Diseases of the Pleural Space and Chest Wall

Diseases of the Pleural Space and Chest Wall

• This presentation covers diseases affecting the pleural space and chest wall.
• Learning outcomes include describing pathological issues, diagnostic procedures/therapeutics, and management of these disorders.

What is the Pleural Space?

• The pleural cavity is a potential space between the chest wall, lungs, diaphragm, and mediastinum.

Approach to the Dyspnoeic Patient

• Minimise stress during examination, working quickly.
• Initial treatment includes oxygen therapy, intravenous access, pain relief (e.g., butorphanol), and potentially thoracocentesis.
• Stabilise the patient before extensive diagnostics.

Diagnostics

• Diagnostic Imaging: X-rays are used. Several views might be taken.
• Diagnostic Echocardiography (TFAST): This ultrasound technique targets specific sites (e.g., chest tube site, pericardial site, diaphragmaticohepatic view).
• Thoracocentesis: This procedure removes fluid or air from the pleural space. It might be diagnostic or therapeutic. Equipment includes a butterfly needle, three-way tap, syringe, and measuring bowl. Patient preparation involves sternal recumbency, sterile technique, shaving a 15cm radius area and aseptic preparation.

Thoracocentesis - Fluid Analysis

• Fluid analysis determines if it's a transudate or exudate based on protein and cell count.
• The specific classification of the fluid could be used for diagnosis.
• Pyothorax or FIP can be diagnosed from fluid characteristics alone.

Differentials for Pleural Space Disease

• Pneumothorax: Caused by air in the pleural space, often from respiratory tract, oesophagus, or penetrating wounds/trauma. Types include closed, open, and tension pneumothorax. Treatment involves thoracocentesis, thoracotomy tube, pain relief, oxygen, and possibly antibiotics if trauma.
• Hemothorax: Blood in the pleural space. Causes include trauma, coagulopathy, or neoplasia. Further diagnostics are needed to determine the underlying cause. Treatment includes treating hypothermia/hypovolemia, blood transfusions, and pain relief.
• Chylothorax: Milky pleural fluid with high triglyceride count. Causes include idiopathic cases, traumatic duct rupture, lung lobe torsion, mediastinal masses, or heart disease. Treatment involves thoracocentesis, addressing underlying causes, and possible low fat diets.
• Pyothorax: Purulent fluid in the pleural space. Causes include foreign bodies (like grass seeds), bite wounds or pneumonia. Diagnosis involves evaluating the appearance and smell of the fluid and looking for neutrophils and intracellular bacteria. Treatment includes thoracic drainage (thoracostomy tube), lavage, surgical foreign body removal, and antibiotics, potentially with a guarded prognosis.

Thoracotomy Tube

• This tube is used for frequent pleural drainage, for medical management of pyothorax, or after thoracic surgery. Preparation includes pre-oxygenating the patient and using local or general anaesthesia.

Diaphragmatic Hernia

• Organs shift into the thoracic cavity.
• Clinical signs include dyspnoea, muffled heart/lung sounds, and an abnormal empty abdomen during palpation.
• Treatment involves stabilising the patient followed by surgery, likely with an abdominal approach. Intubation and pneumothorax drainage may be required post-operative.

Differentials for Chest Wall Injury

• Injuries include trauma, flail chest, open pneumothorax, penetrating trauma, and bite wounds.

Flail Chest

• A freely moving section of chest wall due to multiple consecutive rib fractures.
• Clinical signs include tachypnoea, dyspnoea, thoracic pain, and paradoxical movement of the affected segment (inhalation/exhalation).
• Treatment involves emergency stabilisation, chest banding, aggressive pain management, and potentially surgical stabilisation.

Dog Bites

• Thorax is a common site for dog bites.
• Potential complications include rib fractures, lung laceration, intercostal muscle avulsion, crush injuries and bacterial inoculation.
• Treatment involves surgical exploration, wound flushing, and pain relief. Antibiotics are part of the approach.

Summary

• A logical and controlled approach to animals with compromised breathing is advised.
• Thoracocentesis is a valuable diagnostic and therapeutic approach
• Ultrasounds are crucial tools for diagnosing pleural fluid and chest wall masses.