How do paediatricians communicate with children and parents?

AIM: The outpatient clinic visit is the major focus of the hospital medical process for most paediatricians, children and parents. The importance of children as active participants in this interaction has been recognized. Our study aims are to describe and assess the components of doctor-parent-child communication in the outpatient setting. METHODS: Fifty-one medical paediatric clinic consultations were recorded on audio cassette, and communication was analysed according to quantitative methods. Questionnaires assessed parents' and children's perceptions. RESULTS: Doctors contributed most to the conversation (61%), children only 4%. Behaviour: Doctors' communication was 84% instrumental (e.g. asking questions, giving information or instructions), 13% affective behaviour (expressing concerns and worries) and 3% social (small talk). Parents' communication included giving information (83%), seeking information (13%) and social (4%). The child asked less information (3%) and had more social conversation (19%). CONTROL: Doctors dominated in turn taking (52%). Children took 9% of all turns. Perception: There was no correlation between parents' and children's perception and the informative or affective behaviour of the doctor. CONCLUSION: Communication is mainly instrumental. Doctors tend to direct the interview. Children's contribution is small. The participation of children needs to be encouraged as part of a patient-centred approach.

Protein substitutes for PKU: what's new?

Protein substitutes are an essential component in the management of phenylketonuria. A series of studies at Birmingham Children's Hospital have investigated their optimal dosage, timing and practical administration as well as the efficacy and tolerance of novel protein substitutes. The key findings are as follows. (1). Lower dosages of protein substitute (1.2 g/kg per day of protein equivalent) adversely affect blood phenylalanine control in children aged 1-10 years. (2). There is wide variability in 24 h blood phenylalanine concentrations. (3). Adjusting protein substitute timing during daytime does not reduce blood phenylalanine variability. (4). Repeated 4 h administration of protein substitute throughout 24 h markedly reduces phenylalanine variability and leads to lower phenylalanine concentrations. (5). The new, concentrated, low-volume protein substitutes and amino acid tablet preparations are efficacious and well tolerated by patients. (6). Administration of protein substitute as a gel or paste has reduced difficulties with administration of protein substitute in children. These findings are important in rationalizing treatment strategies, improving patient compliance and overall in improving blood phenylalanine control.

Administration of protein substitute and quality of control in phenylketonuria: a randomized study.

Uneven administration of an L-amino acid protein substitute is an important contributing factor in variability in plasma phenylalanine concentrations over the 24-hour period in patients with phenylketonuria under treatment. The aim of this study was to determine whether manipulating the timing of protein substitution would reduce variability in plasma phenylalanine over 24 h. Sixteen children (aged 1-11 years) with well-controlled phenylketonuria were entered into a randomized crossover study in which four protocols of the same daily dose of protein substitute administration were compared. In protocol A, three equal, divided doses were given with meals over 10 h; in protocol B, three equal doses over 14 h; in protocol C, four equal doses over 14 h; and in protocol D, six equal doses over 24 h (3 subjects only). Four-hourly skin puncture blood specimens were collected for 48 h in each study protocol. In protocols A, B and C, but not in protocol D, there was wide variability in 24 h plasma phenylalanine. The median daily differences (micromol/L) between highest and lowest phenylalanine concentrations were: for protocol A, 140; for protocol B, 100; for protocol C, 120; and for protocol D, 40. In protocol D, 97% of all phenylalanine concentrations were below 120 micromol/L and no concentration fell below 40 micromol/L. Administration of protein substitute overnight as well as during daytime produces stable and lower plasma phenylalanine concentrations and may lead to improved dietary phenylalanine tolerance.

Free use of fruits and vegetables in phenylketonuria.

