Pleural effusion

The accumulation of serous fluid within the pleural space is termed pleural effusion.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 661

According to color, pleural effusion may be:

• Serous (hydrothorax)
• Purulent (empyema or pyothorax)
• Hemorrhagic (hemothorax)
• Straw
• Milky or chylous (chylothorax)

Note

Clinically, only pleural effusion should be mentioned. After drawing the fluid and according to its color, other diagnosis may be done. e.g. if pus, it is empyema.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 104

Light’s criteria is for distinguishing pleural transudate from exudate.

• Plural fluid is likely exudate if one or more of the following criteria are met:
  1. Pleural fluid protein : serum protein ratio > 0.5
  2. Pleural fluid LDH : serum LDH ratio > 0.6
  3. Pleural fluid LDH > two-thirds of the upper limit of normal serum LDH

(LDH = lactate dehydrogenase)

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 662

When pleural fluid protein is between 2.5 and 3.5 gm/dL.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

In empyema thoracis, fluid may come out subcutaneously in the chest wall. This is called empyema necessitans.

Characteristics of empyema fluid:

• Fluid is purulent
• Thick
• Biochemical—glucose low, < 3.3 mmol/L, protein exudative, LDH > 1000 U/L
• C/S—organism may be found
• Pleural biopsy may be done to exclude tuberculosis.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

When the pleural effusion is transudative, it is called hydrothorax. It is usually bilateral due to any cause causing transudative pleural effusion.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

Effusion between the lower surface of lung and upper surface of diaphragm.

• Confused with subphrenic abscess.
• Detected by chest X-ray in lateral decubitus position or USG or CT scan.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

It is the accumulation of fluid in interlobular fissure, usually found along the lateral chest wall.

• Chest X-ray shows rounded homogeneous opacity, misdiagnosed as a tumor.
• It is confirmed by USG (localized or encysted effusion) or CT scan.
• It disappears with resolution of effusion.
• It is commonly found in CCF.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

It is a congenital disorder characterized by:

1. Nails—yellow, thick, onycholysis
2. Lymphedema of legs
3. Pleural effusion or bronchiectasis.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

Note:

If the patient is young, common causes are

• Pulmonary tuberculosis
• Parapneumonic
• Others—Lymphoma and SLE in female (also pulmonary infarction).

If the patient is middle age or elderly, common causes are

• Pulmonary tuberculosis
• Parapneumonic
• Bronchial carcinoma.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 661; Long Cases in Clinical Medicine, ABM Abdullah Page: 103

As follows:

Exudative (protein  >3 g%) :

• Pneumonia (para-pneumonic effusion)
• Pulmonary tuberculosis
• Pulmonary infarction
• Malignant disease, e.g. bronchial carcinoma, lymphoma
• Collagen disease (SLE, rheumatoid arthritis)
• Dressler’s syndrome (post-myocardial infarction syndrome characterised by pain, pyrexia, pericarditis, pleurisy and pneumonitis).
• Others—acute pancreatitis, subphrenic abscess, liver abscess, pleural mesothelioma, secondaries in the pleura, yellow nail syndrome, etc.

Transudative (protein  <3 g%):

• Congestive cardiac failure (CCF)
• Nephrotic syndrome
• Cirrhosis of liver
• Malnutrition
• Hypothyroidism
• Meig’s syndrome (ovarian fibroma, ascites and right sided pleural effusion)
• Chronic constrictive pericarditis
• Acute rheumatic fever.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 103; Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

As follows:

Causes of right-sided pleural effusion

• Liver abscess
• Meig’s syndrome
• Dengue hemorrhagic fever.

