Facilitator Version
Module #4- Pleural Effusions Module
Created by Dr. David Olson
5/2014
Objectives:
1) Understand the physical exam findings consistent with pleural effusions.
2) Recognize the indications and contraindications for a diagnostic thoracentesis.
3) Understand the evaluation of pleural fluid, and its implications.
4) Develop management plans based on history, physical and laboratory analysis.
References:
MKSAP 16
McGrath E, Anderson P. Diagnosis of Pleural Effusion: A Systematic Approach. American Journal of Critical Care; March 2011, Volume 20, No. 2: 119-127.
Light RW. Pleural Effusions. N Engl J Med. 2002; 346(25): 1971-1977.
Wong CL, Holroyd-Leduc J, Straus SE. Does This Patient Have a Pleural Effusion? JAMA, January 21, 2009; Vol 301, No. 3: 309-317.
Light RW. The Light Criteria: The Beginning and Why they are Useful 40 Years Later. Clin Chest Med; 34(2013): 21-26.
Quinn T, Alam N, Marshall MB, Choong C. Decision Making and Algorithm for the Management of Pleural Effusions. Thorac Surg Clin; 23(2013): 11-16.
Porcel JM, Light RW. Diagnostic Approach to Pleural Effusion in Adults. American Family Physician; April 2006, Vol 73, No. 7:1211-1220.
www.UpToDate.com “Diagnostic Evaluation of a Pleural Effusion in Adults”
Case
Mr. J is a 62 year old male who presents to the ED with progressive shortness of breath and mild chest pain that has been getting worse over the past week. Normally he walks one mile every day, but recently he has only been able to walk to the end of his block before getting “winded” and having to turn around. The chest pain is mostly when he is breathing heavily, but he has also noted it at rest when he takes a deep breath or yawns. Subjectively he has noticed recent episodes of chills, and he gets so hot at night that he starts to sweat. He has a chronic cough, which he attributes to years of smoking, but it has been more productive recently. His past medical history includes: Tobacco abuse (current), mild COPD without oxygen dependence, DM, Rheumatoid Arthritis. Currently he takes ibuprofen for his arthritis, Spiriva and a rescue inhaler for his COPD, Glargine Insulin 15U at bedtime, and Aspart 3U with each meal.
On physical examination his temperature is 100.9 oF (38.3 oC), blood pressure 114/74 mmHg, pulse rate 98 bpm, respiratory rate 22, and O2 saturation 85% on RA. In general he is a thin man, appearing his stated age, but shows signs of mild respiratory distress. Heart sounds are normal. Lungs are clear on the left, but decreased breath sounds on the right. Abdomen is soft non-distended with normal bowel sounds, and no hepatosplenomegaly. He does have mild edema in his legs, approximately 1+ to the knees.
Labs: wbc 8.7, Hgb 10.2, Hct 31, Plt 178. Differential shows 82%N, 9%L, 4%M, 2%E, 3.2%IG. NA 131, K 4.1, Cl 100, HCO3 16, BUN 19, Cr 0.99, Glu 145. BNP 386. Liver function tests are normal. Last A1C 9.5%
Chest x-ray: moderately enlarged heart, hyperinflation consistent with COPD, moderate to large pleural effusion (free flowing) on left with associated consolidation.
The ED physician provides you with the history above and requests that the patient be admitted for evaluation of a new pleural effusion.
What more information should you ask for? What should you look for on physical exam?
Pleural effusions have a large list of causes, much of which can be eliminated or highlighted in the history. Abdominal causes such as from cirrhosis, pancreatic disease (ask about alcohol use, changes in weight, pant size). Exposures (i.e. asbestos, tuberculosis, smoking, sick contacts etc.). Weight changes (malignancy, ascites, CHF). New medications. Trauma, or recent procedures.
On physical exam: cardiac: jugular venous distension, hepato-jugular reflex
chest/pulmonary: egophony, percussion, tactile fremitus, bronchial breath sounds
general: fingers for clubbing, lymphadenopathy, symmetry of chest excursion, and is the edema in the legs symmetric?
The patient has been a long time smoker. He worked as a mechanic until he retired, and was a mechanic in the Navy. He has noticed some weight loss recently; he estimates about 25 pounds in the last few months. Your records indicate almost 40 pounds since his last PCP appointment 1 year ago. He does not drink, has no exposures to sick people recently, and no history of TB exposure.
On exam: CV: no JVD, no HJR Chest: Right side clear to auscultation with minimal crackles noted in the base; left side: decreased breath sounds, decreased fremitus 1/2 up the chest, above this an increase in bronchial breath sounds and increased fremitus. Dullness to percussion extends up around 1/2 of chest. No egophony.
What are the indications for a thoracentesis? What studies are important to send?
Unless the underlying cause of the effusion is known, any new pleural effusion should be considered for thoracentesis. The exceptions are for patients with heart failure exacerbations, unless the patient has a fever, or the effusion is unresponsive to diuretic therapy. Effusions less than 1cm on decubitus films should only be tapped using ultrasound guidance.
