01Approach to the Critical Patient/attcp63

Immediate stabilization

›Airway and breathing threats

›Tension pneumomediastinum physiology

›Tracheal deviation

›Hemodynamic collapse with mediastinal air

›If tension physiology, emergent surgical decompression

›Concurrent large pneumothorax

›Absent unilateral breath sounds

›If tension pneumothorax, needle decompression 2nd ICS midclavicular line

›Severe hypoxia

›SpO2 < 90% on room air

›High-flow oxygen immediately

›Airway compromise from subcutaneous emphysema

›Neck swelling with tracheal distortion

›Anesthesia or critical care at bedside

›Hemodynamic targets

›SBP > 90 mmHg

›MAP > 65 mmHg

›HR < 100 beats/min target in stable SPM

›If hemodynamic instability, IV access x2 large bore, fluid resuscitation

Key decision branch: SPM versus esophageal perforation

›Primary spontaneous pneumomediastinum (SPM) features

›Age < 40 years

›Known precipitant (cough, exertion, Valsalva)

›No pleural effusion on imaging

›No mediastinal fluid on CT

›No fever

›No dysphagia or odynophagia suggesting mucosal injury

02History/hx53

Symptom characterization

›Chest pain features

›Retrosternal or substernal location (most common, ~71 to 89%)

›Acute onset

›Radiation to neck, back, or shoulders

›Pleuritic component

›Associated symptoms

›Dyspnea (43 to 57%)

›Neck pain (32 to 55%)

›Sore throat or odynophagia (14%)

›Dysphagia

›Voice change or hoarseness

›Palpitations (tachycardia common in ~31%)

Precipitating events and triggers

›Common precipitants

›Forceful coughing (27 to 34%)

›Retching or vomiting (13 to 24%)

›Physical exertion or heavy lifting (11 to 21%)

›Valsalva maneuvers (straining, weightlifting, childbirth, spirometry)

›Inhaled drug use (marijuana, cocaine, vaping, nitrous oxide)

›No identifiable trigger in 21 to 53% of cases

›Alarm precipitants suggesting secondary cause

›Forceful emesis specifically (Boerhaave concern)

›Recent endoscopy, intubation, or esophageal instrumentation

›High-energy blunt trauma (tracheobronchial injury concern)

›Dental extraction or head and neck procedure

Risk factors and background

›Predisposing conditions

03Physical Exam/exam32

Vital signs and general appearance

›Hemodynamic stability

›Blood pressure bilaterally

›Heart rate (tachycardia ~31% of SPM)

›Respiratory rate (tachypnea as severity marker)

›Temperature (fever is rare in SPM; raises concern for perforation or mediastinitis)

›SpO2 on room air

›General appearance

›Work of breathing

›Inability to speak full sentences

›Diaphoresis or distress

Neck and chest exam

›Neck findings

›Subcutaneous emphysema — palpable crepitus in neck, face, and chest (33 to 54% at presentation)

›Neck swelling

›Tracheal position (midline vs deviation)

›Voice change or muffled quality

›Cardiac auscultation

›Hamman sign — crunching or crackling sound synchronous with cardiac cycle (pathognomonic for pneumomediastinum)

›Muffled heart sounds (if pneumopericardium or tamponade)

›Pulsus paradoxus (if tamponade physiology)

›Pulmonary auscultation

›Bilateral air entry assessment

›Absent unilateral breath sounds (concurrent pneumothorax ~10%)

›Wheeze (underlying asthma)

Abdominal exam

›Peritoneal signs

›Guarding or rigidity (hollow viscus perforation concern)

04Differential Diagnosis/ddx45

Life-threatening diagnoses

›Esophageal perforation (Boerhaave syndrome)

