Inhaled hypertonic saline increases sputum expectoration in cystic fibrosis.

OBJECTIVE: To determine whether inhalation of hypertonic saline (HS) increases sputum expectoration in patients with cystic fibrosis (CF). METHODOLOGY: Ten adolescents with CF, who were receiving inpatient treatment for a pulmonary exacerbation, were enrolled in a controlled cross-over clinical trial. After inhalation of beta adrenergic drug to prevent possible broncho-constriction, each patient inhaled for 10 min either 0.9% isotonic saline (IS) or 6% HS prior to routine physiotherapy. The following day the patient received the alternative solution. Seven patients undertook a second block after 1-5 days. Outcome measures included weight of sputum, a visual analogue score to assess the subjective feeling of a cleared chest after physiotherapy, and spirometry. RESULTS: Sputum expectoration (median; Q1,Q3) from the beginning of the inhalation of HS or IS to the final spirometry measure 60 min post-physiotherapy was significantly greater after HS than IS [17.2g (11.7, 34.8) vs 11.3g (6.5, 16.1): P = 0.006]. A clinical score of the patient's own judgement of a cleared chest was significantly better after HS than IS. Spirometry results did not change following either of the two inhalations. CONCLUSIONS: These data show that the inhalation of 6% HS prior to physiotherapy can increase sputum expectoration in patients with CF and suggest that HS might be an effective, safe and cheap adjunct to regular physiotherapy in patients with CF.

Hypertonic saline challenge in an epidemiologic survey of asthma in children.

To evaluate sensitivity and specificity of a 4.5% hypertonic saline challenge for a diagnosis of asthma, we studied 393 schoolchildren (13 to 15 yr of age) with "current wheeze," "former wheeze," and without history of wheeze in a community-based, cross-sectional survey. These children were selected from 2.836 schoolchildren in 26 schools in greater Melbourne, Australia who completed a self-administered questionnaire on respiratory symptoms, allergic rhinitis, and eczema. Three hundred eighty-two of 393 children successfully completed a 4.5% hypertonic saline challenge with increasing inhalation periods, and 365 of 393 performed a 6-min standardized, free running exercise challenge. The prevalence of bronchial hyperresponsiveness to hypertonic saline was 20.4%. Sensitivity and specificity for the hypertonic saline challenge to identify children with "current wheeze" were 47% and 92% respectively and for the exercise challenge, 46% and 88%. The agreement of response to hypertonic saline and to exercise was only moderate (kappa = 0.43). Factors associated with increased response to hypertonic saline in a multivariate logistic regression model were a history of "current wheeze," hay fever, response to the exercise challenge, female sex, and a lower baseline predicted FEV1. These results suggest that a 4.5% hypertonic saline challenge shows sensitivity and specificity similar to a standardized exercise challenge and pharmacologic challenges and a higher sensitivity than cold air hyperventilation and distilled water to identify asthma in children in a field study. Measurement of responsiveness to hypertonic saline may be of value as an objective marker of asthma to compare prevalence studies of bronchial hyperresponsiveness and of asthma over time and between countries.

Repeatability of response to hypertonic saline aerosol in children with mild to severe asthma.

Non-isotonic aerosols are being used more commonly to perform bronchial provocation tests. In contrast to histamine and methacholine challenge tests they appear to have higher specificity and a higher predictive value. The aim of the present study was to assess the reproducibility of the response to challenge with 4.5% hypertonic saline administered via an ultrasonic nebulizer in children with mild to severe asthma. Seventeen children with asthma aged 10 to 14 years completed two or three challenge tests at the same time of day within a 10 day period. Of these 17 children 9 had mild, 4 moderate, and 4 severe asthma. Children inhaled 4.5% hypertonic NaCl from an ultrasonic nebulizer with an output of 1.9 to 2.5 mL/min (Timeter) using the protocol developed by Anderson with modifications. A fall in forced expiratory volume in 1 second (FEV1) from baseline of 15% or more was considered a positive response and PD15 was calculated. In 16/17 subjects a greater than 15% fall in FEV1 occurred consistently on all study days. One subject with moderate asthma had a less than 15% fall in FEV1 on both study days. The coefficient of repeatability for PD15 was 1.8. This equals 0.85 of a doubling dose difference between the two or three measurements of PD15. The cumulative time of aerosol inhalation causing a fall in FEV1 > or = 15%) (PT15) showed a coefficient of repeatability of 1.59, similar to 0.67 doubling dose difference. The PD15 and PT15 were highly significantly correlated. The 4.5% NaCl challenge test yields good reproducibility in children with mild to severe asthma under laboratory conditions.

