Pleural Diseases

Dr Matthew J Knight

Consultant Respiratory Physician

What do you need to know?

What do you need to know?

• Pleura- normal anatomy and physiology

• Pleural effusions

• Causes and investigations

• Treatment and prognosis

• Mesothelioma

• Pneumothorax

• Causes and investigations

• Treatment and prognosis

• Procedures

• Competent to perform tap (US not yet a core competency)

• Drain for pneumothorax

What we will cover

• The Pleura

• Pleural effusion

• Mesothelioma

• Pneumothorax

• Range of procedures

• How do I get US competent?

Structure

• Definition

• Pathophysiology

• Epidemiology

• History

• Clinical Examination

• Differential diagnosis

• Investigations and diagnostic criteria

• Management – INITIAL, MEDIUM AND LONG TERM

• Prognosis/ Complications

THE PLEURA

THE LUNG

Lun

g Segm

ents

Th

e Pleu

ra

Lun

g surface an

atom

y

Pleu

ra surface

mark

ings

Pleural cavity

• A small space!

• 10 ml of Pleural fluid

• Lubricant to allow smooth sliding

• 20ml is produced per day

• Lymph can resorb 0.2ml/kgbw/hr

• 14 ml per hour in a 70 Kg man

• Normal PH is 7.6

• Adhesive forces help transmit inspiratory expansive force

AT FRC

PLEURAL EFFUSION

Definition

• The accumulation of fluid in the pleural space

• This fluid can be classified as either

• Transudate

• Exudate

• Blood

• Other

Other

• Slightly more unusual causes

• Urinothorax (eg following renal biopsy)

• CSF-’o’-thorax (Duro-pleural fistula)

• Chylothorax (Chyle from the Thoracic duct)

• Food-’o’-thorax (Oesophageal rupture)

Transudate

• Pleural fluid accumulates due to either an increase in the hydrostatic pressure

within vessels or a decrease in the oncotic pressure

• The pleura is usually intact/normal

Tran

sud

ate

Tran

sud

ates

Transudates

• Congestive Cardiac Failure

• Renal failure

• Liver disease

• Malnutrition

• Urino-thorax

• Meigs syndrome (Ascites, Pleural effusion and benign Ovarian tumour)

Exudates

• Result of an inflamed/abnormal pleura

• Increased vascular permeability or decreased lymphatic drainage.

Exu

dates

Exudates

Common

• Pneumonia

• Cancer

• TB

• PE

• Rheumatoid

Less Common • Pancreatitis

• Benign asbestos effusion

• Post MI

• Post CABG

• Yellow nail

• Drugs

Drugs and pleural disease

• www.pneumotox.com

• Methotrexate

• Phenytoin

• Cloazapine

• B Blockers

• Amiodarone

• Nitrofurantoin

Epidemiology of Pleural Effusion

• Incidence is 3/1000/year

• 195,000 cases per year in the UK

Cause Percentage Number

CCF 35% 68,000

Pneumonia 30% 58,500

Cancer 14% 27,500

PE 9% 17,500

Liver Cirrhosis 6% 12,000

GI disease (UC, CD, Panc) 3.75% 7,500

Asbestos related 1.3% 2,500

Rheumatological related 0.4% 800

TB 0.2% 400

Others 0.35% 700

Approximate numbers of Pleural effusions by underlying aetiology

Features of the History

• Dyspnoea

• Pain

• Cough

• Fevers

• Weight loss

• PND, orthopnoea

Examination findings

• Dullness to percussion

• Decreased tactile fremitus

• Diminished breath sounds

• Reduced expansion on side of effusion

• Shift of trachea if large

• Pleural friction rub

• Nothing if less than 300ml

Differential

• Pleural effusion is not a diagnosis- it is the result of a pathological process

• Remember dullness on percussion

• Raised hemidiaphragm or subphrenic abscess

• Previous thoracic surgery resulting in marked pleural thickening

Investigative pathway for a pleural effusion

• Chest x-ray

What next….?

• Do you have a very high suspicion that it is a transudate and safe to leave?

• Volume overloaded dialysis patient

• CCF with pulmonary oedema

• No abnormal infection markers

• Responds well to treatment for the underlying condition

• If so- leave it and treat the cause- if it does not resolve or if you are not

certain US guided pleural tap (look at procedures later)

Why US guided?

