligohydramnios sequence and renal tubular malformation associated with maternal enalapril use

We present the case of a child who died of pulmonary hypoplasia as a result of the oligohydramnios sequence. The mother was taking enalapril, as well as propranolol and hydrochlorothiazide, for treatment of hypertension associated with systemic lupus erythematosus. Autopsy examination revealed severe renal tubular malformation. Correlation of animal data with previous case reports of neonatal anuria in association with maternal angiotensin converting enzyme inhibitors suggests that these agents may have a deleterious effect on fetal renal development and general well-being.

Development of an in vitro model for the disruption of extracellular matrix components in the study of congenital renal parenchymal dysmorphism

We attempted to refine a model system for the study of renal parenchymal malformations and demonstrate its use with a preliminary study of the induction of congenital renal dysmorphism. A technique is described whereby 3-day chick embryos are explanted from their shells and cultured in vitro in specially constructed polyethylene chambers. At 8 days of development, the time of ureteral induction of the metanephric mesenchyme, 6-diazo-5-oxo-norleucine, an inhibitor of proteoglycan biosynthesis, is administered as a single microinjection into the posterolateral body wall. Histological examination of fixed metanephric tissue revealed a gross deficiency in the number of differentiated tubules in norleucine-treated animals. A morphometric analysis was made of the actual area occupied by differentiated tubules in the norleucine-treated and control kidneys between 10 and 15 days of development. This analysis revealed a total tubule surface area of control kidneys of more than 2 times greater than that of embryos injected with norleucine at ureteral induction.

Giant hydronephrosis of a duplex system associated with ureteral ectopia

Giant hydronephrosis is an infrequent urological entity. To our knowledge, only 1 case has been reported previously that was associated with a duplicated collecting system and ureteral ectopia.

Renal tubular dysgenesis: delayed onset of oligohydramnios

Two premature sibs had Potter sequence and died of respiratory failure within the first day. Ultrasonography at 26 weeks during the earlier of the two pregnancies showed complete absence of amniotic fluid, and the urinary bladder was not visualized. Ultrasound examinations during the second pregnancy showed adequate amniotic fluid at 16 and 20 weeks, with a subsequent reduction in fluid volume. Two older sibs had also died of respiratory failure shortly after birth. Postmortem histopathologic studies showed all four sibs to have severely deficient renal tubular development. However, the presence of numerous glomeruli indicated prolific nephrogenesis. Most of the tubules in sections of cortex had the lectin-binding and immunohistochemical characteristics of collecting ducts; proximal tubules were not identified by lectin-binding. Electron-microscopic examination showed a general absence of differentiated characteristics in cortical tubular epithelium, except that rare tubules contained rudimentary proximal tubular brush borders. Three of the sibs were boys, one a girl. The three children that were studied had normal chromosomes. Two unaffected sibs are alive and well. Neither parent has any clinical evidence of renal disease. These studies support the interpretation that renal tubular dysgenesis is autosomal recessive with pleiotropy. However, the relatively late appearance of oligohydramnios makes early diagnosis difficult, even when the condition is suspected.

Isolated congenital renal tubular immaturity in siblings

This paper describes two cases of an unusual renal abnormality discovered in anuric siblings (one male, one female) who were born at 36 and 34 weeks of gestation and died of systemic complications secondary to severe pulmonary hypoplasia shortly after birth. Both gestations were complicated by marked oligohydramnios. Antenatal ultrasound examinations showed slightly enlarged kidneys in the first case and normal kidneys in the second case, with no evidence of hydronephrosis or cystic disease in either. With the exception of enlargement of the first infant's kidneys, autopsies revealed grossly unremarkable kidneys and ureters. Microscopy, however, demonstrated increased glomerulogenesis with normal glomeruli and global immaturity of renal tubules and ducts without concomitant features of dysplasia. Immunoperoxidase staining for epithelial membrane antigen revealed the immaturity or complete absence of proximal convoluted tubules. This precise constellation of findings had not been described previously. One other similar family has been documented in a report implicating genetic factors. In the present cases, the possibility of a cocaine-associated etiology is also addressed.

