Resident Version

Pleural Effusion Module

created by Dr. Farzana Harji

Updated 5/2009

Objectives:

By the end of this module, you should be able to:

  1. Identify top three most common causes of pleural effusion
  2. Recognize indications for thoracentesis
  3. Understand the diagnostic approach to pleural effusion and be able to differentiate transudative versus exudative pleural effusion.
  4. Understand the significance of fluid pH, glucose level, gross appearance of fluid, gram stain and culture.

References:

1.Light, RW. Pleural effusions. Medical clinics of North America Nov 1977; Vol. 61, No. 6, 1339-1352.

2.Light, RW. Pleural effusion. N Engl J Med June 20, 2002; Vol. 346, No. 25, 1971-1977.

3.Uptodate: Diagnostic evaluation of a pleural effusion in adults.

4.Light, RW. Pleural diseases, 3rd ed, Williams Wilkins, Baltimore, 1995.

Pleural effusion

  • Top three most common causes of pleural effusion in the United States are congestive heart failure, pneumonia, and cancer.

FIRST STEP: History and examination

Exam findings:

Chest exam typically reveals dullness to percussion, the absence of fremitus, and diminished breath sounds or their absence.

-Distended neck veins, and S3 gallop, or peripheral edema suggests congestive heart failure.

-Right ventricular heave or thrombophlebitis suggests pulmonary embolus.

-Presence of lymphadenopathy or hepatosplenomegaly suggests neoplastic disease or liver disease.

-Ascites may suggest hepatic cause.

Imaging studies sometimes necessary to verify pleural effusion:

-Lateral decubitus chest x-ray

-Ultrasound

-CT scan (for lung parenchyma or mediastinum)

Indications for thoracentesis:

Presence of a clinically significant pleural effusion (more than 2cm thick on ultrasound or lateral films) with no known cause (not worked up previously). Thoracentesis is performed for diagnosis or therapeutic reasons.

SECOND STEP: Differentiate Exudates versus Transudates

Sensitivity of Tests To Distinguish Exudative From Transudative Effusions:

Sensitivity Specificity

Test for Exudate (%)for Exudate (%)

Light’s Criteria (one or more of the following three)9583

Ratio of pleural-fluid protein level to serum protein level >0.58684

Ratio of pleural-fluid LDH level to serum LDH level >0.69082

Pleural-fluid LDH level >two-thirds the upper limit of normal8289

______

Leading causes of transudative pleural effusions: chf, cirrhosis, nephrosis, and PE

Leading causes of exudative pleural effusions: pneumonia, cancer, and PE

THIRD STEP: Additional Tests and Interpretation:

1.Low glucose level (<60 mg/dL): complicated parapneumonic effusion, malignancy, or rheumatoid pleuritis (not SLE) or tuberculous pleural effusion

2. Pleural fluid pH: useful prognostic factor

<7.2 pleural fluid pH (arterial pH >7.35): strongly suggests that fluid will not resolve spontaneously in parapneumonic effusions and will most likely need a chest tube. Low pH can also occur in malignancy, rheumatoid pleuritis and tuberculous effusion

3.Smears and cultures

-Usually just need aerobic and anaerobic cultures and gram stain

-If chronic febrile illness or fever of unknown origin then include fungal culture

-If >50% lymphocytes, then include AFB smear and culture

4.Amylase: elevated in pancreatic disease, or esophageal rupture, 10% with malignancy

5.Appearance of Pleural FluidInterpretation

1. Bloody

<1% of peripheral hematocrit nonsignificant

1-20% cancer, PE and trauma

>50% hemothorax

2. White/milky/opaque chylothorax, chyliform; pyothorax

3. Putrid odor probably infection due to anaerobic bacteria

6. Total and differential cell count and their values:

A. Neutrophils (limited value): (>50% of cells) parapneumonic, pancreatitis, PE, malignancy, TB

B. Lymphocytes (good value): (>50% of cells) cancer or tuberculous pleuritis

C. Eosinophils (limited value): (>10%) most common cause is trauma resulting in either blood (hemothrax) or air (pneumothorax), or viral pleuritis, or resolving parapneumonic effusion. Unusual causes reactions to drugs or exposures (asbestos)

D. Mesothelial cells: commonly found up to 12 or more can be normal; uncommon in tuberculous effusions; presence of numerous mesothelial cells nearly excludes a diagnosis of tuberculosis

7.Cytologic Exam Efficiency when cancer involving the pleura:

Metastatic adenocarcinoma70% sensitive

Mesothelioma10% sensitive

Squamous-cell carcinoma 20% sensitive

Lymphoma25-50% sensitive

Sarcoma25% sensitive

8.Lipid analysis: if fluid is milky or opaque

-Chylous pleural effusion arises when the thoracic duct is severed or obstructed. High TG, low cholesterol.

