A diaphragmatic hernia is a condition in which a break in the diaphragm allows protrusion of abdominal organs into the chest. It may be caused by trauma, a difficult birth, or recent strenuous activity. The condition is not very common in horses.
The signs of hernia can vary, depending on the duration of the disease and the species affected. In horses, the most frequent sign is acute, severe colic caused by the displaced intestines; respiratory signs occur less frequently.
Careful physical examination by the veterinarian, including listening to and tapping the chest and abdomen, usually suggests the presence of the hernia. The definitive diagnosis is usually made from x-rays, which can reveal changes in the shape of the diaphragm and the displacement of abdominal organs. Ultrasonography can be useful in cases where obtaining an x-ray is difficult. Surgical repair of the hernia is the only treatment.