Low molecular weight protein excretion in glomerular disease: a comparative analysis.

We studied 23 children with steroid-sensitive nephrotic syndrome (SSNS), 21 children with steroid-resistant types of nephrotic syndrome and 32 children with other types of nephritis. Our controls were 43 apparently healthy children. We measured the urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and the low molecular weight (LMW) protein beta 2-microglobulin (B2M), retinol-binding protein (RBP), alpha 1-microglobulin (A1M) and urine protein 1 (UP1). Results for B2M were considered only for a urine pH greater than 6.0. Comparisons were made with urine albumin excretion, glomerular filtration rate (GFR) and tubular abnormalities in selected renal biopsy samples. We found that abnormalities of LMW protein excretion occurred in between 50% (B2M) and 88% (UP1) of all subjects. In children with SSNS, A1M (r = 0.73), UP1 (r = 0.65) and NAG (r = 0.54) excretion were significantly correlated with albumin excretion, but not RBP or B2M excretion. Increased fractional excretion of A1M, B2M and UP1 and increased plasma A1M were demonstrated in 9 children with SSNS, suggesting competition for tubular reabsorption with albumin, most marked for UP1. In the steroid-resistant nephrotic and nephritic syndromes, correlation with albumin was found for all proteins. In these subjects, RBP (r = 0.37), B2M (r = 0.42) and A1M (r = 0.28) were inversely correlated with GFR, but not UP1, NAG or albumin. We found that RBP excretion was significantly greater in the presence of severe tubular abnormalities in 11 children with recent renal biopsies, but not A1M, UP1 or NAG. We conclude that LMW proteinuria is common in children with glomerular disease, and does not necessarily imply a poor prognosis. Factors other than histologically proven tubular abnormality may account for elevated LMW protein excretion. RBP is the LMW protein most closely associated with structural abnormality and least affected by increasing albuminuria.

Mid-aortic syndrome presenting in childhood.

Mid-aortic syndrome (MAS) is an uncommon condition characterized by segmental narrowing of the proximal abdominal aorta and ostial stenosis of its major branches. It is usually diagnosed in young adults, but may present in childhood as a challenging problem. Over the past 20 years 13 patients with MAS have presented to this institution. All had hypertension, four had associated neurofibromatosis, three persistent eosinophilia and three had Williams syndrome. In all cases arteriography showed a smooth segmental narrowing of the abdominal aorta with concomitant stenosis at the origins of the renal arteries. Six children were successfully treated with antihypertensive medication alone. Percutaneous transluminal angioplasty was attempted in two cases with poor result. Surgery was indicated in seven children with refractory hypertension and progressive renal impairment. Techniques used to revascularize the kidneys included thoracoabdominal to infrarenal aortic bypass with renal artery reimplantation, splenorenal bypass, gastroduodenal to renal bypass, aortorenal bypass and autotransplantation.

The negative influence of delayed renal allograft function on longer-term graft survival in a pediatric population.

The influence of delayed graft function on renal allograft survival has been studied in a review of 322 renal transplants performed at one pediatric institution. The appearance of the first radionuclide renal scan was used to indicate early function in patients receiving their first cadaveric allograft. Patients whose first radionuclide renal scan showed both good renal perfusion and good function (n = 52) were compared with those whose scans demonstrated good perfusion but no function (n = 32). the actuarial graft survival of those with no function was significantly worse (P < .05). The difference in graft survival was not solely due to grafts lost in the early posttransplant period. Analysis of serial serum creatinine estimations suggests a process of continued inexorable nephron loss in some patients whose grafts showed a delay in achieving function.

Middle aortic syndrome: clinical and radiological findings.