›ICD-10 K22.3

›Forceful emesis, older age, pleural effusion, mediastinal fluid, fever

›Mortality up to 40% if diagnosis delayed beyond 24 hours

›Tension pneumomediastinum

›Progressive hemodynamic compromise with mediastinal air

›Cardiac compression physiology

›Tracheobronchial injury

›High-energy blunt trauma mechanism

›Persistent air leak, hemoptysis

›ICD-10 S27.5

›Mediastinitis

›Fever, sepsis, post-procedural or post-perforation

›ICD-10 J98.51

Common mimics

›Pneumothorax

›ICD-10 J93.9

›Visceral pleural line on CXR

›Unilateral absent breath sounds

›~10% coexist with SPM

›Acute coronary syndrome

›ICD-10 I24.9

›ECG changes, troponin elevation

›Risk factors for CAD

›Pulmonary embolism

›ICD-10 I26.9

›Pleuritic pain, tachycardia, hypoxia

05Laboratory Tests/lt35

Core diagnostic labs

›Complete blood count

›Leukocytosis common in SPM (~30%) and does not reliably distinguish from perforation

›Markedly elevated WBC more characteristic of esophageal perforation or mediastinitis

›Anemia may suggest blood loss from traumatic cause

›C-reactive protein

›Mild elevation common in SPM (mean ~1.0 mg/dL)

›Markedly elevated CRP suggests secondary cause or perforation

›Trend over 12 to 24 hours if diagnosis uncertain

›Basic metabolic panel

›Glucose to rule out DKA if Kussmaul breathing suspected as precipitant

›Electrolytes for fluid resuscitation guidance

›Renal function for contrast safety if CT planned

Cardiac and perfusion biomarkers

›Troponin

›Indicated if ACS on differential

›Typically normal in SPM

›Elevated in myopericarditis or cardiac compression

›Lactate

›If hemodynamically unstable

›>= 2 mmol/l as hypoperfusion marker

›Repeat in 2 to 4 hours if elevated

›BNP or NT-proBNP

›If heart failure on differential

›Aids differentiation from dyspnea of cardiac origin

Additional targeted labs

›Blood cultures

›Only if febrile or concern for mediastinitis

06Diagnostic Tests/dt89

Scoring Systems

›Risk stratification framework for SPM versus perforation

›Low-risk profile for esophageal perforation

›Age < 40 years

›Known benign precipitant (coughing, exertion, Valsalva)

›No history of forceful emesis

›No pleural effusion or mediastinal fluid on CT

›No fever

›No respiratory compromise

›Conservative management appropriate without esophageal workup

›High-risk profile for esophageal perforation

›Age > 40 with pneumomediastinum

›Forceful emesis as precipitant

›Pleural effusion present

›Mediastinal fluid on CT

›Fever or disproportionate leukocytosis

›Respiratory compromise (43% perforation vs 6% SPM)

›Dysphagia

›Esophagram or CT with oral contrast indicated

›Pittsburgh Pneumothorax Severity Score

›Not validated for pneumomediastinum

›No established scoring tool specific to SPM disposition

›Clinical gestalt and imaging findings guide risk stratification

MRI

›MRI chest

›Not first-line for pneumomediastinum evaluation

›Air signal creates susceptibility artifact limiting evaluation

›May characterize associated soft tissue or mediastinal mass if incidentally noted

›MRI esophagus: limited role; CT esophagram preferred for perforation evaluation

›MRI considerations

›T2 signal may help characterize fluid collections in mediastinitis

›Reserved for specific indications when CT contraindicated

›Prolonged acquisition time limits utility in acute setting

CT

›CT chest without contrast

›More sensitive than CXR for pneumomediastinum detection

›Detects ~30% of cases missed on chest X-ray

›Indicated when CXR equivocal or concern for secondary cause exists

›Key findings

›Air surrounding mediastinal structures

›Air dissecting along bronchovascular planes (Macklin effect)

›Subcutaneous emphysema extent

›Absence of pleural effusion and mediastinal fluid has 100% NPV for esophageal perforation

›Concurrent pneumothorax size assessment

›CT chest with oral contrast

›Alternative to esophagram if esophageal perforation suspected

›Oral contrast extravasation confirms perforation

›Combined pneumomediastinum with pleural effusion on CT: 100% sensitivity for esophageal perforation

