Could isotretinoin flare hidradenitis suppurativa? A case series.

We report eight cases of patients with severe acne who were treated with isotretinoin and developed painful nodules in the axillae and groin, consistent with hidradenitis suppurativa (HS). The pathogenesis of HS is still not completely understood; recent research from a study in 2011 of biopsies from HS lesions showed a reduction or absence of sebaceous glands compared with normal skin in patients with HS, with the report suggesting that this contributes to the pathogenesis of the disease. Interestingly, the main effect of isotretinoin is to decrease the size and action of sebaceous glands, so hypothetically, as isotretinoin acts by reducing the sebaceous glands further it could potentially aggravate HS. Our experience has instilled caution in our prescribing of isotretinoin, and we question patients, particularly those with acne conglobata, about symptoms of HS prior to and during treatment.

Ivacaftor as salvage therapy in a patient with cystic fibrosis genotype F508del/R117H/IVS8-5T.

Ivacaftor is a novel CFTR potentiator that increases CFTR activity and improves clinical outcomes in cystic fibrosis (CF) patients with at least one copy of CFTR-G551D. Clinical trials have shown an improvement in lung function, weight and CF pulmonary exacerbation in adults with CFTR-G551D leading to the approval of ivacaftor as a novel CF therapy [1]. In vitro studies of ivacaftor have also shown significant improvements in CFTR chloride channel opening time in other non-G551D CFTR mutations suggesting that ivacaftor may be of benefit to patients with mutations other than gating mutations [2]. R117H-CFTR is a relatively common CFTR mutation that demonstrates an in-vitro response to ivacaftor [2,3]. A clinical trial has suggested that there may be a role for ivacaftor in older patients with R117H-CFTR although this trial did not include patients with very severe CF lung disease [4]. In 2014, ivacaftor was approved in the United States as a treatment for CF subjects aged greater than 6 years old with a copy of R117H-CFTR. We present a case demonstrating a substantial therapeutic effect of ivacaftor in a CF patient with genotype F508del/R117H and advanced lung disease.

Inhaled dry powder mannitol in cystic fibrosis: an efficacy and safety study.

This international phase III study of inhaled dry powder mannitol was a randomised, double-blind, 26-week study, followed by a further 26-week, open-label (OL) extension. 324 cystic fibrosis (CF) patients were randomised, in a 3:2 ratio, to mannitol (400 mg b.i.d.) and control groups. The primary efficacy end-point was to determine the change in forced expiratory volume in 1 s (FEV1) over the double-blind phase. Secondary end-points included changes in forced vital capacity and pulmonary exacerbations. A significant improvement in FEV1 was seen over 26 weeks (p<0.001) and was apparent by 6 weeks, irrespective of concomitant recombinant human deoxyribonuclease (rhDNase) use. At 26 weeks, there was a significant improvement in FEV1 of 92.9 mL for subjects receiving mannitol compared with controls (change from baseline 118.9 mL (6.5%) versus 26.0 mL (2.4%); p<0.001). Improvements in FEV1 were maintained up to 52 weeks in the OL part of the study. There was a 35.4% reduction in the incidence of having an exacerbation on mannitol (p=0.045). The incidence of adverse events (AEs) was similar in both groups, although treatment-related AEs were higher in the mannitol compared with the control group. The most common mannitol-related AEs were cough, haemoptysis and pharyngolaryngeal pain. Mannitol showed sustained, clinically meaningful benefit in airway function in CF, irrespective of concomitant rhDNase use. Mannitol appears to have an acceptable safety profile for patients with CF.

Time course and recovery of arterial blood gases during exacerbations in adults with Cystic Fibrosis.

INTRODUCTION: Hypoxia and hypercapnia are closely linked to morbidity and mortality in patients with Cystic Fibrosis (CF). The aims of this study were to describe the changes in blood gases during and following an acute pulmonary exacerbation in adults with CF. METHODS: We performed a prospective observational study of patients with CF admitted for management of an acute exacerbation. Blood gas and spirometric analysis was performed on admission, throughout the treatment period, and 31 days after discharge (day 45). RESULTS: At presentation, eight of nineteen patients had evidence of either hypoxia (PaO(2)<8 kPa) and/or hypercapnia (PaCO(2)>6.6 kPa). Blood gas parameters stabilized following two weeks of intravenous antibiotic therapy, with little difference evident in between treatment completion and subsequent review following discharge. Hypercapnia reversed in three patients, with persistent hypercapnia evident in two patients. CONCLUSION: In our study group, hypoxemia and hypercapnia were frequently observed at presentation of the acute exacerbation. Blood gases stabilized following two weeks of intravenous antibiotic therapy, with arterial PCO(2) one month following hospital discharge generally similar to that at time of discharge.

