Pneumothorax
Air in the pleural space. Primary spontaneous (tall thin young male, no lung disease), secondary (COPD, CF), traumatic, or iatrogenic. Tension pneumothorax = clinical diagnosis → needle decompress, don't wait for CXR.
🔍 Overview
Types
| Type | Cause | Key Features |
|---|---|---|
| Primary spontaneous (PSP) | Rupture of apical bleb/bulla in otherwise healthy lung | Tall, thin, young male, smoker. Usually small. Low recurrence after first episode (~30%), high after second (~50%). |
| Secondary spontaneous (SSP) | Underlying lung disease (COPD, CF, Pneumocystis, ILD, LAM) | More dangerous -limited pulmonary reserve. Even small PTX can cause significant compromise. Lower threshold for intervention. |
| Traumatic | Blunt/penetrating chest trauma, rib fractures | Chest tube. Evaluate for hemothorax (check pleural Hct). |
| Iatrogenic | Central line (subclavian > IJ), thoracentesis, lung biopsy, positive pressure ventilation | Post-procedure CXR. Small iatrogenic PTX in stable patient → may observe. |
| Tension | One-way valve effect → progressive air trapping → mediastinal shift → ↓ venous return → hemodynamic collapse | CLINICAL DIAGNOSIS: hypotension + JVD + absent breath sounds + tracheal deviation away. Needle decompression BEFORE imaging. 14–16G needle, 2nd ICS, midclavicular line (or 5th ICS, anterior axillary line). |
Detailed Causes
The Types table above gives the high-level categories. The high-yield differential below is what to look for on history, imaging, and bedside evaluation.
Primary Spontaneous (no underlying lung disease)
- Apical subpleural bleb rupture -most common. Tall, thin, young male; smoker (~20× risk).
Secondary Spontaneous: Obstructive Lung Disease
- COPD / emphysema (bullae rupture) -most common cause of SSP. Older smoker. Even a small PTX is dangerous (no pulmonary reserve).
- Severe asthma -during acute exacerbation. Concomitant pneumomediastinum possible.
- Cystic fibrosis -young patient with recurrent infections and bronchiectasis. PTX is a poor prognostic sign.
- Alpha-1 antitrypsin deficiency -young non-smoker (or modest smoker) with basal-predominant emphysema. Co-existing liver disease.
Secondary Spontaneous: Infectious
- Pneumocystis jirovecii pneumonia (PCP) -HIV/AIDS or other immunocompromise. Can cause bilateral PTX. High recurrence.
- Tuberculosis (cavitary) -endemic exposure, weight loss, night sweats, cavitary lesion on imaging.
Secondary Spontaneous: Cystic / Bullous
- Lymphangioleiomyomatosis (LAM) -young woman of reproductive age with recurrent PTX. Tuberous sclerosis association, renal angiomyolipomas. Treat with sirolimus.
Secondary Spontaneous: Interstitial Lung Disease
- Idiopathic pulmonary fibrosis (IPF) -late-stage disease with honeycombing. PTX heralds poor prognosis.
Secondary Spontaneous: Connective Tissue Disorders
- Marfan syndrome (FBN1) -tall, arachnodactyly, lens dislocation, aortic root dilation. Apical blebs.
- Ehlers-Danlos (vascular type, COL3A1) -hyperextensible skin, joint laxity. Vessel and organ rupture risk.
Secondary Spontaneous: Special
- Catamenial pneumothorax (thoracic endometriosis) -right-sided, recurrent, within 24-72h of menses in reproductive-age women. Treat with hormonal suppression plus VATS.
- Lung malignancy (primary or metastatic) -cavitary lesion erodes into pleura. Smoker, weight loss.
Traumatic
- Blunt chest trauma -rib fracture lacerating pleura. MVC, fall, sports injury. Often associated with hemothorax.
- Penetrating trauma -stab wound, gunshot. Open ("sucking") chest wound: cover with three-sided dressing.
- Barotrauma -diving (rapid ascent without exhalation), blast injury. Concomitant air embolism risk.
Iatrogenic
- Central line placement (subclavian > IJ) -~1-3% rate even with ultrasound guidance. Always get post-line CXR.
- Thoracentesis / pleural drainage -~3% with US guidance, > 10% without.
