Hyperechoic renal medullary pyramids in infants and children

Fifty-five children (34 boys, 21 girls; age range, 1 day to 18 years) with increased echogenicity of the renal medullary pyramids at ultrasound evaluation were identified. The clinical diagnoses associated with hyperechoic medullary pyramids could be separated based on the presence or absence of hypercalciuria. Patients with drug-induced hypercalciuria included 10 infants treated with furosemide, two treated with long-term steroid therapy, and one treated with excessive amounts of vitamin D. Other clinical conditions associated with hypercalciuria included renal tubular acidosis (n = 10), Bartter syndrome (n = 5), hyperparathyroidism (n = 3), Williams syndrome (n = 2) and medullary sponge kidney (n = 2). Ten children with transient renal insufficiency and three with sickle cell disease had normal urine calcium concentration. Isolated disease entities accounted for the remainder of cases. A specific diagnosis can usually be made in a patient with hyperechoic renal medullary pyramids by using a systematic clinical approach that includes evaluation of patient age, serum and urine calcium concentration, and renal function.

Continuous hemodiafiltration in children

Continuous arteriovenous hemofiltration is a form of renal replacement therapy whereby small molecular weight solutes and water are removed from the blood via convection, alleviating fluid overload and, to a degree, azotemia. It has been used in many adults and several children. However, in patients with multisystem organ dysfunction and acute renal failure, continuous arteriovenous hemofiltration alone may not be sufficient for control of azotemia; intermittent hemodialysis or peritoneal dialysis may be undesirable in such unstable patients. Recently, the technique of continuous arteriovenous hemodiafiltration has been used in many severely ill adults. We have used continuous arteriovenous hemodiafiltration in four patients at Children's Hospital Medical Center. Patient 1 suffered perinatal asphyxia and oliguria while on extracorporeal membrane oxygenation. Patients 2 and 4 both had Burkitt lymphoma and tumor lysis syndrome. Patient 3 had septic shock several months after a bone marrow transplant. All had acute renal failure and contraindications to hemodialysis or peritoneal dialysis. A blood pump was used in three of the four patients, while spontaneous arterial flow was adequate in one. Continuous arteriovenous hemodiafiltration was performed for varying lengths of time, from 11 hours to 7 days. No patient had worsening of cardiovascular status or required increased pressor support during continuous arteriovenous hemodiafiltration. The two survivors (patients 2 and 4) eventually recovered normal renal function. Continuous arteriovenous hemodiafiltration is a safe and effective means of renal replacement therapy in the critically ill child. It may be ideal for control of the metabolic and electrolyte abnormalities of the tumor lysis syndrome.

Autoantibody to complement neoantigens in membranoproliferative glomerulonephritis

With the exception of C3 nephritic factor, autoantibody formation has not been commonly associated with membranoproliferative nephritis (MPGN). We measured autoantibodies (nephritic factors) to the C3 convertases C3bBb (NFa) and C3bBbP (NFt), which result in fast and slow C3 activation, respectively, and to a neoantigen on C1q fixed to a solid phase (spC1q) in sera from 29 patients with MPGN type I, 26 with type II, and 28 with type III. Autoantibody formation was common in all MPGN types. An autoantibody to a C3 convertase neoantigen was identified in more than 75% of the hypocomplementemic MPGN sera tested. Anti-C3bBb (NFa) was present in 81% of patients with MPGN type II but was rarely found in either type I or type III. Anti-C3bBbP (NFt) was common in both MPGN I and III. Anti-spC1q was present in 74% of patients with type I and in 38% and 48% of types II and III MPGN, respectively. Patients with MPGN types I, II, and III had one and two serum autoantibodies detected significantly more frequently than did a group of healthy subjects. The presence of any one autoantibody was not specifically associated with the presence of any other autoantibody. The results indicate that multiple autoantibody formation is common in all MPGN types. MPGN II, and possibly MPGN I, tend to form more specific autoantibodies.

Distribution of target-organ abnormalities by race and sex in children with essential hypertension

The prevalence of left ventricular hypertrophy, glomerular hyperfiltration and retinovascular abnormalities was investigated in 43 black and 45 white children with essential hypertension. Whilst 36% of subjects had left ventricular hypertrophy, 49% had glomerular hyperfiltration and 50% had retinal abnormalities, no differences were found between blacks and whites. This pattern differs from that found in adult hypertensives.

