Pleura and pleural space Notes

NOTES NOTES PLEURA & PLEURAL SPACE GENERALLY, WHAT IS IT? DIAGNOSIS PATHOLOGY & CAUSES ▪ Conditions that adversely affect the function of the chest wall, pleura, and lungs resulting in impaired ventilation and oxygenation ▫ Pleural effusion: abnormal accumulation of fluid in the potential space between the visceral and parietal pleura (pleural space) ▫ Pneumothorax: presence of air or gas in the space between the thoracic wall and the lung (pleural cavity) DIAGNOSTIC IMAGING COMPLICATIONS SURGERY ▪ Mediastinal shift → impaired cardiovascular function SIGNS & SYMPTOMS ▪ See individual disorders 906 OSMOSIS.ORG Chest X-ray, CT scan, thoracic ultrasound LAB RESULTS ▪ Pleural effusion ▫ Analysis of pleural fluid confirms etiology TREATMENT ▪ Pleural effusion ▫ Thoracentesis ▪ Pneumothorax ▫ Needle chest decompression, chest tube

Chapter 128 Pleura & Pleural Space PLEURAL EFFUSION osms.it/pleural-effusion PATHOLOGY & CAUSES ▪ Excess fluid accumulates in pleural space ▪ Lung expansion limited → impaired ventilation Origin ▪ Hydrothorax (serous fluid), hemothorax (blood), urinothorax (urine), chylothorax/ lymphatic effusion (chyle), pyothorax (pus, AKA empyema) Pathophysiology ▪ Transudative pleural effusion ▫ Pressure driven filtration: ↑ hydrostatic pressure/↓ oncotic pressure → force imbalance, fluid extravasation → fluid leaks across intact capillary membranes ▫ Alteration in Starling forces ▪ Exudative pleural effusion ▫ Local inflammatory processes → leaky capillaries DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Fluid occupies space between visceral, parietal pleural ▪ Area of whiteness on standard posteroanterior (PA) chest X-ray ▪ Blunted costophrenic angles ▪ Greater density than rest of lung → gravitates towards dependent regions ▫ ↑ fluid on upright X-ray or lateral decubitus X-ray Lung ultrasound ▪ Confirms presence of effusion and detects pleural fluid septations CAUSES ▪ Transudative ▫ Congestive heart failure, liver cirrhosis, severe hypoalbuminemia, nephrotic syndrome, acute atelectasis, myxedema, peritoneal dialysis, Meigs syndrome, obstructive uropathy, end-stage renal disease ▪ Exudative ▫ Infection, malignancy, trauma, pulmonary infarction, pulmonary embolism, autoimmune processes, pancreatitis, ruptured esophagus SIGNS & SYMPTOMS ▪ Asymptomatic (if small) ▪ Pleuritic chest pain ▪ Dyspnea ▫ Worse when lying down (orthopnea) Figure 128.1 A plan chest radiograph demonstrating a large left sided pleural effusion, in this case as a consequence of metastatic melanoma. There is notable tracheal deviation. OSMOSIS.ORG 907

▫ Rheumatoid factor, antinuclear antibody, complement: collagen vascular disease ▫ Triglycerides: chylothorax from thoracic duct leakage (trauma, cancer, lymphoma) OTHER DIAGNOSTICS ▪ Medical history Figure 128.2 A CT scan of the chest in the coronal plane demonstrating a right sided pleural effusion. LAB RESULTS Thoracentesis ▪ Needle inserted through chest wall, 5th– 8th intercostal space, midaxillary line → pleural space → withdraw fluid ▪ Trial diuresis for three days in heart failure before thoracentesis ▪ Effusion analysis ▫ Amylase: pancreatitis, esophageal perforation, malignancy ▫ Blood: traumatic, malignancy, pulmonary embolism with infarction, tuberculosis ▫ Cholesterol: chylous (lymphatic fluid) vs. chyliform effusion (chyle-like fluid from chronic disease) ▫ Cytology: malignancy, infection (reactive effusion) ▫ Differential cell count: lymphocytic effusion in tuberculosis, cancer, lymphoma ▫ Glucose (low): rheumatoid arthritis, tuberculosis, empyema, malignancy ▫ Microscopy, culture: microorganisms ▫ ↓ pH: empyema, tuberculosis, mesothelioma ▫ Protein, LDH: transudative/exudative 908 OSMOSIS.ORG Clinical examination ▪ ↑ fluid on affected side ▫ ↓ chest expansion ▫ Stony dullness to percussion ▫ Diminished breath sounds ▫ ↓ vocal resonance, fremitus ▫ Tracheal deviation away from effusion ▪ If lung compressed above effusion ▫ Bronchial breathing, egophony Light’s criteria ▪ Classification of transudative/exudative effusion ▪ Transudative ▫ Difference between albumin in blood, pleural fluid > 1.2g/dL ▪ Exudative ▫ Ratio of pleural fluid protein to serum protein > 0.5 ▫ Ratio of pleural fluid LDH to serum LDH > 0.6 ▫ Pleural fluid LDH > 0.6, ⅔ times lab specific upper limit for serum Figure 128.3 The cytological appearance of a benign pleural effusion. There are numerous bland mesothelial cells mixed with lymphocytes.

