Approach to Pleural Effusion

Dr Abdalla Elfateh Ibrahim Consultant & Assisstant

Professor of Pulmonary Medicine King Saud University

Pleural Effusion

Pleural effusions are a common medical problem with more than 50 recognized causes including Local pleura disease Underlying lung Systemic conditions Organ dysfunction Drugs It occur as a result of increased fluid formation

and/or reduced fluid resorption.

Mechanism

The pathophysiology of fluid accumulation varies according to underlying aetiologies.

Increase permeability Increase pulmonary capillary

pressure Decrease negative pleural pressure Decrease oncotic pressure Obstructed lymphatics

Types of pleural effusions

Transudates pleural fluid proteins < 30

OR Exudates pleural fluid proteins

>30

Causes of pleural effusion Transudates

Very Common causes Heart failure Liver cirrhosis

Transudates

Less Common causes Hypoalbuminaemia Peritoneal dialysis Hypothyroidism Nephrotic syndrome Mitral Stenosis

Causes of pleural exudates

Common causes Malignancy Parapneumonic effusions Tuberculosis

Exudates

Less Common causes Pulmonary embolism Rheumatoid arthritis and other

autoimmune pleuritis Benign Asbestos effusion Pancreatitis Post-myocardial infarction Post CABG

Exudates

Rare causes

Yellow nail syndrome (and other lymphatic disorders )

Drugs Fungal infections

Clinical assessment and history Thorough history (Infection, malignancy , risk of PE , heart

failure etc.) And physical examination.

History

Drug history is important.

Uncommon cause of exudative effusion

(mesotruxate, Amiodarone Phenytoin, Nitrofurantoin and Beta- blockers )

>100 cases reported globally An occupational history Asbestos exposure and potential secondary

exposure via parents or spouses should be documented.

Symptoms

Asymptomatic Breathlessness Chest pain Cough Fever

Approximately 75% of patients with pulmonary embolism and pleural effusion have a history of pleuritic pain.

Dyspnoea is often out of proportion to the size of the effusion

Asymptomatic if it occupies less than a third of the hemithorax

Signs

Decrease expansion Dull percusion node Decrease vocal resonance Decrease air entry Signs of associated disease (for example :chronic liver

disease-CCF-nephrotic syndrome -SLE-RA-Ca lung)

DIAGNOSIS

CXR Pleural aspiration Pleural biopsy Medical thoracoscopy CT scan VAT Bronchoscopy

CXR

Diagnostic Imaging

Pleural aspiration

The initial step in assessing a pleural effusion is to ascertain whether the effusion is a transudate or exudate

Diagnostic tap

Aspiration should not be performed for bilateral effusions in a clinical setting strongly suggestive of a transudate, unless there are atypical features or they fail to respond to therapy

Pleural aspiration

A diagnostic tap, with a fine bore (21G) needle and a 50mL syringe

Bedside ultrasound guidance is recommended for all diagnostic aspirations

Biochemistry : protein, LDH, PH, and glucose

Microbiology: Gram stain, AFB and culture

Pathology :cytology

Pleural aspiration

Aspirated fluid should immediately be

drawn into a blood gas syringe for PH Biochemical (2-5 ml) Microbiology 5ml 50ml for cytological examination

Pleural effusion Document in the patient file : Aseptic techique (under local

Anathesia) The amount of effusion aspirated Appearance and odour should be noted. (colour usually Straw colour (normal) Smell , unpleasant aroma of anaerobic

infection may guide antibiotic The appearance may be serous blood

tinged or frankly bloody -

Appearance

Milky fluid Empyaema Chylothorax PesudoChylothorax

Centrifuging turbid or milky pleural fluid will distinguish between empyema and lipid effusions.