A properdin dependent nephritic factor slowly activating C3, C5, and C9 in membranoproliferative glomerulonephritis, types I and III

The IgG fraction of serum from patients with membranoproliferative glomerulonephritis (MPGN) types I and III was found to contain a nephritic factor (NFI/III) which differed from that usually present in MPGN type II and partial lipodystrophy (NFII) in that it converts C5 and C9 as well as C3, is dependent on properdin for its activity, and requires an incubation period of several hours rather than 30 min for its demonstration. C3 conversion occurred in the absence of an intact classical pathway. This nephritic factor was found in patients with reduced serum levels of terminal components and its activity, like that of the nephritic factor in MPGN type II, correlated with the serum C3 level indicating that these nephritic factors play a large role in producing hypocomplementemia. Although potentially nephritogenic because of its ability to activate the terminal pathway, the presence of this nephritic factor did not clearly correlate with clinical course.

Serum terminal complement component levels in hypocomplementemic glomerulonephritides

Measurements of serum C3 through C9 are reported for patients with acute poststreptococcal glomerulonephritis (AGN), membranoproliferative glomerulonephritis type I (MPGN I), MPGN II, and MPGN III. Except in MPGN II, depressed C5 levels correlated with depressed C3 levels. In MPGN II, levels of C5 and of other terminal components were normal. In MPGN III, markedly depressed levels of C7 through C9 correlated strongly with depressed levels of C3 and C5. C6 was less severely depressed. In MPGN I, terminal component levels were less often depressed than in MPGN III and in AGN, depression of terminal components was seen only when levels of C3 and C5 were extremely low. The data indicate that late terminal components are activated in MPGN III to a greater extent than in the other nephritides despite C5 activation approximately equal in extent to that in AGN and MPGN I.

Antibody to a cryptic, solid phase C1Q antigen in membranoproliferative nephritis

IgG containing material detected in membranoproliferative nephritis (MPGN) serum with a solid phase (sp) Clq ELISA has been presumed to be immune complexes. However, in serum from 13 MPGN patients containing large amounts of spClq-binding material, sucrose density ultracentrifugation and sieve chromatography showed spClq-binding protein to sediment at 7S or cofractionate with IgG. One serum (stored for 12 years) contained, in addition, spClq-binding material sedimenting at more than 19S. Isolated MPGN IgG was shown to bind to spClq. SpClq-binding material could be totally removed from MPGN serum by absorption with BSA-anti-BSA immune precipitates, and by acid elution of the precipitates IgG binding to spClq could be recovered. F(ab')2, isolated from pepsin digested MPGN IgG, continued to bind spClq. Binding of MPGN IgG or F(ab')2 to spClq was not inhibited by 2 M NaCl. Incubation of MPGN serum with 125I Clq followed by sucrose density ultracentrifugation resulted in a peak of radioactivity at 11S, the sedimentation rate of Clq, giving evidence that material binding fluid phase Clq is not present. SpClq-binding IgG was detected in 54% of 68 MPGN patients. These results indicate that the 7S spClq-binding IgG represents antibody to a cryptic antigen revealed only when Clq fixes to a solid surface.

Effect of calcitonin replacement therapy in idiopathic juvenile osteoporosis

An 8-year-old boy with idiopathic juvenile osteoporosis and multiple fractures had three abnormalities of bone mineral metabolism: calcitonin deficiency, elevated serum calcitriol concentrations, and hypercalciuria. Calcitonin deficiency was documented by two attempts to stimulate calcitonin secretion with intravenous calcium and pentagastrin. Treatment for 11 months with daily subcutaneous injections of human calcitonin and oral administration of calcitriol failed to reduce the excessive bone resorption observed on bone biopsy, and the fracture rate did not decrease. Treatment was discontinued for two months, then resumed with calcitonin injections and oral calcium supplementation. The fracture rate decreased but bone biopsy continued to show excessive resorption. Therapy was discontinued. After the onset of puberty, endogenous calcitonin was detectable. Exogenous calcitonin therapy may have failed to control bone resorption for several reasons: insufficient dose, reduction of bone receptors from long-term calcitonin exposure, secondary hyperparathyroidism, or lack of association between calcitonin deficiency and the bone disease.

