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2025 PACUPrep BCCCP Preparatory Course

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  1. Pulmonary

    ARDS
    4 Topics
    |
    1 Quiz
  2. Asthma Exacerbation
    4 Topics
    |
    1 Quiz
  3. COPD Exacerbation
    4 Topics
    |
    1 Quiz
  4. Cystic Fibrosis
    6 Topics
    |
    1 Quiz
  5. Drug-Induced Pulmonary Diseases
    3 Topics
    |
    1 Quiz
  6. Mechanical Ventilation Pharmacotherapy
    5 Topics
    |
    1 Quiz
  7. Pleural Disorders
    5 Topics
    |
    1 Quiz
  8. Pulmonary Hypertension (Acute and Chronic severe pulmonary hypertension)
    5 Topics
    |
    1 Quiz
  9. Cardiology
    Acute Coronary Syndromes
    6 Topics
    |
    1 Quiz
  10. Atrial Fibrillation and Flutter
    6 Topics
    |
    1 Quiz
  11. Cardiogenic Shock
    4 Topics
    |
    1 Quiz
  12. Heart Failure
    7 Topics
    |
    1 Quiz
  13. Hypertensive Crises
    5 Topics
    |
    1 Quiz
  14. Ventricular Arrhythmias and Sudden Cardiac Death Prevention
    5 Topics
    |
    1 Quiz
  15. NEPHROLOGY
    Acute Kidney Injury (AKI)
    5 Topics
    |
    1 Quiz
  16. Contrast‐Induced Nephropathy
    5 Topics
    |
    1 Quiz
  17. Drug‐Induced Kidney Diseases
    5 Topics
    |
    1 Quiz
  18. Rhabdomyolysis
    5 Topics
    |
    1 Quiz
  19. Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
    5 Topics
    |
    1 Quiz
  20. Renal Replacement Therapies (RRT)
    5 Topics
    |
    1 Quiz
  21. Neurology
    Status Epilepticus
    5 Topics
    |
    1 Quiz
  22. Acute Ischemic Stroke
    5 Topics
    |
    1 Quiz
  23. Subarachnoid Hemorrhage
    5 Topics
    |
    1 Quiz
  24. Spontaneous Intracerebral Hemorrhage
    5 Topics
    |
    1 Quiz
  25. Neuromonitoring Techniques
    5 Topics
    |
    1 Quiz
  26. Gastroenterology
    Acute Upper Gastrointestinal Bleeding
    5 Topics
    |
    1 Quiz
  27. Acute Lower Gastrointestinal Bleeding
    5 Topics
    |
    1 Quiz
  28. Acute Pancreatitis
    5 Topics
    |
    1 Quiz
  29. Enterocutaneous and Enteroatmospheric Fistulas
    5 Topics
    |
    1 Quiz
  30. Ileus and Acute Intestinal Pseudo-obstruction
    5 Topics
    |
    1 Quiz
  31. Abdominal Compartment Syndrome
    5 Topics
    |
    1 Quiz
  32. Hepatology
    Acute Liver Failure
    5 Topics
    |
    1 Quiz
  33. Portal Hypertension & Variceal Hemorrhage
    5 Topics
    |
    1 Quiz
  34. Hepatic Encephalopathy
    5 Topics
    |
    1 Quiz
  35. Ascites & Spontaneous Bacterial Peritonitis
    5 Topics
    |
    1 Quiz
  36. Hepatorenal Syndrome
    5 Topics
    |
    1 Quiz
  37. Drug-Induced Liver Injury
    5 Topics
    |
    1 Quiz
  38. Dermatology
    Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis
    5 Topics
    |
    1 Quiz
  39. Erythema multiforme
    5 Topics
    |
    1 Quiz
  40. Drug Reaction (or Rash) with Eosinophilia and Systemic Symptoms (DRESS)
    5 Topics
    |
    1 Quiz
  41. Immunology
    Transplant Immunology & Acute Rejection
    5 Topics
    |
    1 Quiz
  42. Solid Organ & Hematopoietic Transplant Pharmacotherapy
    5 Topics
    |
    1 Quiz
  43. Graft-Versus-Host Disease (GVHD)
    5 Topics
    |
    1 Quiz
  44. Hypersensitivity Reactions & Desensitization
    5 Topics
    |
    1 Quiz
  45. Biologic Immunotherapies & Cytokine Release Syndrome
    5 Topics
    |
    1 Quiz
  46. Endocrinology
    Relative Adrenal Insufficiency and Stress-Dose Steroid Therapy
    5 Topics
    |
    1 Quiz
  47. Hyperglycemic Crisis (DKA & HHS)
    5 Topics
    |
    1 Quiz
  48. Glycemic Control in the ICU
    5 Topics
    |
    1 Quiz
  49. Thyroid Emergencies: Thyroid Storm & Myxedema Coma
    5 Topics
    |
    1 Quiz
  50. Hematology
    Acute Venous Thromboembolism
    5 Topics
    |
    1 Quiz