Prospective analysis and classification of patients with cystinuria identified in a newborn screening program.

Patients who inherit mutant cystinuria genes excrete high concentrations of cystine, ornithine, arginine, and lysine in the urine. At least three variants of cystinuria can be distinguished in heterozygotes. To determine whether certain combinations of mutant genes are more disadvantageous than others, we analyzed amino acid excretion in families of 17 probands with cystinuria identified by the Quebec neonatal screening program. Parents of the probands were classified into the three known phenotypes by calculating the sum of cystine, ornithine, arginine, and lysine excretion. Although parents of type I/I homozygotes excreted amounts of cystine in the normal range, their offspring excreted significantly greater amounts of urinary cystine than did children who have type I/III genetic compounds. This observation suggests that types I and III cystinuria mutations might involve two distinct genetic loci. Children with type I/I homozygous cystinuria often excrete cystine at levels greater than the theoretic solubility limit and may be at greatest risk for nephrolithiasis. We outline an approach to monitoring children with cystinuria who come to medical attention before formation of cystine stones.

Maple syrup urine disease: interrelations between branched-chain amino-, oxo- and hydroxyacids; implications for treatment; associations with CNS dysmyelination.

Four patients with classical maple syrup urine disease were treated for up to 5885 days per patient with a relaxed protocol allowing branched-chain amino acid levels in plasma to rise about 5 times the normal mean value. The patients have had satisfactory development and lifestyle. They spent 318 days in hospital during 19,937 aggregate treatment days. Plasma levels of leucine and the corresponding 2-oxo acid were shown to be elevated disproportionately relative to the other branched-chain metabolites. Levels of isoleucine and valine were lower than those of leucine apparently because of runout into alternative metabolite pools, namely the R metabolites for isoleucine and the hydroxyacid for valine. The chronic accumulation of branched-chain 2-oxo acid(s) in our patients was associated with chronic dysmyelinating changes in CNS visible by imaging. Another patient with a thiamine-responsive variant of maple syrup urine disease had five acute crises incurring 29 days in hospital in a total of 6910 treatment days. However, she did not have chronic metabolic dyshomeostasis (her average plasma amino acid values were normal) and she had no evidence of dysmyelination. A relaxed treatment protocol for patients with maple syrup urine disease may benefit them in quality of life, but it apparently exacts a cost in metabolic control and CNS pathology.

X-linked hypophosphatemia: the mutant gene is expressed in teeth as well as in kidney.

Mutation at a locus (HPDR) on the X chromosome (McKusick 30780 [HPDR1]; 30781 [HPDR2]) causes impaired renal phosphate transport, hypophosphatemia, and an associated impairment in the process of mineralization in bone and teeth (X-linked hypophosphatemia [XLH]). We measured the dental pulp profile area (PRATIO [= pulp area/tooth area]) and serum phosphorus (Pi) values in uniformly treated XLH patients (six males, 81 teeth, 1,457 Pi values; 11 females, 129 teeth, 1,439 Pi values). Serum Pi values, reflecting the metabolic environment of tooth development, were obtained by repeated measurement between 1 mo and 26 years of age during treatment. PRATIO values calculated from standardized Rinn radiographs were used as outcome measurements of tooth development in XLH patients and in age-matched controls (12 males, 100 teeth; 27 females, 275 teeth). Age-dependent serum Pi values were not different in the treated XLH males and females. In teeth forming primary dentin there was no gene dosage effect on PRATIO values apparent in subjects below 15 years of age. However, in teeth forming secondary dentin a gene dosage was found in the subjects aged 15 to 25 years: XLH male teeth (n = 65) mean +/- SD = 0.163 +/- 0.046; XLH female teeth (n = 75) mean +/- SD = 0.137 +/- 0.039; control teeth (n = 209) mean +/- SD = 0.116 +/- 0.023; (higher PRATIO values mean less development or mineralization of secondary dentin); differences in these PRATIO values (males vs. female and XLH vs. control) were significant by mixed-model analysis of variance.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral findings in patients with autosomal dominant hypophosphatemic bone disease and X-linked hypophosphatemia: further evidence that they are different diseases.