Differences between membranoproliferative glomerulonephritis types I and III in clinical presentation, glomerular morphology, and complement perturbation

Data for 26 patients with membranoproliferative glomerulonephritis, type I (MPGN I) and 22 with membranoproliferative glomerulonephritis, type III (MPGN III), as distinguished by glomerular ultrastructure, were analyzed to determine differences in presentation, complement perturbation, and glomerular morphology by light microscopy. MPGN III was detected with greater frequency by the chance discovery of hematuria and proteinuria in the otherwise healthy individual (MPGN III, 63%; MPGN I, 30%; P = .01) and never, in the absence of renal failure, presented with systemic symptoms such as ease of fatigue, weight loss, and pallor, as may patients with MPGN I. The more frequent detection of MPGN III by chance is evidence that its onset is insidious and that for long periods it produces no symptoms or signs. Glomerular proliferation is also less than in MPGN I. Further, in MPGN III, the complement perturbation and glomerular immunofluorescence give no evidence of classical pathway activation, for which there is abundant evidence in MPGN I. Even with severe hypocomplementemia in MPGN III, C3 nephritic factor, another cause of hypocomplementemia, is rarely detectable and then in very low concentration. The cause of the complement perturbation in MPGN III has so far escaped identification. Although these observations give evidence that MPGN III is distinct from MPGN I, there is compelling evidence from other studies that a predisposition to both types is inherited and that similar genetic factors are operative in the two types. Because their genetic basis appears to be the same, it must be concluded that despite their differences, types I and III are variants of the same disease.

Minoxidil for control of acute blood pressure elevation in chronically hypertensive children

Twenty-three episodes of acute elevation of BP related to renal disease in 13 chronically hypertensive children 2 to 18 years of age were treated with a single oral dose of minoxidil. All except one patient were receiving a diuretic and all but one a beta-blocking agent at the time of minoxidil treatment. The goal of lowering BP to or below the 95th percentile for age within four hours of minoxidil administration was achieved in 14 of 23 treatment episodes. The goal was achieved in nine of 11 (82%) when the dose of minoxidil was greater than or equal to 0.2 mg/kg and in five of 12 (42%) when the dose was less than 0.2 mg/kg (P less than .05). In patients treated with greater than or equal to 0.2 mg/kg of minoxidil, mean systolic and diastolic BP decreased significantly from pretreatment values within one hour. In patients receiving less than 0.2 mg/kg, mean systolic BP was never significantly reduced and mean diastolic BP did not change significantly for two hours. Adverse effects were minimal. The results indicate that minoxidil in a dose of 0.2 mg/kg in combination with a diuretic and beta-blocking agent will lower BP to safe levels in most patients with severe hypertension related to renal disease within four hours with minimal side effects.

Effect of the nephrotic syndrome on the concentration of serum complement components

The concentration of 12 component and four control proteins of the complement system was measured in serum from 43 children with a nephrotic syndrome, which subsequently proved to be steroid-responsive, and from 13 children with focal glomerulosclerosis (FGS) and was compared with values from 197 normal subjects. Of classical pathway complement components, 40% of patients had low C1q levels and 20%, low C2 levels. Mean serum levels of C1s, C4, C1INH, and C4bp were elevated. Of alternative pathway components, factors B and I were low in one third, while levels of C3 and H were commonly elevated. Of the terminal components, only C8 and C9 were low. In five patients with FGS with hypoalbuminemia without edema, all component levels were normal. With the exception of C1q, C1s, and C8, high molecular weight (mol wt) components were in high concentration and low mol wt components in low concentration. The three exceptions may be explained by the subunit structure of C1 and C8. From a practical standpoint, the study indicates that edematous patients with a nephrotic syndrome may have low serum levels of C1q and C2, simulating classical pathway complement activation such as commonly occurs in glomerulonephritis. However, low levels of C4, and possibly C1s, can be used as indicators of classical pathway activation since their levels are not reduced by a nephrotic syndrome.

