Acute and subacute chemical-induced lung injuries: HRCT findings

[Occupational interstitial lung diseases]

A variety of workplace exposures (organic or inorganic dusts as well as gases, fumes, or vapors) can cause diffuse interstitial lung disease. The latency period until onset of the disease can exceed 30 years. The disease course varies greatly and depends on the quantity of the inhaled substance and its fibrogenic effect. Pulmonary high-resolution computed tomography (HRCT) patterns do not differ significantly from those of interstitial lung diseases (ILD) of other etiologies. Therefore, without knowledge of the occupational history, work-related ILDs are often classified as idiopathic. In addition, there is increasing evidence in the recent literature that high exposure to silica dust can trigger autoimmune diseases (also involving the lungs). For this reason, a qualified occupational history is now an indispensable part of the interdisciplinary diagnosis of ILDs.

Expert Consensus on the Diagnosis and Treatment of Anticancer Drug-Induced Interstitial Lung Disease

Drug-induced interstitial lung disease (DILD) is the most common pulmonary adverse event of anticancer drugs. In recent years, the incidence of anticancer DILD has gradually increased with the rapid development of novel anticancer agents. Due to the diverse clinical manifestations and the lack of specific diagnostic criteria, DILD is difficult to diagnose and may even become fatal if not treated properly. Herein, a multidisciplinary group of experts from oncology, respiratory, imaging, pharmacology, pathology, and radiology departments in China has reached the "expert consensus on the diagnosis and treatment of anticancer DILD" after several rounds of a comprehensive investigation. This consensus aims to improve the awareness of clinicians and provide recommendations for the early screening, diagnosis, and treatment of anticancer DILD. This consensus also emphasizes the importance of multidisciplinary collaboration while managing DILD.

Imaging of Occupational and Environmental Lung Disease

The respiratory tract is continuously exposed to and filters toxins from the home and work environments. Certain occupations and environmental exposures can cause unique injuries to the upper and lower respiratory system. Despite increasing federal regulations in the workplace, occupation-associated lung disease is still a major cause of lung disease and disability and continues to evolve with changes in industry, regulation, and new emerging exposures and toxins. Establishing a diagnosis can be difficult, often due to long latency between exposure and clinical disease, insufficient patient history, and nonspecific or varying imaging appearance. Identifying key imaging features of occupational lung disease along with a multidisciplinary approach can aid in accurate and timely diagnosis. In this review, we will discuss the importance of a comprehensive patient history, multidisciplinary approach to diagnosis, and key imaging features of occupation-related lung injuries. Radiographic and computed tomographic findings will be described and illustrated.

Hydrofluorocarbons pneumonitis as a complication of inhalation injury following air‐conditioning repairs

Hydrofluorocarbon (HFC) pneumonitis is an uncommon cause of inhalation injury. HFCs are a group of chemicals predominantly used for refrigeration and cooling. A 19‐year‐old air‐conditioning technician developed acute onset of dyspnoea and chest tightness while servicing an air conditioner in a confined space. We diagnosed him with HFC pneumonitis based on the history of exposure and the high‐resolution computed tomography (HRCT) thorax findings. He was treated with steroids and supportive oxygen therapy. He recovered fully after 5 days of hospitalization and was discharged. Review at 2 weeks in the outpatient setting showed significant radiological improvement on HRCT thorax.

CT Findings and Patterns of E-Cigarette or Vaping Product Use-Associated Lung Injury: A Multicenter Cohort of 160 Cases

BACKGROUND

E-cigarette and vaping-induced lung injury (EVALI) causes a spectrum of CT lung injury patterns. Relative frequencies and associations with vaping behavior are unknown.

RESEARCH QUESTION

What are the frequencies of imaging findings and CT patterns in EVALI and what is the relationship to vaping behavior?

STUDY DESIGN AND METHODS

CT scans of 160 subjects with EVALI from 15 institutions were retrospectively reviewed. CT findings and patterns were defined and agreed on via consensus. The parenchymal organizing pneumonia (OP) pattern was defined as regional or diffuse ground-glass opacity (GGO) ± consolidation without centrilobular nodules (CNs). An airway-centered OP pattern was defined as diffuse CNs with little or no GGO, whereas a mixed OP pattern was a combination of the two. Other patterns included diffuse alveolar damage (DAD), acute eosinophilic-like pneumonia, and pulmonary hemorrhage. Cases were classified as atypical if they did not fit into a pattern. Imaging findings, pattern frequencies, and injury severity were correlated with substance vaped (marijuana derives [tetrahydrocannabinol] [THC] only, nicotine derivates only, and both), vaping frequency, regional geography, and state recreational THC legality. One-way analysis of variance, χ² test, and multivariable analyses were used for statistical analysis.