Eight patients with the middle aortic syndrome are described. They were aged 2 months to 14 years at diagnosis; follow up was one to 11 years. Clinical presentations included asymptomatic hypertension (n = 5), severe headache, nose bleed, and chest pain (n = 1), and cardiac failure (n = 1). All had severe hypertension requiring multiple drug treatment. Diminished peripheral pulses were not helpful in the diagnosis, which is made on aortography. Associated clinical findings were Williams' syndrome (n = 3) and appreciable eosinophilia (n = 3). The differential diagnosis includes Takayasu's arteritis, fibromuscular dysplasia, and neurofibromatosis. Blood pressure was adequately controlled by medical treatment in six patients. Surgical angioplasty was performed in two. One patient remained normotensive without drug treatment 21 months after operation; the other died of sepsis and uncontrollable haemorrhage in the postoperative period. Medical treatment is satisfactory in most cases: surgery should be reserved for those in whom blood pressure cannot be controlled without unacceptable side effects of drug treatment. Although rare, the middle aortic syndrome should be considered in the differential diagnosis of hypertension when commoner causes have been excluded. Aortography is necessary for diagnosis.

The management of renal transplant artery stenosis in children by percutaneous transluminal angioplasty.

Between 1967 and 1989 in this unit 262 children (age at transplantation 9 months to 17 years, mean 9.6 years) had 345 renal transplants performed. Transplant artery stenosis (TAS) was found in 30 (8.7%) as demonstrated by arteriography, performed only when there was unexplained deterioration in transplant function, hypertension that was difficult to control, or in the presence of a vascular bruit. All patients with TAS except one had received a cadaveric allograft. From 1980 onward, percutaneous transluminal angioplasty (PTA) has been available for TAS, and this was attempted on 21 occasions in 16 patients. Nine patients demonstrated angiographic improvement following the procedure, and 7 showed immediate clinical improvement. On one occasion angioplasty precipitated graft loss. Five patients underwent planned corrective surgery, 4 after unsuccessful angioplasties. Our experience suggests that PTA should be the first method of intervention for TAS. Moderate success, both in angiographic and clinical terms, can be achieved, negating the need for surgery, while failure of PTA does not preclude surgical attempts at correction.

Effects of oral phosphocysteamine and rectal cysteamine in cystinosis.

Diurnal variation in leucocyte cystine and the effects of equimolar single doses of oral phosphocysteamine and rectal cysteamine were studied in eight patients with cystinosis, aged 1.8-16.5 years. No significant diurnal variation in leucocyte cystine was found. Absorption of cysteamine was reduced after rectal administration compared with the oral dose: mean (SD) peak concentration 17.2 (6.3) mumol/l v 36.4 (5.5) mumol/l at 40 min and mean (SD) area under the curve 22.3 (14.3) v 59.4 (33.1) mumol/h/l. Oral phosphocysteamine significantly reduced the mean (SD) leucocyte cystine from 8.09 (0.47) to 3.26 (1.48) nmol 1/2 cystine/mg protein at three hours. At 12 hours the mean leucocyte cystine was significantly lower than the pretreatment concentration. Rectal cysteamine did not significantly reduce the mean leucocyte cystine concentration. In conclusion, phosphocysteamine suspension may be administered every 12 hours. Rectal cysteamine administration is feasible but higher doses are required before efficacy can be judged.

A practical approach to evaluating urinary tract infection in children.

All children with urinary tract infections should be investigated by either excretory urography or abdominal X-ray, ultrasonography and technetium 99m - dimercaptosuccinic acid scintigraphy. Patients in the following categories should also have micturating (voiding) cystourethrography to diagnose or exclude vesico-ureteral reflux: infants aged less than 1 year, children with recurrent (second or subsequent) infections, children with clinically diagnosed acute pyelonephritis and those with a family history of reflux or chronic pyelonephritis. Cystography can safely be omitted in children over 1 year of age with unscarred kidneys and none of the additional risk factors listed. They should be followed for 1-2 years following the first infection for evidence of recurrence.

Antidiuretic hormone following surgery in children.

