Stephen P. Dunn

Urinary Tract Infections in Children with Posterior Urethral Valves After Kidney Transplantation

The records of 14 boys with posterior urethral valves who had renal failure and subsequently underwent renal transplantation were reviewed to determine the postoperative incidence of urinary tract infection relative to that of 29 male transplant children without valves, who served as controls. There were no significant differences between the posterior urethral valve patients and controls with regard to age, donor source, immunosuppression, followup after transplantation or mean calculated creatinine clearance. Vesicoureteral reflux was found in 1 child with posterior urethral valves and 3 of the children in the control group (p not significant). A total of 15 urinary tract infections occurred in 5 children (36%) with posterior urethral valves, for a rate of 1 per 30 patient-months of followup, and 6 urinary tract infections occurred in 2 controls (7%), for a rate of 1 per 216 patient-months of followup (p < 0.05). However, only 1 of 26 controls (4%) without vesicoureteral reflux had urinary tract infection, for a rate 1 per 1,144 patient-months (p < 0.01). Conversely, the rate of urinary tract infections in controls with vesicoureteral reflux was similar to that of children with posterior urethral valves. Of the 5 children with posterior urethral valves 4 had the initial urinary tract infection within 2 months of transplantation and 10 of 15 episodes occurred within the first 4 months. Antimicrobial prophylaxis did not appear to decrease the rate of infection in children with posterior urethral valves. A history of posterior urethral valves increases the frequency of urinary tract infection after renal transplantation but the usefulness of antimicrobial prophylaxis and the relationship to long-term graft function remain to be determined. Urinary tract infection rarely develops in other transplanted boys without vesicoureteral reflux.

Isolated liver transplantation for liver failure in patients with short bowel syndrome

The ultimate prognosis for patients with short bowel syndrome (SBS) has become progressively more favorable over the past decade. Advances in long-term total parenteral nutrition (TPN) have allowed this group of patients to meet nutritional needs while the process of intestinal adaptation occurs. Unfortunately, a subgroup of patients with SBS have hepatic failure (HF), most often secondary to TPN-induced cholestasis. Combined small bowel and liver transplantation (LT) offers a sound anatomic solution for cases of HF with SGS, but it remains experimental at this time. We propose that an isolated LT is a viable alternative mode of therapy for the patient with HF and SBS. The following characteristics were reviewed for five patients with SBS and HF who underwent LT: age at transplantation, weight, liver function, survival, intestinal length, volume of feeding before surgery, and current feeding tolerance and liver function. Four boys and one girl, aged 5.5 to 15 months (average, 11.9), had LT. The total bilirubin level at the time of transplantation was 14.4 to 37 mg/dL (average, 24.7). The patients weighed between 3.8 and 12 kg (average, 8.0), and feeding tolerance ranged from no enteric to complete enteric feeding (average, < 33% of calories by enteric feeding). Bowel loss was attributed to necrotizing enterocolitis in two cases, volvulus in two, and birth hypoxia in one. Bowel length ranged from 60 to 120 cm (average, 88.6). Four children (80%) survived LT, and the average follow-up period was 9.3 months. Three (75%) are home; one is on combined hyperalimentation and enteral feeding, and two are on full enteric feeding. One remains in a chronic care facility, on combined enteral and intravenous feeding. The average daily enteral feeding now comprises more than 70% of caloric requirements. The total bilirubin level is .6 to .8 mg/dL (average, .71). Isolated LT for HF in the patient with SBS effectively restores liver function, allowing time for further intestinal adaptation.

Is age less than 1 year a high-risk category for orthotopic liver transplantation?

The aim of this study was to determine if age less than 1 year is a high risk group for orthotopic liver transplantation (OLT). Retrospective analysis was done of patients with liver failure who received OLT. Comparison was made between patients aged < 1 year and > 1 year with regard to survival, allograft survival, hepatic artery thrombosis, and medical status at OLT. Between January 1, 1987 and September 30, 1991, 46 children received OLT. Fifteen (35%) were < 1 year (average age, 7.93 months). Survival in children < 1 year was 80% and children > 1 year was 91%. Allograft survival in children < 1 year was 57% (21 allografts required for 12 survivors) and 78% in children > 1 year (37 allografts required for 29 survivors). Retransplantation was required in 5 of 15 children < 1 year (33%) and in 5 of 29 children (17%) > 1 year. Medical status in children < 1 year was similar to medical status in children > 1 year at the time of transplant. Children with chronic stable liver disease represented 60% of children < 1 year and 60.1% of children > 1 year. Children requiring hospitalization represented 26% of children < 1 year and 29% of children > 1 year. Children in intensive care represented 13% of children < 1 year and 11% of children > 1 year. Survival for all status groups was similar. Hepatic artery thrombosis occurred in one child < 1 year and in 2 children > 1 year. No statistical difference (chi 2 analysis) was found by age between the categories evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrointestinal perforation after pediatric orthotopic liver transplantation.