  51. Drug-Induced Thrombocytopenia
    5 Topics
    |
    1 Quiz
  52. Anemia of Critical Illness
    5 Topics
    |
    1 Quiz
  53. Drug-Induced Hematologic Disorders
    5 Topics
    |
    1 Quiz
  54. Sickle Cell Crisis in the ICU
    5 Topics
    |
    1 Quiz
  55. Methemoglobinemia & Dyshemoglobinemias
    5 Topics
    |
    1 Quiz
  56. Toxicology
    Toxidrome Recognition and Initial Management
    5 Topics
    |
    1 Quiz
  57. Management of Acute Overdoses – Non-Cardiovascular Agents
    5 Topics
    |
    1 Quiz
  58. Management of Acute Overdoses – Cardiovascular Agents
    5 Topics
    |
    1 Quiz
  59. Toxic Alcohols and Small-Molecule Poisons
    5 Topics
    |
    1 Quiz
  60. Antidotes and Gastrointestinal Decontamination
    5 Topics
    |
    1 Quiz
  61. Extracorporeal Removal Techniques
    5 Topics
    |
    1 Quiz
  62. Withdrawal Syndromes in the ICU
    5 Topics
    |
    1 Quiz
  63. Infectious Diseases
    Sepsis and Septic Shock
    5 Topics
    |
    1 Quiz
  64. Pneumonia (CAP, HAP, VAP)
    5 Topics
    |
    1 Quiz
  65. Endocarditis
    5 Topics
    |
    1 Quiz
  66. CNS Infections
    5 Topics
    |
    1 Quiz
  67. Complicated Intra-abdominal Infections
    5 Topics
    |
    1 Quiz
  68. Antibiotic Stewardship & PK/PD
    5 Topics
    |
    1 Quiz
  69. Clostridioides difficile Infection
    5 Topics
    |
    1 Quiz
  70. Febrile Neutropenia & Immunocompromised Hosts
    5 Topics
    |
    1 Quiz
  71. Skin & Soft-Tissue Infections / Acute Osteomyelitis
    5 Topics
    |
    1 Quiz
  72. Urinary Tract and Catheter-related Infections
    5 Topics
    |
    1 Quiz
  73. Pandemic & Emerging Viral Infections
    5 Topics
    |
    1 Quiz
  74. Supportive Care (Pain, Agitation, Delirium, Immobility, Sleep)
    Pain Assessment and Analgesic Management
    5 Topics
    |
    1 Quiz
  75. Sedation and Agitation Management
    5 Topics
    |
    1 Quiz
  76. Delirium Prevention and Treatment
    5 Topics
    |
    1 Quiz
  77. Sleep Disturbance Management
    5 Topics
    |
    1 Quiz
  78. Immobility and Early Mobilization
    5 Topics
    |
    1 Quiz
  79. Oncologic Emergencies
    5 Topics
    |
    1 Quiz
  80. End-of-Life Care & Palliative Care
    Goals of Care & Advance Care Planning
    5 Topics
    |
    1 Quiz
  81. Pain Management & Opioid Therapy
    5 Topics
    |
    1 Quiz
  82. Dyspnea & Respiratory Symptom Management
    5 Topics
    |
    1 Quiz
  83. Sedation & Palliative Sedation
    5 Topics
    |
    1 Quiz
  84. Delirium Agitation & Anxiety
    5 Topics
    |
    1 Quiz
  85. Nausea, Vomiting & Gastrointestinal Symptoms
    5 Topics
    |
    1 Quiz
  86. Management of Secretions (Death Rattle)
    5 Topics
    |
    1 Quiz
  87. Fluids, Electrolytes, and Nutrition Management
    Intravenous Fluid Therapy and Resuscitation
    5 Topics
    |
    1 Quiz
  88. Acid–Base Disorders
    5 Topics
    |
    1 Quiz
  89. Sodium Homeostasis and Dysnatremias
    5 Topics
    |
    1 Quiz
  90. Potassium Disorders
    5 Topics
    |
    1 Quiz
  91. Calcium and Magnesium Abnormalities
    5 Topics
    |
    1 Quiz
  92. Phosphate and Trace Electrolyte Management
    5 Topics
    |
    1 Quiz
  93. Enteral Nutrition Support
    5 Topics
    |
    1 Quiz
  94. Parenteral Nutrition Support
    5 Topics
    |
    1 Quiz
  95. Refeeding Syndrome and Specialized Nutrition
    5 Topics
    |
    1 Quiz
  96. Trauma and Burns
    Initial Resuscitation and Fluid Management in Trauma
    5 Topics
    |
    1 Quiz
  97. Hemorrhagic Shock, Massive Transfusion, and Trauma‐Induced Coagulopathy
    5 Topics
    |
    1 Quiz
  98. Burns Pharmacotherapy
    5 Topics
    |
    1 Quiz
  99. Burn Wound Care
    5 Topics
    |
    1 Quiz
  100. Open Fracture Antibiotics
    5 Topics
    |
    1 Quiz