Recommendations on the use of exercise testing in clinical practice.

Evidence-based recommendations on the clinical use of cardiopulmonary exercise testing (CPET) in lung and heart disease are presented, with reference to the assessment of exercise intolerance, prognostic assessment and the evaluation of therapeutic interventions (e.g. drugs, supplemental oxygen, exercise training). A commonly used grading system for recommendations in evidence-based guidelines was applied, with the grade of recommendation ranging from A, the highest, to D, the lowest. For symptom-limited incremental exercise, CPET indices, such as peak O(2) uptake (V'O(2)), V'O(2) at lactate threshold, the slope of the ventilation-CO(2) output relationship and the presence of arterial O(2) desaturation, have all been shown to have power in prognostic evaluation. In addition, for assessment of interventions, the tolerable duration of symptom-limited high-intensity constant-load exercise often provides greater sensitivity to discriminate change than the classical incremental test. Field-testing paradigms (e.g. timed and shuttle walking tests) also prove valuable. In turn, these considerations allow the resolution of practical questions that often confront the clinician, such as: 1) "When should an evaluation of exercise intolerance be sought?"; 2) "Which particular form of test should be asked for?"; and 3) "What cluster of variables should be selected when evaluating prognosis for a particular disease or the effect of a particular intervention?"

Cystic fibrosis-related diabetes in adults.

We aimed to examine the differences between patients with cystic fibrosis-related diabetes (CFRD), and those with normal glucose handling in adults with cystic fibrosis (CF) in Ireland. We conducted a retrospective analysis of patients who attend the national referral centre for adult CF. Patients were diagnosed as having CFRD by the American Cystic Fibrosis Foundation criteria for diagnosis of CFRD. Of 259 patients, 150 were classifiable and 81 (54%) were classified as having CFRD. The groups with and without CFRD were not significantly different with regard to age (median 28.4 vs 26.0 years), sex (males 56% vs 55%) or BMI (median 20.9 vs 21.3 kg/m2). The group with CFRD had poorer lung function (mean % predicted FEV1 49.9 vs 66.4, P < 0.001), poorer bone mineral density (T-scores at the lumbar spine -1.95 vs -1.44, P < 0.05 and femur -1.19 vs -0.57, P < 0.01) and a greater proportion of PSEUDOMONAS AERUGINOSA positive sputum cultures (82.5% vs 64.2%, P < 0.05). No patients with CFRD carried the R1 17H mutation whilst 19% of the group without CFRD were heterozygous for this defect (P < 0.001). In conclusion, CFRD was highly prevalent in adults. The presence of CFRD was associated with poorer lung function, poorer bone mineral density and an increased prevalence of PSEUDOMONAS AERUGINOSA in sputum. The R1 17H mutation may be protective for CFRD.

Oral bisphosphonates improve Bone Mineral Density in adults with cystic fibrosis.

In adults with Cystic Fibrosis (CF) we sought to establish the effect of oral bisphosphonate therapy. Bone densitometry measured by dual energy X-ray absorptiometry (DXA), and clinical patient data, were reviewed retrospectively. Eighty-one patients (median age 27 years) had baseline and follow-up DXA, with an interval of 19.2 +/- 7.1 months. Thirty-six patients were treated with bisphosphonates (alendronate=23 and risedronate=13). Median follow-up Bone Mineral Density in the bisphosphonate group was 3.7% greater at the lumbar spine (95%CI 1.9 to 5.7%, P<0.0005) and 2.4% greater at the femur (95%CI 0.8 to 3.9%, P<0.005) than the group not treated with bisphosphonates. Oral bisphosphonate therapy had a beneficial effect on BMD in adults with CF.

Effect of respiratory rate on airway deadspace ventilation during exercise in cystic fibrosis.

