PLEURAL EFFUSIONS

PRESENTER: KINARA KENYORUMED/18/11

FACILITATOR: PROF. DIERO

DEFINITION A pleural effusion is present when there is an excess

quantity of fluid in the pleural space (space lies between the lung and chest wall and normally contains a very thin layer of fluid, which serves as a coupling system).

Normally, 10-20 mL of fluid is spread thinly over the visceral and parietal pleurae.

The fluid is similar in composition to plasma except that it is lower in protein (< 1.5 g/dL).

• Incidence – 1 million cases per year• Prevalence – 320/100,000 in industrialised countries.

Aetiology In the normal pleural space, there is a steady state in which

there is a roughly equal rate of the formation (entry) and absorption (exit) of liquid

This balance must be disturbed in order to produce a pleural effusion.

CLASSIFICATION Classified into unilateral or bilateral Into transudative and exudative.

TRANSUDATE

Due to systemic factors Transudates are due to an imbalance between

hydrostatic and oncotic pressures . -Incr. Hydrostatic factors(pleural fluid)-decr. Osmotic pressure(plasma)-decr. Oncotic pressure(plasma)

Aetiology of transudative

Nephrotic syndrome CCF Liver cirrhosis Myxedema SVC Obstruction Hypoproteinemia – malnutrition, malabsorption Biliothorax Peritoneal dialysis

EXUDATE

Due to local factors Change in pleural surface permeability-Incr. microvascular permeability- protein leakage -Injury to adjacent lung tissue Exudates are secondary to a disturbance of the

systems regulating pleural fluid formation and absorption/drainage (as in bacterial, viral, or fungal infection, rheumatologic disease, or malignancy).

Aetiology of Exudative infxn –TB, pneumonia, fungal Pulmonary embolism Malignancy-lung cancer,breast ca, lymphoma,

metastatic Hemothorax Lymphatic obstruction Ureamia CT dse- SLE, rheumatoid arthritis Meig’s syndrome (triad of ovarian tumour w

ascites and p effusion)

Asbestos exposure Radiation Drugs- nitrofurantoin, phenytoin, methotrexate,

amiodarone. Trauma Sarcoidosis Subdiaphragmatic abscess Acute pancreatitis

Exudative pleural effusions meet at least one of the following criteria, whereas transudative pleural effusions meet none of these ratios

• Pleural fluid protein/serum protein >0.5• Pleural fluid LDH/serum LDH >0.6• Pleural fluid LDH more than two-thirds normal

upper limit for serum

Pathogenesis

INCREASED FLUID ENTRY-Increase in permeability-Increase in microvascular pressure-Decrease in pleural pressure-Decrease in plasma osmotic pressure

DECREASED FLUID EXIT -Intrinsic factors

-Cytokines & prod. of inflame- endotoxins- Endocrine abnormalities -hypothyroidism-Injury due to radiation /chemo-Infiltration of lymphatics by cancer -Anatomic abnormalities -yellow nail syndrome (reduced lymphatic drainage)

-Extrinsic factors Limitation of respiratory motion- diaphragm

paralysis Extrinsic compression of lymphatics- pleural

fibrosis, Blockage of lymphatic stomata - pleural

malignancy Decreased intrapleural pressure -fibrous rind

on the visceral pleura Increased systemic venous pressure – decr.

lymphatic flow Decreased liquid availability - pneumothorax

Clinical features Symptoms

-Dyspnea(most common) - because of distortion of diaphragm and chest wall during resp more than from hypoxemia-mild, nonproductive cough.-pleuritic chest pain- chest wall splinting(stiffening of body part to avoid pain)-tachypnea esp with lung compression or more severe infxn.

-Fever-hemoptysis-Constitutional features ( wt loss, myalgia, general malaise, headache)

Signs-Resp distress( FAN, ICR, SCR, use of acces muscles)-Decr. Chest movement. Decreased motion of the hemithorax-Trachea shifted to opp. Side (mostly if massive more than 1000ml)-Tenderness-Tactile fremitus decr-Stony dullness-Diminished or absent breath sounds-Vocal fremitus decr.- Basal crepitations-Friction rub-Egophony (E-to-A change)

Investigations• Chest x-ray -PA

-Lateral–Homogenous opacities with meniscus– Blunting of the costo-phrenic angle– Incr. upper lung field vasculature–Mediastinal shift if large unilateral (>1000ml)

• CT scan of chest – mass, • Pleural biopsy• Thoracocentesis - pleural tap• Thoracoscopy (provides direct view of both

parietal and visceral aspects of pleura)

CT scan of chest showing left sided pleural effusion. Effusion fluid often settles at the lowest space due to gravity; here at the back as the patient is lying under scanner