If the supernatant is clear then the turbid fluid was due to empyema

If it is still turbid : -Chylothorax OR -

Pseudochylothorax

Appearance

Grossly bloody pleural fluid is usually due to Malignancy Pulmonary embolus with infarction Trauma Benign asbestos pleural effusions Post-cardiac injury syndrome

How to differentiate between haemothorax & hagic effusion Pleural fluid haematocrit is greater than 50% of the patient's peripheral blood haematocrit is diagnostic of a haemothorax

Fluid Suspected disease

Putrid odour Anaerobic empyema Food particles Oesophageal rupture Bile stained Cholothorax (biliary

fistula) Milky

Chylothorax/Pseudochylothorax ‘Anchovy sauce’ like fluid Ruptured

amoebic abscess

Differentiating between exudate and transudate effusions

Protein of > 30g/l an exudate Protein of <30 g/l a transudate.

When protein is close to 30g/l (25-30)

Light's criteria

Exudates if one or more of the following:

Pleural fluid protein divided by serum protein is greater than 0.5

Pleural fluid LDH divided by serum LDH is greater than 0.6

Pleural fluid LDH > 2/3 the upper limits of laboratory normal value for serum LDH.

How accurate is Light’s criteria ? In CCF diuretic therapy increases the

concentration of protein, LDH and lipids in pleural fluid

In this context Light's criteria is recognized to misclassify a significant proportion of effusions as exudates .

Clinical judgment should be used Measurement of NT-pro-BNP can be

useful.

Other tests

Glucose < 3.3 mmol/l ? Infection PH <7.2 empyaema Amylase pancreatic ca ,rupture

oesophagus Rheumatoid factor RA ANA for SLE Complement level (reduced in

SLE,RA,Ca)

Pleural fluid differential cell counts

Cell proportions are helpful in narrowing the differential diagnosis but none are disease specific

When any effusion becomes long standing it tends to be populated by lymphocytes (and neutrophils fade away)

Pleural malignancy, cardiac failure and tuberculosis are common specific causes of a lymphocytic effusion

PH Pleural fluid pH should be measured in

non-purulent effusions providing that appropriate collection technique can be observed and a blood gas analyser is available.

Inclusion of air or local anesthetic in samples may significantly alter the pH results and should be avoided.

In a parapneumonic effusion, a pH <7.2 indicates the need for tube drainage

PH

In clinical practice, the most important use for pleural fluid pH is aiding the decision to treat pleural infection with tube drainage.

Pleural effusion cells (cont)

Neutrophil (are associated with acute processes)

Parapneumonic effusions: Pulmonary embolism Acute TB Benign asbestos related disease Eosinophils Pleural eosinophilia when eosinophyls are

greater than 10% of cells ( eosinophilic effusion)

The most common cause eosinophilia is air or blood in the pleural space

Is a fairly non-specific

Causes of lymphocytic p. effusions

lymphocytes account for > 50% nucleated cells)

Malignancy (including metastatic adenocarcinoma and mesothelioma)

Lymphoma Tuberculosis

Causes of lymphocytic pleural effusions Cardiac failure Post CABG Rheumatoid effusion Chylothorax Uraemic pleuritis Sarcoidosis Yellow Nail Syndrome

Glucose

In the absence of pleural pathology, glucose diffuses freely across the pleural membrane and pleural fluid glucose concentration is equivalent to blood

A low pleural fluid glucose level (< 3.4 mmol/l) may be found in

Complicated parapneumonic effusions Empyema Rheumatoid pleuritis Tuberculosis Malignancy Oesophageal rupture .

Glucose

The most common causes of a very low pleural fluid glucose level (< 1.6 mmol/l) are

Rheumatoid arthritis Empyema

Although glucose is usually low in pleural infection and correlates to pleural fluid pH values, it is a significantly less accurate indicator for chest tube drainage when compared to pH

Cytology

The diagnostic yield for malignancy depends on

The skill and interest of the cytologist Tumour type. The diagnostic rate is higher for

adenocarcinoma Than for Mesothelioma, Squamous cell carcinoma lymphoma and sarcoma.

Tumour markers

Pleural fluid and serum tumour markers do not have a role in the investigation of pleural effusions.

Management

Treatment of the cause Drainage (stop drain for 1-2 hours after 1st 1500

ml) may presipitate pul oedema Pleurodesis with - Talc - Tetracycline -BleomycinSurgery