4. Diseases of the thoracic cavity in dogs and cats (hydrothorax, pneumothorax, diaphragmatic hernia). Differential diagnosis of pleural fluid accumulation. Flashcards

1
Q

Hydrothorax?

A

Hydrothorax

Type of pleural effusion whereby transudate accumulates in the

pleural cavity

Disease that is often secondary to CHF (mainly in cats)

Also caused by:

§ Hypoalbuminaemia

§ Diaphragmatic hernia

§ Portal hypertension

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2
Q

Pneumothorax?

A

Pneumothorax

Air accumulation in the pleural space (pneumomediastinum)

Classification

§ Traumatic: Trauma; Penetrating injury

§ Spontaneous: Idiopathic; Secondary (by airway rupture);

Simple/complicated/tension; Open/closed

CSx: Inspiratory dyspnoea; ↓ Lung & heart sounds; ↓ Respiratory

sounds; ↑ Resonance; Underlying trauma; Cyanosis

Dx: Physical exam; Thoracocentesis/Radiography

Radiological features (See Fig. 4.1)

§ Elevation of the heart from the sternum

§ Demarcation of intrathoracic organs

§ Lung lobe compression

§ ↑ Density of the pulmonary parenchymal tissue

§ Free air between visceral & parietal pleura

§ Ø Pulmonary vascular structures in the periphery

Tx: Thoracocentesis/chest tubing; Blood-patch pleurodesis; Oxygen

therapy; Surgery; Control radiography

If complicated case: Insert a thoracic drainage catheter

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3
Q

Diaphragmatic hernia?

A

Diaphragmatic Hernia

Abdominal contents enter the thoracic cavity

Classification

§ Pleuroperitoneal/peritopericardial (PPDH)

§ Traumatic > Congenital (PPDH > Hiatal hernia)

CSx: Mixed/inspiratory dyspnoea; Shock; Stomach distension;

Dullness; Asymmetric respiratory noises; Shock; Cyanosis;

Arrhythmia

Dx: Physical exam; Radiography; Ultrasonography

Beware that performing a thoracocentesis may produce blood-tinged

fluid

Tx: Surgery

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4
Q

Differential diagnosis of pleural fluid accumulation?

A

Differential Diagnosis of Pleural Fluid Accumulation

Pleural fluid accumulation = Pleural effusion

A build-up of excess fluid between the layers of the pleura outside the lungs

Usually caused by multiple factors

Fluid originating from pulmonary capillaries

§ ↓ Plasma oncotic pressure (hypoproteinaemia)

§ ↓ Pleural pressure (atelectasis)

Fluid originating from systemic capillaries

§ ↑ Vascular permeability (inflammation)

§ ↑ Venous pressure (heart failure)

Fluid originating from the abdomen: Through diaphragmatic holes

Cardiac disease Lung lobe torsion

Diaphragmatic hernia Pancreatitis

FIP Pericardial disease

Heartworm Neoplasia

Idiopathic Venous thrombi

Fluid originating from the lymphatic vessels

§ Blockage of lymphatic stoma

§ Compression due to obstruction

§ ↓ Flow due to ↑ venous pressure

§ Injury from chemotherapy/radiation

§ Limitation of respiratory motion

Causes of build-up: ↑ fluid formation or ↓ fluid drainage

Primary causes of pleural effusion

CSx: Inspiratory dyspnoea; Delayed expiration; Extended neck;

Tachypnoea; Open mouth breathing; Cyanosis

Physical exam

§ Percussion: Horizontal dullness; Diernhofer triangle “air-containing angle” disappears

§ Auscultation: Bronchial sounds above fluid; Ø sounds

under the fluid

Dx

§ Radiography: Blunting on costophrenic & cardiophrenic

angles ; Meniscus signs

§ Ultrasonography: Gold standard for dx

§ Lab. D: CBC; Electrolytes; Urea; LFT-protein

§ Thoracocentesis → Transudate; Modified transudate;

Exudate

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5
Q

Types of pleural effusion?

A

TYPES OF PLEURAL EFFUSION

§ Hydrothorax (see earlier)

§ Pyothorax

§ Chylothorax

§ Haemothorax

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6
Q

Pyothorax, Chylothorax and

A

PYOTHORAX

Septic exudate/pus in the pleural cavity

Causes

§ Infection: Severe bacterial infection in the chest cavity;

Blood-borne infection/Penetrating chest wound

§ Obligate anaerobe infection – Mainly via skin injury

§ Migratory foreign material

Other causes

CHYLOTHORAX

Lymph in the pleural cavity

Opaque to pink exudate upon thoracocentesis

Causes

§ ↓ Lymphatic drainage

§ Idiopathic

§ Congenital (weakness of the lymphatic vessels –

Lymphangiectasia)

§ Non-traumatic: RS-HF; Compression of thoracic duct (by

a tumour/inflammatory adhesion)

§ Traumatic: Rupture of thoracic duct

Dx:

§ Thoracocentesis → Cytology;

§ Triglycerides: Pleural fluid > Blood plasma

§ Lymphangiography

Tx: Thoracocentesis; Treat underlying disease; Low-fat diet;

Surgery; Low fat diet

HAEMOTHORAX

Blood in the pleural cavity

Causes

§ Trauma § Ruptured granuloma

§ Neoplasia § Thymus apoplexy (dog)

§ Coagulopathies

Tx: Chest drain; Treat underlying disease; Thoracic lavage; Surgery

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