Does a patient with a large bulla found on computed tomography (CT) in the emergency department require hospital admission?

Hospital Admission for Large Bulla on CT

A patient with a large bulla found incidentally on CT in the emergency department does NOT require hospital admission based solely on the presence of the bulla, provided the patient is clinically stable, the bulla is not ruptured, and there are no complications such as pneumothorax, infection, or hemoptysis. 1, 2, 3

Critical Distinction: Bulla vs. Pneumothorax

The most important immediate concern is differentiating a large bulla from pneumothorax, as misdiagnosis can lead to catastrophic iatrogenic complications:

• Never insert a chest tube into a bulla - this creates a bronchopleural fistula with potentially fatal consequences 1, 2, 3
• CT imaging is essential for accurate differentiation when the diagnosis is uncertain on plain radiograph 1, 2, 3
• Giant bullae can occupy >1/3 of the hemithorax and mimic pneumothorax on chest X-ray, making CT the gold standard for diagnosis 1, 2

Decision Algorithm for Admission

Admit to Hospital if ANY of the following are present:

Respiratory compromise:

• Respiratory rate >24 breaths/min 4
• Room air oxygen saturation <90% 4
• Inability to speak in whole sentences between breaths 4
• Clinical dyspnea or hypoxia 1

Complications of the bulla:

• Pneumothorax (ruptured bulla) - requires chest tube placement and hospitalization 5, 4, 1
• Hemoptysis - mild-to-moderate (>5 mL/24h) or massive (≥200 mL/24h) requires admission 5, 6
• Infection of the bulla - requires IV antibiotics 6, 1
• Active bleeding within the bulla - can lead to cerebral air embolism 7

Hemodynamic instability:

• Heart rate <60 or >120 beats/min 4
• Abnormal blood pressure 4
• Signs of shock 4

Underlying severe lung disease:

• FEV1 <35% predicted - these patients are at high risk for respiratory failure if pneumothorax develops 5
• Chronic respiratory failure requiring BiPAP 5

Safe for Discharge if ALL of the following are met:

• Clinically stable by above criteria 4
• No pneumothorax on CT 5, 4
• No hemoptysis 5, 6
• No signs of infection (fever, productive cough, elevated WBC) 6
• Adequate pulmonary reserve (FEV1 >35% predicted if known) 5
• Reliable follow-up available within 1-2 weeks 4

Outpatient Management Recommendations

For stable patients discharged from the ED:

Activity restrictions to prevent rupture:

• Avoid air travel for 2 weeks 5
• Avoid heavy lifting for 2 weeks 5
• Avoid spirometry testing for 2 weeks 5
• Avoid Valsalva maneuvers 7

Follow-up imaging:

• Repeat chest imaging in 2-4 weeks to assess for interval change 5
• Consider pulmonary function testing if not recently performed 5

Referral considerations:

• Pulmonology referral for evaluation of surgical bullectomy if the bulla is causing symptoms or occupying >1/3 hemithorax 1, 2
• Multidisciplinary team assessment including respiratory physician and radiologist for symptomatic giant bullae 5

Common Pitfalls to Avoid

Do not reflexively place a chest tube - if there is any uncertainty about whether the lucency represents pneumothorax versus bulla, obtain CT imaging first in stable patients 1, 2, 3

Do not discharge patients who live far from emergency services - these patients may require admission for observation even if otherwise stable, given the risk of delayed rupture 4

Do not ignore underlying emphysema - patients with bullous disease often have compromised baseline lung function, making them high-risk for decompensation if complications develop 5, 1

Do not perform needle decompression - if a bulla is mistaken for tension pneumothorax, needle decompression can be catastrophic 1