Pleural Effusions

Abstract

Pleural effusion, a common observation with a variety of causes, is a very nonspecific finding that requires a careful search for associated findings and clinical correlation. Congestive heart failure is one of the most common causes of pleural effusion that is diagnosed by combining the patterns of cardiac enlargement with increased size of the pulmonary vessels and reticular interstitial opacities that may progress to diffuse bilateral airspace opacities. Other associated findings or clinical history may provide clues for the diagnosis of trauma, empyema, metastases, or other systemic diseases. Pleural effusion is always abnormal and requires a specific diagnosis.

Keywords

abdominal diseases, collagen vascular diseases, drug reactions, heart failure, pleural tumors, thoracic trauma

Questions

1.

The most likely diagnosis in the case illustrated in Fig. 4.1 is:
- a.
  
  Necrotizing pneumonia with empyema.
- b.
  
  Tuberculosis.
- c.
  
  Lung cancer.
- d.
  
  Mesothelioma.
- e.
  
  Metastases.
Fig. 4.1
2.

The most likely diagnosis in the case illustrated in Fig. 4.2, A and B, is:
- a.
  
  Right lower-lobe pneumonia.
- b.
  
  Pulmonary embolism.
- c.
  
  Subphrenic abscess.
- d.
  
  Lymphoma.
- e.
  
  Diaphragmatic hernia.
Fig. 4.2

Discussion

Pleural effusions may produce blunting of a costophrenic angle (see Fig 4.1 ), apparent elevation of the diaphragm (see Fig 4.2, A ), peripheral homogeneous opacity with a line that parallels the lateral chest wall ( Fig 4.3 ), opacity in interlobar fissures ( Fig 4.4, A-D ), ⁴⁶⁵or complete opacification of an entire hemithorax, with a shift of the mediastinum ( Fig 4.5 ). Detection and confirmation are often the first steps in the evaluation of a suspected pleural effusion. Small effusions with opacification of the costophrenic angle may be confirmed by a lateral decubitus examination, with the side of the suspected effusion down. The decubitus examination may show a change in position of the opacity and confirm free-flowing effusion. No change in the opacity may be the result of loculated effusion, pleural scarring, or possibly a pleural mass. Prior chest radiographs indicating that the blunting is a new finding also provide a good indicator of pleural effusion. Loculated effusions are difficult to confirm with chest radiograph, but ultrasound, computed tomography (CT), and even magnetic resonance imaging (MRI) may be used to verify a localized collection of pleural fluid. The differential diagnosis of pleural effusion entails consideration of a long list of entities ( Chart 4.1 ), ⁴⁶⁵but the radiologist should not be discouraged. ⁴⁷⁸Pleural effusion is sometimes associated with additional radiologic findings that may be very specific, but clinical and laboratory correlation are almost always required to make a specific diagnosis.

Chart 4.1

I.

Congestive heart failure 6 , 390
II.

Thromboembolic disease ⁶⁶⁰
III.

Infection
- A.
  
  Bacteria ( Klebsiella pneumoniae , Staphylococcus aureus , Streptococcus pyogenes , Nocardia asteroides , ²⁹Streptococcus pneumoniae [Diplococcus] , ⁵⁷⁸anaerobic organisms, ³²⁴anthrax, 125 , 648 actinomycosis, ¹⁶⁴other necrotizing bacterial infections)
- B.
  
  Tuberculosis
- C.
  
  Viral (uncommon)
- D.
  
  Mycoplasma (uncommon)
- E.
  
  Fungus (blastomycosis, coccidioidomycosis, ⁴³¹histoplasmosis, cryptococcosis ⁵⁰⁴[effusion secondary to fungal infection is rare])
- F.
  
  Parasites ( Entamoeba histolytica , ⁶³⁹Echinococcus , Paragonimus , 260 , 262 malaria)
- G.
  
  Infectious mononucleosis
IV.

Neoplasms
- A.
  
  Metastases
- B.
  
  Bronchogenic carcinoma
- C.
  
  Distant (e.g., breast, gastrointestinal, pancreatic)
- D.
  
  Multiple myeloma
- E.
  
  Mesothelioma
- F.
  
  Chest wall—primary bone cancer (e.g., Ewing sarcoma, chondrosarcoma, osteosarcoma, fibrosarcoma)
- G.
  
  Lymphoma ⁶²⁰
- H.
  
  Waldenström macroglobulinemia
V.

Collagen vascular disease (autoimmune)
- A.
  
  Systemic lupus erythematosus ⁶³²
- B.
  
  Rheumatoid arthritis 59 , 532
- C.
  
  Granulomatosis with polyangitis ⁴(formerly Wegener granulomatosis)
- D.
  
  Scleroderma (rare) ¹⁹
VI.

Trauma
- A.
  
  Chest wall trauma
- B.
  
  Rupture of the esophagus
- C.
  
  Rupture of the thoracic duct
- D.
  
  Laceration of great vessels (e.g., aorta, vena cava, pulmonary veins)
VII.

Abdominal diseases
- A.
  
  Pancreatitis
- B.
  
  Pancreatic neoplasms
- C.
  
  Pancreatic pseudocyst
- D.
  
  Pancreatic abscess
- E.
  
  Subphrenic abscess
- F.
  
  Abdominal or retroperitoneal surgery (e.g., renal surgery, splenectomy)
- G.
  
  Urinary tract obstruction with extension of retroperitoneal urine ³¹
- H.
  
  Ovarian tumors (e.g., Meigs syndrome)
- I.
  
  Cirrhosis of the liver
- J.
  
  Peritoneal dialysis
- K.
  
  Renal disease
- L.
  
  Renal failure
- M.
  
  Acute glomerulonephritis
- N.
  
  Nephrotic syndrome
- O.
  
  Whipple disease
VIII.

Diffuse pulmonary diseases
- A.
  
  Lymphangioleiomyomatosis ⁴²⁴(LAM)
- B.
  
  Asbestosis (rare)
- C.
  
  Usual interstitial pneumonitis (rare)
- D.
  
  Sarcoidosis (reported to be 4% of cases) ⁶³⁵
IX.

Drug reactions
- A.
  
  Nitrofurantoin
- B.
  
  Methysergide
- C.
  
  Busulfan
- D.
  
  Procainamide
- E.
  
  Hydralazine
- F.
  
  Isoniazid (INH)
- G.
  
  Phenytoin sodium (Dilantin)
- H.
  
  Propylthiouracil
- I.
  
  Procarbazine
X.

Other
- A.
  
  Postmyocardial infarction syndrome (Dressler syndrome) and postpericardiotomy syndrome
- B.
  
  Coagulation defect
- C.
  
  Radiation therapy (very rare) ⁶²⁸
- D.
  
  Idiopathic
- E.
  
  Pleural fistulas (bronchial, gastric, esophageal, subarachnoid) 220 , 638
- F.
  
  Empyema from retropharyngeal and neck abscess
- G.
  
  Empyema in postpneumonectomy space ²³¹