We studied 13 children subjected to elective tonsillectomy, 6 of whom (study patients) received supplemental intravenous isotonic saline during and after operation, and 7 of whom (controls) did not. Clinical and biochemical evidence of hypovolaemia was present in the control but not in the study patients. Plasma antidiuretic hormone (ADH) and urine osmolality were higher in controls (p less than 0.005 and p less than 0.05 respectively). Plasma sodium concentration and osmolality were similar in the two groups. We conclude that hypovolaemia is the principal stimulus to ADH release following surgery and that, in addition to replacement of observed losses of blood and other fluids by fluids of appropriate composition, hypovolaemia should be prevented by the administration of maintenance quantities of isotonic fluid, rather than exacerbated by fluid restriction, in patients in whom oral fluid intake is interrupted for more than a brief period. Hypotonic and sodium free fluids should be avoided because of the risk of hyponatraemia.

Recurrence of focal segmental glomerulosclerosis in transplanted kidneys: analysis of incidence and risk factors in 59 allografts.

Fifty-nine allografts were placed in 43 patients with renal failure from focal segmental glomerulosclerosis (FSGS): 27 allografts were put into 16 children aged less than 15 years, and 32 allografts into 27 adolescents and adults. Recurrence of FSGS was noted histologically in 13 allografts, 10 in 8 children and 3 in adults. None of the 9 children and 24 adults who never developed an allograft nephrotic syndrome showed FSGS in their allograft biopsies. The age of onset was a strong risk factor for recurrence: recurrent FSGS developed in 8 of 16 children (50%) but only in 11% of adolescents and adults (3 of 27 patients). Although the time from apparent onset to renal replacement treatment was shorter in those with recurrence than those without in the children, there was no difference in the time spent on dialysis prior to transplantation. Mesangial prominence was observed in the original biopsy in 12 of 13 patients with recurrence, and recurrence rate was similar in living and cadaver donor allografts; class I MHC matching was similar in those with and without recurrence. Three allografts treated with cyclosporin A as well as 9 with azathioprine showed recurrence. Of 9 second or subsequent allografts placed in those with recurrence in the first allograft, only 3 showed further recurrence. In 3 re-grafted after 13, 11 and 5 years, normal function was seen.

Radionuclide cystography in vesicoureteric reflux.

We investigated 47 children in whom vesicoureteric reflux was clinically suspected by both conventional radiological and indirect radionuclide cystography. Comparison of the two methods showed no significant difference in their accuracy in detecting vesicoureteric reflux. The advantages and disadvantages of, and indications for, indirect radionuclide cystography are discussed.

Long term outcome of treatment of end stage renal failure.

The most common causes of end stage renal failure in 46 children (mean age 11 years, range 4-14) treated between January 1972 and June 1977 were: reflux nephropathy (n = 12), cystinosis (n = 7), focal and segmental glomerulosclerosis (n = 6), and Schönlein-Henoch disease (n = 5). The quality of life, degree of renal function, and height attainment of the 31 survivors were assessed in June 1985, when their mean age was 22 years (range 14-27), using hospital records and a questionnaire designed to highlight social and psychological problems. Twenty six patients had a functioning transplanted kidney. Average growth during treatment for all survivors was normal, but most were disappointed with their 'final height'. Though five patients had some form of disabling bone disease, all 31 could walk and 27 could run. Sixteen (67%) were in full or part time employment and nine were living independently. A group of 32 patients with juvenile onset diabetes treated at this hospital for at least five years were also asked to complete the questionnaire and of these, 17 responded. On average, their data could usefully be compared with those of cases of end stage renal failure. More of the diabetics had jobs, but most sexually mature patients with renal disease were concerned about their physical appearance and had not achieved any stable long term sexual relationships. We suggest that a poor body image resulting in low self esteem may be responsible for the deficiency and believe that further study in this group is warranted.

Hyperglycemia with and without glycosuria: effect on inulin and para-amino hippurate clearance.