This study aimed to evaluate systematically the effect of the free use of fruits and vegetables containing an intermediate amount of phenylalanine (51-100 mg/100 g) on the biochemical control in children with phenylketonuria (PKU). Fifteen subjects with PKU, with a median age of 6 years (range 1-24 years) were studied. In a three-part prospective 15-week study, subjects sequentially ate fruits and vegetables containing phenylalanine 0-50 mg/100 g for weeks 1 to 3; 51-75 mg/100 g for weeks 4 to 8; and 76-100 mg/100 g for weeks 9 to 15. Plasma phenylalanine concentrations were measured twice daily for three consecutive days in weeks 1, 3, 6, 8, 11, 13 and 15. A standard menu was followed on the blood sampling days. Daily dietary records of fruits and vegetables under study were kept throughout the trial. Control of phenylalanine concentrations was not adversely affected by the free use of fruits and vegetables containing 51-100 mg/100 g. Pre-breakfast median plasma concentrations were: weeks 1 to 3, 260 micromol/L (range 90-890); weeks 4 to 8, 255 micromol/L (range 130-920); and weeks 9 to 15, 278 micromol/L (range 30-880). Pre-evening meal median plasma phenylalanine concentrations were: weeks 1 to 3, 240 micromol/L (range 30-820); weeks 4 to 8, 210 micromol/L (40-880); and weeks 9 to 15, 238 micromol/L (range 20-880). These data suggest that free use of fruits and vegetables containing 51-75 mg/100 g poses no problem for children with PKU.

Are tablets a practical source of protein substitute in phenylketonuria?

BACKGROUND: A phenylalanine-free amino acid based protein substitute is necessary to provide the major source of protein in phenylketonuria (PKU). Protein substitutes in PKU are usually given as drinks. These are unpalatable and compliance is often poor. Tablets containing a suitable mixture of phenylalanine-free amino acids (Aminogran Food Supplement, UCB) are now available. AIMS: To compare the effectiveness and acceptability of these tablets with conventional protein substitute drinks. METHODS: Twenty one subjects with PKU, aged 8-25 years, participated in a randomised crossover study. During one phase, subjects received at least 40% of their protein substitute requirements from the amino acid tablets and the rest from their usual protein substitute tablets. During the other phase, they received their usual protein substitute. Each period lasted 12 weeks. Blood phenylalanine concentrations were measured at least once every two weeks and other plasma amino acids were measured at the beginning, at crossover, and at the end of the study. The subjects kept a diary of all protein substitute taken. RESULTS: Compliance appeared to be better with the new tablets than with patients' usual protein substitutes. Ninety per cent (18/20) recorded that they took the tablets as prescribed, compared with 65% (13/20) fully compliant with their usual protein substitute. Moreover, plasma phenyalanine was lower on the amino acid tablets, and the median difference in blood concentrations between the two groups was 46 micro mol/l (95% CI 14.8 to 89.0, p = 0.02). Tyrosine increased by a median of 16 micro mol/l daily on the amino acid tablets (95% CI 7.1 to 40.5, p = 0.01). Most subjects (70%) preferred incorporating the new tablets into their usual protein substitute regimen. CONCLUSIONS: Amino acid tablets are an effective and relatively popular protein substitute in older children, teenagers, and adults with PKU.

How practical are recommendations for dietary control in phenylketonuria?

In patients with phenylketonuria, blood phenylalanine concentration during childhood is the major determinant of cognitive outcome. Guidelines provide age-related recommendations for treatment. To ascertain the extent to which these aims are achievable, we audited results from four centres for the years 1994-2000. The median proportion of samples with phenylalanine concentrations above those recommended was less than 30% for those younger than age 10 years but almost 80% for those aged 15 years and older. Similarly, the median frequency of blood sampling, expressed as a proportion of that recommended, was more than 80% for patients younger than 10 years but less than 50% by age 15 years. Our results indicate the difficulty of maintaining control in phenylketonuria, especially in older rather than younger children.

Molecular characterization of methylmalonate semialdehyde dehydrogenase deficiency.

Three patients have been reported with (putative) methylmalonic semialdehyde dehydrogenase (MMSDH) deficiency. The urine metabolic pattern was strikingly different in all, including beta-alanine, 3-hydroxypropionic acid, both isomers of 3-amino- and 3-hydroxyisobutyric acids in one and 3-hydroxyisobutyric and lactic acids in a second, and mild methylmalonic aciduria in a third patient. In an effort to clarify these disparate metabolite patterns, we completed the cDNA structure, and characterized the genomic structure of human MMSDH gene in order to undertake molecular analysis. Only the first patient had alterations in the MMSDH coding region, revealing homozygosity for a 1336G > A transversion, which leads to substitution of arginine for highly conserved glycine at amino acid 446. No abnormalities of the MMSDH cDNA were detected in the other patients. These data provide the first molecular characterization of an inborn error of metabolism specific to the L-valine catabolic pathway.