›Preferred modality at most centers over water-soluble esophagram

›CT for traumatic pneumomediastinum (blunt trauma)

›CT chest universally indicated in high-energy mechanism

›Evaluate tracheobronchial tree for injury

›Associated injuries: rib fractures, pneumothorax, hemothorax, vascular injury

›Pneumomediastinum on CT in blunt trauma associated with mortality in JAMA Surgery 2015 cohort (Lee et al)

Ultrasound

›Point-of-care ultrasound (POCUS)

›Pneumothorax protocol

›Absence of lung sliding on B-mode

›Absence of comet-tail artifacts

›Lung point sign confirms pneumothorax border

›Cardiac POCUS

›Pericardial effusion or pneumopericardium

›Tamponade physiology — RV collapse, IVC plethora

›Global ventricular function

›Limitations of POCUS for pneumomediastinum

›Mediastinal air causes acoustic shadowing, limiting mediastinal visualization

›CT required for definitive pneumomediastinum characterization

›Esophageal ultrasound

›Not standard in ED for pneumomediastinum evaluation

›EUS (endoscopic ultrasound) role limited to post-perforation staging

Chest X-ray

›CXR (PA and lateral)

›First-line imaging; diagnostic in ~69 to 90% of cases

›Classic CXR signs

›Air outlining mediastinal structures

›Continuous diaphragm sign (air between pericardium and diaphragm)

›Naclerio V-sign (air in left lower mediastinum)

›Subcutaneous emphysema in neck and soft tissues

›Spinnaker or thymic sail sign in pediatric patients

›Concurrent pneumothorax visible on CXR

›Pleural effusion absence supports SPM diagnosis

Esophagram

›Water-soluble contrast esophagram

›Reserve for high clinical suspicion of esophageal perforation

›Positive study: contrast extravasation into mediastinum or pleural space

›Sensitivity ~75 to 90% for perforation; false negatives occur

›CT with oral contrast now preferred at most centers

›Barium esophagram avoided acutely due to mediastinal contamination risk if perforation present

ECG

›ECG findings in pneumomediastinum

›Usually normal or sinus tachycardia

›Concerning patterns

›ST changes suggest ACS or myopericarditis

›Low voltage may indicate cardiac compression by air or pericardial effusion

›Electrical alternans if tamponade

›Axis deviation

07Disposition/dispo27

Discharge criteria

›Safe for ED discharge (well-appearing SPM)

›Confirmed SPM on imaging with benign precipitant

›Stable vital signs; HR and SpO2 normalizing

›No hypoxia on room air

›No pleural effusion or mediastinal fluid on CT

›No fever; no concern for esophageal perforation

›Tolerating oral fluids

›Adequate pain control achieved

›Reliable follow-up arranged within 1 to 2 weeks

›Study of 166 SPM cases (ages 5 to 25): no significant outcome difference between admitted and ED-discharged patients

Admission criteria

›Indications for admission or observation

›Significant dyspnea or persistent hypoxia

›Hemodynamic instability

›Suspected or confirmed esophageal perforation (pending workup)

›Large concurrent pneumothorax requiring intervention

›Inability to tolerate oral intake

›Significant comorbidities (immunocompromise, severe asthma exacerbation)

›Diagnostic uncertainty requiring further workup

›Pain not controlled with oral analgesics

›Median inpatient length of stay ~27 hours in pediatric cohorts; 1.8 to 2.3 days in adult series

Transfer and consultation criteria

›Transfer indications

›Confirmed esophageal perforation requiring thoracic surgery not available at current facility

›Tension pneumomediastinum requiring operative decompression

›Mediastinitis requiring surgical debridement

›Specialist consultation before discharge

08Treatment/t75

Conservative management (standard of care for SPM)

›Activity restriction

›Rest; avoid Valsalva maneuvers (straining, heavy lifting, coughing exertions)

