Pneumothorax

Air in the pleural space — primary spontaneous (PSP), secondary spontaneous (SSP), traumatic, or tension; tension is immediately life-threatening

Symptoms / Associated Sx

  • Sudden onset ipsilateral pleuritic chest pain

  • Dyspnea (proportional to size and underlying lung reserve)

  • Decreased or absent breath sounds on affected side

  • Hyperresonance on percussion (affected side)

  • Tracheal deviation toward unaffected side (tension — late sign)

  • Subcutaneous emphysema (crepitus palpable on neck/chest — air dissecting into soft tissues)

  • Tension: Hemodynamic instability, JVD, tracheal deviation, absent breath sounds — obstructive shock

Denies

  • Fever + productive cough (rules out pneumonia as primary if absent — though may coexist)

  • Prior thoracic procedure or chest tube (reduces iatrogenic if absent)

  • Bilateral symmetric findings (rules out bilateral pneumothorax — unusual unless bilateral trauma)

Social History (SHx)

Prior pneumothorax (recurrence risk 30–50% without intervention), smoking, tall thin male (PSP), known COPD/emphysema (SSP), asthma, cystic fibrosis, Marfan syndrome, LAM, prior blebs/bullae, mechanical ventilation (iatrogenic — positive pressure), trauma (rib fractures).

Main Etiology

  • Primary spontaneous (PSP): rupture of subpleural bleb/bulla in young, thin, tall males; no underlying lung disease

  • Secondary spontaneous (SSP): rupture of emphysematous bulla in COPD, asthma, PCP (HIV), TB, Marfan, LAM — more serious due to poor pulmonary reserve

  • Traumatic: penetrating (stabbing, gunshot) or blunt trauma (rib fractures); often hemopneumothorax

  • Iatrogenic: central line placement (subclavian > internal jugular), thoracentesis, bronchoscopy, mechanical ventilation (barotrauma)

  • Tension: ball-valve mechanism → air enters but cannot exit → progressive collapse + mediastinal shift → obstructive shock

Most Common DDx

  • Pulmonary embolism (acute pleuritic chest pain + dyspnea; tachycardia; normal breath sounds; D-dimer + CTPA; no hyperresonance)

  • Pericardial tamponade (obstructive shock + JVD + muffled heart sounds + hypotension; echo shows effusion + RV collapse; no breath sound change)

  • COPD exacerbation (dyspnea + decreased breath sounds from hyperinflation; bilateral changes; CXR/POCUS distinguishes)

  • Pleural effusion (dullness to percussion rather than hyperresonance; CXR shows blunting; POCUS confirms fluid not air)

  • Aortic dissection (sudden tearing chest/back pain; pulse differential; no breath sound change; CT aortography)

  • Large bulla in emphysema (mimics pneumothorax on CXR — both appear lucent; CT chest distinguishes; bulla has curvilinear walls; pneumothorax has pleural edge)

DATA

  • CXR (visible pleural line with absent lung markings beyond — upright expiratory CXR most sensitive; estimate size: <2 cm apex-to-cupola = small; >2 cm = large)

  • Point-of-care ultrasound (POCUS) — absent lung sliding + absence of comet-tail artifacts + barcode/stratosphere sign on M-mode; highly sensitive; available instantly in unstable patients

  • CT chest (gold standard for size and characterization; distinguishes bulla from PTX; detects contralateral PTX)

  • ABG (hypoxia + respiratory alkalosis in acute; hypercapnia if tension or severe SSP)

  • SpO2 continuous; EKG (sinus tachycardia; decreased precordial voltage ipsilateral)

  • Do NOT delay treatment for imaging if tension PTX suspected based on clinical exam

Home Meds

  • Inhalers (COPD — continue in SSP; bronchodilators may reduce bronchospasm complicating SSP)

  • Anticoagulants (hold if chest tube required)

  • Mechanical ventilation settings (if intubated — barotrauma risk; reduce tidal volume)

Plan

  • Tension pneumothorax (clinical diagnosis — do NOT wait for imaging):