The response of the clearance of inulin (Cin) and para-amino hippurate (CPAH) to acute hyperglycemia with and without glycosuria was investigated in ten, healthy non-diabetic subjects. Standard methodology (UV/P) was used, with a mean clearance calculated from three, 15-minute urine collection periods. Each subject was studied at three levels of blood glucose (mmol/liter) concentration, mean (SE): Level 1, fasting, 4.5 (0.1); Level 2, hyperglycemia below renal threshold for glucose, 7.2 (0.1); Level 3, hyperglycemia with glycosuria, 12.6 (0.5). There was a significant rise in mean Cin (ml/min/1.73 m2) when changing from Level 1 (112[3]) to Level 2 (121[5]), with no further increase on changing to Level 3 (122[4]). With glycosuria Cin fell in some subjects. Mean CPAH (ml/min/1.73 m2) increased through Level 1 (560[27]) to Level 3 (603[34]), with consequently no change in mean filtration fraction at the three levels of glycemia. Our observations show a rise in glomerular filtration rate with mild hyperglycemia below renal threshold, with no further increase during hyperglycemia sufficient to produce glycosuria.

Hyponatraemia in premature babies and following surgery in older children.

Hyponatraemia implies water retention in excess of sodium with or without increased loss of sodium from the body; extracellular fluid volume may be increased, normal or reduced. It has many causes which are briefly reviewed. Among these is the rare syndrome of inappropriate secretion of antidiuretic hormone (SIADH). It is suggested that SIADH is often diagnosed incorrectly because the raised ADH levels are appropriate for the volume status of the child. Precision in the diagnosis is important because whilst water restriction is necessary for the treatment of SIADH, other measures including the administration of extra fluid are often required if the raised ADH is appropriate. Hyponatraemia in the newborn may be caused by prerenal failure, renal failure or renal sodium wasting which is common in premature infants. Careful control of sodium intake as well as water intake is vital in this age group. Surgery is associated with water retention, but recent studies suggest that ADH levels are raised post-operatively because of volume depletion and that present recommendations for fluid therapy during and following surgery are inadequate. The use of electrolyte-free dextrose solutions should be abandoned and more liberal use of physiological saline or colloid is recommended.

Renal function following surgical correction of vesico-ureteric reflux in childhood.

To assess the effectiveness of the surgical correction of vesico-ureteric reflux, current renal function was determined in 56 children with scarred kidneys who had undergone ureteric reimplantation between 1978 and 1983. The children were aged between 2 and 15 years, had no coexisting urological disease and a glomerular filtration rate (GFR) of less than 90 ml/min/1.73 m2. In the 32 patients who had bilateral reimplantation of ureters draining bilaterally scarred kidneys the improvement in GFR following surgery was highly significant (P less than 0.001), with improvement occurring in 75%. The greatest improvement was in patients where the GFR was less than 50 ml/min/1.73 m2 (29%). Individual kidney GFR was estimated in 42 kidneys and 81% improved after surgery. This improvement was highly significant (P less than 0.001).

Neonatal inferior vena cava and renal venous thrombosis treated by thrombectomy and nephrectomy.

Neonatal inferior vena cava and renal venous thrombosis with obstruction was diagnosed clinically and confirmed by ultrasonography. Successful thrombectomy and nephrectomy were performed at 40 hours of age. Thrombus with obstruction occluding the inferior vena cava favours immediate surgery.

Suppression of secondary hyperparathyroidism in children with chronic renal failure by high dose phosphate binders: calcium carbonate versus aluminium hydroxide.

Secondary hyperparathyroidism was suppressed over a period of one year in 12 children with chronic renal failure by using a regimen of mild dietary phosphate restriction and high dose phosphate binders. The patients were randomised to receive either aluminium hydroxide or calcium carbonate by mouth for six months and then crossed over to the other medication. Vitamin D (dihydrotachysterol) dosage was unchanged. Serum parathyroid hormone concentrations were reduced to within the normal range, urinary cyclic adenosine monophosphate values fell, plasma phosphate concentrations decreased, and the theoretical renal phosphate threshold increased significantly. Transiliac bone biopsy findings improved in four patients with adequate suppression of parathyroid hormone concentrations, deteriorated in two patients who were not compliant, and did not change in five patients in whom initial bone disease was mild. Growth velocity improved significantly. There was no difference in the clinical response, biochemical changes, or incidence of complications during treatment with the two agents. In view of the risk of aluminium toxicity the use of high dose calcium carbonate with dietary phosphate restriction and vitamin D supplementation is recommended in the control of secondary hyperparathyroidism in children with chronic renal failure.