›No strenuous exercise until symptoms resolve

›Smoking cessation counseling

›Avoid inhaled recreational drugs

›Supplemental oxygen

›High-flow oxygen (100% FiO2) when tolerated

›Mechanism: nitrogen washout accelerates reabsorption of mediastinal air

›Duration: several hours of high-flow O2 shortens radiographic resolution

›Target SpO2 94 to 98%

›Nasal cannula at 2 to 6 L/min if mild and no hypoxia

›Analgesia

›NSAIDs for pleuritic/retrosternal chest pain

›Ibuprofen 400 to 600 mg orally every 6 to 8 hours with food

›Ketorolac 15 to 30 mg IV for severe pain in ED

›Acetaminophen 500 to 1000 mg orally every 6 hours

›Maximum 4000 mg/24 hours

›First-line if NSAIDs contraindicated

›Opioid analgesia

›Reserved for severe pain not controlled by above

›Use lowest effective dose; avoid agents that provoke emesis

›Diet

›NPO only if esophageal perforation workup in progress

›Soft diet if odynophagia present

›Resume regular diet when tolerating fluids without discomfort

Treat underlying precipitant

›Asthma exacerbation management

›Short-acting beta-agonist (SABA)

›Salbutamol (albuterol) 2.5 mg nebulized every 20 minutes x3 doses

›MDI 4 to 8 puffs every 20 minutes if cooperative

›Ipratropium bromide 0.5 mg nebulized combined with SABA for moderate-severe exacerbation

›Systemic corticosteroids for moderate-severe asthma

›Prednisone 40 to 60 mg orally x5 days

›Methylprednisolone 125 mg IV if unable to tolerate PO

›Avoid positive-pressure ventilation if possible (worsens air leak)

›Antiemetic therapy

›Ondansetron 4 to 8 mg IV or orally for nausea and vomiting

›Repeat every 4 to 6 hours as needed

›Metoclopramide 10 mg IV if ondansetron insufficient

›Minimize emesis to reduce ongoing Valsalva injury

›Bronchodilators for COPD exacerbation

›SABA plus SAMA combination nebulized

›Systemic steroids per COPD exacerbation protocol

›DKA management

›Insulin infusion per DKA protocol

›IV fluid resuscitation

›Electrolyte correction

Antibiotic therapy

›Prophylactic antibiotics NOT routinely indicated for SPM

›No benefit demonstrated in multiple case series

›Reserve for confirmed secondary infection or perforation

›Esophageal perforation: broad-spectrum antibiotics

›Piperacillin-tazobactam 4.5 g IV every 6 hours

›Covers gram-negative and anaerobic organisms

›Adjust for renal function

›Add antifungal (micafungin 150 mg IV daily) if prolonged hospital course or immunocompromised

›Duration guided by surgical findings and clinical response

›Mediastinitis: broad-spectrum antibiotics plus surgical source control

›Vancomycin 25 to 30 mg/kg IV loading dose (target trough 15 to 20 mg/L or AUC/MIC 400 to 600) for MRSA coverage

›Piperacillin-tazobactam 4.5 g IV every 6 hours

›Surgical drainage and debridement required

Surgical intervention

›Indications for surgical intervention (rare in SPM)

›Tension pneumomediastinum with hemodynamic compromise

›Confirmed esophageal perforation (primary repair, exclusion, or drainage)

›Confirmed tracheobronchial injury

›Mediastinitis requiring surgical debridement

›Large concurrent pneumothorax requiring chest tube

›Esophageal perforation operative options

›Primary repair within 24 hours if tissue viable

›Exclusion and diversion if delayed presentation

›Endoscopic stenting for selected contained perforations

›Thoracic surgery team decision

Positive-pressure ventilation precautions

›Avoid non-invasive ventilation and CPAP if possible in pneumomediastinum

›Increased airway pressure may worsen air leak and extend subcutaneous emphysema

›If required (severe bronchospasm or hypoxia), use lowest effective pressures

›Minimize PEEP to lowest value maintaining oxygenation

›Target tidal volume 6 mL/kg ideal body weight if intubated

09Special Populations/sp58

Pregnancy

›Pneumomediastinum in pregnancy

›Rare; most commonly associated with Valsalva maneuver during labour and delivery