Participants 432

  • Allison Clemens
  • April
  • ababaabhay
  • achoi2392
  • adhoward1
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Lesson 7, Topic 1
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Foundational Concepts in Pleural Disorders

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Introduction to Pleural Disorders

Introduction to Pleural Disorders: Epidemiology, Risk Factors, Pathophysiology, and Presentation

Objectives Icon A clipboard with a checkmark, symbolizing learning objectives.

Learning Objective

  • Describe the foundational principles of pleural disorders—including their epidemiology, risk factors, pathophysiology, and clinical presentation—in critically ill adults.

1. Epidemiology and Etiology of Pleural Disorders

Pleural disorders are common in ICU settings, with distinct patterns that impact detection, management, and outcomes. Understanding incidence and leading causes informs early recognition.

A. Pleural Effusions

  • Affect over 1.5 million hospitalized adults per year in the US; ICU detection ranges from 8% (physical exam) to 60% (ultrasound).
  • Approximately 83% of ARDS patients have effusions on CT scan, often underdiagnosed by physical examination alone.

B. Malignant Pleural Effusion (MPE)

  • Occurs in approximately 15% of cancer patients.
  • Common primary tumors include lung, breast, gynecologic cancers, lymphoma, and mesothelioma.

C. Parapneumonic Effusions & Empyema

  • Develop in about 41% of hospitalized pneumonia cases; 5–10% of these may progress to empyema.
  • Incidence of empyema is around 2.5 per 100,000 adults (data from France).
  • Mortality can be up to 18%, with a mean length of stay of 14 days and estimated cost of around $40,000 per episode.

D. Pneumothorax

  • Less common than effusions but associated with high morbidity, especially in mechanically ventilated patients.
  • Risk is increased with high positive end-expiratory pressure (PEEP) and barotrauma.

E. Hemothorax

  • Causes include blunt trauma (e.g., rib fractures, motor vehicle collisions), penetrating injuries.
  • Iatrogenic causes in medical ICUs can occur from procedures like thoracentesis or central line placement.