Nephronophthisis. A primary tubular basement membrane defect

In order to characterize abnormalities in nephronophthisis, renal tissues from four patients were studied by light and electron microscopies and immunofluorescence using antibodies to laminin, type IV collagen, and tubular basement membranes (TBM). There were constant morphological alterations affecting TBM of all segments of the nephron, with or without cysts. These included extreme thinning and attenuation, layering, and thickening of these structures which ranged in size from 36 nm to 2000 nm. A combination of these features often affected the same TBM simultaneously, with abrupt transitions between different lesions. Although the ultrastructural TBM aberrations were observed in a wide variety of other chronic and acute renal disorders, they rarely occurred to the extent as in nephronophthisis or with abrupt transitions, both suggesting diagnostic significance. Laminin and type IV collagen were present in normal intensity and distribution, however, anti-TBM antibody staining was inconstantly reduced, perhaps signifying lack of a normal antigenic component in the TBM. These findings may well indicate the fundamental defect in nephronophthisis to be production of abnormal TBM, similar to the glomerular basement membrane lesions and consequences in Alport's syndrome.

Primary amyloidosis of renal pelvis with duplicate collecting system

A case of primary amyloidosis localized to the inferior renal pelvis of a kidney with a duplex collecting system is described. The onset of gross hematuria and mild flank pain necessitated investigations which yielded a clinical impression of tumor within the lower pelvis of a duplex collecting system. At laparotomy a grossly hemorrhagic-appearing mass in the lower pelvis was noted and a left ureteronephrectomy was undertaken. Histologic examination of the surgical specimen revealed amyloid deposition within the inferior pelvis, the corresponding distal portions of the papillae, and the most proximal ureter. Amyloid was not present elsewhere within either the renal parenchyma or the superior collecting system.

Congenital hypernephronic nephromegaly with tubular dysgenesis: a distinctive inherited renal anomaly

This paper describes a distinct, apparently inherited renal disorder we call congenital hypernephronic nephromegaly with tubular dysgenesis. The disorder is characterized by oligohydramnios, the Potter phenotype, and enlarged nonfunctional kidneys. Light microscopy demonstrates increased numbers of glomeruli, undifferentiated tubules, and interstitial fibrosis. Microdissection reveals short, immature nephrons that lack proximal convolutions, and abnormal vascularization of the glomerulus. Morphometric analysis demonstrates increased glomerular mass, primarily in the region of the corticomedullary junction, increased interstitial mass, and decreased tubular mass. The parameters that define this anomaly are presented, and the possible mechanisms of pathogenesis are discussed in relation to pathologic observations and current concepts concerning renal embryogenesis and differentiation. The recurrence of this anomaly in the male children of a consanguineous couple suggests an X-linked recessive mode of inheritance, although an autosomal-recessive mode of inheritance cannot be ruled out. This condition indicates that not all cases of the Potter phenotype can be considered to be sporadic.

Tubular gigantism of the kidney in a 41-mm, Streeter's 23rd horizon, human fetus with a comparative study of renal structures in normal human fetuses at a similar stage of development

This is a comparative study of the metanephric development of 1 abnormal and 7 normal human fetuses, all of them measuring approximately 41 mm in vertex-coccyx length (48-50 days of gestation). The abnormal fetus presented with dilatation of the collecting tubules and is, in accordance with our review of current literature, the first case in which this malformation has been described at such an early (embryonal) stage of development. Many theories have tried to explain the pathogenesis of this malformation. Our studies agree with the theory that proposes a delay in tubular canalization, to which changes in the structure of the tubular wall might be added.

Infantile idiopathic hypercalciuria, high congenital myopia, and atypical macular coloboma: a new oculo-renal syndrome?

Four cases of infantile idiopathic hypercalciuria with high congenital myopia and atypical macular coloboma are discussed; two of them are brother and sister. The eye examination shows bilateral congenital myopia of more than 10 diopters in every case. In the fundus examination, there is a bilateral macular colobomatous lesion in two of them and monocular lesion in the remaining ones. Hypercalciuria is considered to be due to renal tubulus malformation. The macular atypical coloboma etiopathogenesis is discussed, with comment on the malformative, dystrophic and inflammatory hypothesis, having discarded the usual inflammatory etiologies. We have only found two cases similar to these in the literature, Given the relative scarce occurrence of each of the three mentioned clinical features we suggest the possibility of a new oculo-renal syndrome rather than a coincidental association.

Sclerosing peritubular nodules: a hereditary renal abnormality in von Recklinghausen's disease

A previously unrecognized type of renal lesion characterized by the formation of multiple hamartomatous sclerosing peritubular nodules in the cortex is described. These lesions were hereditary, appearing in three members of a family, which included the mother and her two sons, in association with familial central von Recklinghausen's disease (bilateral acoustic schwannomas). The nodules originated as concentric peritubular proliferations of collagen producing spindle cells, which ultrastructurally showed myofibroblastic differentiation. Four stages of nodule development leading to progressive sclerosis and tubular destruction are described. In spite of widespread involvement of the cortex with numerous nodules, in none of the three patients was there any clinical manifestation of renal dysfunction or hypertension.