A 72-year-old woman with amyotrophic lateral sclerosis (ALS) and progressive bulbar weakness is counseled about airway management options. She has severe dysphagia and recurrent aspiration pneumonia despite speech therapy and dietary modifications. Her vital capacity is 45% of predicted. She is referred for tracheostomy and non-invasive ventilation. One week after uncomplicated tracheostomy placement, she develops sudden onset of subcutaneous emphysema around the stoma, with crepitus extending to the neck and upper chest. Chest X-ray shows air tracking into the mediastinum. What is the most likely complication?

Explanation

## Acute Subcutaneous Emphysema Post-Tracheostomy **Key Point:** Subcutaneous emphysema and pneumomediastinum appearing within 1 week of tracheostomy indicate an acute air leak — either from tracheal perforation or tube malposition allowing air to escape into the peritracheal tissues. ### Clinical Presentation Analysis - **Timing:** 1 week post-tracheostomy (acute, not chronic) - **Findings:** Subcutaneous emphysema, crepitus, pneumomediastinum on CXR - **Mechanism:** Air tracking from the trachea into soft tissues and mediastinum ### Differential Diagnosis of Post-Tracheostomy Complications | Complication | Timing | Presentation | Mechanism | |---|---|---|---| | **Tracheal perforation / tube malposition** | Acute (days 1–7) | Subcutaneous emphysema, pneumomediastinum, air leak | Tube erodes through posterior tracheal wall or sits too deep; air escapes peritracheal space | | **Tracheal stenosis** | Chronic (weeks–months) | Stridor, dyspnea on exertion, narrowed airway on imaging | Cuff pressure necrosis, fibrosis, scar contracture | | **Tracheoesophageal fistula** | Subacute–chronic (2–4 weeks) | Aspiration, recurrent pneumonia, food in trachea, subcutaneous emphysema (if air enters esophagus) | Tube erosion through posterior tracheal wall into esophagus | | **Mediastinitis** | Acute–subacute (days–weeks) | Fever, chest pain, sepsis, widened mediastinum on CXR | Bacterial infection of mediastinal space | ### Why Tracheal Perforation / Malposition? 1. **Subcutaneous emphysema is pathognomonic for air leak** — Air escaping from the trachea into peritracheal tissues. 2. **Pneumomediastinum indicates air tracking centrally** — Consistent with a breach in the tracheal wall. 3. **Acute onset (1 week) rules out stenosis** — Stenosis develops over weeks to months from cuff pressure ischemia. 4. **Tube malposition is a common cause** — If the tube is placed too deep or at an angle, it can erode through the posterior tracheal wall, creating a fistula or perforation. **Clinical Pearl:** **Subcutaneous emphysema post-tracheostomy is a surgical emergency.** The tube must be repositioned or replaced immediately, and the tracheal defect may require surgical repair if large. Tube malposition is the most common cause in the immediate post-operative period. **High-Yield:** The classic triad of tracheal tube complications: - **Early (days):** Perforation, malposition, hemorrhage, tube obstruction - **Intermediate (1–4 weeks):** Tracheoesophageal fistula, tracheal stenosis (early) - **Late (months–years):** Tracheal stenosis, tracheomalacia, granulation tissue **Mnemonic: STENT** — **S**tenosis (late), **T**racheoesophageal fistula (intermediate), **E**mphysema/erosion (early), **N**ecrosis (cuff-related), **T**ube obstruction (early).