    • Needle decompression immediately: 14–16 gauge angiocath at 2nd intercostal space, midclavicular line (or 4th–5th ICS anterior axillary line per ATLS 2018); audible rush of air confirms

    • Follow immediately with chest tube (needle decompression is temporary)

  • Large PTX (>2 cm apex-to-cupola or symptomatic):

    • Chest tube (tube thoracostomy): 14–20 Fr small-bore pigtail (equivalent to large-bore for simple PTX; less painful); connect to water-seal drainage → suction if lung not re-expanding

    • Large-bore chest tube (28–32 Fr): traumatic PTX, hemopneumothorax, empyema

  • Small primary spontaneous PTX (<2 cm) + clinically stable:

    • Option 1: Observation in ED × 3–6h; repeat CXR; discharge if stable + no progression

    • Option 2: Aspiration (manual or catheter aspiration) — 16–18 gauge angiocath; aspirate up to 2.5 L; 60–70% success in PSP

    • Supplemental O2 (accelerates pleural air reabsorption by 4× — 100% O2 if no CO2 retention risk)

  • Secondary spontaneous PTX (any size — admit all):

    • Poor pulmonary reserve; even small SSP can cause severe decompensation

    • Chest tube placement for most SSP; observation inappropriate

    • Pulmonology consult

  • Persistent air leak (>5 days): Thoracic surgery consult; VATS (video-assisted thoracoscopic surgery) + pleurodesis; chemical pleurodesis (talc or doxycycline) via chest tube

  • Recurrent PTX or second episode: VATS bullectomy + pleurodesis (prevents recurrence ~95%); discuss on first SSP and second PSP

  • Supplemental O2 to target SpO2 ≥92%; avoid positive pressure if possible (worsens tension)

  • Serial CXR (q4–8h after chest tube until stable lung expansion)

  • Daily BMP, CBC; trend SpO2; chest tube output and air leak monitoring

  • Pulmonology + thoracic surgery consult for SSP, persistent air leak, or recurrent PSP

  • PT/OT — breathing exercises; avoid Valsalva maneuvers

  • Discharge: Avoid air travel × 2–3 weeks (pressure changes); avoid diving until definitive treatment; smoking cessation (recurrence risk); follow-up CXR in 1–2 weeks; thoracic surgery consult for recurrent/secondary; aviation and diving restrictions counseling

Red Flags

  • Tracheal deviation + absent breath sounds + hemodynamic instability → tension PTX → needle decompression IMMEDIATELY; do NOT get CXR first

  • SSP in COPD — even small PTX can be life-threatening; never observe SSP without chest tube and admission

  • Iatrogenic PTX post-subclavian line (absent breath sounds post-procedure) → CXR immediately; chest tube if symptomatic or >2 cm

  • Bilateral pneumothorax (rare; trauma, intubated patients) → bilateral chest tubes urgently

  • Persistent air leak >5 days → endobronchial valve or VATS; thoracic surgery urgently

Senior IM Resident Pearls

  • Tension PTX is a clinical diagnosis — absent breath sounds + tracheal deviation + hypotension + JVD = needle decompress immediately; do NOT order CXR before acting; 2 minutes can mean death

  • POCUS for PTX: Lung sliding absent = air in pleural space; M-mode barcode/stratosphere sign = PTX; comet-tail artifacts (B-lines) present = lung touching chest wall = no PTX; faster than CXR in unstable patients

  • Large bulla vs. PTX on CXR — one of the most dangerous misidentifications; bulla has a wall (curvilinear white line); PTX has no wall; CT distinguishes definitively; do NOT tube a bulla (rupture → immediate PTX)

  • 100% O2 accelerates PTX reabsorption by 4× — displaces nitrogen in pleural space; use in PSP without CO2 retention risk; helpful as adjunct to observation

  • Common mistake: Observing a secondary spontaneous PTX in COPD — even a 1 cm SSP in a patient with FEV1 of 30% can be life-threatening; all SSP require chest tube and admission

  • Common mistake: Positioning needle decompression only at 2nd ICS midclavicular line — in obese patients or muscular builds, needle may not reach pleural space; 4th–5th ICS anterior axillary line is often more reliable (ATLS 2018)