F. Chylothorax

  • Traumatic: Often secondary to surgery or injury.
  • Nontraumatic: Can be due to malignancy or idiopathic causes (5–15% of cases).
Key Point Icon A lightbulb, indicating a key point. Key Points
  • Bedside ultrasound increases effusion detection up to 7-fold in the ICU compared to physical exam alone.
  • Retained hemothorax (if not adequately evacuated) carries a greater than 25% risk of developing into empyema.

2. Key Risk Factors in ICU/Acute Care

Critically ill patients harbor multiple overlapping risks for pleural complications. Proactive identification enables targeted prevention and early intervention.

A. Patient-Related Factors

  • Malignancy: Can lead to pleural issues via lymphatic obstruction, direct tumor invasion, or tumor-related bleeding.
  • Coagulopathy: Patients on anticoagulants or with thrombocytopenia are at risk for spontaneous or procedure-related bleeding (hemothorax).
  • Immunosuppression: Increases susceptibility to empyema and opportunistic pleural infections.

B. Procedure-Related Factors

  • Invasive Procedures: Thoracentesis, chest tube insertion, thoracic surgery, and central line placement can cause pneumothorax, hemothorax, or infection.
  • Device Complications: Chest tube displacement occurs in up to 30% of cases; retained guidewires are a known complication.

C. Therapy-Related Factors

  • Mechanical Ventilation: High PEEP and barotrauma can lead to alveolar rupture and pneumothorax. Prolonged ventilation may also impair lymphatic drainage, contributing to effusions.

D. Infectious Factors

  • Sepsis and Pneumonia: These are primary drivers for the development of parapneumonic effusions.
  • Risk Enhancers for Infection: Conditions like diabetes, alcohol use disorder, poor dentition (increasing aspiration risk), and exposure to nosocomial pathogens can worsen the risk or severity of pleural infections.
Clinical Pearl Icon A shield with an exclamation mark, indicating a clinical pearl. Clinical Pearl: Coagulopathy Management

Always assess and correct coagulopathy before any planned thoracic procedure. This includes holding or reversing anticoagulants according to established protocols to minimize bleeding risk.

3. Pathophysiological Mechanisms

Fluid and air accumulate in the pleural space when normal pleural homeostasis or pressure gradients are disrupted. Distinguishing transudates from exudates and recognizing the signs of tension physiology are fundamental to management.

A. Pleural Fluid Homeostasis

  • Starling Forces: A delicate balance between hydrostatic pressure (pushing fluid out of capillaries) and oncotic pressure (pulling fluid into capillaries) across the parietal pleura governs fluid movement.
  • Lymphatic Clearance: Specialized lymphatic channels (stomata) in the parietal pleura actively drain the pleural space, maintaining a minimal physiological fluid volume (typically <1 mL/kg).

B. Transudate vs. Exudate

  • Light’s Criteria for Exudate (at least one must be met):
    • Pleural fluid protein / serum protein ratio > 0.5
    • Pleural fluid LDH / serum LDH ratio > 0.6
    • Pleural fluid LDH > 2/3 the upper limit of normal for serum LDH
  • Limitations & Adjuncts: Light’s criteria can misclassify up to 25% of cardiac effusions (transudates) as exudates, particularly in patients on diuretics. Adjunctive tests like pleural fluid NT-proBNP or the serum-pleural albumin gradient can improve diagnostic accuracy.

C. Air Leak & Tension Physiology

Barotrauma from mechanical ventilation or lung injury can cause alveolar rupture, allowing air to enter the pleural space (pneumothorax).

Tension Pneumothorax Pathophysiology
Air Entry into Pleural Space (One-Way Valve)
Progressive Air Accumulation & Ipsilateral Lung Collapse
Mediastinal Shift (Tracheal Deviation)
Compression of Contralateral Lung & Great Veins
Reduced Venous Return & Hemodynamic Collapse
Figure 1: Tension Pneumothorax. A one-way valve mechanism allows air to enter the pleural space but not exit, leading to progressive air accumulation. This causes ipsilateral lung collapse, mediastinal shift away from the affected side, compression of the contralateral lung and great veins, reduced venous return, and ultimately hemodynamic collapse.