RESULTS

A total of 160 patients (79.4% men) with a mean age of 28.2 years (range, 15-68 years) with EVALI underwent CT scan. Seventy-seven (48.1%), 15 (9.4%), and 68 (42.5%) patients admitted to vaping THC, nicotine, or both, respectively. Common findings included diffuse or lower lobe GGO with subpleural (78.1%), lobular (59.4%), or peribronchovascular (PBV) sparing (40%). Septal thickening (50.6%), lymphadenopathy (63.1%), and CNs (36.3%) were common. PBV sparing was associated with younger age (P = .02). Of 160 subjects, 156 (97.5%) had one of six defined patterns. Parenchymal, airway-centered, and mixed OP patterns were seen in 89 (55.6%), 14 (8.8%), and 32 (20%) patients, respectively. Acute eosinophilic-like pneumonia (six of 160, 3.8%), DAD (nine of 160, 5.6%), pulmonary hemorrhage (six of 160, 3.8%), and atypical (four of 160, 2.5%) patterns were less common. Increased vaping frequency was associated with more severe injury (P = .008). Multivariable analysis showed a negative association between vaping for > 6 months and DAD pattern (P = .03). Two subjects (1.25%) with DAD pattern died. There was no relation between pattern and injury severity, geographic location, and state legality of recreational use of THC.

INTERPRETATION

EVALI typically causes an OP pattern but exists on a spectrum of acute lung injury. Vaping habits do not correlate with CT patterns except for negative correlation between vaping > 6 months and DAD pattern. PBV sparing, not previously described in acute lung injury, is a common finding.

A case of acute inhalation injury caused by premeditated chlorine gas exposure

Chlorine is a toxic gas that causes severe inhalation injury. We report the case of a 43-year-old woman who inhaled chlorine gas generated by mixing household bleach and vinegar. She was referred to our hospital because she had developed respiratory failure. Chest computed tomography (CT) showed diffuse ground-glass opacity and the tree-in-bud pattern. We diagnosed acute inhalation injury compatible with that due to chlorine gas exposure. Six days after admission, her respiratory symptoms and abnormal CT findings fully resolved without the use of bronchodilators or corticosteroids. This is the first report of a patient with acute inhalation injury caused by intentional chlorine gas exposure. It is considered that chlorine gas reached her respiratory tract and induced widespread injury from bronchioles to alveoli.

The Significance of Subpleural Sparing in CT Chest: A State-of-the-Art Review

The subpleural sparing pattern is a common finding on computed tomography (CT) of the lungs. It comprises of pulmonary opacities sparing the lung peripheries, typically 1cm and less from the pleural surface. This finding has a variety of causes, including idiopathic, inflammatory, infectious, inhalational, cardiac, traumatic, and bleeding disorders. Specific disorders that can cause subpleural sparing patterns include nonspecific interstitial pneumonia (NSIP), organizing pneumonia (OP), pulmonary alveolar proteinosis (PAP), diffuse alveolar hemorrhage (DAH), vaping-associated lung injury (VALI), cracked lung, pulmonary edema, pneumocystis jirovecii pneumonia (PJP), pulmonary contusion, and more recently, Coronavirus disease 2019 (COVID-19) pneumonia. Knowledge of the many etiologies of this pattern can be useful in preventing diagnostic errors. In addition, although the etiology of subpleural sparing pattern is frequently indistinguishable during an initial radiologic evaluation, the differences in location of opacities in the lungs, as well as the presence of additional radiologic findings, patient history, and clinical presentation, can often be useful to suggest the appropriate diagnosis. We did a comprehensive search on Pubmed and Google Scholar database using keywords of "subpleural sparing," "peripheral sparing," "sparing of peripheries," "CT chest," "chest imaging," and "pulmonary disease." This review aims to describe the primary differential diagnosis of subpleural sparing pattern seen on chest imaging with a strong emphasis on clinical and radiographic findings. We also discuss the pathogenesis and essential clues that are crucial to narrow the differential diagnosis.

Radiographic diagnosis of Pneumoconioses by AIR Pneumo-trained physicians: Comparison with low-dose thin-slice computed tomography

OBJECTIVES

The Asian Intensive Reader of Pneumoconiosis (AIR Pneumo) is a training program designed to improve diagnostic skills for chest radiographies (CXRs) in accordance with the ILO/ICRP 2000. The purpose was to determine the prevalence of occupational environmental pulmonary disease findings in construction workers on thin-slice computed tomography (thin-slice CT), and to compare the diagnostic performance with CXR evaluated by AIR Pneumo-trained physicians.

