Diagnosis: Spontaneous Pneumothorax

The patient's chest x-ray revealed a right apical pneumothorax estimated 10-15% in size with some mild right basilar atelectasis. No focal consolidation or edema. No acute osseous abnormality.

The pulmonology service was consulted and recommended a period of observation on 100% oxygen. A repeat chest x-ray after 6 hours showed no significant change in size. At discharge the patient continued to endorse pain with deep inspiration, but otherwise reported feeling comfortable. She was given a follow-up appointment with pulmonology for repeat imaging in a week or two.

Pneumothorax

Air between the visceral and parietal pleura

Due to an alveolar-pleural defect between intrapleural space (normally under negative pressure) and the airways (positive pressure)

Defect leads to equalization of pressure until the defect is closed

Simple

• lung collapse on the side of the defect --> decreased lung capacity
• VQ mismatch --> potential hypoxemia depending on size and comorbidities

Tension

• defect acts as a one-way valve --> accumulation of air in the intrapleural space
• mediastinal contents shift away from affected side --> compresses opposite lung
• hypoxia and impaired venous return --> cardiovascular collapse and death

Causes

• Traumatic - blunt or penetrating trauma 
• Iatrogenic - often due to penetrating trauma (i.e. procedure) 
• Spontaneous - no clear precipitating cause
• Primary (no lung disease) = 2/3 cases
• Risk factors: male, smoker, tall, change in ambient pressure, Marfan's
• Secondary (history of lung disease, usually COPD) 
• Risk factors: asthma, cystic fibrosis, lung abscess, TB, interstitial lung disease, malignancy, PJP

Presentation

• sudden onset unilateral chest pain, usually pleuritic, dyspnea, cough
• tachycardia, hyperresonance to percussion, diminished breath sounds

Diagnosis

• clinical suspicion should prompt imaging
• CXR - classically shows pleural line parallel to contour of chest wall with gap of absent lung markings
• CT chest = very sensative
• Grade: small, moderate, large, total

Management

• largely depends on the clinical status of the patient and the size of the pneumothorax

• observation (6 hours) 
• small size pneumothorax <20%
• otherwise young healthy patient
• intrinsic reabsorption 1%-2% per day (increases to 4%-8% on 100% O2)
• may discharge after observation if reliable follow up established for repeat CXR
• simple catheter aspiration 
• moderate size pneumothorax >20%
• less invasive but not always successful
• tube thoracostomy
• most common therapy, especially when more conservative measures fail
• treatment of choice with pleural effusion, respiratory distress, tension pneumothorax
• 20-28 French standard, >28 preferred if pleural fluid present
• water-seal valve (Heimlich or flutter valves) don't require hospitalization
• complications: malposition, infection, pain, obstruction, reexpansion pulmonary edema

management of tension pneumothorax to be discussed in a future post

References: 

Levy SJ, Lex JR, Emergency Medicine: A Focused Review of the Core Curriculum, 1st Ed, 2008, Chapter 4: Thoracic and Respiratory Disorders, pages 237-242

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My Shoulder Really Hurts...

A 27 year-old female presents to the emergency department with chief complaint of right-sided shoulder pain radiating to the chest that started 3 days ago. 

She reports that the pain was initially very severe and exacerbated by every breath on the first day of symptoms. The pain began after waking that morning. The patient went to a local urgent care clinic where she had a shoulder x-ray done that did not show a fracture or dislocation and was discharged with the diagnosis of impingement syndrome. The pain has improved somewhat over the last 2 days but has continues to experience pain with deep inspiration. The pain is also made worse by lying flat.

She denies any recent trauma to her shoulder or chest. She also denies any history of recent long car or plane rides, OCP use, recent surgery, or prior deep venous thrombosis. 

She denies having any shortness of breath, fevers, chills, nausea or vomiting.

Vital signs are within normal limits. The patient appears resting comfortably in bed.

A 2-view chest x-ray was obtained and is shown below: 

What is the diagnosis?

How would you manage this patient? 

Share your thoughts in the comments section below.  

The diagnosis for this case will be posted in approximately 1 week.