2d:I[856015,["/_next/static/immutable/chunks/1xzisbplk9czp.js","/_next/static/immutable/chunks/3j2i1faptc_-9.js","/_next/static/immutable/chunks/0fma7nlq6immz.js","/_next/static/immutable/chunks/08tq8rmv423j5.js","/_next/static/immutable/chunks/1chr5wkk3j58k.js","/_next/static/immutable/chunks/37kmmh_zm4dov.js","/_next/static/immutable/chunks/311zvdjfxff-f.js","/_next/static/immutable/chunks/1a_hqhrsle_n_.js"],"default"] 2e:T65d2,

Summary Table

Category	Details
Risk Factors	Tall, thin young males (primary spontaneous); COPD, asthma, cystic fibrosis, Marfan syndrome, tuberculosis (secondary spontaneous); mechanical ventilation, central line placement (iatrogenic); chest trauma (traumatic)
Etiology	Rupture of subpleural blebs (primary), underlying lung disease (secondary), penetrating or blunt chest injury (traumatic), positive pressure ventilation or procedures (iatrogenic)
Patient Presentation	Sudden onset pleuritic chest pain and dyspnea; in tension pneumothorax: rapidly progressive respiratory distress with hemodynamic instability
Classic Physical Exam	Decreased or absent breath sounds on the affected side, hyperresonance to percussion, decreased tactile fremitus, tracheal deviation away from the affected side (tension)
Key Diagnostic Results	Upright CXR showing a visible visceral pleural line with absent lung markings beyond it; CT chest is the most accurate test; tension pneumothorax is a clinical diagnosis
Management	Small primary spontaneous: observation with supplemental oxygen. Large or symptomatic: needle aspiration or chest tube (tube thoracostomy). Tension: immediate needle decompression at the 2nd intercostal space midclavicular line followed by chest tube
Keywords	"Absent breath sounds," "hyperresonance," "visible pleural line on CXR," "tall thin young male with sudden chest pain," "tracheal deviation," "needle decompression"

1. Pathophysiology

The pleural space normally contains a thin layer of serous fluid between the visceral pleura (coating the lung) and the parietal pleura (lining the chest wall). This space maintains a negative intrapleural pressure (approximately $-5\ \text{cmH}_2\text{O}$ at rest), which is the driving force that keeps the lung expanded against the chest wall. When air enters this space, the negative pressure gradient is lost, and the elastic recoil of the lung causes it to collapse inward.

In primary spontaneous pneumothorax, the mechanism involves rupture of small subpleural blebs or bullae, typically located at the lung apices. These blebs develop due to regional differences in mechanical stress: the transpulmonary pressure gradient is greatest at the apex in an upright individual, making the apical alveoli more distended and more prone to rupture. This is why the classic patient is a tall, thin young male, often a smoker. The taller the individual, the greater the gravitational gradient of pleural pressure from apex to base, amplifying apical stress.

In secondary spontaneous pneumothorax, the mechanism is similar (bleb or bullae rupture, or direct parenchymal disruption), but it occurs on a background of pre-existing lung disease. COPD is the most common cause, where emphysematous destruction creates enlarged airspaces prone to rupture. Other causes include cystic fibrosis, Pneumocystis jirovecii pneumonia (in HIV patients), tuberculosis, and Langerhans cell histiocytosis.

Tension pneumothorax develops when a one-way valve mechanism forms at the site of air leak. Air enters the pleural space during inspiration but cannot escape during expiration. With each breath cycle, intrapleural pressure progressively rises, eventually exceeding atmospheric pressure. The mediastinum is pushed to the contralateral side, compressing the opposite lung and kinking the great veins (superior and inferior vena cava). This drastically reduces venous return, causing a rapid decline in cardiac output, leading to obstructive shock. The patient develops hypotension, tachycardia, jugular venous distension, and tracheal deviation away from the affected side.

Catamenial pneumothorax is a rare but testable entity occurring in women of reproductive age. It is associated with thoracic endometriosis, and episodes typically occur within 24 to 72 hours of the onset of menstruation. The mechanism involves either diaphragmatic defects from endometrial implants or direct endometrial tissue on the visceral pleura.