D. Empyema Cascade

The development of empyema (pus in the pleural space) typically follows a three-phase progression if a parapneumonic effusion is not adequately treated:

Empyema Development Stages
Stage 1: Exudative
Simple effusion
Free-flowing fluid
Stage 2: Fibrinopurulent
Loculations, pus
Thickened pleura
Stage 3: Organizing
Pleural peel
Trapped lung
Figure 2: The Empyema Cascade. Progression from an uncomplicated exudative effusion to a complex, organized empyema with pleural peel formation.
  • Pleural Fluid Criteria for Complicated Parapneumonic Effusion/Empyema (suggesting need for drainage):
    • pH < 7.20
    • Glucose < 60 mg/dL (or < 3.3 mmol/L)
    • LDH > 1,000 U/L (or > 3 times the upper limit of normal for serum LDH)
    • Positive Gram stain or culture
    • Frank pus on aspiration
Clinical Pearl Icon A shield with an exclamation mark, indicating a clinical pearl. Clinical Pearl: Pleural Fluid Analysis

Pleural fluid pH is a critical parameter for guiding drainage decisions in parapneumonic effusions. Glucose and LDH levels further refine risk stratification and help identify complicated effusions that may require intervention.

4. Clinical Presentation and Diagnostic Clues

The clinical presentation of pleural disorders varies widely depending on the etiology, acuity, and volume of fluid or air. Rapid differentiation is essential for timely and appropriate intervention.

A. Symptoms

  • Dyspnea: Shortness of breath, often correlating with the volume and rate of accumulation of pleural fluid or air.
  • Pleuritic Chest Pain: Sharp pain that worsens with inspiration, coughing, or movement, suggestive of pleural inflammation.
  • Empyema-Specific Symptoms: Fever, malaise, and productive cough (sometimes with purulent sputum) may indicate an underlying pleural infection.

B. Physical Exam Findings

  • Pleural Effusion:
    • Dullness to percussion over the affected area.
    • Decreased or absent breath sounds.
    • Decreased tactile fremitus.
  • Pneumothorax:
    • Hyperresonance to percussion over the affected area.
    • Absent breath sounds.
    • Tension Pneumothorax Signs: Tracheal deviation away from the affected side, distended neck veins, severe respiratory distress, hypotension.
  • Hemothorax: Signs of hypovolemia may be present, such as tachycardia and hypotension, in addition to effusion signs.

C. Red Flags (Requiring Urgent Attention)

  • Sudden onset of hypotension, increased central venous pressure (CVP), and unilateral hyperresonance/absent breath sounds strongly suggest tension pneumothorax.
  • Persistent fever and leukocytosis despite appropriate antibiotic therapy for pneumonia should raise suspicion for empyema.

D. Diagnostic Strategy

  • Point-of-Care Ultrasound (POCUS): First-line imaging modality for effusion detection, characterization (e.g., simple vs. complex/loculated), and guiding procedures like thoracentesis.
  • Chest X-ray (CXR): Often the initial screening tool; can identify larger effusions, pneumothoraces, and some underlying lung pathology.
  • Computed Tomography (CT) Scan: Provides detailed evaluation of pleural abnormalities (e.g., loculations, pleural thickening, empyema) and underlying lung disease; essential for complex cases.
  • Pleural Fluid Analysis: Crucial for differentiating transudates from exudates and identifying infection (pH, glucose, LDH, cell count, Gram stain, culture).

Case Vignette: A 60-year-old patient with ARDS on high PEEP develops sudden hypotension, increased CVP, and absent breath sounds on the right side. Urgent needle decompression is performed, confirming a tension pneumothorax, with subsequent improvement in hemodynamics.

Key Point Icon A lightbulb, indicating a key point. Key Points
  • Always perform ultrasound to guide thoracentesis and other pleural procedures to improve safety and reduce complications.
  • Immediate decompression (e.g., needle thoracostomy followed by chest tube) is a lifesaving intervention in tension pneumothorax.