Improved growth of three uremic children by nocturnal nasogastric feedings

Three children with high-output renal insufficiency (estimated creatinine clearance, 20 to 25 mL/min/1.73 sq m) and linear and ponderal growth retardation were administered nocturnal nasogastric (NG) feedings at home by trained parents. The NG feedings were initiated at 50 kcal/kg/night and increased as needed to establish and maintain weight gain. Nocturnal feedings were continued for 13.5, 16, and 11 months, respectively. Improved caloric intake reestablished the velocity of weight gain from less than 5% to greater than 95% in each patient. Linear growth velocity improved from less than 5% in two patients and 40% in one patient to greater than 95% in two patients and 80% in the third patient. No change was observed in serum creatinine, electrolyte, calcium, or phosphorus levels. The serum urea nitrogen level remained below 100 mg/dl. Ensuring adequate caloric intake by nocturnal NG feedings, in addition to standard therapy, improved both ponderal and linear growth velocity.

Atypical hypocomplementemic vasculitis syndrome in a child

We report a patient who developed recurrent urticaria and angioedema at age 2 years, severe hypocomplementemic glomerulonephritis at 11 years, and end-stage renal disease at 14 years. His disease resembled the hypocomplementemic vasculitis syndrome but was atypical in its early age of presentation, severe hypocomplementemia, and progression to end-stage renal disease. Serum C1q levels were extremely low, and C4, C2, C3, and C5 levels were significantly reduced. Serum C1 inhibitor (C1INH) levels were slightly low, presumably from consumption. Circulating C1INH-C1r-C1s complexes were evidenced by reduced ratios of functional to antigenic C1INH and antigenic C1r to C1s. Family members had normal functional and antigenic levels of all complement components studied. The patient's serum, erythrocytes, platelets, and mononuclear cells did not activate complement when mixed with normal target serum. Absence of a circulating complement activator and the low serum C3 and C5 levels suggested the presence of a solid-phase complement activator, possibly related to renal or systemic vascular endothelium. As in patients with homozygous deficiencies of classical pathway components, a severe, prolonged, acquired C1q deficiency may have predisposed this patient to the development of glomerulonephritis.

Reduction of phagocyte adherence by nephritic sera: relation to complement activation

Phagocytes isolated from either normal donors or from patients with poststreptococcal (P-SGN), lupus erythematosus (SLE-GN), or membranoproliferative (MPGN) glomerulonephritis showed normal adherence to glass (PAg) after incubation in normal human serum (NHS), but was reduced after incubation in patient serum. Low PAg was the consequence of incubation of normal phagocytes with the earliest available sera from all 22 P-SGN patients, 28 of 37 SLE-GN patients, 19 of 25 patients with MPGN type I, all 10 with types II and III, and all 5 with nephritis associated with chronic bacteremia. Low C3 and decreased PAg were related by regression analysis in sera from patients with P-SGN (P less than 0.001), SLE-GN (P less than 0.005), and MPGN (P less than 0.001) type I. In patients with P-SGN and one patient with nephritis associated with chronic bacteremia, complement levels and PAg returned to normal in parallel with clinical improvement. In vitro, PAg was reduced by NHS treated with either zymosan or bovine serum albumin (BSA)-anti-BSA complexes but neither BSA-anti-BSA complexes or zymosan, previously incubated in NHS, reduced PAg. PAg was normal in serum deficient in C4 or C5 unless treated with zymosan.

Type III membranoproliferative glomerulonephritis: long-term clinical and morphologic evaluation

Seventeen patients with Type III membranoproliferative glomerulonephritis (MPGN) have been followed for more than two years; 16 were treated with alternate day prednisone. Clinical deterioration correlated with nephrotic syndrome (NS) at diagnosis: 3 of 7 patients with NS at diagnosis developed end-stage disease. Serial biopsies in the others showed progressive disease in one, improvement in one and no change in two. Of 10 patients without NS at diagnosis, 6 have improved clinically, 2 are unchanged and 2 are worse. In serial biopsies, 6 showed improved morphology and 4 were unchanged. The results indicate that Type III MPGN will stabilize or improve in most treated patients. The absence of ultrastructural transition of a Type III glomerular lesion to another type and the presence of distinctive immunofluorescent findings and complement abnormalities confirm that Type III is a unique form of MPGN.