Causes of left-sided pleural effusion

• Acute pancreatitis
• Rheumatoid arthritis
• Dressler’s syndrome (pleurisy, pericarditis, and pyrexia-3P)
• Esophageal rupture (Boerhaave’s syndrome)
• Dissecting aneurysm.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 103

As follows:

• All causes of transudative effusion (CCF, nephrotic syndrome, cirrhosis of liver, malabsorption or malnutrition or hypoproteinemia).
• Collagen diseases (rheumatoid arthritis and SLE).
• Lymphoma
• Bilateral extensive pulmonary TB.
• Pulmonary infarction.
• Malignancy (usually multiple metastases involving both lungs).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 103

As follows:

• Chest injury or trauma
• Bronchial carcinoma
• Pulmonary infarction
• Pleural mesothelioma
• Others – SLE, lymphoma, acute pancreatitis.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 105

As follows:

• Bacterial pneumonia
• Lung abscess (bursting in pleural cavity)
• Bronchiectasis
• Tuberculosis
• Secondary infection after aspiration
• Rupture of subphrenic abscess or liver abscess
• Infected hemothorax.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 105

Injury or obstruction of thoracic duct due to any of the following causes:

• Traumatic (surgery and trauma to the thoracic duct)
• Neoplastic (bronchial carcinoma and metastasis)
• Infective (tuberculosis and filariasis)
• Lymphoma involving thoracic duct.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

In both cases, fluid may be cloudy. It is centrifuged and following is observed:

• If clear, empyema
• If persistent cloudy or milky, chylothorax.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

As follows:

• Bronchial carcinoma
• Pleural mesothelioma
• Lymphoma
• Collagen disease (SLE)
• All causes of transudate (CCF, nephrotic syndrome, cirrhosis of liver).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

As follows:

• Pulmonary eosinophilia
• Polyarteritis nodosa
• Rarely lymphedema.

Note

• High eosinophil in the pleural fluid but not in the blood is likely due to pulmonary embolism.
• High eosinophil in pleural fluid is unlikely to be malignant.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

Excess pleural fluid accumulation occurs when pleural fluid formation exceeds absorption or normal pleural fluid formation with reduced absorption. Probable mechanisms are:

• Increased hydrostatic pressure (as in CCF)
• Reduced plasma colloidal osmotic pressure (as in hypoproteinemia)
• Involvement of pleura causing increased permeability (as in TB and tumor)
• Impaired lymphatic drainage of pleural space (as in obstruction of lymphatic system by tumor, TB and radiation)
• Transdiaphragmatic passage of fluid (in liver disease, ascites and acute pancreatitis).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

Hypersensitivity to tuberculous protein in pleural space.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 108

Pleuritic chest pain is localized, sharp or lancinating in nature, worse on coughing, deep inspiration or movement.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 102

As follows:

• Pleural effusion (stony dullness)
• Thickened pleura
• Consolidation (woody dullness)
• Collapse of the lung
• Raised right hemidiaphragm (due to hepatomegaly or liver pushed up)
• Mass lesion.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 102

Stony dullness on percussion and reduced or absent breath sound (confirmed by aspiration).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 102

• Inspection
  • Movement diminished on right side
• Palpation
  • Trachea and apex beat deviated to left
  • Expansibility reduced on right side
  • Vocal fremitus diminished on right side
• Percussion
  • Stony dull on right side
• Auscultation
  • Breath sound diminished or absent on right side
  • Vocal resonance diminished or absent on right side.

* Pre-exam preparation for medicine, HN Sarker

As follows:

1. X-ray chest P/A view
2. Hb%, TC, DC, ESR (high ESR in TB, leukocytosis in pneumonia)
3. Mantoux test (MT)
4. Aspiration of pleural fluid for analysis-
5. Physical appearance (straw colored, serous, hemorrhagic, chylous)
   • Gram-staining, cytology (routine) and exfoliative cytology (malignant cells)
   • Biochemistry (protein and sugar), also a simultaneous blood sugar, protein and lactate dehydrogenase (LDH) may be done
   • ADA (high in tuberculosis)
   • Culture and sensitivity (C/S)
   • AFB and mycobacterial C/S
6. Pleural biopsy by Abram’s or Cope’s needle
7. Other investigation of pleural fluid (according to suspicion of cause):
   • Cholesterol, LDH and rheumatoid factor (in rheumatoid arthritis)
   • Amylase (high in acute pancreatitis, esophageal rupture, malignancy)
   • Trigycerides (in chylothorax)
8. Sputum (if present) for Gram staining, C/S, AFB, mycobacterial C/S and malignant cells (exfoliative cytology)
9. If palpable lymph node: FNAC or biopsy (for lymphoma, metastasis)
10. Other investigations according to suspicion of causes include:
    • ANF, anti-ds DNA (SLE)
    • Liver function tests
    • Urine for protein and serum total protein (nephrotic syndrome)
    • Bronchoscopy and biopsy (if needed in bronchial carcinoma)
    • CT scan in some cases (it helps to clarify pleural abnormalities more readily than chest X-ray and ultrasonogram, and also helps to distinguish between benign and malignant diseases).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 101

