Symptoms. In true accidental diaphragmatic hernia visceral displacement only occurs on the right side, and symptoms of this are immediately apparent. The passage of the liver, reticulum, or omasum into the right pleural sac compresses the lung, causes attacks of dyspnœa and acceleration of the heart’s action.
Fig. 223.—Intra-mediastinal diaphragmatic hernia (viewed in position from the left side). P, Lung; C, heart (displaced); D, diaphragm; H, hernial mass.
Percussion may not reveal any important change, but on auscultation digestive sounds can plainly be heard within the chest.
The symptoms are far from being well defined. They may be more or less intense, and colic may or may not be present. Mediastinal hernia (Fig. 223) appears to develop slowly, and it is only by degrees that the viscera become displaced.
There is then no sudden change, no clearly marked disturbance, but simply a certain amount of digestive irregularity, together with loss of appetite, cessation of rumination, slight indigestion, and moderate tympanites. The disturbance is really due to obstruction in the alimentary canal and displacement of the reticulum and omasum, so that rumination and deglutition are affected.
Very often this condition may last for weeks, in either a stationary or more or less aggravated form, so that there is an appearance of chronic gastro-enteritis, motor dyspepsia, or chronic indigestion.
Though a diagnosis in this sense would be correct, the atony of the rumen is not primary, but of mechanical origin.
One indication is constantly present, which might suggest indigestion due to overloading of the rumen, and which is also seen in ulcerative gastritis, viz., progressive stasis of food in the cavity of the rumen. When the patients remain for some time under observation, this stasis becomes every day more marked, and, being recognised, the diagnosis becomes easier. Animals suffering from mediastinal hernia lose condition, waste away, and in the end may die in a state of cachexia.