2. Classification and Clinical Manifestation

By Etiology

Type	Cause	Key Features
Primary Spontaneous	Rupture of apical blebs in patients without known lung disease	Young, tall, thin males; smokers; often recurrent
Secondary Spontaneous	Complication of underlying lung disease (COPD, CF, TB, PCP, Marfan)	Older patients; more symptomatic and more dangerous due to limited pulmonary reserve
Traumatic	Penetrating or blunt chest injury, rib fractures	History of trauma; may coexist with hemothorax (hemopneumothorax)
Iatrogenic	Central venous catheter insertion (subclavian), thoracentesis, mechanical ventilation, lung biopsy	Temporal relationship with a procedure
Tension	Any of the above with a one-way valve mechanism	Medical emergency; obstructive shock physiology
Catamenial	Thoracic endometriosis	Women of reproductive age; recurrent right-sided pneumothorax coinciding with menses

By Size (BTS Guidelines)

Size	CXR Finding	Clinical Significance
Small	Visible rim of air < 2 cm between lung margin and chest wall at the level of the hilum	Often managed conservatively in primary spontaneous
Large	Visible rim of air ≥ 2 cm between lung margin and chest wall at the level of the hilum	Typically requires intervention (aspiration or chest tube)

By Severity

Feature	Simple Pneumothorax	Tension Pneumothorax
Onset	Sudden pleuritic chest pain, dyspnea	Rapidly progressive dyspnea, severe distress
Heart rate	Normal or mildly elevated	Tachycardia
Blood pressure	Normal	Hypotension (obstructive shock)
Breath sounds	Decreased on affected side	Absent on affected side
Percussion	Hyperresonant	Hyperresonant
Trachea	Midline	Deviated away from affected side
JVP	Normal	Elevated (impaired venous return)
Hemodynamics	Stable	Unstable, may progress to PEA arrest

3. Diagnostic Workup

Test	Role	Key Findings
Upright PA chest X-ray	Best initial test (for simple pneumothorax)	Visible visceral pleural line with absent lung markings peripheral to it; deep sulcus sign on supine film
CT chest	Most accurate / confirmatory test	Detects small pneumothoraces missed on CXR; quantifies size precisely; identifies blebs/bullae
Ultrasound (E-FAST)	Rapid bedside assessment in trauma/ICU	Absent lung sliding, absent comet-tail artifacts, presence of "lung point" (confirms diagnosis)
ABG	Assess respiratory compromise	Hypoxemia; hypocapnia (early) or hypercapnia (secondary spontaneous with poor reserve)
No imaging needed	Tension pneumothorax	Clinical diagnosis only; do not delay treatment for imaging

The upright posteroanterior (PA) chest X-ray is the best initial test for a hemodynamically stable patient with suspected pneumothorax. The hallmark finding is a thin visceral pleural line visible as a sharp white line parallel to the chest wall, with complete absence of lung markings (vascular shadows) lateral to this line. An expiratory film can improve sensitivity by reducing lung volume and making the pleural line more conspicuous, though this is not routinely required.

In the supine patient (trauma, ICU), air rises anteriorly and basally, making a standard pleural line difficult to see. Instead, look for the deep sulcus sign, which is an abnormally deep and lucent costophrenic angle on the affected side. This is a commonly tested finding.

CT of the chest is the most accurate test and is used when the clinical suspicion is high but the CXR is equivocal, when quantification of the pneumothorax size is needed for surgical planning, or when differentiating between a large bulla and a pneumothorax (a common diagnostic dilemma in COPD patients). CT also identifies underlying causes such as blebs, bullae, or parenchymal disease.

Point-of-care ultrasound (lung ultrasound) has become increasingly important in emergency and critical care settings. The key finding is absent lung sliding on the affected side. Normally, the visceral and parietal pleurae slide against each other during respiration, creating a shimmering appearance at the pleural line. In pneumothorax, air separates the pleurae, abolishing this movement. The lung point, the location on the chest wall where lung sliding transitions from absent to present, is essentially pathognomonic for pneumothorax.

For tension pneumothorax, the diagnosis is entirely clinical. The combination of respiratory distress, hypotension, absent breath sounds on one side, jugular venous distension, and tracheal deviation is sufficient. Ordering a chest X-ray before intervention is a dangerous and testable mistake.