- CT-guided transthoracic needle biopsy -highest iatrogenic rate (~15-20%). Most resolve with observation alone.
- Mechanical ventilation barotrauma -high PEEP, high tidal volumes, ARDS. Watch for progression to tension PTX, especially in patients with bullous disease.
- CPR -rib fractures, occasionally direct pleural injury. Always check post-resuscitation CXR after prolonged or vigorous CPR.
High-yield clue patterns:
- Tall thin young male, sudden pleuritic pain at rest: primary spontaneous (apical bleb).
- Recurrent right-sided PTX in reproductive-age woman, around menses: catamenial / thoracic endometriosis.
- Young woman with renal angiomyolipomas, recurrent PTX: LAM (check for tuberous sclerosis).
- PTX + skin fibrofolliculomas + renal tumors: Birt-Hogg-Dubé.
- HIV with bilateral PTX: PCP until proven otherwise.
- Post-procedure PTX in a previously stable patient: recently placed line, biopsy, or thoracentesis.
🚨 Management
Management by Size and Type
| Scenario | Management |
|---|---|
| Small PSP (< 2 cm at apex), stable | Observation + high-flow O₂ (accelerates reabsorption 4×). Repeat CXR in 4–6h. Discharge if stable and improving. |
| Large PSP (≥ 2 cm) or symptomatic | Needle aspiration (14–16G, 2nd ICS) → recheck CXR. If re-expands → observe. If fails → chest tube. BTS Guidelines, 2023: aspiration first-line for PSP. |
| SSP -any size | Chest tube (14–28 Fr) connected to water seal or low suction (−20 cmH₂O). These patients have no reserve. Do NOT just observe SSP. |
| Tension PTX | Immediate needle decompression → chest tube. Do not wait for CXR. |
| Recurrent PSP (≥ 2 episodes ipsilateral) | VATS with pleurodesis (mechanical or chemical). Recurrence after first: ~30%. After VATS: < 5%. |
High-flow O₂ (15 L/min via non-rebreather) accelerates pneumothorax reabsorption by creating a nitrogen gradient -the pleural air (mostly N₂) is absorbed faster when alveolar N₂ is reduced. Speeds reabsorption from ~1.25%/day to ~5%/day.
📋 On Rounds
Why does high-flow O₂ speed pneumothorax reabsorption?
Pleural air is ~78% nitrogen. High-flow O₂ washes nitrogen out of the blood (by displacing it in the alveoli), creating a partial pressure gradient for N₂ between the pleural space and the capillary blood. This draws N₂ from the pleural collection into the bloodstream, where it's exhaled. The rate of reabsorption increases from ~1.25%/day to ~5%/day -approximately 4× faster.
When does a pneumothorax require a chest tube vs observation?
Tension PTX → immediate needle decompression (14–16G needle, 2nd intercostal space midclavicular line) followed by chest tube. Large PTX (> 2–3 cm at apex) or symptomatic → chest tube (14–16 Fr pigtail for PSP, 24–28 Fr for traumatic/secondary). Small PTX (< 2 cm), asymptomatic, primary spontaneous → observe 3–6 hours with repeat CXR. If stable → discharge with 24–48h follow-up CXR. Secondary PTX (in COPD, ILD, CF)
What is tension pneumothorax and how do you treat it before imaging?
Tension PTX is a CLINICAL DIAGNOSIS -do NOT wait for imaging. Mechanism: one-way valve effect → air enters pleural space with each breath but can't exit → progressive pressure buildup → mediastinal shift → IVC compression → obstructive shock. Signs: severe dyspnea, tachycardia, hypotension, absent breath sounds on affected side, tracheal deviation AWAY from affected side (late sign), distended neck veins, subcutaneous emphysema.
What is the Fleischner Society recommendation for incidentally detected pneumothorax?
Trick question -Fleischner is for pulmonary nodules, not pneumothorax. This is a common confusion. For pneumothorax management: BTS guidelines are the standard. Small primary spontaneous PTX (< 2 cm at hilum) + minimal symptoms → observation + supplemental O₂ + repeat CXR in 2-4h. If stable → discharge with 24-48h follow-up. Large (> 2 cm) or symptomatic → aspiration (with small-bore catheter) or chest tube. Secondary PTX (COPD, ILD, CF)
Clinical Examples
📋 Case 1, Primary Spontaneous Pneumothorax
Patient: 24M, tall and thin (6'3", 155 lb), sudden right-sided pleuritic chest pain while at rest. SpO₂ 96%. CXR: 25% right pneumothorax. Hemodynamically stable. No underlying lung disease.
