Notes
Pleural Effusions & Chest Wall Disorders
Sections
Misc. Restrictive Disorders
Pleural Effusions, Ankylosing spondylitis, and Kyphoscoliosis
Pleural Effusions
Pleural effusion is excess fluid in the pleural space, which occurs when production of pleural fluid exceeds pleural reabsorption.
Healthy Pleural Space & Pleural Fluid
We draw a lung and label the visceral pleura, which is directly in contact with the lung tissue (recall that "viscera" = organ) and, the parietal pleura, which is the outer, more fibrous covering. Although not shown here, be aware that the parietal and visceral pleura are continuous with each other.
Pleural Details
The visceral and parietal pleura are separated by a thin layer of fluid that resides in the pleural space (which is exaggerated for our purposes).
Both the visceral and parietal pleura comprise a thin layer of mesothelial cells and underlying connective tissue.
Capillaries and lymphatic vessels lie in the connective tissue; the lymphatic vessels open to the pleural space through the parietal pleura; these openings are called stomata.
The capillary and lymphatic vessels are vital to the production and reabsorption of pleural fluid.
The majority of the pleural fluid is formed by the parietal pleura; this is a low-protein ultrafiltrate that comes from the parietal capillaries.
The majority of pleural fluid resorption occurs via drainage by parietal lymphatic vessels (via the stomata).
The normal volume of fluid within the pleural space is 10-20 mL, (the volume depends on a person's size), and that it has a low protein concentration.
Thus, disorders that alter the formation of ultrafiltrate or reabsorption can produce pleural effusions.
EFFUSIONS
Transudate effusions are the result of increased hydrostatic pressure and/or decreased plasma oncotic pressure, which will alter the formation of ultrafiltrate from the capillaries (as described by the Starling equation).
Because this occurs in the presence of intact vessels, the fluid is generally clear.
Key causes include heart failure (which increases hydrostatic pressure), cirrhosis, and nephrotic syndrome (which reduces plasma oncotic pressure).
Notice that none of these etiologies involves direct damage to the lung parenchyma.
Exudative effusions, on the other hand, are the result of damage to the lung tissue.
Exudative effusions occur when there is increased capillary permeability, for example, due to inflammation, which allows larger molecules to leak into the pleural space.
In contrast to the fluid in transudate effusions, exudative effusions produce fluid that is cloudy with proteins and cell contents.
Key causes include pneumonia, pulmonary embolism, cancers, Tuberculosis, and other infections of the lungs.
Specific types of effusions based on their contents:
- Hemothorax (blood in the pleural space; beware of clotting)
- Chylothorax (exudate rich in triglycerides)
- Chyliform, aka, pseudo-chylothroax (rich in cholesterol)
- Empyema, which is pus (think of infections)
Signs, Symptoms:
Patients with pleural effusions may present with pleuritic chest pain, dyspnea, and dry cough.
Upon exam, you may hear dull percussion notes over the area of effusion, and decreased breath sounds.
Diagnosis:
Diagnosis is aided by chest x-rays; we show an area of effusion arising from the diaphragm and filling up the lower portion of the right side of the thoracic cage.
Needle aspiration and fluid analysis can help us to diagnose the cause of effusion (Is the fluid clear? Does it contain evidence of pathogens or inflammation?).
Treatments:
Treatments involve fluid drainage and treatment of the underlying condition; in some cases, surgery may be necessary.
Chest wall Disorders
These disorders limit chest wall restriction and limit air intake.
Review compliance and restriction
Ankylosing spondylitis
Ankylosing spondylitis is a systemic inflammatory disease that affects the joints of the axial skeleton.
Pulmonary involvement can be both direct and indirect:
Direct involvement is via the development of interstitial lung disease.
Indirect involvement occurs when joints of the thoracic cage, such as the costovertebral joints, become fused; thus, movement is limited, and chest wall compliance is reduced.
Kyphoscoliosis
Kyphoscoliosis is characterized by abnormal curvatures in both the coronal and sagittal planes; the resulting rib displacement can restrict chest wall movement.
Kyphoscoliosis is a combination of two skeletal abnormalities:
– Kyphosis is characterized by a posterior curvature.
– Scoliosis is characterized by a lateral curvature.
When restriction of the pulmonary system is severe, hypoxemia can result.
Hypoxemia is the root of two common pulmonary complications of kyphoscoliosis: pulmonary hypertension and cor pulmonale.
Neuromuscular diseases
Neuromuscular diseases that affect the thorax can also cause pulmonary restriction:
Pneumothorax
Occurs when air enters the pleural space, which disrupts the negative pressure and causes lung collapse.
Pneumothorax can be broadly categorized as spontaneous or traumatic:
Primary spontaneous pneumothorax occurs in the absence of underlying pulmonary disease; this type of pneumothorax is thought to be caused by rupture of pulmonary blebs, and is most common amongst smokers, especially young, tall, thin men. Be aware that primary spontaneous pneumothorax is often recurrent, especially in women.
Secondary spontaneous pneumothorax is associated with underlying pulmonary disease, such as COPD.
Traumatic pneumothorax can be the result of penetrating or blunt trauma to the chest.
Iatrogenic is a sub-type of traumatic pneumothorax that results from medical intervention, most commonly pulmonary needle biopsy.
