4) diseases of the thoracic cavity in dogs and cats Flashcards
General information about the thorax
General information
Anatomy of the pleural space
- Visceral pleura: lung
- Parietal pleura: thoracic wall, mediastinum, diaphragm
- Mesothelial cells (pleural fluid!), vessels, lymphatic vessels (lymphatic drainage)
Pleural effusion - causes
you dont have to know all of them
• Cardiac disease, diaphragmatic hernia, FIP, heartworm, idiopathic, immune-mediated lymphadenitis, lung lobe torsion, pancreatitis, pericardial disease, thoracic duct rupture, thoracic lymphangiectasia, thoracic neoplasia (mesothelioma), venous thrombi
pleural effusion clinical signs and physical exam
Inspiratory type dyspnoea, with delayed expiration, extended neck, tachypnoea, open mouth breathing, cyanosis
• Percussion: horizontal dullness, Diernhofer-triangle
➢ “air-containing angle”
• Auscultation: bronchial sounds above and zero sounds under the fluid
Types of effusions?
Transudate (true), modified transudate, exudate (protein, cell count)
Hydrothorax
Hypoalbuminemia
➢ CHF: mainly in cats
➢ Diaphragmatic hernia
➢ Portal hypertension
Pyothorax
septic exudate
➢ Pleuritis exudativa
➢ Causes
o Obligate anaerobes (Actinomyces, Nocardia): both in dogs and cats, mainly via skin injuries (rarely aerogenic or enteral infection), reddish-brownish, turbulent grits-like exudate
o Penetrating thoracic wounds, migratory foreign material (grass awns), haematogenous metastasis
o FIP: in cats, honey-like, viscous exudate (++ fibrinogen and globulin), can be in both body cavities (peritonitis)
➢ Diagnosis: cytology, culture
➢ Treatment
o Pain relief
o IV antibiotics – cephalothin, metronidazole and enrofloxacin (but culture!)
o Chest drainage – drain as much as possible
o Thoracic lavage: 10 ml/kg warmed 0.9% saline or Ringer Lactate every 8 hours
o Surgery: lobectomy, foreign body removal?
Chylothorax
➢ Opaque to pink exudate
➢ Usually due to
o Decreased lymphatic drainage due to
o Rupture or obstruction of lymphatic flow: neoplasia, traumatic, idiopathic, congenital weakness of the lymphatic vessels (lymphangiectasia)
o Secondary to heart failure (especially cats)
o Pseudochyle (usually formed by lymphoma)
congenital cause: weakness of the lymphatic vessels
non traumatic: right sided heart failure, compression of the thoracic duct
traumatic: rupture of the thoracic duct
diagnosis: thoracocentesis, cytology, triglycerides
Haemothorax: causes
o Trauma o Neoplasia o Coagulopathies (dicoumarol poisoning) o Ruptured granuloma o Thymus apoplexy (dog)
Pneumothorax
- Air accumulation in the pleural space
- Classification
• Open pneumothorax: communication with the outside, usually due to trauma
• Closed pneumothorax: no communication with the outside, due to air leaking from the airways or parenchyma
➢ Spontaneous closed pneumothorax: not due to trauma
• Idiopathic: large, deep-chested dogs, Huskies!
• Secondary: rupture of airways (bullae? Inflammation?)
➢ Traumatic closed pneumothorax: due to trauma but closed - Clinical signs, history
• Acute inspiratory obstructive dyspnoea with tachypnoea
• Reduced lung sounds dorsally
• Decreased heart sounds and respiratory sounds
increased resonance
• Hypoxaemia, cyanosis
• Underlying disease (wounds, rib fractures, coughing) - Diagnosis
• Physical examination
• Thoracocentesis
• Radiographs! - Treatment
• Thoracocentesis / chest tubing - bilateral
• Cage rest
• Oxygen therapy
• Pain relief!
• Surgery: open chest wound, airway leaking
thoracostomy tube, if negative pressure cant be obtained or if air rapidly accumulates. every 4 hours should be aspirated
strict cage rest minimum 1 week
removal of the tube after 24 hours
exploratory thoracostomy for long term management: if bullae or mass lesions are present
radiological features: elevation of the heart from the sternum
obvious demarcation of the intrathoracal organs
compression of the lung loves
Diaphragmatic hernia
- Abdominal contents enter the thoracic cavity
- Classification
• Pleuroperitoneal / peritoneo-pericardial (PPDH)
• Traumatic > congenital (PPDH > hiatal hernia)
- Clinical signs, physical examination • Mixed or inspiratory type dyspnoea • Shock • Stomach distension • Dullness • Asymmetric respiratory noises • Cyanosis • Arrhythmia
- Diagnosis • Physical examination • Radiography +/- contrast studies • Ultrasonography • CAVE: thoracocentesis: can be blood-tinged fluid
- Treatment
• Surgery
Mediastinitis causes and clinical signs
Acute, chronic: underlying disease
Causes: Tracheal- and esophageal perforation, infection (pleural spcae, lung, pericardium)
Clinical signs: head and neck edema, tachypnea, dyspnea, cough, regurgitation, fever, voice changes (recurrent laryngeal nerve)
Physical exam: decreased lung sounds
Radiography: focal or diffuse widening, PTX, pneumomediastinum, pleural effusion
Treatment: antibiotics, perforation of trachea, esophagues, surgical resection of mediastinal mass
treat pyothroax
Mediastinal neoplasia
Origin: lymphoma, thymoma, chemodectoma, esophagus, trachea
clinical signs: tachypnea, head neck and forelimb edema, regurgiation, PD/PU, Horners syndrome
physical exam: dislocation of the heart, compressibility of the cranial thorax is decreased (cats), dyspnea because of the mass, dull areas on percussion of the chest
usually you can hear the heartbeat from both areas of the chest but if there is a tumor it can be onesided
thorax can also be asymetric in case of tumors
e.g. unilateral mesothelioma
there can be edema of the forelimb - rare, thoracal wall thickening, asymetric breathing movements and sounds or circumscribed dullness, cardiac dislocation, in the cat the thorax is not compressed
additional diagnostics: radiography, thoracal ultrasonography: fine needle aspiration, cytology, puncture or biopsy
blood count, punctuate cytology, histology of biopsy sample
pneumomediastinum
trauma of the neck, subcutaneous emphysema
rupture of the airways
esophageal rupture
normal communication between the neck, mediastinum and retroperitoneal region of the abdomen
clinical signs: tachypnea, dyspnea, regurgitation, emphysema of the neck
radiography: pneumomediastinum, PTX, pneumoperitoneum
treatment: spontaneous recovery, PTX, underlying disease
diagnostic aspects of pleural effusions
clinical signs and physical examn:
inspiratory type dyspnea, with delayed expiration, extended neck, tachypnea, open mouth breathing, cyonosis
percussion: horizonal dullness, diernhofer triangle!
auscultation: bronchial sounds above and zero sounds under the fluid
radiography
ultrasonography
thoracocentesis
diaphragmatic hernia
classification: pleuroperitoneal, peritoneopericardial
traumatic > congenital
clinical signs: mixed or inspiratory type dyspnea, shock, stomach distension, dullness, asymmetric respiratory noises, shock, cyanosis, arrythmia
diagnosis: physical exam, radiography, ultrasound
cave! thoracocentesis: can be blood-tinged fluid
treatment: surgery!
