Diffuse panbronchiolitis: case report and review of the literature.

Diffuse panbronchiolitis is an uncommon disease of unknown aetiology mainly occurring in Asian races. Treatment with erythromycin acting through unclarified mechanisms is promising and may improve the poor prognosis currently associated with the disease. A case is presented illustrating how the imaging features of the disease, particularly on high-resolution computed tomography, may be used to support a diagnosis suggested on clinical grounds.

Lymphomatoid granulomatosis: case report and review of the literature.

Lymphomatoid granulomatosis (LG) is an uncommon disease now regarded by most authors as an unusual form of lymphoma with the ability to affect any bodily system. The disease and its complications may result in a spectrum of radiological appearances. A case illustrating how cerebral lesions may mimic demyelinating plaque, neoplasm or infection and how pulmonary lesions may lead to pneumopericardium is presented. The difficulty in establishing a definitive diagnosis, due to the non-specificity of symptoms, pathological investigations and radiological appearances of the disease, is emphasized. Clinicians must therefore consider LG in their differential diagnoses, as delayed treatment may affect prognosis.

Chemodectoma of the trachea.

The case history is described of a patient with lower tracheal chemodectoma who presented with haemoptysis. After conservative management for eight years she represented with airways obstruction. Preoperative tumour embolisation was followed by laser ablation, stenting, and radiotherapy.

Inspiratory muscle training compared with physiotherapy in patients with chronic airflow limitation.

The effects on exercise performance of physiotherapy (PT) (8 patients) were compared with those of inspiratory muscle training (IMT) (9 patients) in severe chronic airflow limitation. Exercise performance was measured by 3 tests: the distance walked in 12 min, peak oxygen uptake on a progressive multistage exercise test, and endurance time at two thirds of maximal power output. Measurements were repeated after a 1-month control period during which no change was observed apart from an increase in the distance walked in 12 min in the PT group. The PT patients then performed graded exercise in a physiotherapy program 3 times weekly, whereas the IMT patients trained for 30 min daily, inspiring against a resistance. Measurements were repeated after 1 and 2 months of training. Physiotherapy was associated with insignificant increases in exercise performance, whereas IMT produced both an increase in endurance time and in the distance walked in 12 min. We concluded that a simple at-home training program of inspiratory muscles was more effective than this particular physiotherapy program in improving exercise performance of some patients with severe chronic airflow limitation.

The effects of inspiratory muscle training on exercise performance in chronic airflow limitation.

Using a simple, inexpensive, at-home program, 12 patients with moderate-to-severe chronic air flow limitation trained their inspiratory muscles. All showed increased inspiratory muscle endurance with no change in inspiratory muscle strength. Seven of the twelve patients increased their endurance time for submaximal exercise beyond the 90% confidence limits determined by 2 pretraining tests (i.e., a more than 40% increase in endurance time). The same group of 7 patients increased the maximal power output (p less than 0.005) and peak oxygen uptake (p less than 0.05) on a progressive exercise test after 2 months of training and increased the distance walked in 12 min after both 1 (p less than 0.005) and 2 (p less than 0.005) months of training. In 6 of the 7 patients in this group, the pretraining submaximal exercise tests were accompanied by electromyographic changes heralding inspiratory muscle fatigue. Their increased endurance time post-training was associated with a delay or absence of these changes. In the other group of 5 patients, who showed no change in exercise performance with training, electromyographic changes heralding inspiratory muscle fatigue were never observed in submaximal exercise tests. We concluded that although the endurance of the inspiratory muscles of patients with chronic airflow limitation is increased, specific training of the inspiratory muscles is usually associated with improved exercise performance only in those who demonstrate electromyographic changes heralding inspiratory muscle fatigue during exercise.

Occlusion pressure responses in asthma and chronic obstructive pulmonary disease.

During CO2 rebreathing we measured ventilation and the pressure generated during the first 0.1 sec of inspiratory effort against a closed airway (P 0.1) in 12 asthmatics during acute exacerbation, 10 normal subjects, and 10 patients with chronic obstructive pulmonary disease. In normal subjects, the ventilatory responst to CO2 correlated with the P 0.1 response measured as delta In P 0.1. Patients with chronic obstructive pulmonary disease showed depressed responses to CO2 in terms of both ventilation and deltaIn P0.1. However, P 0.1 values in the patients with chronic obstructive pulmonary disease were greater than those of the normal subjects when they were compared at an alveolar PCO2 of 60 mm Hg. Asthmatics' responses to CO2 were similar to those of patients with chronic obstructive pulmonary disease. When measured at an alveolar PCO2 of 60 mm Hg, asthmatics' P 0.1 values were greater than those of both normal subjects and patients with chronic obstructive pulmonary disease. As the asthmatics' airway obstruction decreased so did their P 0.1. The asthmatics, and to a lesser extent the patients with chronic obstructive pulmonary disease, demonstrated increased inspiratory muscle activity that could not be explained on the basis of chemical drive or alterations in functional residual capacity. In the case of the asthmatics it was possible that the increased inspiratory muscle activity was a response to airway obstruction.

