Vaping-associated pulmonary injury


Vaping-associated pulmonary injury, also known as vaping-associated lung injury or e-cigarette, or vaping, product use associated lung injury, is an umbrella term, used to describe lung diseases associated with the use of vaping products that can be severe and life-threatening. Symptoms can initially mimic common pulmonary diagnoses, such as pneumonia, but sufferers typically do not respond to antibiotic therapy. [|Differential diagnoses] have overlapping features with VAPI, including COVID-19. According to a systematic review article, "Initial case reports of vaping-related lung injury date back to 2012, but the ongoing outbreak of EVALI began in the summer of 2019." Many cases were initially misdiagnosed as COVID-19.
Sufferers usually present for care within a few days to weeks of symptom onset. Starting in September 2019, the US Centers for Disease Control and Prevention reported on a nation-wide outbreak of severe lung disease linked to vaping, or the process of inhaling aerosolized substances with battery-operated electronic cigarettes, ciga-likes, or vape mods.
All CDC-reported cases of VAPI involved a history of using e-cigarette, or vaping, products, with most samples having tested positive for tetrahydrocannabinol by the US FDA and most patients reporting a history of using a THC-containing product. CDC data show that the outbreak peaked in September 2019, and declined steadily to a low level through January 2020. In late February 2020, a CDC-authored article in the NEJM stated that the VAPI outbreak was "driven by the use of THC-containing products from informal and illicit sources." However, the CDC also stated, "Evidence is not sufficient to rule out the contribution of other chemicals of concern, including chemicals in either THC or non-THC products, in some of the reported EVALI cases." In 2021, analysis of the aerosols from popular vape brands such as Juul and Vuse found "nearly 2,000 chemicals, the vast majority of which are unidentified."
The CDC has stated that the THC cutting agent vitamin E acetate is very strongly implicated in VAPI, but evidence was not sufficient to rule out a contribution from other chemicals of concern to VAPI as of January 2020.
Sharing vaping devices can spread COVID-19. Several organizations, including Purdue University and Public Health England, strongly advise against sharing vapes.

Prevention

To reduce the risk of EVALI public health agencies such as CDC have recommended several precautionary measures. Avoidance of e-cigarette or vaping products containing tetrahydrocannabinol has been emphasized, particularly those obtained from informal or unregulated sources, which have been strongly linked to EVALI cases.
Vitamin E acetate, an additive sometimes used in THC vaping liquids, has also been identified as a primary chemical of concern due to its association with lung injury.
Health authorities further advise that all vaping products should be purchased from licensed and reputable retailers to minimize the risk of contamination or mislabeling.
Educational campaigns targeting adolescents and parents have been implemented to raise awareness of the health risks associated with vaping, in an effort to reduce youth initiation.
In addition, public health experts have advocated for policy measures such as age restrictions and bans on flavored vaping products to help curb youth access and use.

Signs and symptoms

Commonly reported symptoms include shortness of breath, cough, fatigue, body aches, dizziness, fever, nausea, vomiting, diarrhea, weight loss, chest pain, abdominal pain, and chills. Symptoms can initially mimic common pulmonary diagnoses like pneumonia, but individuals typically do not respond to antibiotic therapy. In some patients, gastrointestinal symptoms can precede respiratory symptoms. Individuals typically present for care within a few days to weeks of symptom onset.
At the time of hospital presentation, the individual is often hypoxic and meets systemic inflammatory response syndrome criteria, including fever. Physical exam can reveal rapid heart rate or rapid breathing. Auscultation of the lungs tends to be unremarkable, even in patients with severe lung disease. In some cases, the affected individuals have progressive respiratory failure, leading to intubation. Several affected individuals have needed to be placed in the intensive care unit and on mechanical ventilation. Time to recovery for hospital discharge has ranged from days to weeks.

Possible causes

No single cause of these illnesses has been established as of 2019. Many different substances and product sources continued to be under investigation.