Key findings: Primary spontaneous PTX, rupture of apical subpleural blebs in a classic demographic (tall, thin, young male, smoker). No underlying lung disease. Moderate size (> 2 cm at hilum).
Management:
- Needle aspiration with small-bore catheter (14-16G, 2nd ICS MCL), first-line for large primary spontaneous PTX per BTS guidelines
- If aspiration successful (lung re-expands on repeat CXR): observe 4-6h → discharge with 24-48h follow-up CXR
- If aspiration fails: small-bore chest tube (12-14 Fr) with Heimlich valve or underwater seal
- Supplemental O₂ (increases nitrogen gradient → accelerates pneumothorax reabsorption 4×)
- Smoking cessation counseling (recurrence risk 30% if continues smoking vs 15% if stops)
Teaching point: Needle aspiration is first-line for primary spontaneous PTX, it's as effective as chest tube with less pain, shorter hospital stay, and fewer complications. Large-bore chest tubes are overused for simple pneumothoraces.
📋 Case 2, Secondary Pneumothorax in COPD
Patient: 68M with severe COPD (FEV1 28%). Acute worsening dyspnea. SpO₂ 82% on 2L NC (baseline 90%). CXR: left pneumothorax ~20%. HR 112, BP 108/68.
Key findings: Secondary spontaneous PTX in COPD, even a small PTX is dangerous because of minimal pulmonary reserve. BTS guidelines: ALL secondary PTX > 1 cm or symptomatic need intervention (lower threshold than primary).
Management:
- Small-bore chest tube (12-14 Fr), not aspiration (higher failure rate in secondary PTX)
- Connect to underwater seal with -20 cmH₂O suction
- Admit to monitored bed (not discharge like primary PTX)
- If persistent air leak > 5 days: thoracic surgery consult for VATS pleurodesis
- Careful O₂ titration, target SpO₂ 88-92% (COPD CO₂ retainer risk)
Teaching point: Secondary PTX is always more dangerous than primary, the diseased lung cannot compensate. Threshold for intervention is lower (any symptomatic PTX), and these patients require admission, not outpatient management.
📋 Case 3, Recurrent Pneumothorax Requiring Pleurodesis
Patient: 28M with third right-sided spontaneous PTX in 2 years. Current episode: 35% PTX, managed with chest tube (resolved in 48h). Previous 2 episodes also required chest tubes.
Key findings: Recurrent ipsilateral PTX, after first episode, recurrence risk is ~30%. After second episode, ~50%. After third, > 80%. Definitive prevention is indicated.
Management:
- VATS (video-assisted thoracoscopic surgery) with blebectomy + mechanical pleurodesis, gold standard for recurrent PTX
- VATS: resect apical blebs + abrade parietal pleura → adhesion formation prevents recurrence (< 5% recurrence after VATS)
- Alternative: chemical pleurodesis via chest tube (talc slurry) if not a surgical candidate
- CT chest to assess bleb distribution before surgery
- Absolute indication for pleurodesis: second ipsilateral PTX, first contralateral PTX (bilateral), occupational risk (pilots, divers)
Teaching point: Pleurodesis after second ipsilateral PTX is standard of care. VATS blebectomy + pleurodesis reduces recurrence from > 50% to < 5%. Pilots and scuba divers should have pleurodesis after FIRST episode due to occupational hazard.
📣 Sample Presentation
One-Liner
"Mr. Scott is a 22-year-old tall, thin male presenting with sudden right-sided pleuritic chest pain and dyspnea. CXR shows 30% right pneumothorax. Hemodynamically stable. SpO₂ 97%."
