Claude Prestidge

Liver transplantation for cholestasis associated with cystic fibrosis in the pediatric population.

Abstract: The most common hepatic complications of cystic fibrosis (CF) are steatosis, fibrosis, biliary cirrhosis, atretic gallbladder, cholelithiasis, and sclerosing cholangitis. Cholestatic liver disease is a slow progressive disorder, but will stabilize for many patients. CF patients may suffer from the consequences of their liver disease and without liver transplantation, variceal hemorrhage, malnutrition, or end‐stage liver disease can lead to death. Prospective data were collected and reviewed on 311 liver transplants performed in 283 patients at the Childrens Medical Center of Dallas between October 1984 and November 2000. Ten children received an orthotopic liver transplant (OTLX) for end‐stage liver disease associated with cystic fibrosis. Pulmonary function tests were obtained preoperatively in all cases. There were nine boys and one girl. Six are currently alive, and four are dead. Both patient and graft survival was 5.75 yr. Among those currently alive, mean patient and graft survival is 7.71 yr (range 0.10–12.62 yr). Mean patient and graft survival of those who died was 2.35 yr (range 0.78–5.33 yr). No survivor required re‐transplantation and currently, all have normal serum aminotransferase values. Chronic sinusitis was not a significant pre‐ or post‐transplant morbidity, although systematic radiographic evaluation of the sinuses did not occur. Pulmonary deaths occurred in three patients from pulmonary hemorrhage, pulmonary infection with Aspergillus and Candida glabrata, and acute bronchopneumonia associated with polymicrobial sepsis because of Pseudomonas, Klebsiella, and Candida albicans 1.44, 0.78, and 1.83 yr, respectively, after transplantation. The fourth death was associated with chronic rejection, and occurred 5.33 yr after transplantation. All non‐survivors were below the 5th percentile for height and weight at the time of liver transplantation. Mean age at transplantation was 9.72 yr (range 1.23–19.09, median 9.61). Survivors were transplanted at a younger age than non‐survivors (mean of 9.21 yr vs. 10.66 yr), and had shorter waiting times from diagnosis of end‐stage liver disease to transplantation (6.87 months vs. 13.83 months). Eighty percentage (n = 8) of patients had pretransplant variceal bleeds (83% of survivors, 75% of non‐survivors). While all non‐survivors had a history of meconium ileus and preoperative need of pancreatic enzymes, only 67% of those alive experienced these complications. Preoperative forced vital capacity FVC was 103% for survivors and 95% for non‐survivors. The corresponding numbers for forced expiratory flow (FEF) 25–75 were 74–84% respectively. Preoperative Aspergillus was identified in 30% of patients (n = 3). Two of these patients are alive. Cystic fibrosis constitutes an indication for 3.5% of pediatric liver transplants. Evaluation and transplantation for end‐stage liver disease associated with cystic fibrosis should be undertaken at an early age. Most deaths were associated with pulmonary/septic events, and occurred less than 2 yr after OLTX. Those children who did not survive had poor growth and nutrition, prolonged waiting times prior to transplantation, were transplanted at an older age, and had a higher incidence of pancreatic insufficiency and meconium ileus. The presence of Aspergillus in the sputum does not constitute a contraindication for OLTX.

Active Intestinal Chloride Secretion in Human Carriers of Cystic Fibrosis Mutations: An Evaluation of the Hypothesis That Heterozygotes Have Subnormal Active Intestinal Chloride Secretion

To explain the very high frequency of cystic fibrosis (CF) mutations in most populations of European descent, it has been proposed that CF heterozygotes have a survival advantage when infected with Vibrio cholerae or Escherichia coli, the toxins of which induce diarrhea by stimulation of active intestinal chloride secretion. Two assumptions underlie this hypothesis: (1) chloride conductance by the CF transmembrane conductance regulator (CFTR) is the rate-limiting step for active intestinal chloride secretion at all levels of expression, from approximately zero in patients with CF to normal levels in people who are not carriers of a mutation; and (2) heterozygotes have smaller amounts of functional intestinal CFTR than do people who are not carriers, and heterozygotes therefore secrete less chloride when exposed to secretagogues. The authors used an intestinal perfusion technique to measure in vivo basal and prostaglandin-stimulated jejunal chloride secretion in normal subjects, CF heterozygotes, and patients with CF. Patients with CF had essentially no active chloride secretion in the basal state, and secretion was not stimulated by a prostaglandin analogue. However, CF heterozygotes secreted chloride at the same rate as did people without a CF mutation. If heterozygotes are assumed to have less-than-normal intestinal CFTR function, these results mean that CFTR expression is not rate limiting for active chloride secretion in heterozygotes. The results do not support the theory that the very high frequency of CF mutations is due to a survival advantage that is conferred on heterozygotes who contract diarrheal illnesses mediated by intestinal hypersecretion of chloride.

