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Night blindness and conjunctival xerosis caused by vitamin A deficiency in patients with cystic fibrosis.

Forty three patients with cystic fibrosis, aged 8-44 years (median 16 years), were examined for evidence of vitamin A deficiency. Eight patients had abnormal dark adaptation tests and three had conjunctival xerosis. Serum vitamin A and retinol binding protein concentrations were significantly lower in the affected patients who were also more likely to have abnormal liver function tests. Five patients were treated with 100,000-200,000 IU water miscible vitamin A orally and their daily vitamin supplements were increased to maintain normal concentrations. In four patients dark adaptation tests were repeated. Three were normal, but one patient required three further doses of water miscible vitamin A and a daily supplement of 12,000 IU vitamin A before her dark adaptation threshold returned to normal. Adolescents with cystic fibrosis are liable to develop night blindness and conjunctival xerosis, particularly if they have liver disease or fail to take daily vitamin supplements.

Adolescent↗

The effect of pregnancy on survival in women with cystic fibrosis.

STUDY OBJECTIVES: Patients with cystic fibrosis (CF) are currently living to their fourth decade and are making reproductive decisions. Information concerning the reproductive health of women with CF has been limited to small or single-center studies. DESIGN: We conducted a matched parallel-cohort study to assess the impact of pregnancy on the survival of women with CF. PARTICIPANTS: A parallel-cohort study included all women > 12 years of age who were enrolled in the US Cystic Fibrosis Foundation National Patient Registry from 1985 to 1997. MEASUREMENTS AND RESULTS: Six hundred eighty of the 8,136 women in the cohort became pregnant. These 680 women were matched on an index year to 3,327 control women with CF. At the inception of entry into the cohort, women who reported pregnancy were more likely to have had a higher percentage of predicted FEV(1) (67.5% predicted vs 61.7% predicted, respectively; p < 0.001) and a higher weight (52.9 vs 46.4 kg, respectively; p < 0.001). Using Kaplan-Meier survival curves, the 10-year survival rate in pregnant women (77%; 95% confidence interval [CI], 71 to 82%) was higher than in those women who did not become pregnant (58%; 95% CI, 55 to 62%). A separate analysis, matching pregnant patients on FEV(1) percent predicted, age, Pseudomonas aeruginosa colonization, and pancreatic function, obtained similar results. Using Cox proportional hazard modeling to adjust for baseline age, FEV(1) percent predicted, weight, height, and pulmonary exacerbation rate per year, pregnancy was not associated with an increase risk of death. Pregnancy was not harmful in any subgroup including patients with FEV(1) < 40% of predicted or diabetes mellitus. CONCLUSIONS: Women with CF who became pregnant were initially healthier and had better 10-year survival rates than women with CF who did not become pregnant. After adjustment for the initial severity of illness, women who became pregnant did not have a significantly shortened survival.

Adult↗

Early pulmonary manifestation of cystic fibrosis in children with the DeltaF508/R117H-7T genotype.

We report 3 cystic fibrosis newborn screen-positive infants with the DeltaF508/R117H-7T genotype who had Pseudomonas aeruginosa detected in oropharyngeal cultures early in life and a fourth who had pulmonary symptoms and Gram-negative growth on multiple oropharyngeal cultures. All 4 patients were followed prospectively from the time of genetic diagnosis. As many regions implement newborn screening for cystic fibrosis, there is concern regarding which mutations should be included in genetic panels used to make the cystic fibrosis diagnosis. Some have recommended that mutations not specifically associated with classic cystic fibrosis be excluded. Our cases highlight the importance of considering keeping so-called mild mutations on cystic fibrosis newborn screening panels and the need to follow children with these mutations closely.

Age of Onset↗

Glucose tolerance in cystic fibrosis.