Key Points to Cover on Rounds
Primary spontaneous pneumothorax -classic demographics (tall, thin, young male). Large (30% at apex), symptomatic. Treatment: 14 Fr pigtail chest tube placed under US guidance, connected to water seal. Post-procedure CXR: lung re-expanded, no residual PTX. Air leak: resolved by 12h. O₂ applied (accelerates pleural nitrogen reabsorption). Plan: chest tube to water seal ×12h → if no recurrence on CXR → remove and observe ×6h → discharge if stable. Recurrence counseling: 30% chance of recurrence. If 2nd episode → VATS with pleurodesis. Avoid flying ×2 weeks, avoid scuba diving permanently.
🧪 Workup
Confirming the Diagnosis
Tension pneumothorax is a clinical diagnosis and imaging is a delay, not a step. Hypotension with absent breath sounds, distended neck veins and tracheal deviation gets needle decompression now. Sending an unstable patient to radiology to confirm what you already suspect is how tension pneumothorax kills, and a normal-looking film in a patient who is decompensating does not overrule the examination.
Choosing the Test
| Test | What You Are Looking For | Why, and Where It Fails |
|---|---|---|
| Upright PA chest radiograph FIRST TEST | A visible visceral pleural line with no lung markings beyond it. Measure the rim of air to size it, using the thresholds in the Management tab. | Fast, available, and adequate for most stable presentations. Upright matters: air collects at the apex, so an upright film puts the abnormality where you are already looking. |
| Supine radiograph EASY TO MISS | Deep sulcus sign: an abnormally deep, lucent costophrenic angle. Also a lucent upper abdomen and a sharply outlined hemidiaphragm or cardiac border. | This is where pneumothoraces get missed. Supine, the air layers anteriorly rather than at the apex, so there is often no pleural line to see. Trauma and ICU patients are filmed supine precisely when the diagnosis matters most. |
| Lung ultrasound BEDSIDE | Absent lung sliding and absent B-lines, with a lung point where sliding starts again. On M-mode the normal seashore pattern becomes a barcode (stratosphere) pattern. | Outperforms the supine film: pooled sensitivity 0.91 and specificity 0.99 against supine radiography in trauma across 13 studies (Cochrane, 2020). Sliding or B-lines present rules out pneumothorax in the zone scanned, and a lung point is essentially diagnostic at 100% specificity, though only 66% sensitive Lichtenstein, 2000. Absent sliding alone is not enough: it also occurs in mainstem intubation, pleural adhesions, ARDS and apnea. |
| CT chest DEFINITIVE | The most sensitive test, and the one that finds occult pneumothorax invisible on a supine film. | Reserve it for the questions a plain film cannot answer: a complex or uncertain picture, suspected underlying lung disease, bleb distribution before surgery, or distinguishing a large bulla from a pneumothorax. That last distinction is the one worth slowing down for, because draining a giant bulla mistaken for a pneumothorax creates a persistent air leak. |
Imaging confirms the pneumothorax; it no longer decides the treatment on its own. CHANGED 2023 The BTS 2023 pleural disease guideline made symptoms and clinical condition the deciding factors rather than size alone, and it allows conservative management of a minimally symptomatic or asymptomatic primary spontaneous pneumothorax regardless of size. Measure the rim of air because it still informs the conversation, but do not intervene on a number in a comfortable patient.
Alongside the Imaging
- Pulse oximetry and an ABG if hypoxic or hypercapnic, since a pneumothorax in someone with existing lung disease decompensates far faster than the same size in a healthy chest.
- ECG in a left-sided pneumothorax, which can mimic ischemia with reduced voltages, axis shift and precordial T-wave changes. Recognizing it prevents an unnecessary cardiac workup.
- Ask what caused it, because it changes what happens next. Height, low body mass and smoking point to primary spontaneous; COPD, prior tuberculosis or malignancy point to secondary, which is treated more aggressively; recent central line, thoracentesis, biopsy or positive-pressure ventilation points to iatrogenic.
- Ask about recurrence and about air travel or diving, since a recurrent pneumothorax changes the threshold for definitive surgical management, and diving is a lifelong contraindication after an untreated spontaneous pneumothorax.
⚡ Summary
Summary
Tension Is a Clinical Diagnosis
Hypotension, distended neck veins, absent breath sounds and tracheal deviation away from the affected side. Needle decompress immediately; do not wait for a chest x-ray. The film adds minutes the patient does not have, and the diagnosis is made at the bedside.