Familial juvenile nephronophthisis, Jeune's syndrome, and associated disorders.

Fourteen patients with familial juvenile nephronophthisis are described, eight of whom displayed one or more additional disorders. One boy with short limbed dwarfism and an abnormal chest was considered to have Jeune's syndrome; review of the published reports supports the view that nephronophthisis is the principal cause of renal failure in this disorder. Another patient with renal failure and retinitis pigmentosa at presentation developed progressive neurological and neuromuscular impairment leading to the discovery of ragged red fibre disease (mitochondrial cytopathy). Cardiomyopathy was present in this and one other patient. Tapeto-retinal degeneration, hepatic fibrosis, cerebellar ataxia, and oculomotor apraxia were among the other disorders encountered. Three patients presented in extremis with acute heart failure and irreversible oligo-anuria and this complication developed in another child who was already known to have nephronophthisis. Awareness of this disease and its associations is important for early diagnosis and appropriate management.

Idiopathic mesangiocapillary glomerulonephritis. Comparison of types I and II in children and adults and long-term prognosis.

Of 104 patients with idiopathic mesangiocapillary glomerulonephritis studied for at least two years, 69 patients had type I disease and 35 had type II. Forty-five patients were children, and 59 were adults. Type II mesangiocapillary glomerulonephritis was more common in children than in adults, but no other clinical feature distinguished the two types at onset. Complement studies revealed that patients with type II had lower serum C3 concentrations and more frequently showed C3-splitting activity (C3 nephritic factor) in the serum. Children had hypertension or a lowered glomerular filtration rate less frequently at onset than did adults, but children had a higher incidence of a hematuric onset; C3 nephritic factor was also more frequent in the children. During a follow-up period of two to 21 years (mean eight years), only seven patients (five with type I and two with type II) showed clinical remission, whereas 38 percent of patients with type I and 49 percent of patients with type II died or required dialysis; a further 23 percent of patients with type I and 16 percent of patients with type II had continuing disease and reduced glomerular filtration rate. Only the presence and persistence of a nephrotic syndrome in type I predicted renal failure. In both types, the presence of sclerosis or crescents in the initial renal biopsy specimen was associated with a poorer prognosis, but no other feature was of major prognostic value.

Effect of indomethacin on clinical progress and renal function in cystinosis.

Three children with nephropathic cystinosis were treated with indomethacin 3 mg/kg a day for periods ranging from 9 to 18 months. The drug produced worthwhile clinical improvement in all, with marked beneficial effects on polyuria, polydipsia, and general wellbeing. Clearance studies performed under conditions of maximal water diuresis showed that proximal tubular sodium reabsorption was increased in all children, with consequent reduction in sodium delivery to the distal nephron leading to reduced free water clearance and distal tubular cation exchange. Plasma sodium and potassium concentrations became normal in all patients, with improvement in phosphate and bicarbonate concentrations in one. Renal function continued to deteriorate, but without obvious acceleration of the process by the drug. We were unable to demonstrate a beneficial effect on growth; nevertheless, indomethacin is a useful adjunct to the symptomatic treatment of children with severe nephropathic cystinosis.

Diagnostic puncture in renal cystic dysplasia (multicystic kidney). Evidence on the aetiology of the cysts.

Five cases of cystic dysplastic (multicystic) kidney occurring in infancy are described, in whom diagnostic puncture was used to confirm the suspected diagnosis. The characteristic finding on contrast injection was that the cystic spaces communicated via tubular structures, presumably nephronic, so ruling out the possibility of hydronephrosis. This finding also supports the view that cysts in multicystic kidney derive from nephrons and are not due to dilated calices. Although urography and ultrasonography both give appearances highly suggestive of multicystic kidney, the appearances on renal puncture are pathognomonic. When such appearances are demonstrated there is no urgent need for operative removal, except when necessitated by the size of the mass.