Studies to send routinely: 1) pH <7.2 is an indication that the effusion may be infected and a chest tube may be needed (low pH is also seen with esophageal rupture, rheumatoid arthritis and some malignant effusions)
2) Protein for Light’s Criteria
3) LDH for Light’s Criteria
4) Glucose levels that are low can be an indication of empyema, Tb, RA, SLE and some malignant neoplasms. Glucose <60 in parapneumonic effusions can be an indication for chest tube.
5) Cell count can indicate the presence of wbc’s and rbc’s, >10,000 per mm3 is abnormal and >50% neutrophils is indication of parapneumonic effusion, or PE. >50% lymphocytes is more often associated with malignancy, and TB.
6) Culture; positive culture or Gram stain are indications to consider chest tube.
7) Cytology if malignancy is suspected, overall sensitivity is 60% (65% on first sample, ~30% on the second sample) .
What are Light’s Criteria?
If 1 or more of the following criteria are met, then the fluid is exudative:
1) Pleural fluid LDH > 2/3 the upper limit of normal
2) Ratio of pleural fluid LDH to serum LDH > 0.6
3) Ratio of pleural protein to serum protein >0.5
Light’s Criteria is 100% sensitive for exudates, however around 25% of transudates are falsely classified as exudates. Most of the misclassification is in patients with heart failure on diuretics, leading to the term pseudo-exudative effusion.
The patient’s fluid analysis shows a wbc of 11,000 split evenly as neutrophils and lymphocytes, moderate blood, no bacteria. Culture is negative. His TP is 3.3 (serum 6.1), LDH 1,200 (serum 1,300). pH 7.23. Cytology was sent to the pathology department.
What is the most likely cause of this effusion?
The two most common causes of exudative effusions are parapneumonic effusion and malignancy. Other possibilities include PE, rheumatoid arthritis, pancreatitis related effusion, post-MI. Discuss that if the fluid had been transudative then heart failure, hypoalbuminemia, cirrhotic liver disease, hypothyroidism and nephrotic syndrome would be the more likely differential.
What is your next step in managing the patient?
The patient has a number of risk factors and signs that a malignancy could be the cause of his effusion, however given the fevers, left shift in his wbc and recent symptoms, this patient likely has an underlying malignancy and a post obstructive pneumonia. Starting antibiotics is appropriate, although he does not meet criteria for a chest tube (pH <7.2, frank pus/positive culture, loculations, fluid >1/2 thoracic space). Discuss what antibiotics would be most appropriate for a post-obstructive pneumonia and the type of bacteria most likely responsible. Same as community acquired pneumonia, except a higher probability of anaerobic bacteria, therefore a beta-lactam/beta-lactamase inhibitor (Zosyn, Unasyn) plus anaerobic coverage (clindamycin) is preferred.
Also better imaging at this point is appropriate; a CT of the chest may find a mass and possibly a second thoracentesis with fluid sent for cytology if the initial cytology is negative.
CT scan shows a 5cm mass obstructing the left lower lobe with associated consolidation and inflammation behind consistent with post obstructive pneumonia. Bronchoscopy reveals a non-small cell carcinoma in the left lung. The patient had no signs of metastasis and is started on chemotherapy treatments after antibiotic treatment for his pneumonia is completed.
If time:
Large malignant pleural effusions very often recur, so there are several options for treatment of the effusions. 1) Watchful waiting – if the patient is relatively symptom free, then treatment of the underlying malignancy may eventually improve the effusions.
2) Repeated therapeutic thoracentesis, as many effusions will re-accumulate. They may take several weeks to months to become symptomatic.
3) Pleurodesis can be achieved by introducing a sclerosing agent into the pleural space (most commonly talc, tetracyclin or doxycycline) which creates a diffuse inflammatory state and adherence of the visceral and parietal pleura.
4) For patients with a short life expectancy or who are too frail for pleurodesis, there are indwelling catheters that can be introduced which allow for symptomatic removal of fluid over time.
Other fluid analysis that can be done on pleural fluid:
ADA (adenosine deaminase) is a marker for tuberculosis
Hematocrit can be performed to look for hemothorax
Amylase can be an indication of pancreatitis or esophageal rupture
NT-proBNP can be run on pleural fluid and would indicate active heart failure
Complement C4 is severely reduced in rheumatoid arthritis effusions
Cholesterol/triglycerides can diagnose a chylothorax
Appearance of the pleural fluid can also reveal its possible origin:
Milky white can be from chylothorax or empyema
Urine colored might indicate a urinothorax
Putrid/turbid is an indication of infection/empyema
Black can indicate the presence of a fungal infection (aspergillus)
Brown “anchovy paste” may indicate the presence of an aemebic abscess
Bloody could indicate a traumatic tap or a possible hemothorax
MKSAP Questions (Pulmonary Section)
# 14 A; Diagnosing Tb on fluid analysis
# 71 D; Repeat thoracentesis to establish diagnosis and stage 4
# 74 A; Heart failure (pseudoexudate)
# 100 D; Complicated parapneumonic effusion