Glucose tolerance was evaluated in 356 living and dead patients with cystic fibrosis who were recorded at the Danish Cystic Fibrosis Centre. Twenty two patients (6%) were treated elsewhere, 25 (7%) were unable, unwilling or too young (age less than 2 years) to participate; 309 patients (87%) were therefore eligible for the study of whom 99 (32%) were dead and 210 (68%) were alive. Of the dead patients, 13 also had diabetes mellitus (13%). Of the living patients (median age 14 years, range 2-40), nine (4%) were known to have diabetes and all were being treated with insulin. In the remaining 201 patients an oral glucose tolerance test (1.75 g/kg body weight, maximum 75 g) was carried out. A total of 155 patients (74%) had normal glucose tolerance, 31 (15%) had impaired glucose tolerance, and 15 (7%) had diabetes mellitus according to the WHO criteria. The percentage of glycated haemoglobin (HbA1c) (reference range 4.1-6.4%) increased significantly as glucose tolerance decreased: when glucose tolerance was normal the median was 5.2%; when it was impaired the figure was 5.5%; in patients whose diabetes was diagnosed by the oral glucose tolerance test it was 5.9%; and in patients already known to have diabetes mellitus it was 8.6%. The incidence and prevalence of impaired glucose tolerance and diabetes mellitus increased with age. From the age of 15 to 30 years the decrease in the prevalence of normal glucose tolerance was almost linear. Within this age span the proportion of patients with cystic fibrosis with normal glucose tolerance was reduced by roughly 5%/year. Only 35% (95% confidence interval (CI) 22 to 48%) of the patients with cystic fibrosis who were alive at the age of 25 years had normal glucose tolerance; 32% (95% CI 14 to 49%) were diabetic. The prevalence of glucose intolerance in cystic fibrosis is rapidly increasing with age; its potentially harmful effect on the prognosis of cystic fibrosis is of increasing importance as the length of survival of these patients increases.

Adolescent↗

Munchausen syndrome by proxy simulating cystic fibrosis.

The case of a child with apparent cystic fibrosis whose many signs, symptoms, and laboratory results were convincingly portrayed by his mother is presented. The mother falsified the history, and cunningly altered sweat tests and stool fat analyses, and stole sputum from patients with cystic fibrosis to make her child appear to have cystic fibrosis. This case of Munchausen syndrome by proxy highlights the extent to which the diagnosis of cystic fibrosis rests on reliable history and laboratory data and emphasizes the extremes to which perpetrators of this form of child abuse may go to make their case. Medical personnel must educate civil authorities about this syndrome and the dangers it represents to the child.

Body Weight↗

Obstruction of the respiratory pathways, its evaluation by methods of functional examination of the lungs and development in patients with cystic fibrosis.

In 28 patients with cystic fibrosis aged 5--24 years the values of maximum expiratory flow rates (Vmax) at lower volume levels were assessed, as well as the "specific" conductance of the respiratory pathways (Gaw/TGV), the vital capacity (VC), total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC), RV/TLC and FRC/TLC ratios and the one-second forced expiration of the vital capacity (FEV1) to evaluate obstruction of the respiratory pathways. Most markedly and most frequently abnormal were the values of Vmax, RV and of the RV/TLC ratio. These findings revealed that in almost all patients with CF there was already during the initial examination an obstruction of the peripheral respiratory pathways and hyperinflation of the lungs. During repeated measurement of the above values of lung function in 15 patients with cystic fibrosis during a period of 1--5 years when the patients increased in height by 10 cm on average, the above values did not deteriorate on average. There was, however, an individual variability of the investigated values during this period. The comprehensive treatment provided in our country prevented in patients with CF a deterioration of obstruction of the respiratory pathways during the period of investigation.

Adolescent↗

Effect of double-blind crossover selenium supplementation on biological indices of selenium status in cystic fibrosis patients.

Twenty-seven cystic fibrosis patients received selenium supplementation (2.8 micrograms of sodium selenite per kilogram of body weight per day) or a placebo. This 5-month trial was conducted as a double-blind, placebo-controlled study. After an interval of 2 months, treatments of the two groups were interchanged (crossed over) for another 5-month period. A group of healthy subjects, living in the same area, was investigated simultaneously. No selenium deficiency was found either in plasma or in erythrocytes before the supplementation. This result was inconsistent with a previous study performed in 1988 in our laboratory. This change in selenium status can be explained by progress in the nutritional nursing care of children and by the addition of selenium to the diet. During the study, selenium concentrations in plasma decreased when patients received placebo treatment and increased during selenium intake. In one of the two groups a similar variation was found for glutathione peroxidase activities in plasma and erythrocytes, whereas erythrocyte selenium was normal and did not change in any group. Nowadays, in the Grenoble area, the selenium status of cystic fibrosis patients is close to normal. Nevertheless, this study indicates a fragile equilibrium, given that selenium concentrations cn be lowered by placebo or mildly increased by supplementation.

