E-cigarette or vaping product use-associated lung injury (EVALI) is a potentially life-threatening condition presenting with lung damage and resultant respiratory symptoms associated with vaping or use of e-cigarettes. The prevalence of vape use in the United States has significantly increased in recent years, with up to 4.9% of adults using the devices in 2018 and up to 10.5% of middle school age children and 27.5% of high school age children reporting vape use as of 2019. 

The US Centers for Disease Control and Prevention (CDC) case definition of EVALI requires the use of an electronic vaping device within 90 days of onset of symptoms, infiltrates on chest x-ray or chest CT, and no other diagnosis to explain the patient's symptoms. While the cause of EVALI has not been elucidated, many patients reported having used tetrahydrocannabinol (THC) products in vaping devices (particularly during the 2019-2020 EVALI outbreak linked to the vaping of THC-containing products), although a wide variety of vaping products and devices have been reported before and since. In THC-oil-associated EVALI, researchers have identified a potential toxicant, vitamin E acetate, used as a thickening agent to dilute THC oil, that may have been added to THC vaping products and which has been associated with interference with pulmonary surfactant function resulting in alveolar collapse and inflammation. 

The exact mechanism by which different e-liquid components cause lung injury is still under investigation and is likely multifactorial. EVALI can present with a wide range of clinical symptoms that mimic many acute pulmonary diseases, with 97% of patients reporting cough, 85% reporting shortness of breath, and 56% reporting chest pain in one series. Gastrointestinal symptoms are reported in 77% of patients, including abdominal pain, nausea, or vomiting, and up to 85% report systemic symptoms of fatigue, fevers, chills, weight loss, or malaise.

On examination, 55% of patients were noted to be tachycardic, 45% were noted to be tachypneic, and 57% had saturations on room air of less than 95%. In general, pulmonary findings on auscultation were unremarkable, even among those with severe lung injury.

Laboratory findings are fairly nonspecific, with 87% of patients having a WBC of greater than 11 000 and 93% with elevated ESR greater than 30 mm/hr. Half of patients (50%) have elevated liver transaminases (aspartate transaminase / alanine transaminase [AST / ALT] greater than 35 U/L).

All patients with symptoms compatible with EVALI should have a chest x-ray in the case of mild symptoms and a chest CT in the case of more severe symptoms or oxygen saturation less than 95% on room air. Radiographic findings of EVALI included infiltrates on chest x-ray and opacities on chest CT but were nonspecific. Chest x-ray most commonly shows bilateral hazy opacities with central sparing, and chest CTs classically show bilateral ground glass opacities of both lungs, most often bibasilar.

EVALI remains a diagnosis of exclusion, as no specific test or marker exists for diagnosis. All patients with compatible symptoms should be asked about vaping device use in the 3 months preceding symptom onset.

Patients should be evaluated for alternative etiologies, including viral respiratory tract infections (eg, influenza) and common etiologies of community-acquired pneumonia.

Hypoxic patients and those in respiratory distress warrant hospitalization, and patients with even mild symptoms can deteriorate rapidly over 48 hours. Some patients, particularly those older than 50 years, may progress to respiratory failure, necessitating endotracheal intubation and mechanical ventilation.

The reported mortality rate for EVALI is 2.4%. Patients with EVALI and a history of asthma or other respiratory disease, cardiac disease, a mental health condition, or obesity may be at increased risk of death.

Related topics: cannabis use disorder, nicotine dependence, synthetic cannabinoid poisoning