Oral examinations were performed on 5 patients with hypophosphatemic bone disease (HBD) (2 males and 3 females), 14 patients with X-linked hypophosphatemia (XLH), and 4 affected XLH relatives (6 males and 12 females). The control subjects were the unaffected siblings and parents of the patients and unrelated healthy, gender- and age-matched subjects. Serum phosphorus values were the same by disease type and gender in patients with HBD and XLH. They shared certain dental abnormalities, in particular pulpal necrosis and large pulp spaces. However, only patients with XLH had Class III malocclusions and mild enamel defects, and males with XLH had more severe occlusal and enamel defects than females with XLH. Different dental phenotypes are further evidence that XLH and HBD are different diseases. The dental abnormalities were not prevented by treatment, instituted early in life, which raised serum phosphorus to the near normal range.

Nephrocalcinosis and its relationship to treatment of hereditary rickets.

Renal ultrasonography was performed on 23 patients with X-linked hypophosphatemic rickets (XLH) and 11 patients with autosomal recessive vitamin D-dependent rickets (ARVDD). A pattern of increased echogenicity of the renal pyramids (ERP) was identified in 11/23 patients with XLH and 3/11 patients with ARVDD; this ultrasonographic finding has previously been associated with medullary nephrocalcinosis. Patients with XLH and ERP had significantly higher mean serum calcium and phosphate concentrations, more frequent episodes of hypercalcemia, and higher doses of oral vitamin D and phosphate during the first 3 years of therapy. Episodes of hypercalcemia were more frequent when patients received higher doses of vitamin D2 (greater than 4000 IU/kg/day) or 1,25-dihydroxycholecalciferol (greater than 40 ng/kg/day). Episodes of hypercalciuria were significantly increased at doses of greater than 20 ng/kg/day 1,25-dihydroxycholecalciferol. In patients with ARVDD, ERP was also correlated with vitamin D dose and frequency of hypercalcemia episodes. ERP was not associated with an elevation of serum creatinine or loss of urinary concentrating ability in either patient group.

Audiometric evidence for two forms of X-linked hypophosphatemia in humans, apparent counterparts of Hyp and Gy mutations in mouse.

Two forms of X-linked hypophosphatemia occur in the mouse. One form, caused by the Hyp gene, is a counterpart of human X-linked hypophosphatemic "vitamin D-resistant rickets". The other, recently characterized, is caused by a different gene (Gy) closely linked to Hyp on the mouse X-chromosome. The Gy mutation also impairs cochlear function in the mouse. We measured hearing in 22 patients with X-linked hypophosphatemia; five, including 2 mother-son pairs, had sensorineural hearing deficits due to cochlear dysfunction. We suggest the disease in these persons may be the human counterpart of the Gy phenotype in the mouse, which implies there are 2 forms of X-linked hypophosphatemia in humans.

The Hartnup phenotype: Mendelian transport disorder, multifactorial disease.

The Hartnup mutation affects an amino acid transport system of intestine and kidney used by a large group of neutral charge alpha-amino acids (six essential and several nonessential). We compared developmental outcomes and medical histories of 21 Hartnup subjects, identified through newborn screening, with those of 19 control sibs. We found no significant differences in means of growth percentiles and IQ scores between Hartnup and control groups (but all low academic performance scores were found in the Hartnup group, and various skin lesions occurred in five Hartnup subjects), no significant difference between means of the summed plasma values for amino acids affected by the Hartnup gene in Hartnup and control groups, two Hartnup subjects with clinical manifestations--impaired somatic growth and IQ in one, impaired growth and a "pellagrin" episode in the other--who had the lowest summed plasma amino acid values in the Hartnup group; the corresponding values for their sibs were the low outliers in the control group, and two tissue-specific forms of the Hartnup (transport) phenotype: renal and intestinal involvement (15 families) and renal involvement alone (one family), both forms having been inherited as autosomal recessives (the symptomatic probands had the usual form). Whereas deficient activity of the "Hartnup" transport system is monogenic, the associated plasma amino acid value (measured genotype) is polygenic. The latter describes the parameter of homeostasis and liability to disease. Cause of Hartnup disease is multifactorial.