Tension pneumothorax occurs when air becomes trapped in the pleural space; accumulating air exerts pressure on the lungs and heart, and can reduce venous return and cardiac output.
Because hypoxemia and even shock can occur, tension pneumothorax requires emergency treatment.
Clinical Cases
Case 1: Respiratory Emergency
A 51-year-old male is brought to the Emergency Department in a C-collar and strapped to a stretcher. He was extracted from the driver's seat of a midsize car after having been involved in a head-on collision with a similar sized vehicle. Paramedics report the airbags deployed; however, the patient was not wearing a seatbelt.
On physical examination, the cervical spine is adequately immobilized, neck veins are distended, heart rate is 90/min, blood pressure is 80/50 mmHg, and his respiratory rate is 32/min. The patient's breathing is labored, and he appears to be in acute respiratory distress. Auscultation of his chest demonstrates absent breath sounds in the right lung field. He has a large scalp laceration, and there is blood and pink-tinged fluid leaking from his nose.
At this time, what should be your first priority?
Answer
- Perform an immediate needle decompression
Explanation
The most likely cause of this patient's respiratory distress is a tension pneumothorax. It is a common life-threatening injury that needs to be immediately identified and treated. Clues from the history and physical exam include unrestrained occupant in a motor vehicle accident, absence of breath sounds in an entire lung field, tachycardia, and hypotension in the presence of distended neck veins. Under these circumstances, it would be entirely appropriate to insert a needle into the chest wall cavity to decompress the potentially life-threatening tension pneumothorax. The preferred insertion site is the 2nd intercostal space in the midclavicular line in the affected hemithorax.
The most common error in this situation would be to transport the patient out of the emergency department to obtain a chest x-ray without a physician present. Radiographic findings in a tension pneumothorax will demonstrate a relative lucency of the entire affected hemithorax, depression of the diaphragm, and displacement of the mediastinum to the contralateral side of the chest.
Board Review
Pleural Effusions
Getting ready for boards? Review these concise, bulleted high yield reviews for your exam.
USMLE & COMLEX-USA
Nurse Practitioner (NP)
Physician Assistant (PA)
Internal Medicine (ABIM)
References
ATLS Subcommittee; American College of Surgeons' Committee on Trauma; International ATLS working group. Advanced trauma life support (ATLS): the ninth edition. J Trauma Acute Care Surg. 2013 May;74(5):1363-6.
Roberts DJ, Leigh-Smith S, Faris PD, Ball CG, Robertson HL, Blackmore C, Dixon E, Kirkpatrick AW, Kortbeek JB, Stelfox HT. Clinical manifestations of tension pneumothorax: protocol for a systematic review and meta-analysis. Syst Rev. 2014 Jan 04;3:3.
Rojas R, Wasserberger J, Balasubramaniam S. Unsuspected tension pneumothorax as a hidden cause of unsuccessful resuscitation. Ann Emerg Med. 1983 Jun;12(6):411-2.
- Berdal, Gunnhild, Silje Halvorsen, Désirée van der Heijde, Morten Mowe, and Hanne Dagfinrud. "Restrictive Pulmonary Function Is More Prevalent in Patients with Ankylosing Spondylitis than in Matched Population Controls and Is Associated with Impaired Spinal Mobility: A Comparative Study." Arthritis Research & Therapy 14, no. 1 (January 25, 2012): R19. https://doi.org/10.1186/ar3699.
- D'Agostino, Horacio P., and Mary Ann Edens. "Physiology, Pleural Fluid." In StatPearls. Treasure Island (FL): StatPearls Publishing, 2019. http://www.ncbi.nlm.nih.gov/books/NBK513353/.
- Garske, Luke A., Kuhan Kunarajah, Paul V. Zimmerman, Lewis Adams, and Ian B. Stewart. "In Patients with Unilateral Pleural Effusion, Restricted Lung Inflation Is the Principal Predictor of Increased Dyspnoea." PLOS ONE 13, no. 10 (October 3, 2018): e0202621. https://doi.org/10.1371/journal.pone.0202621.
- Miserocchi, G. "Physiology and Pathophysiology of Pleural Fluid Turnover." European Respiratory Journal 10, no. 1 (January 1, 1997): 219–25.
USA, Yale Rosen from. A Massive Left Pleural Effusion Displacing the Heart and Trachea to the Right, The Cause Is
- Pulmonary Adenocarcinoma with Pleural Spread Which Is Obscured by the Effusion and Cannot Be Recognized in This Radiograph. June 30, 2012. Pleural effusion - Left lung Uploaded by CFCF. https://commons.wikimedia.org/wiki/File:Pleural_effusion_-Left_lung(7471755836).jpg.
- Weinberger, Steven E., Barbara A. Cockrill, and Jess Mandel. "Disorders of the Respiratory Pump." In Principles of Pulmonary Medicine, 7th ed., 248–58. Philadelphia, PA: Elsevier, 2019. http://www.clinicalkey.com/#!/content/book/3-s2.0-B9780323523714000222?scrollTo=%23hl0000268.
- ———. "Pleural Disease." In Principles of Pulmonary Medicine, 7th ed., 206–20. Philadelphia, PA: Elsevier, 2019. http://www.clinicalkey.com/#!/content/book/3-s2.0-B9780323523714000180?scrollTo=%23hl0000419.