Acute pulmonary intoxications. Overview and practical guidelines

Three types of inhalatory intoxications can be distinguished. In the first type the pulmonary symptoms are seen promptly (chlorine, hydrogen chloride) and are related to destruction of the mucosal membranes of the upper airways. In the second type (nitrogen dioxide, phosgene) the pulmonary symptoms become manifest after several hours and are related to alveolar and small airway involvement. There is no pulmonary damage in the third type of inhalatory intoxication (xylene, toluene). The intoxicating substances are absorbed in the lung and induce toxic effects in other organs. Thus, for example, serious central nervous system depression causing respiratory failure can be observed. There is no need for observation when the patient has no symptoms and the substance belongs to type one. This is totally different for intoxications of the second type. Even where there are no symptoms immediately after exposure, clinical observation is advisable. Sometimes pulmonary symptoms become manifest after ingestion and adsorption of intoxicating substances from the gastro-intestinal tract (paraquat). A real threat after ingestion of petroleum distillates is aspiration resulting in serious chemical pneumonitis. Respiratory symptoms are rarely seen after dermal exposure (hydrogen fluoride).