PURPOSE The aim of this review was to determine the incidence of gastrointestinal perforation after pediatric liver transplantation and to identify risk factors and clinical indicators that may lead to an earlier diagnosis. METHODS A retrospective chart review of all children who presented with gastrointestinal perforation after liver transplantation at our institution between January 1, 1987 and August 1, 1996 was performed. RESULTS One hundred fifty-seven orthotopic liver transplants were performed in 128 children. Fifty-eight reexplorations, excluding those for retransplantation, were performed in 38 children. Ten perforations occurred in six children (incidence, 6.4%). Two children required multiple reexplorations because of several episodes of perforation. The sites of perforation were duodenum (n=1), jejunum (n=8), and ileum (n=1). A single-layer closure was used to repair five perforations, two-layer closures in four, and resection with primary anastomosis in another. The type of repair did not affect the occurrence of subsequent perforations. All the children were less than 18 months old. Four children had undergone prior laparotomy. All children had choledochoenteric anastomoses, but only one had a perforation associated with it. One child sustained bowel injury during the dissection for the liver transplant, but none of the perforations occurred at this site. Bowel function had returned before perforation in five children. Five children were receiving systemic antibiotics at the time of their perforation, and none had been dosed with pulse steroids for rejection. All of the children had significant changes in their temperature. Acute leukopenia developed in one child. A leukocytosis developed in the rest of the children. Abdominal radiographs demonstrated pneumoperitoneum in only one child. All children had positive culture findings from their abdominal drains. Cytomegalovirus developed in one child. Although the diagnosis of gastrointestinal perforation after pediatric liver transplant remains difficult, positive drain culture findings and significant alterations in temperature and leukocyte counts suggest its presence. Pneumoperitoneum is rarely present. CONCLUSION A high index of suspicion and timely laparotomy, especially in children less than 2 years of age, may be the only way to rapidly diagnose and treat this potentially devastating complication of liver transplant.

Pharmacokinetics of cyclosporine after renal transplant in children.

The pharmacokinetics of cyclosporine and the relationship between blood levels and average drug concentration were prospectively evaluated in 18 children 1 month after renal transplantation. All children had normal renal function and no hepatic or gastrointestinal dysfunction. Cyclosporine was administered after an overnight fast, and serial blood samples were drawn over a 24‐hour period. Analysis of cyclosporine levels was performed by means of monoclonal radio immunoassay on whole blood. Children were divided into three age groups for comparison: 2–5 years, 5–10 years, and >10 years. There were no differences between age groups in serum protein, serum lipids, or hemoglobin levels, or in the pharmacokinetic parameters of cyclosporine except as follows: significant differences were noted in cyclosporine dose based on body weight, apparent steady‐state volume of distribution, and apparent blood clearance, with the youngest children (2–5) requiring higher doses, a relative greater distribution, and exhibiting more rapid drug clearance than those > 10 years of age. In addition, we observed diurnal variation in trough levels, with morning levels (0 hr) significantly higher than those obtained in the evening (12 hours after administration of cyclosporine). Trough levels demonstrated a fair correlation with area under the concentration‐time curve (AUC) and average concentration (Cav), but an abbreviated kinetic profile using cyclosporine levels 1 and 3.5 hours after administration accurately predicted AUC.

Effects of Carbamazepine on Cyclosporine Metabolism in Pediatric Renal Transplant Recipients

This study documents a pharmacokinetic interaction between carbamazepine and cyclosporine (CsA) in pediatric renal transplant recipients. Noncompartmental steady‐state CsA pharmacokinetics were determined in three pediatric renal transplant recipients who were receiving both CsA and carbamazepine as long‐term therapy (carbamazepine group) and in three matched renal transplant subjects who were not receiving carbamazepine (control group). Even though the mean daily dosage of CsA was consistently higher in the carbamazepine group than in the control group (16.2 mg/kg/24 hrs vs 10.8 mg/kg/24 hrs, respectively), the predose trough CsA blood concentrations were significantly lower in the carbamazepine group (57 ng/ml vs 162 ng/ml, respectively; p=0.0023). Mean average steady‐state blood concentrations of CsA (Cav) per mg of CsA administered were less than 50% in the carbamazepine group compared with the control group. This reflects either an induction of CsA hepatic metabolism or a reduced systemic bioavailability (possible induction of pre‐hepatic metabolism) by concurrent use of carbamazepine.

