Spontaneous pneumothorax

"Spontaneous" essentially refers to all pneumothoraxes of "non-traumatic" etiologies

Background

  • Primary Pneumothorax
    • No underlying pulmonary disease
  • Secondary Pneumothorax
    • With underlying pulmonary disease
    • Worse prognosis

Secondary Causes

  • Smoking (90%)
  • COPD
  • Asthma
  • Cystic fibrosis
  • Necrotizing pneumonia
  • Lung abscess
  • PCP pneumonia
  • TB
  • Neoplasm
  • Interstitial lung disease
  • Connective tissue disease
  • Pulmonary infarct
  • Catamenial pneumothorax

Clinical Features

  • Sudden onset pleuritic chest pain evolving to dull constant ache over days
  • Most often occurs at rest, not during exertion
  • Tachypnea, hypoxemia, increased work of breathing
  • Reduced ipsilateral lung excursion
  • Hypotension→ tension pneumothorax

Differential Diagnosis

Pneumothorax Types

Acute dyspnea

Emergent

Non-Emergent

Evaluation

Clinically Stable

Defined as having all of the following:

  • Resp rate < 24
  • Heart rate 60-120 beats per minute
  • Normal BP
  • SaO2 >90% on room air and patient can speak in whole sentences

Workup

Pneumothorax.jpeg
  • CXR
    • Displaced visceral pleural line without lung markings between pleural line and chest wall
    • Upright is best
      • Expiratory films DO NOT improve accuracy[1]
    • Supine CXR = deep sulcus sign
  • CT Chest
    • Very sensitive and specific
  • Ultrasound
    • NO comet tail artifact
    • No sliding lung sign
    • Bar Code appearance on M-mode (absence of "seashore" waves)

Estimating Pneumothorax Size

Measuring pneumothoraxes. Line A = lung apex to cupola. Line B = interpleural distance.
  • On a conventional, upright posterior-anterior chest radiograph:
    • Very small: <1 cm interpleural distance (confined to upper 1/3 of chest) OR only seen on CT
    • Small: ≤3cm lung apex to cupola (chest wall apex) on CXR
    • Large: >3cm lung apex to cupola (chest wall apex) on CXR
3cm apex to cupola measurement is roughly equivalent to 2cm interpleural distance (at the level of the hilum)
Both roughly correlate with a 50% pneumothorax by volume

Management[2]

Supplemental oxygen (non-rebreather mask) initially for all

Unstable

Primary Spontaneous Pneumothorax (Stable)

First Episode

  • Small AND asymptomatic (no dyspnea)
  • Large OR symptomatic (e.g. dyspnea)
    • Aspiration (see below)
      • If fail, admit with chest tube to suction for thoracoscopy (VATS)^

Recurrent OR Hemopneumothorax

^If thoracoscopy (VATS) is not readily available, chemical pleurodesis through the chest tube

Secondary Pneumothorax (Stable)

  • Asymptomatic AND very small (<1 cm interpleural distance)
  • Asymptomatic AND small
    • Chest tube (some centers may choose needle aspiration under ultrasound guidance)
    • Observation alone associated with some mortality
  • Symptomatic OR large OR bilateral
Admit all secondary pneumothoraxes

Needle Aspiration of Pneumothorax

  • Use thoracentesis or "pig-tail" kit, if available
  • Place in 2nd IC space in midclavicular line or 4th/5th IC space in anterior axillary line
  • Withdraw air with syringe until no more can be aspirated
    • Assume a persistent air leak (failure) if no resistance after 4 liters of air has been aspirated AND the lung has not expanded
  • Once no further air can be aspirated:
    • Option 1
      • Place closed stopcock and secure catheter to the chest wall
      • Obtain CXR four hours later
      • If adequate lung expansion has occurred, remove catheter
      • Following another two hours of observation, obtain another CXR
      • If the lung remains expanded, may discharge patient
    • Option 2
      • Leave catheter in place
      • Attached a Heimlich (one-way) valve
      • May discharge with follow-up within two days
  • If 2.5 L of air has been aspirated, and a significant PTX remains, tube thoracostomy is indicated

Reexpansion pulmonary edema

  • Incidence may be as low as 1% or as high as 14%[3]
    • Typically progresses over 2 days immediately after thoracentesis
    • Radiographic opacities in previously collapse lung
    • After 2 days, subsequent rapid improvement
  • To avoid this complication, consider using a small bore chest tube
  • Other strategies include applying water seal only or attaching only a Heimlich valve without suction
  • If development occurs, treatment is supportive as is with other forms of noncardiogenic pulmonary edema
    • If a patient requires intubation, positive pressure ventilation improves symptoms after 24-48 hours
  • Risk factors are poorly understood but may include:
    • PTX > 30% in size
    • PTX symptoms for prolonged time, > 3 days

Adult Chest Tube Sizes

Chest Tube Size Type of Patient Underlying Causes
Small (8-14 Fr)
  • Alveolar-pleural fistulae (small air leak)
  • Iatrogenic air
Medium (20-28 Fr)
  • Bronchial-pleural fistulae (large air leak)
  • Malignant fluid
Large (36-40 Fr)
  • Bleeding (Hemothorax/hemopneumothorax)
  • Thick pus

Disposition

Primary

  • See Management section

Secondary

  • All admitted (even if small and clinically stable)

Special Instructions

Flying

  • Can consider flying 2 weeks after full resolution of traumatic pneumothroax[2]

See Also

References

  1. Eur Respir J. 1996 Mar;9(3):406-9
  2. 2.0 2.1 "Management of spontaneous pneumothorax: British Thoracic Society pleural disease guideline 2010" British Thoracic Society Guidelines. Thorax 2010;65:ii18-ii31 doi:10.1136/thx.2010.136986 PDF
  3. Mukhopadhyay A, Mitra M, Chakrabati S. Reexpansion pulmonary edema following thoracentesis. J Assoc Chest Physicians [serial online] 2016 [cited 2018 Oct 11];4:30-2. Available from: http://www.jacpjournal.org/text.asp?2016/4/1/30/159871.