Gas exchange during exercise in patients with cystic fibrosis (CF) is characterised by an elevated physiological deadspace to tidal volume ratio. While this has been attributed to alveolar ventilation perfusion mismatch, there are other potential causes of the high proportion of wasted ventilation, including factors relating to the volume and the ventilation of the airway deadspace. CF (n = 6, F = 1, FEV1 26-63% pred) and control (n = 6, F = 2) subjects completed steady-state exercise on a cycle ergometer. Gas exchange was measured breath-by-breath and the volume of the airway deadspace (V(Daw)) determined using the equal areas method. Exercise data were interpolated to a CO2 output of 0.7 l/min. V(Daw) was similar in the two groups both at rest and during exercise. However, the airway deadspace ventilation (V(Daw)) (median (inter-quartile range)), patients, 6.8 (5.1-7.1) l/min; controls, 4.9 (3.5-5.6) l/min, P < 0.05) was significantly greater in the CF group due to a greater respiratory frequency. These results indicate that in CF patients, abnormally increased V(Daw) is an important contributor to the total (physiological) deadspace ventilation. Exercise performance in CF might be enhanced by efforts directed at facilitating an increase in exercise tidal volume and therefore the adoption of a more efficient pattern of breathing.

The shuttle walk exercise test in idiopathic pulmonary fibrosis.

The shuttle walk test (SWT) is a validated, incremental walking test for chronic obstructive pulmonary disease, but not for idiopathic pulmonary fibrosis (IPF). The measurement of maximal oxygen consumption (VO2 max) is considered to be the gold standard measurement of functional capacity. This study examines the relationship between IPF patients' performance on the SWT and VO2 max. Twenty patients were recruited for the study, which consisted of two separate experiments. Firstly, the relationship between SWT performance on a conventional corridor SWT, with that on a programmable treadmill SWT designed to reproduce the corridor SWT was examined (n=10). In the second experiment, the relationship between performance on the treadmill equivalent SWT and VO2 max measurements was studied (n=10). There was a significant correlation between distance walked on the corridor SWT, and that walked on the treadmill equivalent SWT without VO2 max measurements (367 m vs. 410 m) (r=0.91, P=0.0003). There was a significant correlation between distance walked on the treadmill equivalent SWT (277 m), and the directly determined VO2 max (14.87 ml/kg/min) (r=0.74, P=0.01). During both experiments, a significant correlation was also observed between baseline PaO2 and SWT performance, and between DLCO and SWT performance. The shuttle walk test is a simple objective measure of functional capacity in IPF patients, which should facilitate the evaluation of new therapeutic compounds for IPF.

A randomised clinical trial of nebulised tobramycin or colistin in cystic fibrosis.

Chronic infection with Pseudomonas aeruginosa is associated with progressive deterioration in lung function in cystic fibrosis (CF) patients. The purpose of this trial was to assess the efficacy and safety of tobramycin nebuliser solution (TNS) and nebulised colistin in CF patients chronically infected with P. aeruginosa. One-hundred and fifteen patients, aged > or = 6 yrs, were randomised to receive either TNS or colistin, twice daily for 4 weeks. The primary end point was an evaluation of the relative change in lung function from baseline, as measured by forced expiratory volume in one second % predicted. Secondary end points included changes in sputum P. aeruginosa density, tobramycin/colistin minimum inhibitory concentrations and safety assessments. TNS produced a mean 6.7% improvement in lung function (p=0.006), whilst there was no significant improvement in the colistin-treated patients (mean change 0.37%). Both nebulised antibiotic regimens produced a significant decrease in the sputum P. aeruginosa density, and there was no development of highly resistant strains over the course of the study. The safety profile for both nebulised antibiotics was good. Tobramycin nebuliser solution significantly improved lung function of patients with cystic fibrosis chronically infected with Pseudomonas aeruginosa, but colistin did not, in this study of 1-month's duration. Both treatments reduced the bacterial load.

The role of supplemental oxygen during submaximal exercise in patients with cystic fibrosis.