Treatment of steroid-resistant post-transplant nephrotic syndrome with cyclophosphamide in a child with congenital nephrotic syndrome

A child with congenital nephrotic syndrome underwent renal transplantation, was treated for acute rejection, and then developed nephrotic syndrome and renal failure. He was felt to have minimal change disease on allograft biopsy, but failed to respond to therapy with corticosteroids. Cyclophosphamide was substituted for cyclosporine and rapidly induced a complete remission of his nephrotic syndrome. We feel that this case not only represents an important example of a useful therapeutic approach to the child with congenital nephrotic syndrome who develops nephrotic syndrome post transplantation, and also raises questions concerning the pathogenesis of congenital nephrotic syndrome.

Growth after conversion to alternate-day corticosteroids in children with renal transplants: a single-center study.

During the 1980s all children with growth potential and stable/adequate renal function at 6–9 months after kidney transplantation underwent conversion to alternate-day corticosteroids in an attempt to maximize growth. Conversion was attempted in 79 of 160 children who received allografts during this decade and was considered successful if they remained on alternate-day prednisone for more than 1 year, with a calculated creatinine clearance of at least 75% of the pre-conversion baseline value. Conversion succeeded in 55 children but failed in 24. Growth was markedly improved among those successfully converted when compared with the failure group, as measured by standard deviation score for growth velocity based on chronological age (+0.94±1.58 vs. −0.86±1.53,P<0.001) and bone age (+0.49±0.61 vs. −1.24±1.47,P<0.001). The improved growth among the successfully converted patients is believed to have been related to the combined effects of lower corticosteroid dose (0.36±0.16 vs. 0.48±0.21 mg/kg per day,P<0.02) and better renal function (calculated creatinine clearance 87±32 vs. 47±21 ml/min per 1.73 m2,P<0.001) at 1 year post conversion. Two factors appeared to improve the likelihood of successful conversion: the use of cyclosporine and receiving a live-related rather than cadaver transplant. Cyclosporine was associated with improvement in the overall rate for successful conversion in all recipients, from 59% to 83% (P<0.05). Recipients of allografts from live-related donors underwent successful conversion in 90% of cases compared with 58% receiving cadaver allografts (P<0.05). Successful conversion to alternate-day corticosteroid therapy is of significant benefit for linear growth, but may be associated with a risk of rejection and loss of renal function. The risk is small in live-related recipients and has been made safer for cadaver recipients with the introduction of cyclosporine.

Peritoneal dialysis catheter infections in children after renal transplantation: choosing the time of removal

As a foreign body, the peritoneal dialysis (PD) catheter represents a potential source of infection, particularly for immunosuppressed renal transplant patients. A retrospective study was therefore undertaken to compare the risks and benefits of our policy of removing PD catheters at 3 months following renal transplant, which was established to allow for early re-initiation of dialysis. Between 1984 and 1990, 43 renal transplants were performed in 35 children who had been receiving maintenance PD. During the 1st month post transplantation, the PD catheter was used in 25 patients (58%) because of acute rejection or primary allograft non-function. Thirty-one patients were eventually discharged with functioning allografts and a PD catheter in place. Of them, 43% developed a catheter-related infection within the next 2 months, a period during which PD was not performed. Potential contributing factors included a history of catheter-related infection prior to transplantation, use of high-dose methylprednisolone to treat acute rejection, and the type of maintenance immunosuppression prescribed; conversely, the use of prophylactic antibiotics appeared to decrease this risk. This study established the potential need for the catheter during the first few weeks, but because of the infection risk of 43% by 3 months post transplantation, our protocol was revised to include catheter removal at the time of hospital discharge. From 1990 until the end of 1992, an additional 19 PD recipients underwent transplantation. In this group, catheters were used during the 1st month in 6 children (32%). Fifteen patients were discharged with a functioning allograft and only 1 patient returned to PD at 12 months post transplant. It is concluded that PD catheters represent an additional source of infection following transplantation and should be removed at the time of hospital discharge, after which the likelihood of use is low.

Value of plasmapheresis in hepatic encephalopathy

Plasmapheresis is used for treating the complications of liver failure. We performed plasmapheresis on 6 children with hepatic encephalopathy resulting from acute hepatic failure and prospectively assessed its effects on neurologic and electrophysiologic (electroencephalography and evoked potentials) function. Clinical improvement was observed in 3 of 6 patients; changes in the serum ammonia value or the results of initial electrophysiologic tests did not predict the patient response. Two patients underwent transplantation after neurologic improvement was produced by plasmapheresis; however, despite plasmapheresis, 4 patients progressed to brain death. Our data demonstrate that plasmapheresis may transiently improve the encephalopathy of acute hepatic failure but is not curative alone. Therefore, plasmapheresis may be a useful adjunct in the treatment of liver failure, potentially improving the pretransplantation status of the patient.