Classify It, Because Management Differs
Primary spontaneous: tall thin young male, no lung disease, from an apical bleb. Secondary spontaneous: COPD, cystic fibrosis, and far less well tolerated because reserve is already gone. Traumatic and iatrogenic, most often after central line placement, thoracentesis or biopsy. Secondary pneumothorax is managed more aggressively at any given size, because a small one can be fatal in a patient with an FEV1 of 30%.
Size and Symptoms Drive the Decision
Small (under about 2 to 3 cm), primary and asymptomatic: observation with high-flow oxygen, and repeat imaging. Large or symptomatic: needle aspiration or a small-bore chest tube. Any secondary pneumothorax, any tension, any bilateral or hemodynamically significant one: chest tube. Increasingly, conservative management is favored even for larger primary pneumothoraces in stable patients.
High-Flow Oxygen Is Therapeutic, Not Just Supportive
15 L/min by non-rebreather accelerates reabsorption roughly fourfold, from about 1.25% of the volume per day to 4 to 5%. It works by washing nitrogen out of the alveoli, creating a gradient that draws the mostly-nitrogen pleural air back into the blood. Give it even to a patient who is not hypoxemic.
Know the Clue Patterns
Tall thin young male with sudden pleuritic pain at rest: primary spontaneous. Recurrent right-sided pneumothorax in a reproductive-age woman around menses: catamenial, from thoracic endometriosis. Young woman with cystic lung disease: lymphangioleiomyomatosis. Recurrent pneumothorax with a family history: Birt-Hogg-Dube.
Place the Tube Safely
The safe triangle: lateral border of pectoralis major, anterior border of latissimus dorsi, above the level of the nipple. Insert over the top of the rib to avoid the neurovascular bundle running under it. Small-bore catheters are as effective as large-bore for most non-traumatic pneumothoraces and are far more comfortable.
Watch for Re-Expansion Pulmonary Edema
Do not drain a large or chronic pneumothorax rapidly. Re-expanding a lung that has been collapsed for more than a few days can cause unilateral pulmonary edema, so control the rate and avoid immediate suction. Manage the same risk when removing large volumes of pleural fluid.
Prevent Recurrence and Counsel
Recurrence after a first primary spontaneous pneumothorax is roughly 30%, and higher after a second. Refer for VATS with pleurodesis or bullectomy after a second ipsilateral event, a first contralateral event, persistent air leak beyond 3 to 5 days, or in high-risk occupations such as diving and flying. Smoking cessation is the highest-yield preventive measure, and patients must not fly until resolution is confirmed.
📄 One Pager
Text version
Pulmonology / Emergency · One Pager
Pneumothorax
Tension = clinical diagnosis → needle decompress immediately. Primary spontaneous: small → observe, large → aspiration/tube. Secondary: lower threshold for tube. Recurrence → VATS + pleurodesis.
Types
Primary spontaneous: tall thin young male, no lung disease. Secondary: COPD, ILD, CF, PCP (lower threshold for intervention -can't tolerate lung loss). Tension: one-way valve → obstructive shock.
Tension PTX -Don't Wait for Imaging
Absent breath sounds + tracheal deviation + hypotension + JVD. Needle decompress: 14-16G, 2nd ICS MCL or 4th/5th ICS AAL. Then chest tube. Clinical diagnosis -decompress first, image after.
Management
Small primary (<2cm) + minimal symptoms → observe + O₂ + repeat CXR. Large/symptomatic → aspiration or chest tube (14-28 Fr pigtail). Remove tube when: no air leak + expanded on CXR × 12-24h.
Key Drugs
Needle decompression14-16G, 2nd ICS MCL (tension)
Pigtail chest tube14 Fr (small catheter)
Supplemental O₂Accelerates reabsorption
Pain controlOpioids/NSAIDs as needed
Pitfalls
- Waiting for CXR in tension PTX (clinical diagnosis → decompress)
- Discharging without recurrence counseling (30% after 1st episode)
- Not admitting secondary PTX (these patients decompensate quickly)
- Flying within 2 weeks (risk of re-expansion)
Related Topics
AsthmaCOPD -Chronic ManagementHemoptysisInterstitial Lung DiseaseObstructive Sleep ApneaPFT Interpretation