Membranoproliferative glomerulonephritis and alpha 1-antitrypsin deficiency in children

Two white girls had reduced serum concentration of alpha 1-antitrypsin (alpha-AT), phenotype ZZ, and liver disease. Hepatocytes exhibited the microscopic criteria of alpha-AT deficiency. Hypocomplementemia, elevated circulating immune complexes (patient 1), clinical signs of renal disease, and the histologic findings of membranoproliferative glomerulonephritis (MPGN) type I developed. Immunoglobulin A (but not alpha-AT) was demonstrable immunologically as a component of glomerular deposits in patient 1. Among 53 patients with MPGN but without clinical signs of liver disease, none had Pi type Z. Among 23 patients with phenotype ZZ but without clinical signs of kidney disease, six had abnormal complement protein levels, but the pattern did not resemble that of idiopathic MPGN type I. These results are consistent with the conclusion that MPGN in the two patients reported here is a consequence of their chronic liver disease and is not directly related to the presence of the allelic alpha-AT variant PiZ.

Nonabsorptive hydrocephalus associated with nephropathic cystinosis

A child with nephropathic cystinosis developed seizures and coma. CT showed prominent sulci and slight ventricular enlargement. Nuclear cisternogram was normal. Despite successful renal transplantation and treatment of hypothyroidism, neurologic recovery was poor. CT and nuclear cisternogram 5 months later showed moderate panventricular and subarachnoid space enlargement and abnormal ventricular isotope retention. Ventriculoperitoneal shunt placement was followed by improved intellectual function, resolution of pyramidal tract signs, and control of seizures. Anisotropic crystals consistent with cystine were demonstrated in biopsy samples of arachnoid and cerebral cortex. Nonabsorptive hydrocephalus may have resulted from deposition of cystine in the meninges.

Membranoproliferative glomerulonephritis characterized by focal, segmental proliferative lesions

Of 61 children with membranoproliferative glomerulonephritis (MPGN), 6 (10%) were distinguished by segmental lesions in up to 1/3 of glomeruli. Light microscopy showed mild to moderate generalized mesangial proliferation in addition to segmental membranoproliferative lesions. Mesangial fluorescence with antiserum to C3 was present in all glomeruli while focal lesions were characterized by segmental granular fluorescence with antiserum to IgG. Segmental lesions, identified by electron microscopy in four biopsies, were produced by prominent mesangial proliferation. Subendothelial deposits were present in two. Contiguous subendothelial and subepithelial deposits were present in one, and in a fourth, capillary wall deposits could not be found although mesangial deposits were present. Circulating immune complexes were present in 2 of the 4 hypocomplementemic patients and 1 normocomplementemic patient. Clinically, all patients presented with hematuria (gross in 3) and five had proteinuria. Only one had hypoalbuminemia. All patients have improved (5 treated with alternate day prednisone) as judged by the return of complement levels to normal and by improvement in urinalysis and in glomerular morphology on subsequent biopsy. The results give evidence that focal, segmental MPGN is an early manifestation of Type 1 or, uncommonly, Type III MPGN and that the patients have an excellent prognosis.

Hypocomplementemia in Reye syndrome: relationship to disease stage, circulating immune complexes, and C3b amplification loop protein synthesis

Measurement of C1q, C2, C4, C5, C6, factor B, properdin, beta1H, and C3bINA were made in acute sera from 31 patients with Reye syndrome. Abnormalities were found in 18 patients. The magnitude of the complement component depression correlated with disease severity. Sera from patients with stage IV illness had significantly lower complement levels than did sera from patients with state I (P less than 0.001), II (P less than 0.05), and III (P less than 0.05) disease. Circulating immune complex measurements were performed on all 31 acute sera and were present in six (19%). However, from the results of the present study, it would appear that in the majority of the patients circulating immune complexes are not the cause of the lowered levels of, at least, C3 and factor B. Rather, these low levels could be explained as secondary to reductions in the levels of the C3b amplification loop control proteins beta1H and C3bINA.

Experience with a low volume ultrafiltration cell in small children*

A low volume (16 ml) ultrafiltration cell was used ten times in two small, fluid overloaded children to remove plasma water. The device was simple to use and, at slow blood flow rates (25-50 ml/minutes) and low transmembrane pressures (10-30 mm Hg), provided controlled removal of excess fluid. Although no major complications were encountered, hypothermia and hypotension (at ultrafiltrate flux rates exceeding 0.5 ml/kg/minute) were observed. The ultrafiltrate solute concentration was similar to plasma and no significant shifts in serum electrolytes were induced. The ultrafiltrate protein concentration of 64 to 2,760 mg/dl was much higher than previously reported.