X-ray chest PA view showing:

• Dense homogenous opacity in left lower zone with a curvilinear upper border (concave upper margin).
• There is obliteration of left costophrenic angle.
• Trachea and heart (mediastinum) are shifted to the right.
• Rest of the lung field is normal and bony case and soft tissue shadows are normal.

Radiological diagnosis: Left-sided pleural effusion.

X-ray chest PA view showing dense homogenous opacity with curvilinear upper border in both lower zones obliterating both costophrenic angles.

Radiological diagnosis: Bilateral pleural effusion.

* Short Cases in Clinical Medicine, ABM Abdullah, 5th Edition Page: 536

By doing:

• X-ray in lateral decubitus position
• Ultrasonogram (USG) of lower part of the chest
• Occasionally, CT scan of chest may be needed.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 102

At least 500 mL clinically and 300 mL radiologically in PA film.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

1. Diagnostic purposes
   • To detect the cause.
2. Therapeutic purposes
   • To reduce breathlessness

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

At least 50 mL for diagnostic purpose and not more than 1.5 L on first occasion.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

As follows:

• Straw or amber color
• Exudative
• High lymphocyte in pleural fluid
• AFB is found in 20% cases
• Culture for AFB is found in one-third cases
• Pleural biopsy is positive in 80% cases.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 662

As follows:

• Infection (empyema)
• Tuberculosis
• Advanced malignancy
• SLE
• Rheumatoid arthritis
• Esophageal rupture.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 108

• Pleural fluid amylase may be higher than serum amylase in acute pancreatitis, bacterial pneumonia, esophageal rupture and malignancy.
• It is high in adenocarcinoma of lung and may be useful in differentiating it from mesothelioma.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 108

Right sided pneumothorax.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 242

This is not right-sided pneumothorax as onset is insidious and percussion note is stony dull. In pneumothorax, there is hyper-resonance on percussion.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

This is more likely to be tubercular, because:

• In the history, there is low grade fever with evening rise and night sweating
• Marked weight loss
• Cough with slight mucoid sputum.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 100

Example:

The patient is young, bronchial carcinoma is less common (but he is a heavy smoker for 15 years, so carcinoma should be excluded.)

* Long Cases in Clinical Medicine, ABM Abdullah Page: 101

In this case, there is history of breathlessness, weight loss and fever which are not present in thickened pleura. Also, on examination, there is mediastinal shifting with stony dullness on the affected side. These are not found in thickened pleura.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 101

There is stony dullness and reduced breath sound and vocal resonance in the affected area along with mediastinal shifting. These are against consolidation (In consolidation, there is woody dullness, bronchial breath sound, increased vocal resonance and no shifting of the mediastinum).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 101

In para-pneumonic effusion,

• Patient usually has high remittent fever with pleuriac chest pain of short duration.
• Patient is usually toxic.
• On auscultation there may be bronchial breath sound and crepitations though bronchial breath sound is a usual finding above pleural effusion.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

In case of collapse, the apex beat and trachea will be shifted to the same side. In addition, if there is collapse with patent bronchus, there will be bronchial breath sound and increased vocal resonance.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 101

As follows:

• Fluid may be thick (empyema)
• Thickened pleura
• Mass lesion.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 102

Note:

• Pleural fluid cholesterol level < 60 mg/dl indicates transudate. In all malignant effusion, pleural fluid cholesterol > 60 mg/dL. So, this test is useful to separate these two types of effusion.
• High pleural fluid ADA indicates tubercular pleural effusion.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 104

* Long Cases in Clinical Medicine, ABM Abdullah Page: 105

As follows:

From history:

• High fever, sometimes hectic, may be associated with chill, rigor and sweating. Fever is persistent or recurrent despite treatment with a suitable antibiotic.
• Malaise, weight loss.
• Pleuritic chest pain, breathlessness.
• Copious purulent sputum if empyema rubtures into a bronchus (bronchopleural fistula).