Renal ultrasound in metabolic bone disease.

Fifty-one patients aged 1 year to 56 years with metabolic bone disease underwent renal ultrasound. Medullary nephrocalcinosis was found in nine of 24 patients with X-linked hypophosphatemic rickets and is considered to be iatrogenic, related to vitamin D therapy. Another three in this group of 24 with both medullary and cortical increased renal echogenicity had suffered from repeated episodes of vitamin D intoxication and had secondary hyperparathyroidism. Nephrocalcinosis was less frequent in patients with treated vitamin D-dependent rickets or hypophosphatemic bone disease where generally smaller doses of vitamin D are given. Patients with pseudohypoparathyroidism, on small doses of vitamin D, had a normal renal ultrasound. In cystinosis and Fanconi's syndrome, the kidneys are small, echodense (both the cortex and medulla) with a tendency to cyst formation.

Ontogeny modifies manifestations of cystinuria genes: implications for counseling.

Among 339,868 newborn infants screened at 3 weeks of age (91% compliance rate), 730 had elevated rates of excretion of cystine and the dibasic amino acids lysine, ornithine, and arginine; 191 infants had persistent "infantile cystinuria" on follow-up screening (100% compliance). Apparent incidence of the phenotype was 562 per million infants; this rate is seven times higher than for classic cystinuria in the adult segment of the Quebec population. We studied longitudinally 26 probands 2 to 4 months of age. Initially, each excreted cystine and dibasic amino acids at much higher levels than did normal infants or either parent. From parental phenotypes (heterozygous or homozygous normal) and urine amino acid excretion values at 6 months of age in probands, the infants were classified as either heterozygous for the various classic cystinuria genotypes--type I ("silent"), eight infants; type II (high excretor), three; type III (moderate excretor), nine--or homozygous (and genetic compound), six. Urine amino acid excretion diminished steadily with age, to reach the variant parental value in heterozygous infants but not in homozygotes. Cystinuria heterozygotes, with the possible exception of some type I individuals, could not be distinguished reliably from homozygotes in early infancy, although homozygotes had significantly higher excretion values as a group. We deduce that renal ontogeny amplifies phenotypic expression of cystinuria alleles, thus influencing correct classification of genotype (heterozygote vs homozygote, and type of allele). These findings have implications for counseling and the need for follow-up of infantile cystinuria.

Serum osteocalcin in the treatment of inherited rickets with 1,25-dihydroxyvitamin D3.

Osteocalcin is a vitamin K-dependent protein, synthesized in bone, which can be detected in serum. We have measured circulating osteocalcin levels in 10 patients with x-linked hypophosphatemia (XLH) and in 6 patients with autosomal recessive vitamin D dependence (ARVDD) who started 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] therapy. Patients with XLH were studied before and after 7-12 months of therapy that included 1,25-(OH)2D3 (10-72 ng/kg x day) and oral phosphate. Serum osteocalcin rose from 28 +/- 12 to 52 +/- 12 ng/ml (mean +/- SE; P less than 0.01) in concert with improvements in biochemical status and bone mineralization. Vitamin D therapy was withdrawn for 2 weeks from patients with ARVDD. The vitamin D-deplete status was evidenced by low 1,25-(OH)2D3 levels (12 +/- 2 pg/ml; n = 6). After 1 week of therapy with 1,25-(OH)2D3, serum calcium rose from 9.03 +/- 0.21 to 9.67 +/- 0.25 mg/dl (P less than 0.002), while serum phosphorus and alkaline phosphatase remained unchanged. Serum osteocalcin rose from 35 +/- 7 to 83 +/- 32 ng/ml (P less than 0.05). At 3 weeks, serum calcium remained elevated (9.63 +/- 0.18 ng/dl) over control levels (P less than 0.01); phosphorus and alkaline phosphatase were still unchanged. Serum osteocalcin rose to 114 +/- 42 ng/ml, significantly greater than values at 1 week (P less than 0.05). Thus, serum osteocalcin increases after 1,25-(OH)2D3 therapy in both ARVDD and XLH.

Panostotic fibrous dysplasia: a congenital disorder of bone with unusual facial appearance, bone fragility, hyperphosphatasemia, and hypophosphatemia.

