1.1.3: Pleural space disease Flashcards
An animal presents with difficulty breathing. Which areas could this be localised to?
- URT obstruction
- Loss of thoracic capacity = pleural space disease
- Pulmonary parenchymal disease
- Non-CRS conditions e.g. anaemia, heat stroke -> breathing tends to be rapid and shallow rather than dyspnoea per se
To identify which, use clinical exam. Ultrasound also helps.
Conditions leading to loss of thoracic capacity ± cyanosis
- Pleural effusion
- Pneumothorax
- Neoplasia (pleural or mediastinal)
- Ruptured diaphragm
- Abdominal abnormality e.g. severe ascites, mass
- Gross cardiomegaly
Pleural space disease
accumulation of fluid (pleural effusion), air (pnuemothorax), or soft tissue mass in the pleural space.
How does pleural space disease lead to difficulty breathing?
- There is direct compression of the lungs by fluid/air/mass
- There is loss of negative pressure leading to lung collapse
- If fluid -> this restricts the ability of the lungs to inflate so is known as restrictive lung disease
Clinical signs of pleural space disease
- Restrictive breathing pattern: short, shallow breaths, with the thorax and abdomen looking like a set of bellows (thorax in, abdo out, then thorax out, abdo in)
- Tachypnoea
- Open-mouthed breathing
- Dyspnoea
- Orthopnoea: elbow abduction, sternal recumbency; some CHF patients won’t lie down as abdominal contents restrict diaphragmatic movement
- Cyanosis
- May be acute or chronic
What clinical exam findings might you expect from a patient with pleural space disease?
- Observe the characteristic restrictive respiratory pattern
- Muffled heart/lung sounds
- Percussion of chest e.g. fluid line in pleural effusion
What effect could a mass in the mediastinum have on the apex beat?
A mass in the mediastinum could displace the heart and the apex beat
Why might a pleural effusion form?
If there is:
* Decreased pleural fluid absorption into lymphatics
OR
* Increased fluid formation
True/false: lung lobe torsion could cause chylothorax or haemothorax.
True
* Chylothorax -> occurs if there is disruption to the thoracic duct
* Haemothorax -> occurs if there is bleeding
Exudate
high cellularity and high protein.
e.g. FIP
Pleural effusion
* Lungs float in fluid
* Diaphragmatic lung lobe especially may move
* The cardiac silhouette is obscured by fluid
Pleural effusion
Immediate treatment of pleural effusion
- Oxygen supplementation
- Emergency thoracic ultrasound
- If severely dyspnoeic do not radiograph - unstable and stressed!
- Thoracocentesis: provides immediate relief and stabilisation, can be diagnostic (cell counts, protein, bacterial culture)
How to perform a thoracocentesis for pleural effusion
- Clip and quick surgical prep
- Butterfly needle/catheter at IC 6-8 (ICS 7 usually safe). Insert at level of the costochondral junction.
- Idealise localise a large pocket of fluid with ultrasound first.
- Use aseptic technique (colleague holds syringe while you remain sterile)
Indications for thoracostomy and chest drain placement
- Animals that will require multiple thoracocentesis over a short period of time
- If large volumes of effusion
- If pneumothorax
- Chest wall injuries e.g. flail chest (portion of rib cage is separated from the rest)
- Bite wounds
- Most pyothorax cases - pus is hard to aspirate, in-dwelling chest drain allows periodical lavage
- Following chest surgery
Management of pleural effusion
Depends on cause -> ideally treat primary cause where possible
* Heart failure -> treat where possible
* Pericardial effusion -> treat and drain
* Pyothorax -> chest drain and lavage, need broad spectrum + anaerobe antibiotic coverage
* Chylothorax -> diet and/or surgery
Pneumothorax
accumulation of air within the thorax but outside the lung.
True/false: rupture of the oesophagus can produce pneumothorax.
True
Clinical signs of pneumothorax
- Restrictive breathing (slow to rapid breathing)
- Dull lung sounds dorsally (air rises to dorsal part of thorax)
- Increased lung sounds ventrally (lung gets compressed here)
- Percussion -> increased resonance (like a drum)
Pneumothorax
* There is characteristic displacement of the heart caused by movement of the lung lobes ventrally
* The lung lobes have in turn been displaced by air
* Free air surrounds the collapsed lung lobes
Diagnosis of pneumothorax
- Physical exam
- Assessment of respiratory status
- Radiographs if stable enough
- Thoracic ultrasound -> there is loss of the normal glide sign in pneumothorax
Treatment of pneumothorax
- Provide oxygen
- Drain pnuemothorax: ICS 7-8; may have to drain 2-3 times but often good prognosis
- Strict cage rest for 2 weeks
- Some patients may require chest drains (a.k.a. in-dwelling thoracostomy tube)
Diaphragmatic rupture
Diagnosis of mediastinal masses
- Diagnostic imaging: CT - very useful for surgical planning
- If radiography -> may be hidden behind pleural effusion; check for displacement/tracheal position