Repeated bouts of submaximal exercise are an important part of most pulmonary rehabilitation programmes. Patients with moderate-to-severe cystic fibrosis (CF) often demonstrate oxygen desaturation during submaximal exercise, which may limit their ability to participate in these programmes. This study examines whether arterial desaturation contributes to submaximal exercise limitation by testing whether supplemental O2 improves submaximal exercise capacity. Eight patients with CF (mean forced expiratory volume in one second 41% predicted) each underwent two submaximal exercise tests on a bicycle ergometer at 80% of maximal workload. The two tests were identical except for the addition of supplemental O2 (inspiratory O2 fraction 39%) during one of the tests. Exercise duration was significantly longer in the supplemental O2 study versus control (673+/-63 s versus 835+/-99 s). Arterial O2 saturation was also higher in the supplemental O2 study than the control exercise test (96+/-0.3% versus 86+/-1.5%). There was no statistical difference at end exercise between O2 consumption, minute ventilation and heart rate. There was a significant relationship between improvement in exercise capacity and the amount of desaturation during the control exercise test. Results indicate that supplemental oxygen improves submaximal exercise capacity in patients with moderate-to-severe cystic fibrosis. Oxygen therapy may be an important intervention to improve participation and maximise the benefits of pulmonary exercise rehabilitation programmes.

New clinical evidence from the European tobramycin trial in cystic fibrosis.

The major cause of morbidity and mortality in patients with cystic fibrosis (CF) is respiratory disease (Penketh et al., Thorax 1987; 42: 526-532). Recent studies in the USA have shown that intermittent administration of inhaled tobramycin is beneficial to patients with CF who are chronically infected with Pseudomonas aeruginosa (Ramsey et al., N Engl J Med 1999; 340: 23-30; Ramsey et al., Proceedings of the 12th Annual North American Cystic Fibrosis Conference, 1998, Montreal, Canada; Ramsey et al., Abstract from 23rd European Cystic Fibrosis Conference, 1999, the Hague, Netherlands). In Europe, the use of nebulised colistin in patients chronically infected with P. aeruginosa is widespread. A recently published study compared the efficacy and safety of tobramycin nebuliser solution (TNS) and nebulised colistin in CF patients . One hundred and fifteen patients were randomised to receive either TNS or colistin in a multi-centre open-labelled study that assessed change from baseline in FEV(1) and sputum P. aeruginosa density. TNS produced a mean 6.7% improvement in lung function (P=0.006), whilst there was no significant improvement in the colistin-treated patients. The TNS-treated patients had a significantly greater improvement in lung function than those treated with colistin (P=0.008). The safety profile of both treatments was good. We conclude that patients treated with TNS for 1 month experience improved lung function compared with patients treated with colistin.

Ventilatory response to incremental and constant-workload exercise in the presence of a thoracic restriction.

In the presence of an externally applied thoracic restriction, conflicting ventilatory responses to exercise have been reported, which could be accounted for by differences in exercise protocol. Seven male subjects performed two incremental and two constant-workload ergometer tests either unrestricted or in the presence of an inelastic corset. Ventilatory variables and arterial estimates of PCO(2) were obtained breath by breath. Subjects hyperventilated in the presence of restriction during the constant-workload test (38.4 +/- 3.0 vs. 32.8 +/- 3.0 l/min for the average of the last 3 min of exercise, P < 0.05), whereas, at an equivalent workload during the incremental test, ventilation was similar to unrestricted values (unrestricted = 26.3 +/- 1.6 vs. restricted = 27.9 +/- 2.3 l/min, P = 0.36). We used a first-order linear model to describe the effects of change in workload on minute ventilation (24). When the time constants and minute ventilation values measured during unrestricted and restricted constant-workload exercise were used to predict the ventilatory response to the respective incremental exercise tests, no significant difference was observed. This suggests that hyperventilation is not seen in the restricted incremental test because the temporal dynamics of the ventilatory response are altered.

Ventilatory responses to hypercapnia and hypoxia in relatives of patients with the obesity hypoventilation syndrome.