Composition of electronic cigarette aerosol

Chemicals

  • Glycerin: One report suggests that glycerine derived from incompletely processed vegetable oil might be a cause of lipid pneumonia.
  • MCT oil: In vivo mouse exposure of inhaled MCT oil induces acute pulmonary inflammation and toxicity.
  • Vitamin E acetate: On September 5, 2019, the United States Food and Drug Administration announced that 10 out of 18, or 56% of the samples of vape liquids sent in by states, linked to recent vaping related lung disease outbreak in the United States, tested positive for vitamin E acetate which had been used as a thickening agent by illicit THC vape cartridge manufacturers. The CDC states that vitamin E acetate is a very strong culprit of concern in VAPI, having been found in 29 out of 29 lung biopsies tested from ten different states, but evidence is not yet sufficient to rule out contribution of other chemicals of concern to VAPI. The CDC stated as of 11 February 2020 that previous research suggested inhaled vitamin E acetate may interfere with normal lung functioning. A 2020 study found that vaped vitamin E acetate produced exceptionally toxic ketene gas, along with carcinogenic alkenes and benzene.
  • Psychoactive substances:
  • *CBD is one among the most suspected ingredients involved in VAPI. Conversion of CBD to THC can occur when CBD is heated to temperatures between 250–300 °C, potentially leading to its partial transformation into THC.
  • * Synthetic cannabinoids: Can cause pneumonia via CB1 activation. Synthetic cannabinoids are increasingly offered in e-cigarette form as "c-liquid".
  • Unknown chemicals
  • * THC cartridges : An outbreak of lipid pneumonia occurred in North Carolina between July–August 2019

    Pathogens

Products have been found to be contaminated with fungi and bacteria, which may cause fungal pneumonia, and bacterial pneumonia respectively.
Nicotine-containing e-liquids are extracted from tobacco that may contain impurities. Tobacco-specific impurities such as cotinine, nicotine-N'-oxides, and beta-nornicotyrine are believed to be the result of bacterial action or oxidation during the extracting of nicotine from tobacco.
Re-used vapes, and vape sharing
by pathogens uncleaned vapes and/or vape sharing:
In addition to vaping, some individuals have also experienced VAPI through "dabbing". Dabbing uses a different type of device to heat and extract cannabinoids for inhalation. It is a process that entails superheating and inhaling particles into the lungs that contain THC and other types of cannabidiol plant materials.

Mechanism

refers to the practice of inhaling an aerosol from an electronic cigarette device, which works by heating a liquid that can contain various substances, including nicotine, tetrahydrocannabinol, flavoring, and additives ). The long-term health impacts of vaping are unknown.
Most individuals treated for VAPI report vaping the cannabis compounds THC and/or cannabidiol, and some also report vaping nicotine products. A small but consistent minority of EVALI patients have been found not to be users of THC products.
VAPI appears to be a type of acute lung injury, similar to acute fibrinous pneumonitis, organizing pneumonia, or diffuse alveolar damage. VAPI appears to be a general term for various causes of acute lung damage due to vaping. There is no evidence of an infectious etiology causing VAPI.

Diagnosis

High clinical suspicion is necessary to make the diagnosis of VAPI. As of October 2019, VAPI was considered a diagnosis of exclusion because no specific tests or markers existed for its diagnosis. Healthcare providers were advised to evaluate for alternative diagnoses as suggested by clinical presentation and medical history, while also considering multiple etiologies, including the possibility of VAPI occurring with a concomitant infection.
All healthcare providers evaluating patients for VAPI were urged to consider obtaining a thorough patient history, including symptoms and recent use of e-cigarette, or vaping, products, along with substances used, duration and frequency of use, and method of use. Additionally a detailed physical examination was recommended, specifically including vital signs and pulse-oximetry. Laboratory testing guided by clinical findings, which might include a respiratory virus panel to rule out infectious diseases, complete blood count with differential, serum inflammatory markers, liver transaminases, and urine toxicology testing, including testing for THC were recommended.
Imaging, typically a chest X-ray, with consideration for a chest CT if chest X-ray results did not correlate with the clinical picture or to evaluate severe or worsening disease were urged. It was pointed out that consulting with specialists could help guide further evaluation. The diagnosis is commonly suspected when the person does not respond to antibiotic therapy, and testing does not reveal an alternative diagnosis. Many of the reported cases involved worsening respiratory failure within 48 hours of admission, following the administration of empiric antibiotic therapy. Lung biopsies are not necessary for the diagnosis but are performed as clinically indicated to rule out the likelihood of infection.
There are non-specific laboratory abnormalities that have been reported in association with the disease, including elevations in white blood cell count, transaminases, procalcitonin, and inflammatory markers. Infectious disease testing, including blood and sputum cultures and tests for influenza, Mycoplasma, and Legionella were all found to be negative in the majority of reported cases. Imaging abnormalities are typically bilateral and are usually described as "pulmonary infiltrates or opacities" on chest X-ray and "ground-glass opacities" on chest CT.
Bronchoalveolar lavage specimens may exhibit an increased level of neutrophils in combination with lymphocytes and vacuole-laden macrophages. Lavage cytology with oil red O staining demonstrated extensive lipid-laden alveolar macrophages. In the few cases in which lung biopsies were performed, the results were consistent with acute lung injury and included a broad range of features, such as acute fibrinous pneumonitis, diffuse alveolar damage, lipid-laden macrophages, and organizing pneumonia. Lung biopsies often showed neutrophil predominance as well, with rare eosinophils.