4. Management and Treatment

Scenario	Management	Details
Tension pneumothorax	Immediate needle decompression, then chest tube	14-16G needle at 2nd intercostal space, midclavicular line (or 4th/5th ICS, anterior axillary line); followed by tube thoracostomy
Small primary spontaneous, asymptomatic	Observation + supplemental $O_2$	Admit for 6 hours of observation with repeat CXR; supplemental oxygen accelerates reabsorption (rate: ~1.25% per day without $O_2$, up to ~4-6x faster with high-flow $O_2$)
Large primary spontaneous or symptomatic	Needle aspiration (first attempt) or chest tube	BTS guidelines favor initial aspiration with a 16-18G cannula; if aspiration fails, proceed to chest tube
Secondary spontaneous (any size)	Chest tube (tube thoracostomy)	These patients have limited pulmonary reserve; more aggressive approach needed; size 16-28 Fr
Traumatic pneumothorax	Chest tube	Tube thoracostomy (28-32 Fr); address concurrent injuries (hemothorax, flail chest)
Recurrent pneumothorax	Surgical intervention (VATS)	Video-assisted thoracoscopic surgery with bullectomy and pleurodesis
Persistent air leak (> 5-7 days)	Surgical intervention	VATS with bullectomy + mechanical or chemical pleurodesis

Tension Pneumothorax (Emergency)

This is the single most important management concept for exams. The next best step is immediate needle decompression, not imaging. Insert a large-bore (14-16 gauge) needle into the 2nd intercostal space at the midclavicular line on the affected side, just above the upper border of the 3rd rib (to avoid the neurovascular bundle running along the inferior rib margin). A rush of air confirms the diagnosis. This is a temporizing measure only. Definitive treatment is tube thoracostomy (chest tube insertion), typically placed at the 4th or 5th intercostal space in the anterior axillary line (the "safe triangle").

Primary Spontaneous Pneumothorax

For a small (< 2 cm rim), asymptomatic primary spontaneous pneumothorax, observation with supplemental high-flow oxygen is appropriate. Supplemental $O_2$ is not just supportive; it creates a nitrogen gradient between the pleural air (which is mostly nitrogen) and the blood. By washing out nitrogen from the blood with high-concentration oxygen, the partial pressure gradient favoring reabsorption of pleural air increases substantially, accelerating resolution by up to 4 to 6 times.

If the pneumothorax is large (≥ 2 cm) or the patient is symptomatic (dyspnea at rest), needle aspiration using a 16-18 gauge cannula is the recommended first intervention per BTS guidelines. If aspiration fails (defined as persistent pneumothorax on repeat CXR or persistent symptoms after aspirating > 2.5 L of air), proceed to chest tube insertion.

Secondary Spontaneous Pneumothorax

All secondary spontaneous pneumothoraces require more aggressive management because these patients have limited respiratory reserve and are at higher risk for respiratory failure. Even a "small" pneumothorax in a patient with severe COPD can be life-threatening. The recommended approach is chest tube insertion (tube thoracostomy) regardless of size in most cases. Small (< 1 cm), truly asymptomatic cases may be observed, but this requires very close monitoring.

Recurrence Prevention

After a first episode of primary spontaneous pneumothorax, the recurrence rate is approximately 30%. After a second episode, the recurrence rate rises to about 50-60%. Surgical intervention, typically video-assisted thoracoscopic surgery (VATS) with bleb resection (bullectomy) and pleurodesis, is indicated after:

A second ipsilateral pneumothorax (recurrence)
A first contralateral pneumothorax (bilateral disease)
Persistent air leak beyond 5 to 7 days
Bilateral pneumothorax
Occupational risk (pilots, divers)
First episode of secondary spontaneous pneumothorax (some guidelines)

Pleurodesis (mechanical abrasion or chemical with talc) creates adhesions between the visceral and parietal pleurae, obliterating the pleural space and preventing recurrence.