BACKGROUND: It is unclear why some morbidly obese individuals have waking alveolar hypoventilation while others with similar obesity do not. Some evidence suggests that patients with the obesity hypoventilation syndrome (OHS) may have a measurable premorbid impairment of ventilatory chemoresponsiveness. Such an impairment of ventilatory chemoresponsiveness in OHS, however, may be an acquired and reversible consequence of severe obstructive sleep apnoea (OSA). We hypothesised that, in patients with OHS who do not have coincident severe OSA, there may be a familial impairment in ventilatory responses to hypoxia and hypercapnia. METHODS: Sixteen first degree relatives of seven patients with OHS without severe OSA (mean (SD) age 40 (16) years, body mass index (BMI) 30 (6) kg/m(2)) and 16 subjects matched for age and BMI without OHS or OSA were studied. Selection criteria included normal arterial blood gas tensions and lung function tests and absence of sleep apnoea on overnight polysomnography. Ventilatory responses to isocapnic hypoxia and to hyperoxic hypercapnia were compared between the two groups. RESULTS: The slope of the ventilatory response to hypercapnia was similar in the relatives (mean 2.33 l/min/mm Hg) and in the control subjects (2.12 l/min/mm Hg), mean difference 0.2 l/min/mm Hg, 95% confidence interval (CI) for the difference -0.5 to 0.9 l/min/mm Hg, p=0.5. The hypoxic ventilatory response was also similar between the two groups (slope factor A: 379.1 l/min * mm Hg for relatives and 373.4 l/min * mm Hg for controls; mean difference 5.7 l/min * mm Hg; 95% CI -282 to 293 l/min * mm Hg, p=0.7; slope of the linear regression line of the fall in oxygen saturation and increase in minute ventilation: 2.01 l/min/% desaturation in relatives, 1.15 l/min/% desaturation in controls; mean difference 0. 5 l/min/% desaturation; 95% CI -1.7 to 0.7 l/min/% desaturation, p=0. 8). CONCLUSION: There is no evidence of impaired ventilatory chemoresponsiveness in first degree relatives of patients with OHS compared with age and BMI matched control subjects.

Role of respiratory function in exercise limitation in chronic heart failure.

OBJECTIVE: To test the hypothesis that respiratory function contributes to limit maximal exercise performance in patients with chronic heart failure by using the technique of dead space loading during exercise. DESIGN: Blinded subjects underwent two maximal incremental exercise tests in random order on an upright bicycle ergometer: one with and one without added dead space. SETTING: : Tertiary-care university teaching hospital. SUBJECTS: Seven patients with stable chronic heart failure (mean +/- SEM left ventricular ejection fraction, 27 +/- 3%). RESULTS: Subjects were able to significantly increase their peak minute ventilation during exercise with added dead space when compared with control exercise (57.4 +/- 5.9 vs 50.0 +/- 5.6 L/min; p < 0.05). Peak oxygen uptake, workload, heart rate, and exercise duration were not significantly different between the added dead space and control tests. Breathing pattern was significantly deeper and slower at matched levels of ventilation during exercise with added dead space. CONCLUSION: Because patients with chronic heart failure had significant ventilatory reserve at the end of exercise and were able to further increase their maximal minute ventilation, we conclude that respiratory function does not contribute to limitation of exercise in patients with chronic heart failure.

Evolution of inspiratory and expiratory muscle pressures during endurance exercise.

We investigated the relationship between minute ventilation (VE) and net respiratory muscle pressure (Pmus) throughout the breathing cycle [Total Pmus = mean Pmus, I (inspiratory) + mean Pmus, E (expiratory)] in six normal subjects performing constant-work heavy exercise (CWHE, at approximately 80% maximum) to exhaustion on a cycle ergometer. Pmus was calculated as the sum of chest wall pressure (elastic + resistive) and pleural pressure, and all mean Pmus variables were averaged over the total breath duration. Pmus, I was also expressed as a fraction of volume-matched, flow-corrected dynamic capacity of the inspiratory muscles (P(cap, I)). VE increased significantly from 3 min to the end of CWHE and was the result of a significantly linear increase in Total Pmus (Delta = 43 +/- 9% from 3 min to end exercise, P < 0.005) in all subjects (r = 0. 81-0.99). Although mean Pmus, I during inspiratory flow increased significantly (Delta = 35 +/- 10%), postinspiratory Pmus, I fell (Delta = -54 +/- 10%) and postexpiratory expiratory activity was negligible or absent throughout CWHE. There was a greater increase in mean Pmus, E (Delta = 168 +/- 48%), which served to increase VE throughout CWHE. In five of six subjects, there were significant linear relationships between VE and mean Pmus, I (r = 0.50-0.97) and mean Pmus, E (r = 0.82-0.93) during CWHE. The subjects generated a wide range of Pmus, I/P(cap, I) values (25-80%), and mean Pmus, I/P(cap, I) increased significantly (Delta = 42 +/- 16%) and in a linear fashion (r = 0.69-0.99) with VE throughout CWHE. The progressive increase in VE during CWHE is due to 1) a linear increase in Total Pmus, 2) a linear increase in inspiratory muscle load, and 3) a progressive fall in postinspiratory inspiratory activity. We conclude that the relationship between respiratory muscle pressure and VE during exercise is linear and not curvilinear.