On examination:

• Toxic, emaciated.
• Tachypnea.
• Tachycardia.
• Features of pleural effusion.
• Clubbing.
• To be confirmed—aspiration which shows pus or purulent fluid.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 105

Clinically this can be diagnosed by:

• Presence of primary cause like CCF, nephrotic syndrome, cirrhosis of liver, etc.
• Associated edema which may be generalized, also ascites, pericardial effusion.
• No history of fever or acute infection.
• Aspiration of fluid shows transudative in nature (serous in color and protein < 3 g%).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

As follows:

• Clincally—elderly emaciated or cachexic patient having clubbing with nicotine stain, palpable lymph node, radiation mark on the chest, etc.
• Pleural fluid is hemorrhagic and there is rapid accumulation after aspiration.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

Treatment should be according to cause. For example:

• If tuberculosis:
  • Full course antitubercular therapy.
  • Prednisolone 20 to 30 mg daily may be given for 4 to 6 weeks, especially in large effusion.
• If parapneumonic:
  • Aspiration of fluid, may be repeated (if necessary if patient becomes breathless)
  • Antibiotic should be given.
  • If complicated case, especially empyema, thoracostomy may be done.
  • Sometimes, if all fails, thoracotomy with decortication may be necessary.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 108

Usually up to 1500 mL.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 108

Not more than 1.5 L.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243

Re-expansion pulmonary edema.

Mechanism

• Because of effusion, lung is compressed and there is ischemia to lung parenchyma and necrosis of pulmonary vessels.
• If more fluid is drawn, there is rapid expansion of the lung, as no regeneration of necrotic vessels.
• As a result, more leakage of fluid causing pulmonary edema.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 243; Long Cases in Clinical Medicine, ABM Abdullah Page: 108

• Steroid is mostly given in tubercular pleural effusion.
• Although its role is controversial, some evidences suggest that it promotes rapid absorption of pleural fluid and gives the patient quick symptomatic relief.
• It also prevents pleural fibrosis and adhesion.
• Steroid should be used along with antitubercular therapy.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 108

According to cause:

1. Non-tuberculus:
   • Drainage of pus with wide bore intercostal tube using water seal drainage.
   • Antibiotic for 2 to 6 weeks. IV Co-amoxiclav or cefuroxime plus metronidazole. May be given according to C/S.
   • Surgical intervention if pus is thick or loculated. Surgical decortication of the lung may be needed, if visceral pleura is grossly thickened.
2. Tuberculous empyema:
   • Antitubercular drug
   • Wide bore needle aspiration or intercostal tube drainage
   • Sometimes surgical ablation of pleura.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 106

Treatment of recurrent pleural effusion is done by pleurodesis in the following way:

• A plain rubber tube is introduced in the intercostal space, and fluid is removed as far as possible. Introduce the drug, tetracycline (500 mg) or kaolin or talc through the tube, clamp it and keep for 4 to 8 hours (may be overnight). In malignant pleural effusion, bleomycin 30 to 60 mg is introduced.
• Patients’ posture should be changed 2 hourly to allow the drug to spread in pleural space.
• After 4 to 8 hours, remove any remaining fluid and take out the drainage tube at the height of inspiration.
• The patient usually complains of severe chest pain after pleurodesis. In such case, analgesic should be given.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 107

• Pleural fluid normally present: 5 to 15 mL
• At least 500 mL of fluid is necessary to detect clinically
• At least 300 mL of fluid is necessary to detect radiologically in PA view
• At least 100 mL of fluid is necessary to detect radiologically in lateral decubitus position
• Less than 100 mL or small amount of fluid is detected by ultrasonography (even 20 to 25 mL fluid can be detected).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 102