›Typically managed conservatively; generally benign and self-limited

›Imaging considerations

›CXR acceptable with abdominal shielding when clinically indicated

›CT chest with abdominal shielding if CXR equivocal; fetal radiation dose low and acceptable when diagnosis requires it

›Contrast use: iodinated IV contrast considered safe in pregnancy; monitor newborn thyroid function

›Analgesia in pregnancy

›Acetaminophen preferred first-line

›NSAIDs avoid in third trimester (premature ductus arteriosus closure risk)

›Opioids with caution and shortest effective duration

›Supplemental high-flow oxygen: beneficial for air reabsorption; generally safe in pregnancy with standard monitoring

›Obstetric involvement: notify obstetrics team for any pregnant patient with pneumomediastinum

›Boerhaave syndrome in pregnancy carries high maternal and fetal mortality; early surgical consultation mandatory if suspected

Geriatric

›Pneumomediastinum in older adults (age > 40)

›SPM uncommon; secondary cause must be excluded more aggressively

›Age > 40 is rare for true SPM; raises concern for esophageal perforation, malignancy-related, or COPD-related cause

›Esophageal perforation workup indicated in most older patients with pneumomediastinum

›Comorbidities increase risk of complications

›COPD, ILD, malignancy, esophageal motility disorders

›Polypharmacy considerations

›NSAIDs: increased GI bleeding risk; consider PPI co-prescription

›Opioid analgesia: higher sedation and aspiration risk; lower starting doses

›Surgical risk higher if esophageal repair needed

›Frailty assessment prior to operative planning

›Mortality of traumatic pneumomediastinum higher in elderly

10Background/b63

Epidemiology

›Incidence and prevalence

›Rare condition; estimated incidence 1 in 30,000 ED visits

›SPM predominates in young males; mean age ~23 years

›Male-to-female ratio approximately 3:1

›Secondary pneumomediastinum accounts for minority of cases in referral center series

›Rising incidence attributed to vaping and e-cigarette use

›Outcomes and prognosis

›SPM: no reported mortality across large case series (hundreds of patients)

›Self-limited with symptom resolution within 1 to 2 days in most

›Radiographic resolution within 1 to 2 weeks

›Recurrence rate ~4.6%; asthma is only independent risk factor for recurrence (OR ~7 to 8)

›Traumatic pneumomediastinum from blunt injury: higher mortality (Lee et al, JAMA Surgery 2015)

›Esophageal perforation: mortality up to 40% if diagnosis delayed > 24 hours

›Classification

›Primary spontaneous pneumomediastinum (SPM): no identifiable cause beyond alveolar rupture precipitant

›Secondary pneumomediastinum: identified underlying structural cause

›Esophageal perforation (Boerhaave syndrome)

›Tracheobronchial injury

›Iatrogenic (post-intubation, post-endoscopy, post-surgical)

›Mechanical ventilation barotrauma

›Extension from neck (dental, pharyngeal) or abdominal source

Pathophysiology

›Macklin effect (primary mechanism of SPM)

›Sudden increase in alveolar pressure causes alveolar rupture

›Air escapes into peribronchial and perivascular adventitia

›Air dissects centrally along bronchovascular sheaths toward mediastinum

›Air may further extend into neck (subcutaneous emphysema), pericardium, or retroperitoneum

›No direct tracheal or esophageal injury present in true SPM

›Alveolar rupture triggers

›Increased intrathoracic pressure against closed glottis (Valsalva)

›Forceful cough generating high transalveolar pressure gradients

›Asthma: air trapping and increased alveolar pressure distal to obstructed airways

›Inhaled drugs: cocaine, marijuana, vaping — deep inhalation with Valsalva maneuver

›Tension physiology (rare)

