Again, during the course of diseases complicated with paralysis of the pharynx (cow-pox, parturient apoplexy), obstruction of the pharynx and œsophagus (tympanitic indigestion), intense pharyngeal dysphagia (foot-and-mouth disease), etc., the risk of broncho-pneumonia due to foreign bodies is much greater still. It may even occur spontaneously in animals in the enjoyment of complete freedom (foot-and-mouth disease).
Lastly, cases of broncho-pneumonia have been described as a consequence of inhaling foreign bodies, when the animals are fed, for example, with meal made from undecorticated cotton-seed. Under such circumstances the lesions produced are similar to those of pneumoconiosis in man (the chronic forms of pneumonia of miners, charcoal-burners, quarrymen, stonemasons, etc.).
Symptoms. The symptoms of gangrenous broncho-pneumonia become apparent immediately after the foreign body has entered the trachea. They commence with a violent, spasmodic cough, produced by reflex action, which in its turn is due to the laryngeal mucous membrane having been touched. But this cough is now too late to be of use, for the food, drug or liquid has passed into the depths of the trachea, and cannot be ejected. The cough soon ceases, and the animals may even return to their food. These appearances, however, are deceptive, for twelve, twenty-four or forty-eight hours later the cough reappears, whilst appetite diminishes. The attacks of coughing are succeeded by the discharge of a greyish or reddish-grey offensively smelling material; respiration becomes more rapid, the heart’s action violent, and the temperature rises to 103° or even 105° Fahr. (39·5 to 40·5° C.).
The patients soon refuse all solid food, and if the chest is then examined by percussion one finds partial dulness, rarely simple dulness, over the cardiac lobes opposite the point where the girth passes. The partial dulness may rise to a varying height on both sides; sometimes it is confined to one side.
On auscultation the respiratory murmur in the upper two-thirds of the lung appears exaggerated on both sides, and is found to have greatly diminished, or disappeared altogether in the inferior zone.
Auscultation through the scapula almost always shows that the anterior lobes are affected; but, at all events, in the examinations we have made, checked by post-mortem examination, the cardiac lobes have always proved to be most affected, a fact attributable to the direction of the principal bronchi. The lower portion of the posterior lobes may also be affected, but this is rarer. All the lower zone is irregularly hepatised, and on auscultation one hears large moist râles, whilst respiration sometimes appears of a blowing character, and divided by a pause, but there is no tubal souffle. If the patient survive for a certain time, the sounds heard on auscultation undergo change; gurgling noises and sometimes true cavernous souffles are heard, as a result of suppuration in the bronchi and gangrene of one or more areas in the lung. Diffuse gangrene is rare, and the inferior zone is usually the only portion affected.
During this phase the expired air has an absolutely characteristic gangrenous odour.
Death occurs by asphyxia and intoxication, but some animals hold out for a fortnight and more.
Lesions. Post-mortem examination reveals a suppurative but secondary inflammation of the mucous membrane of the nasal cavities, pharynx, larynx, and trachea.
In the bronchi, sometimes very deeply placed, remains of foreign bodies are found in cases where some solid material has been inhaled. The mucous membrane of the bronchi is violet in colour, in places appears to be sloughing, and is covered by gangrenous patches immersed in a reddish-grey putrid fluid of offensive odour. In places the pulmonary tissue has undergone gangrene; and incision of the diseased centres discovers irregular cavities, filled with a pultaceous, greyish material, which often makes its way into the bronchi. These are the irregular cavities which give rise to the gurgling sounds. The walls of these cavities are formed of disintegrating pulmonary tissue, which again is surrounded by a zone of grey hepatisation. The gangrenous areas may unite, forming vast caverns. If near the surface they cause adhesive or septic pleurisy.