Pharmacokinetics and pharmacodynamics of linezolid in children with cystic fibrosis

Alternative antimicrobial regimens are needed for treatment of methicillin‐resistant Staphylococcus aureus (MRSA)‐associated pulmonary exacerbations in children with cystic fibrosis (CF). There are no published pharmacokinetic (PK) and pharmacodynamic (PD) data for linezolid in children with CF.

Growth hormone improves bone mineral content in children with cystic fibrosis

AIM Osteoporosis and osteopenia have been reported as common complications of cystic fibrosis (CF); however, little is known about accrual of bone mineral in CF. The goal of our study was to measure bone mineral content (BMC) in non-acutely-ill, but poorly growing children with CF, and to determine the relationship between height, lean body mass and BMC. Our second aim was to evaluate the effect of one year of treatment with human recombinant growth hormone (GH) on total body BMC. METHODS We measured total-body BMC using dual energy X-ray absorptiometry in 32 poorly growing (height < or =10th percentile for age) prepubertal Caucasian children (ages 7 years 6 months-12 years 9 months, 17 M and 15, F) with CF. BMC and lean tissue mass (LTM) were measured at baseline, at 6 months and one year. One half of the children were randomly assigned to receive treatment with GH (GHTX). Results were compared to reference data maintained for healthy children matched for age and ethnicity. Sex steroid and IGF-I levels were also measured. RESULTS Children with CF exhibited lower total body BMC and LTM than age-, ethnicity- and gender-matched controls. This was still apparent when the data were matched for height and bone age. BMC correlated with height, LTM, and IGF-I levels. Although at baseline the groups were similar, the GHTX group demonstrated significantly greater increase in height, weight, LTM and BMC than the NonTX group. These differences remained despite correction for increase in height CONCLUSION Our study is the first to evaluate BMC in children with CF and suggests that poor accumulation of bone mineral is a problem. We have further demonstrated that GH treatment improves accumulation of bone mineral.

A retrospective study of growth hormone use in adolescents with cystic fibrosis.

Objectives Studies of growth hormone (GH) effectiveness in prepubertal children with cystic fibrosis (CF) have been published previously. We present a retrospective study of GH treatment in adolescents with CF.

Comparison of piperacillin vs. ticarcillin plus tobramycin in the treatment of acute pulmonary exacerbations of cystic fibrosis

During a 22-month period 35 children with cystic fibrosis received 52 courses of antibiotic therapy for acute pulmonary exacerbations, including 26 cases of therapy with piperacillin and 26 courses with ticarcillin plus tobramycin. Groups were similar in age (5 vs. 5.4 years), disease severity based on Schwachman scores and presenting symptoms. Pseudomonas aeruginosa was the most common organism isolated in 90% of sputum cultures. Mean minimal inhibitory concentrations for piperacillin, ticarcillin and tobramycin were 8, 64 and 1 microgram/ml, respectively. Piperacillin pharmacokinetic data revealed an average half-life in serum of 36 minutes. Peak serum concentrations averaged 144 micrograms/ml, and after 4 hours serum concentrations continued to exceed the P. aeruginosa 90% minimal inhibitory concentration in 50% of children. The dosage requirement for tobramycin was quite variable, necessitated monitoring of aminoglycoside serum concentrations and in most cases resulted in at least one dosage adjustment. Emergence of resistant bacteria was not seen in 26 courses of piperacillin therapy. Both regimens were effective and well-tolerated. Single agent therapy has the advantage of providing reliable serum concentrations and, in contrast to the standard therapy, does not necessitate monitoring of serum drug concentrations.