We report a boy with unusual facial appearance, melanotic patches ("coast-of-Maine" type), myelofibrosis, recurrent femoral fractures, and widespread fibrous dysplasia of bone. Biochemical findings included raised serum alkaline phosphatase (bone isozyme) and 1,25-(OH)2 vitamin D, and low serum phosphorus levels. Elevated urinary excretion rates of total hydroxyproline, glycylproline, and gamma-carboxyglutamic acid indicated increased turnover of bone matrix. Transiliac bone biopsy showed a dearth of marrow elements, greatly increased bone turnover, and absence of normal trabecular organization. Serial radiographs showed progressive cortical thinning and loss of bony trabeculae. Calcitonin and etidronate treatments had no lasting effect on the progressive bone disease. The term "panostotic fibrous dysplasia" is suggested for this condition.

Outcome of early and long-term management of classical maple syrup urine disease.

The outcome of 8,400 treatment days in the lives of four patients with classical maple syrup urine disease (MSUD) (present ages: 1 3/12, 5 7/12, and 8 11/12 years) are described. Each diagnosis was made by clinical signs rather than by newborn screening. Acute-phase treatment beginning on the 11th day of life comprised peritoneal dialysis, intravenous lipid, and early intestinal alimentation. Mean age at discharge from hospital was 29 days. There were 16 readmissions to the hospital for the group (89 days, 1.05% treatment days) without any serious neurologic symptoms. The mean level of plasma leucine for the group (for levels below 1 mM) during treatment was 0.42 mM (normal for age range, 0.077 +/- 0.021 mM [mean +/- SD]). Plasma leucine exceeded 1 mM during 1.02% of treatment days (representing 8.6% of 1,042 measurements. Mean levels of plasma valine and isoleucine were 60% and 70% of the plasma leucine value for the group. Tolerance for dietary leucine did not exceed 620 mg/day in any patient. Somatic growth was normal and the mean current IQ/development quotient (DQ) score is 101 (range 89 to 117); the three oldest patients attend regular schools. A characteristic EEG pattern resembling the teeth of a comb was observed in three patients during the acute phase in the newborn period but not during long-term treatment. These results were obtained in an ambulatory program with home visiting.

X-linked hypophosphatemia: effect of calcitriol on renal handling of phosphate, serum phosphate, and bone mineralization.

Eleven patients with the Mendelian phenotype of x-linked hypophosphatemia (XLH) were treated with calcitriol [1,25-(OH)2D3] and phosphate. Ten patients had received prior treatment with ergocalciferol and phosphate. Five subjects were prepubertal and six were postpubertal. Response to calcitriol was measured under nonfasting and overnight fasting protocols. Bone biopsies were obtained before and after treatment. Calcitriol (mean dose, 30 ng/kg. day) 1) raised serum phosphorus uniformly in prepubertal patients but in only two of six postpubertal subjects; 2) did not change the theoretical renal phosphate threshold in the total patient group and thus had no effect on the primary transport defect in XLH; 3) improved trabecular bone mineralization in the total patient group, as determined by bone histomorphometry. The beneficial effect on extracellular phosphorus homeostasis was attributed to improved intestinal absorption of phosphorus; improvement in bone mineralization may reflect an additional effect of 1,25-(OH)2D3 on bone itself in XLH. Mild transient hypercalcemia occurred during 0.6% of 3545 treatment days and was readily controlled by adjusting the dosage of 1,25-(OH)2D3.

Autosomal hypophosphataemic bone disease responds to 1,25-(OH)2D3.

We diagnosed non X-linked hypophosphataemic bone disease in a 38-month-old girl. Findings included: genu varum, shortened stature, fasting hypophosphataemia (2.3-2.5 mg/100 ml; 0.74-0.81 mmol/l), diminished theoretical renal threshold for phosphate (TmP/GFR), and osteomalacia without rickets. One patient (the father) had fasting hypophosphataemia (2.3-2.7 mg/100 ml; 0.74-0.87 mmol/l) and low TmP/GFR without osteomalacia or shortened stature. Treatment of the girl with 1,25-(OH)2D3 (1 microgram a day) raised the level of serum phosphorus, improved tubular reabsorption of phosphate, and healed the bone deformity; this combination of responses is not present in X-linked hypophosphataemia. There was no correction of hypophosphataemia or TmP/GFR with 1,25-(OH)2D3 treatment (1-3 micrograms a day) in the father.