Adolescent↗

Newborn screening for cystic fibrosis is complicated by age-related decline in immunoreactive trypsinogen levels.

Detection of elevated levels of immunoreactive trypsinogen (IRT) in dried neonatal blood spots has been used as a screening test for cystic fibrosis. In other cystic fibrosis newborn-screening studies, a sweat chloride test is generally performed only if an infant has a persistent IRT level above a selected cutoff value on both the initial and subsequent specimens. Neither the timing of the second specimen nor the value of the cutoff point for the second specimen has been comprehensively evaluated. In this randomized, controlled study, 145,024 infants were screened in the neonatal period for cystic fibrosis using the 99.8 percentile (180 ng/mL) as the neonatal cutoff point. A total of 129 infants had elevated neonatal IRT levels and had negative results on sweat tests (false-positive by IRT screening). A total of 54 children with cystic fibrosis were identified in the screened and comparison groups. Excluding patients with meconium ileus, 4 infants with cystic fibrosis had neonatal IRT values less than 180 ng/mL, and an additional 9 infants with cystic fibrosis had values decline to less than 180 ng/mL within the first 2 1/2 months of age. The IRT values of infants with and without cystic fibrosis overlapped considerably beyond 30 days of age. These findings suggest that further refinement of cystic fibrosis screening methodology will be necessary to achieve an acceptable sensitivity and specificity.

Aging↗

The clinical spectrum of chronic appendiceal abscess in cystic fibrosis.

OBJECTIVE: To describe the varied characteristics seen in patients with cystic fibrosis who develop chronic abscess formation secondary to unrecognized appendicitis. DESIGN: Patient series. SETTING: Cystic Fibrosis Care Centers in Columbus, Ohio, and Tucson, Ariz. PARTICIPANTS: Five patients with cystic fibrosis who developed chronic abdominal abscesses secondary to occult appendicitis are described. Two patients developed fistula formation with purulent fluid drainage before diagnosis. One patient developed an extensive psoas abscess. Another presented with prolonged fever of unknown origin. These patients were identified by retrospective review of the past 20-year experience at two Cystic Fibrosis Care Centers. CONCLUSIONS: Development of chronic abdominal abscess related to unrecognized appendicitis is a rare but important complication in patients with cystic fibrosis. Prompt diagnosis depends on physician familiarity with the varied presentations of this entity. Diagnostic abdominal computed tomography and/or ultrasonography should particularly be considered when patients with cystic fibrosis present with pain, mass, or drainage from the right flank; prolonged fever; a limp; or failure of suspected meconium ileus equivalent syndrome to respond promptly to cathartic measures.

Abscess↗

Defective cholinergic Cl(-) secretion and detection of K(+) secretion in rectal biopsies from cystic fibrosis patients.

Rectal biopsies from cystic fibrosis (CF) patients show defective cAMP-activated Cl(-) secretion and an inverse response of the short-circuit current (I(sc)) toward stimulation with carbachol (CCh). Alternative Cl(-) channels are found in airway epithelia and have been attributed to residual Cl(-) secretion in CF colon. The aim of the present study was to investigate ion conductances causing reversed I(sc) upon cholinergic stimulation. Furthermore, the putative role of an alternative Ca(2+)-dependent Cl(-) conductance in human distal colon was examined. Cholinergic ion secretion was assessed in the absence and presence of cAMP-dependent stimulation. Transepithelial voltage and I(sc) were measured in rectal biopsies from non-CF and CF individuals by means of a perfused micro-Ussing chamber. Under baseline conditions, CCh induced a positive I(sc) in CF rectal biopsies but caused a negative I(sc) in non-CF subjects. The CCh-induced negative I(sc) in non-CF biopsies was gradually reversed to a positive response by incubating the biopsies in indomethacin. The positive I(sc) was significantly enhanced in CF and was caused by activation of a luminal K(+) conductance, as shown by the use of the K(+) channel blockers Ba(2+) and tetraethylammonium. Moreover, a cAMP-dependent luminal K(+) conductance was detected in CF individuals. We conclude that the cystic fibrosis transmembrane conductance regulator is the predominant Cl(-) channel in human distal colon. Unlike human airways, no evidence was found for an alternative Cl(-) conductance in native tissues from CF patients. Furthermore, we demonstrated that both Ca(2+)- and cAMP-dependent K(+) secretion are present in human distal colon, which are unmasked in rectal biopsies from CF patients.