References

  1. Tian P, Qiu R, Wang M, et al. Prevalence, causes, and health care burden of pleural effusions among hospitalized adults in China. JAMA Netw Open. 2021;4:e2120306.
  2. Moore PK, Moore HB, Moore EE. Pleural effusion in the intensive care unit. In: [Book]. Elsevier; 2025:58–66.
  3. Skok K, Hladnik G, Grm A, et al. Malignant pleural effusion and its current management: a review. Medicina (Kaunas). 2019;55:490.
  4. Porcel JM, Esquerda A, Vives M, et al. Etiology of pleural effusions: analysis of more than 3,000 consecutive thoracenteses. Arch Bronconeumol. 2014;50:161–165.
  5. Ferreiro L, San José ME, Valdés L. Management of parapneumonic pleural effusion in adults. Arch Bronconeumol. 2015;51:637–646.
  6. Abdulelah M, Abu Hishmeh M. Infective pleural effusions—A comprehensive narrative review article. Clin Pract. 2024;14:870–881.
  7. Farjah F, Symons RG, Krishnadasan B, et al. Management of pleural space infections: a population-based analysis. J Thorac Cardiovasc Surg. 2007;133:346–351.
  8. Wilshire CL, Jackson AS, Vallières E, et al. Effect of intrapleural fibrinolytic therapy vs surgery for complicated pleural infections: a randomized clinical trial. JAMA Netw Open. 2023;6:e237799.
  9. Mummadi SR, Stoller JK, Lopez R, et al. Epidemiology of adult pleural disease in the United States. Chest. 2021;160:1534–1551.
  10. Arnold DT, Hamilton FW, Morris TT, et al. Epidemiology of pleural empyema in English hospitals and the impact of influenza. Eur Respir J. 2021;57:e2003546.
  11. Gilbert RW, Fontebasso AM, Park L, et al. The management of occult hemothorax in adults with thoracic trauma: a systematic review and meta-analysis. J Trauma Acute Care Surg. 2020;89:1225–1232.
  12. McGrath EE, Blades Z, Anderson PB. Chylothorax: aetiology, diagnosis and therapeutic options. Respir Med. 2010;104:1–8.
  13. Karpathiou G, Péoc’h M, Sundaralingam A, et al. Inflammation of the pleural cavity: pathogenesis, diagnosis and implications in tumor pathophysiology. Cancers. 2022;14:1415.
  14. Maskell NA, Batt S, Hedley EL, et al. The bacteriology of pleural infection by genetic and standard methods and its mortality significance. Am J Respir Crit Care Med. 2006;174:817–823.
  15. Chalmers JD, Singanayagam A, Murray MP, et al. Risk factors for complicated parapneumonic effusion and empyema on presentation to hospital with community-acquired pneumonia. Thorax. 2009;64:592–597.
  16. DuBose J, Inaba K, Okoye O, et al. Development of posttraumatic empyema in patients with retained hemothorax: a prospective observational AAST study. J Trauma Acute Care Surg. 2012;73:752–757.
  17. Light RW, Macgregor MI, Luchsinger PC, Ball WC. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Intern Med. 1972;77:507–513.
  18. Cincin A, Abul Y, Ozben B, et al. Pleural fluid amino-terminal brain natriuretic peptide in patients with pleural effusions. Respir Care. 2013;58:313–319.
  19. Kolditz M, Halank M, Schiemanck CS, et al. High diagnostic accuracy of NT-proBNP for cardiac origin of pleural effusions. Eur Respir J. 2006;28:144–150.
  20. British Thoracic Society. BTS guideline for pleural disease. Thorax. 2023;78(suppl 1):s1–s42.
  21. De Troyer A, Leduc D, Cappello M, et al. Mechanics of the canine diaphragm in pleural effusion. J Appl Physiol. 2012;113:785–790.
  22. Hassan M, Patel S, Sadaka AS, et al. Recent insights into the management of pleural infection. Int J Gen Med. 2021;14:3415–3429.
  23. Park HJ, Choi CM. Can parapneumonic effusion be diagnosed only with pleural fluid analysis? J Thorac Dis. 2020;12:3422–3425.
  24. Qureshi NR, Rahman NM, Gleeson FV. Thoracic ultrasound in the diagnosis of malignant pleural effusion. Thorax. 2009;64:139–143.