›Continued air leak without decompression pathway

›Progressive mediastinal air compresses cardiac structures

›Reduces venous return and cardiac output

›Analogous to tension pneumothorax but less common

›Secondary mechanisms

›Boerhaave: transmural esophageal tear from forceful emesis with sudden intraluminal pressure rise

›Barotrauma: positive-pressure ventilation causes alveolar over-distension and rupture

›Traumatic: direct tracheobronchial laceration or tracheal disruption

Therapeutic Considerations

›Nitrogen washout rationale for supplemental oxygen

›Mediastinal air is ~80% nitrogen at atmospheric partial pressure

›Administration of 100% FiO2 creates nitrogen pressure gradient favouring washout

›High-flow oxygen accelerates air reabsorption by 3 to 4 times compared to room air

›Mechanism analogous to high-flow oxygen for pneumothorax

›Antibiotic stewardship

›Prophylactic antibiotics offer no benefit in confirmed SPM

›Leukocytosis in SPM (~30%) should not trigger reflexive antibiotic prescribing

›Reserve antibiotics for fever, hemodynamic instability, or confirmed secondary cause

›Positive-pressure ventilation risk

›Avoid NIV, CPAP, and BiPAP when pneumomediastinum is present if clinically possible

›If required, use minimum pressures; monitor for clinical deterioration

›Intubation decision should weigh respiratory failure risk against barotrauma risk

›Recurrence prevention

›Asthma: optimise controller therapy and trigger avoidance

›Inhaled drug cessation essential

›No proven pharmacologic prophylaxis for recurrence in SPM

›Inform patients of small recurrence risk (~5%) and recurrence symptoms

›Unnecessary workup avoidance

›EGD invariably negative in low-risk SPM; should not be routinely performed

›Esophagram reserved for high-risk features (age > 40, emesis precipitant, pleural effusion, fever)

›CT not always required if CXR diagnostic and clinical picture consistent with low-risk SPM

11Patient Discharge Instructions/pdi31

copy discharge instructions

›Diagnosis and expected recovery

›Diagnosis: air trapped in the chest cavity around the heart and major airways (pneumomediastinum)

›This is most commonly a benign, self-limited condition in young otherwise healthy individuals

›Symptoms (chest pain, neck discomfort, voice change) typically improve within 1 to 2 days

›The air is gradually reabsorbed by your body; imaging clears within 1 to 2 weeks

›Activity restrictions

›Rest and avoid strenuous physical activity until follow-up appointment

›Avoid heavy lifting, straining, or any activity that increases chest pressure

›No competitive sport until cleared by your follow-up physician

›Avoid holding your breath (Valsalva maneuvers)

›Medications prescribed

›Take NSAIDs or acetaminophen for pain as directed

›Do not take more than the prescribed dose

›Take NSAIDs with food to protect your stomach

›If prescribed inhalers or other medications, use exactly as instructed

›What to avoid

›Smoking: quit smoking; this increases your risk of recurrence

›Inhaled recreational drugs: marijuana, cocaine, vaping — these can cause this condition to return

›Avoid cough suppressants only if prescribed; treating cough may reduce recurrence

›Follow-up

›Outpatient physician visit in 1 to 2 weeks

›Repeat chest X-ray only if symptoms persist or worsen

›If asthma is suspected as your trigger, pulmonary function testing will be arranged

›Return to emergency department immediately for

›Worsening or severe chest pain

›Increasing shortness of breath or difficulty breathing

›Fever (temperature > 38.5 C)

12References/r22

Guidelines and key sources

›Primary literature and systematic reviews

›Morgan CT, Maloney JD, Decamp MM, McCarthy DP. A Narrative Review of Primary Spontaneous Pneumomediastinum: A Poorly Understood and Resource-Intensive Problem. Journal of Thoracic Disease. 2021. PMID 34277063

›Morgan CT, Kanne JP, Lewis EE, et al. One Hundred Cases of Primary Spontaneous Pneumomediastinum: Leukocytosis Is Common, Pleural Effusions and Age Over 40 Are Rare. Journal of Thoracic Disease. 2023. PMID 37065555

