Hydrothorax, Haemothorax and Pneumothorax
Hydrothorax, Haemothorax and Pneumothorax respectively denote the accumulation of transudate fluid, blood, and air in the pleural cavity or sac.
Hydrothorax
Hydrothorax is the accumulation of transudate in the pleural sac, or pleural cavity.
Etiology of Hydrothorax
- Hypoproteinemia is the most important cause of hydrothorax. Reduced osmolarity in the blood leads to the escape of plasma into the body cavities. Liver diseases, parasitic infestations, and malnutrition are a few examples of hypoproteinemia.
- Congestive heart failure and subsequent escape of plasma into tissue spaces.
- Few viral infections, like African horse sickness and enzootic bovine leukosis.
Haemothorax
Haemothorax is the accumulation of blood in the pleural sac, or pleural cavity.
Etiology of Haemothorax
- Traumatic injury to the chest wall and subsequent haemorrhage.
- Hemangiosarcoma of the pleural surface.
- The best example of aneurism is spirocerca lupi infestation in canines, aortic aneurysm, and exercise-induced spontaneous rupture leading to hemothorax, as has been observed in dogs.
Pneumothorax
Pneumothorax is the accumulation of air in the pleural cavity or sac.
Etiology of Pneumothorax
- Injury to the chest wall, e.g., fracture of the ribs, stab injury to the chest wall, perforation of the pleural membrane by a foreign body.
- Thoracotomy
- Spontaneous rupture of nodules in the lung, e.g., tuberculosis.
Pathogenesis
Accumulation of fluid and blood results in the collapse of the natural portion of the lungs and atelectasis. The severity of dyspnea depends on the degree of atelectasis.
In pneumothorax, air entered in the pleural sac causes compression of the lung on the affected side. Pneumothorax is fatal in horses because the mediastinum is communicating, whereas it is suitable in bovines as the mediastinum is separate. Collapse of the lung causes alveolar hypoventilation, hypoxia, and cyanosis, which can lead to compression and collapse of the vena cava.
In hydrothorax and haemothorax, gradual development of dyspnea, percussion dullness over ventral parts of the lung, absence of breath sounds, and rapidly developing anaemia are observed.
In pneumothorax, acute inspiratory dyspnea, collapse of the rib cage on the affected side, compensatory increase and bulging of the unaffected side of the chest wall, complete absence of lung sound, and tympanie sound on percussion (hyper-resonance) on the affected side are observed. Displaced heart sounds can be characteristic.
Diagnosis
- Thoracocentesis in the hydrothorax and hemothorax is useful.
- Radiographic examination shows a collapsed lung and displacement of the mediastinum.
Treatment
Treatment of the primary condition is hydrothorax, and hemothorax is necessary. Temporary drainage of the fluid in the pleural sac is helpful. Parenteral coagulants and blood transfusions can be life-saving measures in severe hemothorax.
Rest and preventing excitation are priorities in the treatment of pneumothorax. An external wound on the chest wall should be sealed as soon as possible. Emergency decompression of the pleural cavity with a needle connected to a rubber tube submerged in water or saline provides water-sealed drainage.