Animals liable. Causes, irritation through effusion and exudate acting
on susceptible pleura, or by other disease products in lung or pleura.
Unhygienic surroundings and management predisposes. Frequent chills in
cold water. Symptoms, unthriftiness, easily blown, fatigued, or
sweated, cough, paroxysmal under exertion, pallor of mucous membranes
becoming congested on slight exertion, difficult breathing when
recumbent, percussion and auscultation signs of pleurisy and
hydrothorax. Lesions, great liquid effusion, clotting on exposure,
with much albumen and cell forms. False membranes partially organized.
Treatment, tonic, diuretic, derivative, diet nourishing,
counterirritants, paracentesis.
In all domestic animals acute pleurisy may merge into the chronic form,
the irritation being maintained by the presence of the residuum liquid
and the false membranes and adhesions which interfere with the free
dilatation of the chest. The pleura too, having been once inflamed,
retains an increased susceptibility to such disturbing conditions. In
other cases the affection is symptomatic of other chronic affections, as
tuberculosis, glanders, and neoplasms of various kinds. It has been seen
especially in old, weak and debilitated subjects, kept in confined,
impure stables or habitually exposed to undue cold and damp. Hence dairy
cows in unhygienic conditions, and hunting dogs, which plunge in water
when heated, are among the most frequent victims.
_Symptoms_ are often obscure. The affected horse may be bright and
lively, showing little respiratory disturbance unless under exertion.
Yet there is a general appearance of unthriftiness, with erect, dry
hair, hidebound, and a small, dry cough. Under work there is hurried
breathing, early exhaustion, ready perspiration, and aggravation of the
cough which then occurs in paroxysms. Auscultation and percussion give
characteristic signs according as there may or may not be false
membranes or effusion at particular points. It is usually bilateral in
horses, unilateral in other animals.
In cows in addition to the corresponding symptoms, there is pallor of
the mucous membranes when at rest, quickly transformed into congestion
under exercise, suppression of the milk, and weak heart beats unless
when excited. In the advanced condition the animal has difficulty of
breathing when recumbent on the sound side and subcutaneous infiltration
is felt or seen beneath the sternum or in the limbs. The affected side
shows an increased dimension, vertical and longitudinal, of the chest,
and the intercostal spaces in their lower part bulge out and fluctuate.
In cows and indolent animals there may be a quiescent condition or very
slow progress, but any violent exertion is likely to give a sudden
stimulus to the morbid process.
_Lesions._ The liquid effusion, usually unilateral, except in the horse
may amount to 40 quarts in the latter animal, 30 quarts in the ox
(Rigot), and 5 to 6 quarts in the dog. Unless there has been a recent
sudden accession of inflammation it is of a pale straw color, with, in
the dog, a slight rosy tinge. It clots loosely on exposure to the air
and contains a large amount of albumen and few cell forms. The false
membranes are thick and white at some points and red and vascular at
others. In the main they are completely organized. The lung is more or
less collapsed and the right heart dilated and attenuated.
_Treatment_ must be in the main tonic, diuretic and derivative. Food
must be nourishing, digestible and in liberal amount; diuretics and
bitter tonics with digitalis and, (if there is little fever)
preparations of iron are to be pushed as far as the strength will allow;
and the counterirritants applied to the sides of the chest a number of
times in succession. Iodides may be used internally and externally, and
_paracentesis_ must be employed unless early improvement is manifested.