What are the hallmark clinical features, laboratory findings, and imaging characteristics of e‑cigarette or vaping‑associated lung injury (EVALI)?

Hallmarks of E-Cigarette or Vaping-Associated Lung Injury (EVALI)

EVALI characteristically presents with a triad of respiratory symptoms (shortness of breath, cough), constitutional symptoms (fever), and gastrointestinal manifestations (nausea/vomiting), combined with bilateral ground-glass opacities on chest imaging and elevated inflammatory markers, in a patient with recent vaping history within 90 days.

Clinical Features

Symptom Presentation

The clinical presentation is remarkably consistent across patients:

• Respiratory symptoms occur in 87.1% of cases, with shortness of breath (82.7%) and cough (77.4%) being most prominent 1
• Constitutional symptoms appear in 87.3%, with fever present in 79.9% 1
• Gastrointestinal manifestations affect 77.1%, particularly nausea/vomiting (75.0%) 1

This combination of respiratory, constitutional, and GI symptoms creates a "flu-like illness" presentation that is characteristic of EVALI 2. The gastrointestinal component is particularly distinctive and helps differentiate EVALI from other acute lung injuries.

Patient Demographics

• Predominantly affects adolescents and young adults (median age 24 years) 2
• Male predominance (77-79%) 1, 2
• Most patients report vaping for >3 months prior to symptom onset 1
• 94% report THC-containing product use 2

Laboratory Findings

Elevated serum inflammatory markers are universally present 2. While the guidelines emphasize laboratory testing to rule out infectious etiologies 3, the key finding is the elevation of inflammatory biomarkers in the absence of infectious causes 4.

Bronchoscopic Findings

When bronchoscopy is performed (in 82% of hospitalized patients):

• Lipid-laden macrophages (LLMs) present in 91% of bronchoalveolar lavage samples 2
• High incidence of false-positive infectious testing (Pneumocystis jirovecii, rhinovirus) that are clinically inconsequential 2

Important caveat: Bronchoscopy has limited utility in typical EVALI presentations without risk factors for alternative diagnoses 2. The high false-positive rate for infections can lead to unnecessary antimicrobial therapy.

Imaging Characteristics

CT Chest Patterns

The imaging findings follow a predictable spectrum, with organizing pneumonia (OP) pattern being most common (84.4% combined) 5:

Primary patterns include:

• Parenchymal OP pattern (55.6%): Regional or diffuse ground-glass opacity ± consolidation without centrilobular nodules 5
• Mixed OP pattern (20%): Combination of GGO and centrilobular nodules 5
• Airway-centered OP pattern (8.8%): Diffuse centrilobular nodules with minimal GGO 5

Specific imaging hallmarks:

• Bilateral pulmonary involvement in 98.1% 1
• Ground-glass opacities in 94.9% 1
• Subpleural sparing in 78.1% 5
• Lobular sparing in 59.4% 5
• Peribronchovascular (PBV) sparing in 40% - a novel finding not previously described in acute lung injury 5
• Septal thickening (50.6%) and lymphadenopathy (63.1%) are common 5

Less Common Patterns

• Diffuse alveolar damage (DAD): 5.6% - associated with higher mortality 5
• Acute eosinophilic-like pneumonia: 3.8% 5
• Pulmonary hemorrhage: 3.8% 5

Critical distinction: Increased vaping frequency correlates with more severe injury (P=.008), but vaping >6 months is negatively associated with DAD pattern (P=.03) 5. The two deaths (1.25% mortality) occurred in patients with DAD pattern 5.

Pathologic Features

The histopathology mirrors the imaging spectrum:

• Lipid-laden alveolar macrophages are characteristic 4
• Spectrum from organizing pneumonia to diffuse alveolar damage 6
• Novel findings include coarse lipid vacuolization (35%) and "grungy" proteinosis-like deposits (18%) 7
• Airway-centered macrophages with variable airway-centered fibrosis in patients with chronic symptoms post-EVALI 7

Diagnostic Criteria

EVALI is a diagnosis of exclusion requiring ALL of the following 6, 4:

1. History of vaping within last 90 days
2. Abnormal chest imaging findings
3. Negative evaluation for infection
4. No other plausible diagnosis

Disease Severity and Outcomes

• Hospitalization required in 94.4% 1
• ICU admission in 35.7% 1
• Overall mortality is 0.9% 1, though this represents significant morbidity given the young patient population
• At early follow-up, residual symptoms (65%), radiographic opacities (40%), and abnormal pulmonary function tests (44%) are common 2

Clinical Pitfalls to Avoid

1. Don't rely on bronchoscopy in typical presentations - high false-positive infection rates lead to unnecessary antibiotics 2
2. Don't miss the GI symptoms - their presence is a key diagnostic clue distinguishing EVALI from other pneumonias
3. Don't discharge too early - 25% of rehospitalizations and deaths occur within 2 days of discharge 3
4. Don't overlook PBV sparing on imaging - this finding is characteristic and not seen in other acute lung injuries 5
5. Recognize DAD pattern urgency - lower threshold for ventilation support and corticosteroids when this pattern is present 4

The combination of bilateral ground-glass opacities with subpleural/lobular/PBV sparing, lipid-laden macrophages on BAL, elevated inflammatory markers, and the characteristic symptom triad in a young vaper creates a highly recognizable clinical syndrome.