Pleural disease

Question 1

Describe the structure of the pleura.

Answer 1

A single layer of mesothelial cells and sub-pleural connective tissue. 2 layers: visceral and parietal. There is a potential space between the pleural layers. Pleura is lubricated by 2-3 ml of pleural fluid and this has a dynamic turnover. Net fluid is pulled into the lungs and there is a negative pressure inside the lungs.

Question 2

Where does the pleura start and end?

Answer 2

Pleura goes above 1st rib into subclavian fossa. It then extends down towards the liver spleen and kidneys. This is so that the lungs are protected as they expand.

Question 3

Define pleural effusion.

Answer 3

An abnormal collection of fluid in the pleural space.

Question 4

What are the symptoms of a pleural effusion?

Answer 4

Asymptomatic if effusion is small and accumulates slowly. As fluid begins to squash the lungs this causes symptoms. > breathlessness, pleuritic chest pain (inflammatory this may improve, malignant will get worse), dull ache, dry cough, weight loss, fever, malaise and night sweats.

Question 5

What questions would you ask in history about pleural effusion?

Answer 5

Peripheral oedema, liver disease, orthopnea and PND.

Question 6

What are the clinical signs of a pleural effusion?

Answer 6

Chest on affected side: less expansion, stony dullness to percussion, band of bronchial breathing and reduced vocal resonance. Clubbing, tar staining, cervical lymphoadenopathy, raised JVP, deviated trachea and peripheral oedema.

Question 7

What are the causes of a pleura effusion?

Answer 7

Either transudates or exudates.

Question 8

Define transudates.

Answer 8

An imbalance of hydrostatic forces influencing the formation and absorption of pleural fluid. Normal capillary permeability. Usually bilateral.

Question 9

What are the common causes of transudates?

Answer 9

LVF, liver cirrhosis, hypoalbuminaemia and peritoneal dialysis (holes in diaphragm). LiPH.

Question 10

Name some less common and rare causes of transudates.

Answer 10

LESS COMMON: hypothyroidism, nephrotic syndrome, mitral stenosis and PE (2/3 exudate).

RARE: constrictive pericarditis, ovarian hyperstimulation syndrome (IVF), Meigs syndrome.

Question 11

Define exudates.

Answer 11

An increased permeability of pleural surface and/or local capillaries. Usually unilateral. > 30g/L of pleural fluid protein.

Question 12

What are the common causes of exudates?

Answer 12

Malignancy: lung, breast, mesothelioma or metastatic cancer. Parapneumonic: lung abscess, pneumonia or bronchiectasis.

Question 13

Name some less common and rare causes of exudates.

Answer 13

LESS COMMON: PE, RA, autoimmune disease, benign asbestos effusion, pancreatitis, post-MI.

RARE: yellow nail syndrome, drug induced.

Question 14

What are the steps from investigation to diagnosis of a pleural effusion?

Answer 14

CXR, CT, aspiration, biopsy, and thoracoscopy. These usually aren’t required for transudates as the clinical picture is normally characteristic.

Question 15

Describe the different investigations for a pleural effusion.

Answer 15

CXR: confirm presence of effusion. Needs to be > 200 ml before it can be seen. CT thorax: usually differences between benign and malignant disease. ASPIRATION and BIOPSY: use lidocaine, Abrams’ needle blind and Tru-Cut CT guided. Take 4 biopsies, send 3 to cytology and 1 to microbiology if TB is suspected. LOOK: foul (anaerobic empyema), food (oesophygeal rupture), milky (chylothorax - lymphoma), blood (malignancy). BLOOD GAS ANALYSER: pH

Question 16

Transudate or exudate?

Answer 16

Transudate if 35 g/L. In between? LIGHT’S criteria. It is an exudate if 1 or more of the following criteria are met:

Pleural/serum protein > 0.5
Pleural/serum LDH > 0.6
Pleural LDH > 0.66 of upper limit of serum LDH

Question 17

What is the management of pleural effusion?

Answer 17

Depends on the cause: chemotherapy, anti-tuberculous chemotherapy, corticosteroids. Palliative (malignancy): repeated pleural aspiration. Pleurodhesis: attach patient to underwater seal and drain to dryness. When lung re-expands chemical pleurodhesis: talc slurry which sticks lung to chest wall to stop fluid accumulating again. Can also do this surgically during diagnostic thoracoscopy.

Question 18

Define pneumothorax.

Answer 18

Presence of air within pleural cavity. Causes lung to collapse away from chest wall due to elastic recoil. This can be spontaneous, traumatic or tension.

Question 19

When would a tension pneumothorax occur?

Answer 19

When air inside the pleura accumulates progressively and exerts positive pressure on mediastinal and intra-thoracic structures. Air can get in but cannot get out –> very serious.

Question 20

What are the different types of spontaneous pneumothorax?

Answer 20

Primary: no clinical disease, young people (

Question 21

What are the types of traumatic pneumothorax?

Answer 21

Non-iatrogenic: penetrating or blunt chest injury. Iatrogenic: pleural aspiration/biplsy, subclavian vein cannulation, acupuncture etc.

Question 22

What are the symptoms of pneumothorax?

Answer 22

Asymptomatic if patient has a good respiratory reserve. Acute/worsening breathlessness, pleuritic chest pain, extreme breathlessness (usually tension).

Question 23

What are the clinical signs of pneumothorax?

Answer 23

Surgical emphysema (air under skin). Non-tension: trachea deviated towards affected side, lower expansion, hyper resonance, absent or low breath sounds all on affected side. Tension: trachea deviated away from affected side, high JVP, haemodynamic compromise.

Question 24

Is pneumothorax small or large?

Answer 24

Small when rim of air is 2cm or less, large when rim of air is 2cm or more.

Question 25

How is pneumothorax treated?

Answer 25

Tension: cannula and chest drain. Small primary, not breathless: usually resolves, CXR and observe, return if becomes breathless. Primary, breathless: aspirate, CXR, if not resolved chest drain. Secondary, breathless: aspirate if small, not successful chest drain.

Question 26

What is the ideal outcome of pneumothorax treatment?

Answer 26

Lung inflates 1-2 days, drain stops bubbling, CXR confirmation that lung is inflated. Clamp drain for 24 hours, re-CXR, n change then remove drain.

Question 27

What is the less than ideal outcome of pneumothorax treatement?

Answer 27

Lung fails to re-inflate after 48 hours and drain continues to bubble. Apply high volume low pressure suction to drain. Fails to re-inflate? Cardiothoracic surgeon at 3 says for thoracoscopy and talc pourage pleurodhesis.

Question 28

What are the risks of subsequent pneumothorax?

Answer 28

High - 54% recurrence within 4 years, 10-25% within 4 months. Refer for surgical pleurodhesis if:second ipsilateral pneumothorax, first contralateral pneumothorax, bilateral spontaneous pneumothorax or first pneumothorax in high risk professions like pilots or divers; talc poudrage or pleurectomy.