-Chyliform pleural effusion has been present for a long time and cholesterol accumulates. High cholesterol, normal TG.

Case:

HPI:75 yom w/ 50 pack year smoking history, and MI x2, presents to the ED with increasing shortness of breath for one month. He also complains of low grade fever, sweats, coughw/ white sputum., and orthopnea. No sick contacts, no chest pain, no hemoptysis, no weight loss. His exam reveals diminished BS lower 2/3 of L lung, lower ½ of R lung, no egophony, decreased tactile fremitus bilaterally lower regions, + dullness to percussion over same area, normal chest excursion bilaterally. Heart regular rate and rhythm, no murmurs, gallops or rub, jvp 13 cm, bilateral lower extremity edema.

He is found to have bilateral pleural effusion on cxr, L>R.

T 100.5 BP 150/85 HR 82 RR 28 O2Sat 86% RA  94% 2L

CBC:WBC 10.0, Hbg 14, Hct 40, Plts 120

  1. What is your differential diagnosis for this patient?
  1. Does the patient need any additional studies?
  1. Does the patient need thoracentesis?

Pleural fluid analysis reveals:

Color: pale yellow

Total Nucleated cell count 168, segs 43%, lymphs 42%, macrophage 7%, mesothelial 8%, rbc 56

pH: 7.80

Total protein pleural fluid: 3.2

LDH pleural fluid: 216

Total protein serum: 7.8 (range 6.3-8.5)

LDH serum: 462 (range 300-670)

Gram stain: negative

Culture pending

  1. Is this a transudative or exudative pleural effusion?
  1. What is the most likely diagnosis?

Review Questions:

  1. A 43 year-old male nurse presents to your office for evaluation. For the past 2 months, he has experienced intermittent fever, night sweats, and a 20-lb weight loss. He denies having any cough or sputum production. The patient states that about 3 months ago, he tested positive on purified protein derivative (PPD) screening. He denies any drug abuse, nor does he report any HIV risk factors. The patient states that he was prescribed isoniazid, but he chose not to follow this regimen. His chest x-ray is remarkable only for a moderate left pleural effusion.

Which of the following statements regarding tuberculous pleuritis is true?

  1. Pleural effusion is more often a manifestation of reactivation tuberculosis than of primary tuberculosis.
  2. Without therapy, this patient’s pleural effusion will likely persist for many years.
  3. In most cases of this illness, pleural fluid cell differential will reveal greater than 85% neutrophils.
  4. Acid-fast bacilli are rarely seen in pleural liquid, and cultures are positive in only 20% to 40% of patients.
  1. A 55-year-old man visits your office with a complaint of fatigue and increasing dyspnea on exertion. He has been experiencing these symptoms for 2 weeks. He denies having fever, chills, cough, or weight loss, and he has no significant cardiac history. He denies having been in contact with anyone who was ill. He recently quit smoking, after having smoked cigarettes for 35 years. He does have a history of alcoholism and chronic pancreatitis; the pancreatitis has been well controlled with analgesics and pancreatic enzyme replacement therapy. His serum chemistries and complete blood count are unremarkable. A chest x-ray reveals a large left pleural effusion. A diagnostic thoracentesis is performed.

Which of the following statements regarding laboratory studies of pleural fluid is true?

  1. An elevated pleural fluid amylase level is uncommon in patients with a malignant pleural effusion
  2. Pleural fluid eosinophilia is diagnostic of a pulmonary parasitic infection.
  3. A pleural liquid hematocrit that exceeds half of the simultaneous peripheral blood hematocrit indicates frank bleeding into the pleural space and is diagnostic of a hemothorax.
  4. A pleural effusion with a pH of 5.8 is suggestive of empyema

Post Module Evaluation

Please place completed evaluation in an interdepartmental mail envelope and address to Dr. Wendy Gerstein, Department of Medicine, VAMC (111).

1) Topic of module:______

2) On a scale of 1-5, how effective was this module for learning this topic? ______

(1= not effective at all, 5 = extremely effective)

3) Were there any obvious errors, confusing data, or omissions? Please list/comment below:

______

4) Was the attending involved in the teaching of this module? Yes/no (please circle).

5) Please provide any further comments/feedback about this module, or the inpatient curriculum in general:

6) Please circle one:

Attending Resident (R2/R3)Intern Medical student