Biochemical monitoring of treatment for galactosaemia: biological variability in metabolite concentrations.

Red cell galactose 1-phosphate (Gal-1-P) concentrations and urinary galactitol excretion have been suggested as biochemical indices of dietary compliance in classical transferase-deficient galactosaemia. We report our experience of measuring both in 32 patients over 0-10.9 years (median 3.45). A total of 438 blood specimens for Gal-1-P and 383 urine specimens for galacitol assay were received; 317 pairs of specimens were collected at the same time. Concentrations of both analytes fell rapidly over the first 2-3 months following dietary intervention, to mean (geometric SD) levels of 225 (1.60) mumol/L red cells for Gal-1-P and 388 (1.19) mumol/mmol creatinine for galactitol. Concentrations then fell exponentially over the next 7-8 years, with times to half-disappearance of 6.3 years for Gal-1-P and 6.4 years for galactitol, to levels of 104 (1.58) and 193 (1.36) respectively in patients aged over 10 years. Concentrations of both analytes were independent of the presence of the common Q188R mutation. Mean intra- and inter-individual coefficients of variation (CV) across the range of values studied were 36% and 61% for Gal-1-P, and 37% and 42% for galactitol. Analytical CVs were 3.6% for Gal-1-P and 5.5% for galactitol, indicating that the major source of variability is biological. The correlation coefficient between Gal-1-P and galactitol in paired samples overall was 0.33; the regression equation being [Galactitol] = 0.84[Gal-1-P] + 176. Serial measurements of both Gal-1-P and galactitol may be valuable in monitoring galactosaemia, but high intra-individual biological variability limits their usefulness. Standardization of sample collection times may improve this. Further work is needed to assess the predictive values of both analytes for long-term outcome.

Definitive diagnosis of nut allergy.

OBJECTIVE: To compare findings of tests for nut allergy in children. DESIGN: Retrospective survey of a clinical practice protocol. SETTING: Children's hospital paediatric outpatient clinic. SUBJECTS: 96 children referred by general practitioners and accident and emergency doctors over 27 months (1994-96). MAIN OUTCOME MEASURES: Allergic manifestations (generalised urticarial rash, facial swelling, bronchospasm, anaphylactic shock, vomiting on three occasions) related to specific nut IgE concentrations and following touch, skin prick, or oral ingestion of nuts. RESULTS: 16 children from a sample of 51 who were tested for nut allergy had no reaction to an oral challenge. Positive IgE against peanuts was found in nine of these 16 children. CONCLUSIONS: Skin prick testing and IgE measured by radioallergosorbent testing are inadequate tests for nut allergy. The definitive diagnostic test for nut allergy in the hospital setting is direct oral challenge.

Does a single plasma phenylalanine predict quality of control in phenylketonuria?

A 1993 MRC working group on phenylketonuria suggested standardising blood phenylalanine measurements by taking blood samples at the same time each day. Since it is not known how representative of a 24 hour period a single phenylalanine concentration is, the aim of this study was to investigate the 24 hour variability of plasma phenylalanine in well controlled children with phenylketonuria. Sixteen subjects, 12 girls and four boys aged 1 to 18 years, had hourly venous blood samples collected for 13 hours between 09.00 and 21.00 on one day. Serial skin puncture blood specimens were then collected at 24.00, 03.00, and 06.00 within the same 24 hour period. All food and drink was weighed. The median variation in plasma phenylalanine concentration was 155 mumol/l/day, with a minimum of 80 and a maximum of 280. The highest concentration occurred in the morning between 6.00 and 9.00 in 63% of subjects; the lowest occurred between midday and midnight in 94%. Concentrations < 100 mumol/l occurred in 46% of children below 11 years, three having concentrations < 30 mumol/l for two, six, and seven hours respectively. Three of five subjects had concentrations above the MRC guidelines for 24% of the period studied. Except in two subjects, the blood concentrations did not rise in response to phenylalanine consumption. However, the greater the quantity of protein substitute taken between waking and the 16.00 specimen, the larger the decrease in daytime phenylalanine concentration (r = -0.7030) (p < 0.005). There is therefore wide variability in phenylalanine concentrations in a 24 hour period in children with phenylketonuria which is not reflected in a single observation. Further study is needed to investigate the effects of timing of protein substitute on the stability of phenylalanine concentrations.