Relation between occupational asthma case history, bronchial methacholine challenge, and specific challenge test in patients with suspected occupational asthma

Abstract

Inhalative methacholine challenge (MC) was performed in 229 subjects presumed to suffer from occupational asthma due to exposure to airborne latex allergens (n = 62), flour (n = 28), isocyanates (n = 114), or irritants in hairdressers' salons (n = 25). They were also subjected to specific challenges with the occupational agents they were exposed to, completed a questionnaire using an abbreviated version of the ATS‐DLD, and were interviewed by an experienced physician. Bronchial hyperresponsiveness in MC was defined by the results obtained in a previous study with 81 healthy volunteers. The threshold in these controls was set at a cumulative MC dose of 0.3 mg, corresponding to a sensitivity of 95%. The main purpose of the study was to investigate whether the MC and/or the occupational asthma case history are reliable predictors of the specific challenge test outcomes. In 40–72% of examined subjects, workplace‐related asthma complaints occurred, with bronchial hyperreactivity in the MC ranging from 48% to 61%. However, only 12–25% demonstrated a significant bronchoconstructive reaction in the specific challenge test. MC results are only moderately associated with workplace‐related asthma case histories. Positive outcomes of challenges with occupational agents are well correlated with positive MC results plus occupational asthma case histories. The combination of MC and occupational asthma case history shows a relatively high specifity (62%, 86%, 80%), but the sensitivity was moderately low (83%, 71%, 52%). MC sensitivities were 92%, 71%, and 62% (case histories of hairdressers were not available). We conclude that in most cases, occupational asthma (as defined by a specific challenge test response) is combined with bronchial hyperresponsiveness and workplace‐related asthmatic symptoms. However, subjects of each exposure group demonstrated bronchial hyperresponsiveness and complained of workplace‐related asthmatic symptoms, but occupational asthma could not be proved in the specific challenge test. In subjects with a positive occupational asthma case history, a negative MC test result can almost rule out a positive specific challenge test result. Hence, the MC test can reduce performance of the laborious specific challenge test. Am. J. Ind. Med. 33:114–122, 1998. © 1998 Wiley‐Liss, Inc.

Occupational asthma caused by samba (Triplochiton scleroxylon) wood dust in a professional maker of wooden models of airplanes: A case study

“…In our case 18% fall in FEV 1 was recorded in the 2nd and the 5th h after the SOCT. It is suggested by some evidence that in the case of a delayed reaction, FEV 1 fall ≥ 15% may be considered as positive SICT [31][32][33][34][35]. In the presented case occupational history of asthma symptoms, type of exposure, positive results of SPT to occupational allergens, the high level of bronchial hyperresponsiveness as well as significant decrease in FEV 1 and clinical symptoms with bronchial obstruction induced by the specific challenge test confirmed a positive reaction to the occupational allergen.…”

Haemorrhagic hypersensitivity pneumonitis due to naphthylene-1,5-diisocyanate

“…The challenge performed in this subject proved safe in a high number of asthmatic subjects and also in a small number of subjects with hypersensitivity pneumonitis due to diisocyanates [7]. Nonetheless a 10-min step with diisocyanate concentrations only slightly above the detection limit of the monitoring device was used.…”

“…Single-breath carbon monoxide diffusing capacity as well as arterial blood gases at rest and after 6 min of treadmill exercise with 125 watts were normal. There was no bronchial hyperresponsiveness [7]. Blood glucose was elevated.…”

Challenge inhalation tests in the diagnosis of occupational asthma: the guidelines of European Respiratory Society

“…Такой способ расчета более чувствителен, чем фиксированные пороговые значения [50], но требуются повторные измерения ОФВ 1 в течение по крайней мере 3 дней для адекватной оценки колеба ний этого показателя [50,[104][105][106]. Для интерпрета ции изменений ПСВ после СИПТ единое мнение отсутствует, но при оценке этого параметра также должна учитываться естественная (при отсутствии воздействий) вариабельность ПСВ у данного паци ента; возможно, что вариабельность ПСВ выше та ковой ОФВ 1. Снижение специфической проводимости дыха тельных путей > 50 % (0,5 кПа / с) либо повыше ние специфического бронхиального сопротивле ния > 100 % (превышающее пороговую величину 2 кПа / с) также обычно расценивается как положи тельная реакция на аллергены и производственные вещества [65,107].…”