›Keogan AG, Rybachok A, Patel S, et al. Diagnostic Utility of Computed Tomography in Patients With Spontaneous Pneumomediastinum Evaluated for Suspected Esophageal Perforation. World Journal of Surgery. 2025. PMID 41266101

›Yu MH, Kim JK, Kim T, Lee HS, Kim DK. Primary Spontaneous Pneumomediastinum: 237 Cases in a Single-Center Experience Over a 10-Year Period and Assessment of Factors Related With Recurrence. PloS One. 2023. PMID 37494372

›Kim KS, Jeon HW, Moon Y, et al. Clinical Experience of Spontaneous Pneumomediastinum: Diagnosis and Treatment. Journal of Thoracic Disease. 2015. PMID 26623105

›Noorbakhsh KA, Williams AE, Langham JJW, et al. Management and Outcomes of Spontaneous Pneumomediastinum in Children. Pediatric Emergency Care. 2021. PMID 31464878

›Bakhos CT, Pupovac SS, Ata A, Fantauzzi JP, Fabian T. Spontaneous Pneumomediastinum: An Extensive Workup Is Not Required. Journal of the American College of Surgeons. 2014. PMID 25053221

›Lee WS, Chong VE, Victorino GP. Computed Tomographic Findings and Mortality in Patients With Pneumomediastinum From Blunt Trauma. JAMA Surgery. 2015

›Caceres M, Ali SZ, Braud R, Weiman D, Garrett HE. Spontaneous Pneumomediastinum: A Comparative Study and Review of the Literature. Annals of Thoracic Surgery. 2008. PMID 18721592

›Wald L, Yergin C, Petroze R, Larson S, Islam S. The Unnecessary Workups and Admissions of Adolescents and Young Adults With Spontaneous Pneumomediastinum. Scientific Reports. 2024. PMID 38402248

Additional references

›Supporting and imaging literature

›Kouritas VK, Papagiannopoulos K, Lazaridis G, et al. Pneumomediastinum. Journal of Thoracic Disease. 2015. PMID 25774307

›Mendes J, Boas NV, Gomes C, Santos SD. Hamman Sign and Syndrome: A Reminder of Important Clinical Clues. Pediatric Pulmonology. 2025

›Ebina M, Inoue A, Takaba A, Ariyoshi K. Management of Spontaneous Pneumomediastinum: Are Hospitalization and Prophylactic Antibiotics Needed? American Journal of Emergency Medicine. 2017. PMID 28330688

›Zylak CM, Standen JR, Barnes GR, Zylak CJ. Pneumomediastinum Revisited. Radiographics. 2000. PMID 10903694

›Bejvan SM, Godwin JD. Pneumomediastinum: Old Signs and New Signs. AJR American Journal of Roentgenology. 1996. PMID 8615238

›Yamamichi T, Ibuka S, Yamashita S, et al. Surgical Drainage of Tension Pneumomediastinum in a Newborn: A Rare Lifesaving Intervention. Pediatric Pulmonology. 2025

›Expert Panel on Pediatric Imaging, Dorfman SR, Chan SS, et al. ACR Appropriateness Criteria Chest Pain-Child. Journal of the American College of Radiology. 2026

›Prevost B, Leger PL, Sileo C, et al. Spontaneous Pneumomediastinum: A Complication of SARS-CoV-2 Variant Delta Infection in Children. Pediatric Pulmonology. 2024

›Takada K, Matsumoto S, Hiramatsu T, et al. Management of Spontaneous Pneumomediastinum Based on Clinical Experience of 25 Cases. Respiratory Medicine. 2008. PMID 18585025

›Koullias GJ, Korkolis DP, Wang XJ, Hammond GL. Current Assessment and Management of Spontaneous Pneumomediastinum: Experience in 24 Adult Patients. European Journal of Cardio-Thoracic Surgery. 2004. PMID 15082293

Evidence & Review

Evidence & Review