Pleural Effusions
Systemic factors (increased hydrostatic pressure, decreased oncotic pressure) -> transudate
Local factors (increased pleural surface permeability) -> exudate
Light’s criteria: EXUDATE if ANY of the following 3 are found
-Total protein effusion / total protein serum > 0.5
-LDH effusion / LDH serum > 0.6
-LDH effusion > 2/3 upper limit of normal of LDH serum
| Transudative effusions | Exudative effusions |
| Congestive heart failure Pericarditis Cirrhosis Nephrotic syndrome | Infection (bacterial, fungal, mycobacterial) Malignancy Pulmonary embolism Collagen Vascular Dz (RA, SLE) GI disease (pancreatitis, esoph rupture) Hemothorax (Hct eff/Hct blood > 50%) |
| Etiology | Appear | WBC diff | RBC | pH | Gluc | Comments |
| CHF | Clear, straw | <1000 | <5000 | normal | normal | Bilateral, cardiomegaly |
| Parapneumonic | turbid | 5-40,000, neutrophils | <5000 | Normal/low | normal | |
| Empyema | pus | 25-100,000, neutrophils | <5000 | <7.2 | low | Needs drainage! |
| TB | serosang | 5-10,000, lymphocytes | <10,000 | Normal | Normal or low | +AFB |
| Malignancy | Bloody | 1-100,000, lymphocytes | <100,000 | Normal | Normal | +cytology |
| PE | Sometimes bloody | 1-50,000, neutrophils | <100,000 | Normal | Normal | |
| Hemothorax | Bloody | 1-50,000 | >100,000 | Normal | Normal | Hct ratio |
| Esophageal rupture | Turbid | 5-50,000 | <10,000 | Very low | Low | High amylase |
Pneumothorax:
Definition: accumulation of air or gas in the pleural space
Etiology:
-Frequently caused by trauma. can also be iatrogenic from a procedure like thoracentesis or lung biopsy
-Primary spontaneous pneumothorax occurs in patients without an apparent underlying disease. Chest pain on the affected side with dyspnea is the typical presenting complaint. This often occurs at rest and is rarely life threatening. It occurs more freuqnently in med than women, and especially in young men (20-40 years old)
-Secondary spontaneous pneumothorax occurs in associationwith underlying lung disease. Although it most commonly occurs secondary to COPD, many other conditions are associated such as tuberculosis, PCP, malignancy, fibrosis.
Clinical features and diagnosis:
The major symptoms are chest pain and dyspnea.
Physical exam reveals hyperresonance and decreased breath sounds over the involved side. If the pneumothorax is large enough to impair right heart filling/function, then there will JVD and a pulsus paradoxus and you may also find deviation of the trachea to the contralateral side.
Chest x-ray shows an absence of lung markings beyond the distinctly white line of the visceral pleura. If the patient is upright, air rises to the apex. When the patient is supine, air rises to the anterior chest. May see a deep sulcus sign: anterior costophrenic angle is sharply delineated. On a lateral decubitus film, place the suspected side up (whereas it should be down for fluid). 5 ml of air is detectable.
Therapy:
A small pneumothorax of less than 15 % in a hemodynamically stable patient may be managed with observation as they can often resolve themselves.
If the pneumothorax is larger than 15%, it is managaed by direct aspiration or tube thoracostomy.
Tension pneumothorax occurs when there is a build up of positive pressure in the pleural space. Because of a ball-valve mechanism, air enters the pleural space but cannot leave. Patients who are intubated on mechanical ventilation are at particularly high risk.
Spontanous pneumothorax has a tendency to recur. After 2 or 3 occurrences, consider pleurodesis--abrasion of the pleural surfaces which results in adherence of the visceral and parietal pleura, preventing re-accumulation of air in the pleural space.
Case 1
34 year-old M with no past medical history presents with cough, subjective fever and chills, night sweats and chest pain. He has had a cough for 3 months and it is productive of white sputum, he denies hemoptysis. He reports night sweats for the past month. His chest pain is right sided and is pleuritic in nature. Review of systems is notable for weight loss.
Vital signs are T 37.3, BP 120/70 P 85, RR 20. On exam, he is noted to have a dry hacking cough but otherwise appears comfortable and in no acute distress. He is mildly wasted. Chest exam is notable for an absence of breath sounds and dullness to percussion in the bottom third of the right chest; the remainder of the lung exam is normal.
He is admitted to the medical ward and IV ceftriaxone is begun empirically.
WBC 7,000 (29% Lymphocytes, 45% Neutrophils)
Hgb 9.0, Platelets 335
Total Protein 5.0 g/dl, LDH 407
Chest X-ray: Moderate-Large right sided pleural effusion, diffuse reticulonodular changes noted throughout lung parenchyma
A diagnostic thoracentesis is performed. The fluid is noted to be serosanginous.
Pleural Fluid Investigations:
WBC 507 (30% Neutrophils, 59% Lymphocytes), Protein 4.0 g/dl, LDH 205
a. Is this patient’s effusion transudative or exudative? (exudate)
b. Are there any additional studies that would be beneficial in evaluating the etiology of this patient’s pleural effusion? (Pleural fluid AFB can be helpful, but a
pleural biopsy has much higher yield. Would check the pleural fluid glucose level which will be low in cases of infection. Pleural fluid cytology and pleural biopsy can identify malignancy. Check sputum gram stain, culture and AFB)
c. What is the differential diagnosis for a serosanguinous or bloody pleural effusion? (Tuberculosis, malignancy, pulmonary embolism, hemothorax)
After you complete the thoracentesis, your patient complains of increased dyspnea, and new right sided chest pain. Pre procedure you had noted your patient's oxygen saturation to be 94%. Now, his oxygen saturation has dropped to 88%.
d. What do you think has occurred? (Iatrogenic pneumothorax from the thoracentesis)
e. What findings do you suspect you will find on lung exam now? (Decreased breath sounds on the right with hyper-resonant percussion note, and decreased tactile fremitus. If this is a tension pneumothorax, you may find contralateral shift of the trachea, as well as elevated jugular venous pressure and a pulsus paradoxus
f. What is your next step in managing this patient? (Administer oxygen therapy, preferable 100% FiO2 so that nitrogen in the pleural space air can be more efficiently reabsorbed down its concentration gradient into the blood stream; obtain repeat CXR. If patient shows signs of tension pneumothorax, than urgent decompression with a chest tube is necessary.
g. How could this complication have been prevented? (Remember the best treatment is prevention--- be careful when you perform thoracenteses to minimize risk of pneumothorax. Advance needle slowly until you start aspirating fluid. Do not blindly advance the catheter all the way to the hub. After you have completed the thoracentesis, remove the needle/catheter when the patient is exhaling to reduce the risk of introducing air into the pleural space)
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