Adolescent↗

Antilipopolysaccharide antibodies and differential diagnosis of chronic Pseudomonas aeruginosa lung infection in cystic fibrosis.

Chronic lung infection in cystic fibrosis is characteristically associated with polyagglutinable, serum-sensitive, mucoid strains of Pseudomonas aeruginosa. Enzyme-linked immunosorbent assay (ELISA) methods for standard-free quantitation of immunoglobulin G (IgG) and IgM antibodies to P. aeruginosa lipopolysaccharides (LPSs) have been developed. We now report the development of assays for quantitation of monomer and dimer total IgA and IgA anti-LPS antibodies. Use of these methods in diagnosis of early chronic P. aeruginosa lung infection was assessed. IgG and IgA anti-LPS levels increased significantly at the onset of chronic infection and continued to increase to very high levels in the later stages of infection. IgM anti-LPS levels also rose at the onset of chronic infection but did not increase further. The function of true- and false-positive rates was illustrated by using various concentrations of IgG, IgA, and IgM anti-LPS for discrimination of patients. Values that gave optimum separations were used for statistical evaluation of the diagnostic sensitivities and specificities of anti-LPS antibody concentrations. The results obtained in these assays were compared with a diagnosis, based on the number of precipitins in crossed immunoelectrophoresis, of serum samples from cystic fibrosis patients. In 64 paired serum samples taken before and immediately after the onset of chronic infection, as defined by crossed immunoelectrophoresis precipitins, the predictive values of a positive ELISA were 86% for IgG and 89% for IgA. The predictive values for a negative ELISA were 98% for IgG and 97% for IgA. Results of the IgM anti-LPS ELISA had a lower predictive value. Immunoblotting and absorption studies showed that IgG anti-LPS antibodies were directed specifically against LPS of P. aeuruginosa. ELISAs were developed to determine the specific IgG sublclasses involved. The increase in IgG anti-LPS involved all four subclasses. Highest anti-LPS titers were seen with IgG1 and IgG4, but the largest relative increases were seen with IgG2 and IgG3.

Antibodies, Bacterial↗

Analysis of the complete coding region of the CFTR gene in ten Algerian cystic fibrosis families.

The spectrum of cystic fibrosis (CF) mutations in the North African population remains poorly known. In order to offer an effective diagnostic service and to determine accurate risk estimates, we decided to identify the CF mutations in 10 Algerian CF families. We carried out a chemical-clamp denaturing gradient gel electrophoresis analysis of the CFTR gene and automated direct DNA sequencing. We identified 5 mutations and we characterized 60% of the CF chromosomes. Taking advantage of the homogeneity of the sample, we report clinical features of homozygous CF patients.

Algeria↗

Diltiazem improves cyclosporine dosage in cystic fibrosis lung transplant recipients.

Maintenance of therapeutic blood levels of cyclosporine in lung transplant patients with cystic fibrosis can be challenging. In addition, total daily dosage can be high when compared with patients who do not have cystic fibrosis. We report the advantage of adding diltiazem to decrease the cyclosporine dosage and maintain adequate therapeutic levels. Diltiazem 60 mg twice daily was initiated in four patients with cystic fibrosis and in four patients who did not have cystic fibrosis. In patients with cystic fibrosis, mean dosage and mean diltiazem efficacy ratio (dose milligrams per kilograms per day/cyclosporine blood level) were significantly reduced. Dosage was reduced from 13.9 +/- 8 to 8.1 +/- 2.6 mg/kg mean +/- standard deviation). The latter was similar to patients who do not have cystic fibrosis (6.5 +/- 1.8 mg/kg). Diltiazem efficacy ratio was reduced from 85 +/- 22 to 27 +/- 4. In patients who did not have cystic fibrosis, the ratio was significantly reduced from 42 +/- 13 to 19 +/- 3. Resting blood pressure, pulse, and serum creatinine levels remained normal or normalized. Although cyclosporine dosage was not significantly reduced by adding diltiazem in patients who did have cystic fibrosis, adequate cyclosporine blood levels were achieved. We conclude that the addition of diltiazem can be useful in the maintenance of adequate cyclosporine therapy in lung transplant recipients who do or who do not have cystic fibrosis.

