approach to pleural effusion dr abdalla elfateh ibrahim consultant & assisstant professor of...
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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