Effect of gas physical properties and flow on lower pulmonary resistance.

We measured lower pulmonary resistance (Rlp) in eight dogs and three men breathing gas mixtures having different densities (p) and similar viscosities (mu). Rlp increased with gas density and with flow rate (V). In the dogs, these effects were not observed in lung segments subtended from 4-mm-ID bronchi; in more central airways, resistance varied approximately as (mup V)0.5. These results are compatible with Poiseuille flow in peripheral airways, and, in central airways, with flow resistance described by the equation of boundary layer growth. Rather than two discrete flow regimes, it is likely that flow patterns undergo a continual metamorphosis as Reynolds' numbers (Re) decrease between trachea and alveoli. Accordingly, the airways pressure-flow relationship is not described by any single fluid dynamics equation, but may be explained by the general equation, P = Kmu2-apa-1Va, where a reflects the proportion of inertial to viscous pressure losses and varies between 1 and 2 according to Re. Rohrer's equation described the observed pressure-flow relationships and predicted the change in Rlp with gas physical properties, suggesting a physical basis underlying this adequate mathematical description.

Congenital esophagobronchial fistula in a 62-year-old woman.

A 62-year-old woman had symptoms of cough provoked by ingestion of liquids and radiologic changes compatible with repeated bouts of aspiration pneumonitis. A left bronchoesophageal fistula was easily demonstrated by barium esophagogram and fiberoptic bronchoscopy. Division of the fistula resulted in immediate disappearance of the symptoms, gradual resolution of the radiologic abnormalities, and marked improvement in the results of pulmonary function tests. The fistula appeared to be of congenital origin, but the reason that symptoms developed so late in life remains obscure.

The early detection of airway obstruction.

To assess the sensitivity of tests for early, small airway obstruction, we selected 52 cigarette smokers with a ratio of 1-sec forced expiratory volume to forced vital capacity greater than 70 per cent from a smoking cessation clinic. From these subjects, 29 of the 46 tested demonstrated frequency dependence of dynamic compliance, a finding arbitrarily defined as indicative of small airway obstruction in this group. Dynamic compliance was correlated with the British Medical Research Council questionnaire, routine pulmonary function tests, closing volume as a per cent of vital capacity, maximal expiratory flow-volume curves, and flow dependence of distribution of inhaled boluses of xenon-133 (finite difference Xe). Symptoms of respiratory disease, and abnormal flow-volume curves, specific conductances, and ratios of residual volume to total lung capacity were also present in some subjects, but they correlated very poorly with frequency dependence of dynamic compliance. On the other hand, finite difference Xe was abnormal in 85 per cent of cases with frequency dependence of compliance and closing volume was abnormal in 70 per cent. In 8 of 12 subjects restudied 2 months after they stopped smoking, dynamic compliance was less frequency dependent than before smoking cessation. Similar improvements were noted in finite difference Xe, but closing volume was unchanged. Although closing volume and dynamic compliance tended to be abnormal in the same subject, concordance was not excellent, and the effects of smoking cessation suggested that the 2 tests had different determinants.

Site of airway obstruction in asthma as determined by measuring maximal expiratory flow breathing air and a helium-oxygen mixture.

Because maximum expiratory flow-volume rates in normal subjects are dependent on gas density, the resistance between alveoli and the point at which dynamic compression begins (R(us)) is mostly due to convective acceleration and turbulence. We measured maximum expiratory flow-volume (MEFV) curves in asthmatics and chronic bronchitics breathing air and He-O(2). In the latter and in some asthmatics, MEFV curves did not change, indicating that R(us) is mostly due to laminar flow. Therefore, the point at which dynamic compression begins must be further upstream than in normal subjects and the site of obstruction must be in small airways. In other asthmatics, flow increased normally indicating obstruction in larger airways. The response to He-O(2) did not correlate with initial values of pulmonary resistance, the initial MEFV curves or the response to bronchodilators. We conclude that the site of airway obstruction varies among asthmatics and that the site of obstruction is not detectable by measurement of the usual parameters of lung mechanics.