Massive right-sided pleural effusion (white area) in a patient presenting with lung cancer

Contraindication to Pleural tap (relative)

- Low volume of effusion <1cm thickness on lateral decubitus Xray

–Bleeding diathesis or systemic anticoagulation

–Mechanical ventilation–Cutaneous disease over the puncture site

Complications– pain at site– Spleen/liver puncture– Pneumothorax -Use of needles larger

than 20 gauge increases the risk–Cutaneous or internal bleeding

Pleural tap Colour -pale yellow/straw-transudate

-hrrghic-malignancy, trauma, TB,-milky/whitish-chylothorax-Brown-long standing hrrg(amoebic liver abscess)-Black- aspergillosis-Yellow green –arthritis-Dark green- biliothorax

Character –presence of pus (empyema)-viscous(mesothelioma)-Debris (rheumatoid arthritis)-Turbid (inflamm. conditions)

Biochemistry (lights criteria)- All exudates evaluated for amylase level, differential cell count, glucose level.-Culture & sensitivity-Microbiology -Gram stain-ZN stain (TB)Cytology (Tumour markers: CEA,VIM)

Pleural fluid lymphocytosis, with lymphocytes greater than 85% of the total nucleated cells, suggests tuberculosis (TB), lymphoma, sarcoidosis, chronic rheumatoid pleurisy, yellow nail syndrome, or chylothorax. Pleural lymphocytes of 50-70% of the nucleated cells suggests malignancy.

Pleural fluid eosinophilia, with eosinophils greater than 10% of nucleated cells, is seen in hydropneumothorax, hemothorax, pulmonary infarction, benign asbestos pleural effusion, parasitic disease, fungal infection, drugs, and malignancy.

Mesothelial cells are found in variable numbers in most effusions, but their presence at more than 5% of total nucleated cells makes a diagnosis of TB unlikely.

Markedly increased numbers of mesothelial cells, especially in bloody or eosinophilic effusions, suggests pulmonary embolism as the cause.

Type S. G Protein

LDH Protein

(Fluid serum

)

LDH(Fluid

serum)

PH

Transudate

< 1.016

< 3.0 g/dl

< 200 U/L

< 0.5 < 0.6 7.4 – 7.55

Exudate > 1.016

> 3.0 g/dl

> 200 U/L

> 0.5 > 0.6 7.3 – 7.45

Difference between transudate and exudate (Lights criteria)

CBC ESR UEC-nephrotic

syndrome LFT-liver cirrhosis Urinalysis ANA, RF Pleural biopsy Thoracoscopy Bronchoscopy

• Suspect TB pleuritis in patients with a history of exposure or a positive purified protein derivative (PPD) finding and in patients with lymphocytic exudative effusions, especially if less than 5% mesothelial cells are detected on differential cell counts.– Because most tuberculous pleural effusions probably result from a

hypersensitivity reaction to the mycobacterium rather than from microbial invasion of the pleura, acid-fast bacillus stains of pleural fluid are rarely diagnostic (<10% of cases), and pleural fluid cultures grow Mycobacterium tuberculosis in less than 65% of cases.

– In contrast, the combination of histology and culture of pleural tissue obtained by pleural biopsy increases the diagnostic yield to 90%.

– Adenosine deaminase (ADA) activity of more than 43 U/mL in pleural fluid supports the diagnosis of TB pleuritis. However, the test has a sensitivity of only 78%; therefore, pleural ADA values less than 43 U/mL do not exclude the diagnosis of TB pleuritis.

– Interferon-gamma concentrations in pleural fluid greater than 140 pg/mL also support the diagnosis of TB pleuritis, but this test is not routinely available.

Management Supportive -Supplemental oxygen-IV fluid hydration-Chest physiotherapy-Therapeutic/diagnostic thoracentesis-Antibiotics-Empirically by age/social circumstances and

modified by blood and pleural effusion fluid culture results

 

Definitive Treat underlying cause chest tube for continuous drainage pleuroperitoneal shunt and chemical pleurodesis Chemical pleurodesis -Doxycycline 500 mg,

-Bleomycin 60 IU-TALC in a slurry(rarely used)

Empyema: -Antibiotics alone with close monitoring in children-Antibiotics with chest tube drainage in adults

Pleurectomy - trapped lung (Excision of pleura, usually parietal)

Pleural fluid deloculation (If unsuccessful, then either thoracoscopic adhesiolysis or decortications via thoracotomy are indicated)

Diuresis as appropriate for effusions secondary to congestive heart failure and ascites

• Indication for chest tube• Recurrent pleural effusion• Empyema• Pneumothorax & hydrothorax

• Malignant pleural effusion• Repeated effusions- pleurodesis