Adolescent↗

Strategies for identifying modifier genes in cystic fibrosis.

Even in patients with cystic fibrosis (CF) with identical CFTR genotypes, there is a wide range in the severity of lung disease, with some individuals facing death or lung transplantation early in life and others demonstrating mild lung disease well into adulthood. Although numerous environmental factors have been identified that influence CF pulmonary phenotype, there is now growing evidence that polymorphic variants in genes besides CFTR play an important role in determining severity of CF lung disease. This article reviews the most recent findings regarding genetic modifiers in CF and also discusses in detail the strategies currently being used to identify novel modifiers of CF pulmonary phenotype. These include single- and multicenter studies, twin and sib studies, microarray approaches, and whole genome association studies.

Cystic Fibrosis↗

Glycosidases in serum of cystic fibrosis patients.

In a study of eight glycosidases in serum samples from 72 cystic fibrosis patients, 85 cystic fibrosis parents and 34 healthy and diseased controls, significant elevations of mean alpha-glucosidase levels were found in cystic fibrosis patients. All other glycosidases did not show any significant change. Mean alpha-glucosidase levels in obligate heterozygotes were the same as in control individuals. Moreover, alpha-glucosidase levels in cystic fibrosis patients correlated with the degree of clinical impairment as measured by the Schwachman score.

Acetylglucosaminidase↗

The lactoperoxidase system links anion transport to host defense in cystic fibrosis.

Chronic respiratory infections in cystic fibrosis result from CFTR channel mutations but how these impair antibacterial defense is less clear. Airway host defense depends on lactoperoxidase (LPO) that requires thiocyanate (SCN-) to function and epithelia use CFTR to concentrate SCN- at the apical surface. To test whether CFTR mutations result in impaired LPO-mediated host defense, CF epithelial SCN- transport was measured. CF epithelia had significantly lower transport rates and did not accumulate SCN- in the apical compartment. The lower CF [SCN-] did not support LPO antibacterial activity. Modeling of airway LPO activity suggested that reduced transport impairs LPO-mediated defense and cannot be compensated by LPO or H2O2 upregulation.

Anions↗

Gender gap in cystic fibrosis mortality.

The authors conducted the largest study to date of survival in cystic fibrosis. The study cohort consisted of all patients with cystic fibrosis seen at Cystic Fibrosis Foundation-accredited care centers in the United States between 1988 and 1992 (n = 21,047), or approximately 85% of all US patients diagnosed with cystic fibrosis. Cox proportional hazards regression analysis was used to compare the age-specific mortality rates of males and females and to identify risk factors serving as potential explanatory variables for the gender-related difference in survival. Among the subjects 1-20 years of age, females were 60% more likely to die than males (relative risk = 1.6, 95% confidence interval 1.4-1.8). Outside this age range, male and female survival rates were not significantly different. The median survival for females was 25.3 years and for males was 28.4 years. Nutritional status, pulmonary function, and airway microbiology at a given age were strong predictors of mortality at subsequent ages. Nonetheless, differences between the genders in these parameters, as well as pancreatic insufficiency, age at diagnosis, mode of presentation, and race, could not account for the poorer survival among females. Even after adjustment for all these potential risk factors, females in the age range 1-20 years remained at greater risk for death (relative risk = 1.6, 95% confidence interval 1.2-2.1). The authors concluded that in 1- to 20-year-old individuals with cystic fibrosis, survival in females was poorer than in males. This "gender gap" was not explained by a wide variety of potential risk factors.

Adolescent↗

Intestinal permeability to 51Cr-EDTA and orocecal transit time in cystic fibrosis.

Intestinal permeability was investigated in 16 children with cystic fibrosis and 14 age-matched controls, making use of 51Cr-EDTA as probe molecule. Orocecal transit time was also evaluated using the lactulose/hydrogen breath test. There was an increase in permeability to 51Cr-EDTA in patients with cystic fibrosis (mean 13.62%) compared with the control group (mean 1.08%). The orocecal transit time was prolonged in patients with cystic fibrosis compared with controls. Mean fasting breath hydrogen concentration was significantly greater in cystic fibrosis patients (13 ppm) compared with control patients (3 ppm). There was no correlation between the percentage of 51Cr-EDTA excreted and the orocecal transit time in either control or cystic fibrosis patients.

Administration, Oral↗