Chapter 128 Pleura & Pleural Space TREATMENT SURGERY ▪ Therapeutic aspiration ▪ Insertion of intercostal drain ▪ Repeated effusions ▫ Surgical pleurodesis: obliteration of pleural space; prevents fluid accumulation OTHER INTERVENTIONS ▪ Supplemental oxygen ▪ Repeated effusions ▫ Chemical pleurodesis: obliteration of pleural space; prevents fluid accumulation (talc, bleomycin, tetracycline/doxycycline) ▪ Pleural catheter ▫ User-operated daily draining ▪ Treat underlying cause OSMOSIS.ORG 909

PNEUMOTHORAX osms.it/pneumothorax PATHOLOGY & CAUSES ▪ Abnormal collection of air in pleural cavity ▪ Air enters through damage to chest wall/ lung/gas-producing microorganisms ▫ Positive pressure in pleural space if air enters → lung partial/complete collapse TYPES Primary pneumothorax ▪ No clear cause/no preexisting lung disease ▫ Secondary to ruptured blebs (small sacs of air on lung surface) Secondary pneumothorax ▪ Occurs with existing lung disease Tension pneumothorax ▪ One-way valve formed by damaged tissue → air enters, can’t escape → intrathoracic pressure builds up → impaired cardiac, respiratory function Traumatic pneumothorax ▪ Follows physical trauma to chest (e.g. blast injury); result of medical procedure (e.g. iatrogenic pneumothorax) RISK FACTORS ▪ Smoking, chronic obstructive pulmonary disease (COPD), asthma, tuberculosis ▪ More common in individuals who are biologically male ▪ Changes in atmospheric pressure ▪ Family history of pneumothoraces SIGNS & SYMPTOMS ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ Sharp chest pain (one-sided) Dyspnea Tachycardia Cyanosis Hypercapnia → confusion, coma Diminished/absence of breath sounds (affected side) Hyperresonance to percussion ↓ vocal, tactile fremitus Trachea displaced away from affected side Tension pneumothorax ▫ ↓ blood pressure ▫ ↓ oxygen saturation ▫ Epigastric pain ▫ Displaced apex beat ▫ Distended neck veins DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray/CT scan ▪ Identifies atypical collections of gas, changes in lung markings, presence of mediastinal shift and/or tracheal deviation; lucent/dark lung field, deep sulcus sign (a deep costophrenic angle) Ultrasound ▪ Reverberation echoes of the pleural line, absence of lung sliding at the pleural line OTHER DIAGNOSTICS ▪ Clinical history, physical examination 910 OSMOSIS.ORG

Chapter 128 Pleura & Pleural Space Figure 128.4 A CT scan of the chest in the coronal plane demonstrating a right-sided pneumothorax. TREATMENT SURGERY Pleurodesis/pleurectomy ▪ Repeated pneumothoraces Tension pneumothorax: needle chest decompression ▪ AKA needle thoracostomy ▪ Emergency procedure ▪ Not definitive, improves cardiopulmonary function ▪ Large bore intravenous catheter needle inserted into pleural space ▫ Midclavicular line: second/third intercostal space ▫ Anterior/mid axillary line: fifth intercostal space ▫ Listen for air escaping ▫ Remove needle, leave catheter in place ▪ May cause injury, reserve for ▫ Mechanism of injury suggestive of pneumothorax ▫ Clinical signs of respiratory distress, persistently low oxygen saturation despite supplemental oxygen ▫ Hemodynamic instability ▫ Prolonged transport time OTHER INTERVENTIONS ▪ Supplemental oxygen ▫ Improves rate of pneumothorax reabsorption ▪ Small pneumothoraces may resolve spontaneously ▪ If wound present, cover with dressing ▫ Dressing secured on three sides to create “vent dressing” ▪ Chest tube (connected to water-seal drainage system) ▫ Inserted into “safe triangle,” damage to internal organs avoided ▫ Horizontal line, nipple to lateral chest well; between latissimus dorsi, pectoralis major OSMOSIS.ORG 911