Allergic alveolitis due to herb dust exposure.
(1/93)
We report an episode of allergic alveolitis in a female farmer due to massive exposure to organic dust contaminated with microorganisms during threshing of herbs (thyme). The patient's medical history, the results of exposure test, inhalation challenge, and bronchoalveolar lavage suggested the diagnosis of allergic alveolitis (+info)
High-resolution computed tomographic characteristics in acute farmer's lung and in its follow-up.
(2/93)
High resolution computed tomography (HRCT) scans are increasingly used in hypersensitivity pneumonitis (HP). This study looked at HRCT findings at different phases of farmer's lung (FL), a common form of HP. A cross sectional analysis of 95 HRCT scans of FL cases (20 acute, 75 with a history of FL, 48 still in contact (Ex +) (dairy farm), and 27 who had ceased contact (Ex-)) was made. All scans were read independently by two, and if needed by three, radiologists blinded to the category. The lungs were divided into six regions (fives lobes + lingula), and read for attenuation/mosaic, ground-glass, micronodules, fibrosis, and emphysema. A score of 0-3 was given for each region and each variable: 0 = absence, 1 =<25% of the surface, 2 = 25-50%, 3 =>50%. Mediastinal lymphadenopathy was also noted. Ground glass, predominating in the lower lobes, was the most frequent feature in the acute and Ex+ cases. Other abnormalities had no preferential distribution. Ex+ had more ground-glass than the Ex- (p=0.0025). Emphysema was more frequently seen than interstitial fibrosis (p=0.004). Mediastinal lymphadenopathy was present in 26 cases (9 acute, 10 Ex+ and 7 Ex-). In conclusion, in farmer's lung: 1) ground-glass predominates in the lower lobes while the other abnormalities have no anatomic predilection; 2) contact avoidance allows a better resolution of computed tomography abnormalities than continued exposure; 3) emphysema is a more frequent finding than interstitial fibrosis; and 4) the presence of mediastinal lymphadenopathy has no negative diagnostic value. (+info)
An animal model of hypersensitivity pneumonitis in the rabbit.
(3/93)
This study was devised to produce an animal model of hypersensitivity pneumonitis in order to study both the induction and the elicitation of the disease. Rabbits exposed by aerosol to large quantities of pigeon antigens developed a humoral, but not cellular, immunologic response. Moreover, their lungs were essentially normal histologically. A single i.v. injection of killed BCG in oil permitted the induction of pulmonary cell-medid hypersensitivity to the inhaled antigen, as well as the development of pulmonary lesions which were more severe than that caused by the administration of BCG alone. The humoral immunologic response to the inhaled antigen was not increased after BCG injection. Since many individuals are exposed to the etiologic agents of hypersensitivity pneumonitis for extended periods without developing the disease, these findings in animals suggest that some event may occur to induce cell mediated hypersensitivity in order to initiate the disease process. In addition, we have shown that animals with normal lung histology and circulating complement-fixing antibodies undergo serum complement (CH50) depression after an aerosol challenge with the specific antigen. Animals with circulating, complement-fixing antibodies, and inflamed lungs (BCG-induced failed to undergo a complement depression subsequent to an aerosol challenge with specific antigens. These results re consistent with those seen in symptomatic and asymptomatic pigeon breeders and suggest that antigen distribution through the lung is important in the pathogenesis of hypersensitivity pneumonitis. (+info)
The effect of soluble material from mouldy hay dust on the complement system.
(4/93)
The soluble material derived from the respirable fraction of mouldy hay dust has anti-complementary as well as enzyme activity. The anti-complementary activity resides in a heavy molecular weight fraction (approx. 800,000) and acts directly on C1 without combination with or alteration of IgG or IgM. The enzyme function has a lower molecular weight (approx. 30,000-38,000) and is related to papain in that IgG is split into two distinct components of similar molecular weight and with antigenic determinants the same as Fab and Fc pieces respectively. C1 activation leads to C3-9 depletion and on a per sample basis it is calculated that the soluble mouldy hay dust material is up to sixty-six times more active at C3-9 activation than the particulate material in mouldy hay dust. It is probable that the capacity to activate C1 resides in other dusts and may be a basis for non-immune histamine release in the lungs when such a dust is inhaled. It is also probable that non-specific skin reactions are related to C1 activation. The finding of an enzyme with papain-like activity is significant since the introduction of papain into the lungs of the experimental animal leads to emphysema and this has been described as a feature of farmer's lung. (+info)
Chest symptoms in farming communities with special reference to farmer's lung.
(5/93)
Surveys were carried out on random samples of the farming population in Devon and Wales in order to estimate the prevalence of respiratory symptoms and of positive precipitin reactions to thermophilic fungi. Bronchitis, as defined, was common among the Welsh hill farmers, and the proportion of positive serological tests was higher in both the areas surveyed in Wales as compared with Devon. All three surveys confirmed a previous finding that the proportion of positive precipitin tests was higher among non-smokers than smokers. Although the numbers were small there was some indication that measurement of peak expiratory flow showed different relationships with age in non-smokers according to the presence or absence of positive precipitin tests. The difficulty of determining prevalence rates for farmer's lung is discussed, but the results suggest a rate not dissimilar to those found in two areas of Scotland which were more than 20 times higher than any figure previously reported in Britain. (+info)
Farmer's lung in Devon.
(6/93)
Farmer's lung is a cause of disability to agricultural workers in Devon and there is no evidence that the incidence is falling. A survey of known cases was made to assess the degree of disability in relation to the clinical history, the presence of farmer's lung precipitins, tests of lung function, and radiographic changes. Information was obtained about 200 patients diagnosed between 1939 and 1971. A survey of 148 of these patients showed that the disease was most commonly diagnosed in men aged 40 to 50 years and the most important symptom at diagnosis was dyspnoea related to occupational exposure to hay or grain. The onset was often insidious and only 67 patients (45%) were diagnosed during the first year of the disorder. Disability was severe in about one-third of the cases. The degree of disability did not seem to be related to the serological changes recorded either at diagnosis or at the time of our survey. Disability was commonly associated with restriction and reduced gas transfer factor and with airways obstruction in more severe cases. Many individuals reporting significant disability had only slightly abnormal ventilatory function tests at rest. Radiographic changes were found at survey in about one-third of the subjects reporting disability. Many farmers had not used an efficient mask. Treatment is unsatisfactory but steroid therapy is effective in acute episodes. (+info)
Use of a serologically distinct strain of Thermoactinomyces vulgaris in the diagnosis of farmer's lung disease.
(7/93)
During investigations into farmer's lung disease it was noticed that Micropolyspora faeni (MF) was isolated and identified with ease, but difficulty was encountered in the identification of Thermoactinomyces vulgaris (TV), although an organism resembling TV was frequently isolated. Extracts prepared from the isolates resembling TV (called Thermoactinomyces vulgaris variant, TVV) when tested against the standard TV antiserum by double diffusion, did not produce any precipitin lines. When TVV extracts were tested against the serum of a patient from whom TVV had been isolated from the sputum, +++ precipitin lines were observed. With the TVV extracts the authors have demonstrated the existence of a serologically distinct strain of TV, and also that it would be a useful addition to the routine testing of antibodies to farmer's lung disease. (+info)
Coeliac disease with farmers' lung.
(8/93)
Two patients with allergic alveolitis due to mouldy hay antigens (farmer's lung) were shown to have malabsorption due to coeliac disease. As similar associations have been found with other alveolar diseases, this association is probably not fortuitous and further population screening should be done. (+info)