5. Differential Diagnosis and Distractors

Differential	Why It Looks Similar	Key Discriminator
Acute coronary syndrome (ACS)	Sudden chest pain in a young patient; can present with dyspnea	ACS pain is substernal/pressure-like, not pleuritic; ECG shows ischemic changes; breath sounds are equal bilaterally; risk factors differ (obesity, HTN, DM vs. tall thin habitus)
Pulmonary embolism (PE)	Sudden onset pleuritic chest pain and dyspnea; tachycardia	PE presents with pleuritic pain but breath sounds remain present bilaterally; look for DVT risk factors, elevated D-dimer, CT angiography findings; CXR in PE is often normal or shows Hampton hump/Westermark sign
Pleural effusion	Decreased breath sounds on one side	Effusion produces dullness to percussion (not hyperresonance); CXR shows meniscus sign/blunting of costophrenic angle; fluid vs. air distinction is the key
COPD exacerbation / large bulla	Dyspnea, decreased breath sounds, hyperresonance; CXR may mimic pneumothorax	A large bulla on CXR can look like a pneumothorax; CT chest is needed to distinguish; bullae have a concave inner margin; pneumothorax has a convex visceral pleural line. Inserting a chest tube into a bulla is a dangerous error
Pericardial tamponade	Hypotension, JVD, and dyspnea (overlaps with tension pneumothorax)	Tamponade produces muffled heart sounds (Beck triad: hypotension, JVD, muffled heart sounds); breath sounds remain present bilaterally; pulsus paradoxus is prominent; echocardiography confirms
Diaphragmatic hernia	Decreased breath sounds on one side (usually left); can present after trauma	Bowel sounds audible in the chest; CXR shows visceral contents above the diaphragm; NG tube in the chest on X-ray
Acute asthma exacerbation	Dyspnea, tachypnea; may have decreased breath sounds if severe ("silent chest")	Asthma has diffuse bilateral wheezing; expiratory phase is prolonged; responds to bronchodilators; CXR shows hyperinflation but no pleural line

6. Traps and High-Yield Pearls

The most common way students lose points on pneumothorax questions is by ordering a chest X-ray for a tension pneumothorax. Tension pneumothorax is a clinical diagnosis, and the next best step is always immediate needle decompression, never imaging. Any delay for radiographic confirmation can result in cardiovascular collapse and death. If the vignette describes a trauma patient or a ventilated patient with sudden hypotension, absent breath sounds on one side, JVD, and tracheal deviation, the answer is needle decompression at the 2nd intercostal space midclavicular line, followed by chest tube. No exceptions.

A second common trap involves the COPD patient with a large bulla versus a pneumothorax. On CXR, a large emphysematous bulla can appear identical to a pneumothorax, showing a lucent space with an apparent "pleural line." If a student does not recognize this distinction and recommends chest tube insertion into a bulla, the result is catastrophic parenchymal injury. The correct next step when the differentiation is unclear is CT of the chest, not blind tube placement.

Students also frequently confuse the percussion findings: pneumothorax produces hyperresonance, while pleural effusion produces dullness. Both cause decreased breath sounds on the affected side, so percussion is the discriminating physical exam finding.

Another tested concept is the role of supplemental oxygen in conservative management. Students often dismiss oxygen as merely supportive, but in pneumothorax it serves a therapeutic purpose by creating a nitrogen washout gradient that accelerates pleural air reabsorption. This mechanism is worth understanding.

For recurrence, remember the "rule of increasing risk": 30% after the first episode, rising substantially after the second. Surgical intervention (VATS with bullectomy and pleurodesis) is the standard recommendation after a second ipsilateral recurrence, and this is a commonly tested decision point.

Finally, always consider catamenial pneumothorax when a vignette describes a young woman with recurrent right-sided pneumothorax coinciding with her menstrual cycle. This diagnosis is rare but highly testable precisely because it requires pattern recognition across multiple presentations.

The core competency being tested across pneumothorax questions is the ability to recognize clinical urgency (tension vs. simple), sequence the workup and management correctly (clinical diagnosis before imaging in emergencies; observation vs. aspiration vs. chest tube based on type and size), and distinguish pneumothorax from its look-alikes using physical exam and imaging findings.

1e:["$","$L2d",null,{"article":{"id":"74b9ad06-05b4-46d0-a739-055cc5505633","title":"Pneumotoraks","content":"$2e","category":"Respirologi","created_at":"2026-07-02T01:16:24.344313+00:00","status":"published","subcategory":null},"questionCount":2,"sections":[{"id":"section-pathophysiology","num":"01","title":"Pathophysiology"},{"id":"section-classification-and-clinical-manifestation","num":"02","title":"Classification and Clinical Manifestation"},{"id":"section-diagnostic-workup","num":"03","title":"Diagnostic Workup"},{"id":"section-management-and-treatment","num":"04","title":"Management and Treatment"},{"id":"section-differential-diagnosis-and-distractors","num":"05","title":"Differential Diagnosis and Distractors"},{"id":"section-traps-and-high-yield-pearls","num":"06","title":"Traps and High-Yield Pearls"}],"hasSummaryTable":true}]