• More accurate

• Reduces risk of complciations from 8.6% to 1.1% (by experienced

operatives)

• Helps pick up other diagnosis

What should I send the fluid for?

• PH (in a normal gas syringe)- unless pus

• MCS and AFB – both in a universal container and also culture bottles

• Cytology (and flow cytometry if suspecting lymphoma)

• Protein, LDH, Glucose

Other tests on fluid

• Adenosine Deaminase and TB PCR if suspecting TB

• Cholesterol, Triglycerides and Chylomicrons if suspecting Chylothorax

• Mesothelin (prognostic marker) in mesothelioma

• Amylase – if considering pancreatitis

• B Transferin if considering CSF

• RF, ANA, BNP no more sensitive in pleural fluid than in the blood.

Evaluation- arriving at a diagnosis

• Starts with US

• Is there fluid- Yes or no?

• How much- depth and extent (Ant, Medial, posterior)?

• Simple or complex?

• Septated?

• Unilateral or bilateral?

• Any abnormalities on the pleural, liver, spleen, kidney, pericardium?

• Normal diaphragmatic movement?

US characteristic of effusions

• Simple (anechoic)

• Echogenic (suggestive of an exudate)

• Septated (empyema = activation of clotting/fibrin cascade)

Anechoic simple effusion

Echogenic effusion

Septated effusion

Look at the fluid

• Clear/ straw coloured -

• Heavily proteinaceous – more likely exudate

• Blood stained

• Pus - empyema

• Milky (café-au-lait) – Chylothorax or Pseudochylothorax

PH

• <7.2 very sensitive marker for

• Empyema

• Rheumatoid effusion

• TB

• Oesophageal rupture

• Note that serial measures of pleural effusion from chronic maligant effusions become progressively more acidotic

• A low glucose is also found in empyema, RA and TB

Light’s criteria

• Any one of the following criteria to class as an exudate

• Pleural fluid to serum protein ratio > 0.5

• Pleural fluid to serum LDH ration > 0.6

• Pleural fluid LDH > 66% upper end of normal serum LDH

• Be careful if on diuretics

Cell differential

• Predominantly neutrophils

• Para-pneumonic

• Cancer

• PE

• Predominantly Eosinophils

• Pneumothorax and trauma (eg surgery)

• Drug induced

• Churg Strauss

• Predominantly Lymphocytes

• Chronic effusion

• TB

• Lymphoma (flow)

• Sarcoid

• Rheumatoid

• Yellow Nail syndrome (Lymphoedema,

effusion, bronchiectasis and yellow nail)

Cholesterol, Triglycerides and Chylomicrons

• Chylothorax

• Cholesterol > 5.17 mmol/L

• Triglycerides > 1.24 mmol/L

• Chylomicrons on electrophoresis

• Implies damage or obstruction to

Thoracic Duct

• Pseudochylothorax

• Cholesterol > 5.17

• Triglycerides < 1.24

• No Chylomicrons

• Can happen with any chronic

effusion

Microbiology

• Community Acquired

• Strep milleri group – 24%

• Strep pneumoniae- 21%

• Staph aureus – 10%

• H.influenzae, E.Coli, Pseudomonas,

Klebsiella- 10% but more in patients

with comorbidities

• Anaerobes- 10%

• Hospital Acquired

• MRSA

• E.Coli

• Enterbacter

• Pseudomonas

Next step

• Treat what you have diagnosed (CCF, infection)

• Or

• Investigate further

Further imaging

• CT chest

• Best done with pleural fluid present (although partial drainage if a massive effusion)

• So can visualise the pleura better

• Ask for a pleural protocol (delayed contrast) to better visualise the pleura

What about MRI and PET in pleural imaging?

• MRI

• Not much routine use (although good for deciding on surgical margins)

• CT-PET

• Not sensitive for malignancy, but can help focus location for biopsy

• Track progress for chemotherapy in Mesothelioma

Options for tissue diagnosis

• Blind pleural (Abrams) biopsy

• Good for TB in high incidence areas

• CT or US guided biopsy – v sensitive

• Medical Thoracoscopy

• Sensitive- multiple biopsies, and can drain effusion and perform pleurodesis