METHODS

Ninety-seven male construction workers underwent low-dose thin-slice CT and CXR on the same day. NIOSH B reader and a board-certified radiologist each interpreted the thin-slice CTs independently. The concordant findings on thin-slice CT were established as the reference standard and were statistically compared with CXRs. Four physicians interpreted CXRs independently according to the ILO/ICRP 2000.

RESULTS

Of the 97 cases, nine showed irregular or linear opacities, and 44 had pleural plaques on thin-slice CT. Five, four, three, and two of nine cases with irregular opacity were detected by the four readers on CXRs, respectively. Sixteen, 14, 9, and 5 of the 44 cases with pleural plaques were detected by the four readers, respectively. Specificities for irregular opacities ranged from 94% to 100%, and those for pleural plaques were from 86% to 96%.

CONCLUSIONS

Thin-slice CT-detected irregular opacity was found in 9.3%, whereas pleural plaque was found in 45.4% among the construction workers. Chest radiography showed acceptable performance in classifying pneumoconiotic opacities according to ILO/ICRP 2000 by the AIR Pneumo and/or NIOSH-certified physicians.

Hypersensitivity Pneumonitis High-resolution Computed Tomography Findings, and Their Correlation with the Etiology and the Disease Duration

Hypersensitivity pneumonitis (HP) is an immune-mediated diffuse parenchymal lung disease induced by inhaled antigens. High-resolution computed tomography (HRCT) is widely used in the diagnosis and follow-up of patients and determining the progression and prognosis of the disease. In this retrospective study, 45 consecutive patients with the final diagnosis of HP, seen at a large tertiary care center during a period of 4 years, were included and their HRCT findings were evaluated. The most common HRCT findings were ground glass opacity and reticulation. Some HRCT patterns were detected more severely in bird fanciers in comparison with other etiologies. There is no "gold standard" for the diagnosis of HP. HRCT findings play an important role in hypersensitivity pneumonitis diagnosis and CT scan also help to define the severity of hypersensitivity pneumonitis injuries. In our study, reticulation and ground glass opacity were the most common findings in HRCT of patients with HP. We also find that patients with avian contacts had a significantly higher rate of fibrosis.

Pulmonary Tumor Thrombotic Microangiopathy Mimicking Inhalation Lung Injury

Pulmonary tumor thrombotic microangiopathy (PTTM) is a complication characterized by dyspnea, pulmonary hypertension, and occasionally sudden death. We encountered a man who developed PTTM and had an inhalation history of chemical herbicides and abnormal findings on chest computed tomography, mimicking chemical inhalation lung injury. He was diagnosed with PTTM with adenocarcinoma by a transbronchial lung biopsy and received chemotherapy and anticoagulant therapy. He survived for one month. An autopsy revealed primary gastric cancer with PTTM that can have a presentation similar to diffuse pulmonary diseases, including chemical inhalation lung injury. The examination of a biopsy specimen is crucial in such patients.

Imaging of Hypersensitivity Pneumonitis

The management of hypersensitivity pneumonitis (HP) depends on early identification of the disease process, which is complicated by its nonspecific clinical presentation in addition to variable and diverse laboratory and radiologic findings. HP is the result of exposure and sensitization to myriad aerosolized antigens. HP develops in the minority of antigenic exposures, and conversely has been documented in patients with no identifiable exposure, complicating the diagnostic algorithm significantly. Prompt diagnosis and early intervention are critical in slowing the progression of irreversible parenchymal damage, and additionally in preserving the quality of life of affected patients.

A Curious Case of Inhalation Fever Caused by Synthetic Cannabinoid

BACKGROUND

This case report describes inhalation fever as an uncommon pulmonary adverse effect of synthetic cannabinoids.

CASE REPORT

A 29-year-old man was brought in for severe agitation after smoking K2, a synthetic cannabinoid. He required multiple doses of lorazepam and haloperidol for sedation. His vital signs were notable for a mild fever and tachycardia. Otherwise, the rest of his exam was unremarkable. The laboratory test was significant for leucocytosis and diffuse reticular-nodular and interstitial infiltrates on chest radiograph. Urine drug toxicology was negative. Interestingly, his symptoms and pulmonary infiltrates on the chest radiograph resolved spontaneously after 24 hours of observation.

CONCLUSIONS

This patient developed transient pulmonary infiltrates and fever following the synthetic cannabinoid inhalation, as seen in self-limiting inhalation fever. Inhalation fever as a consequence of synthetic cannabinoid has not been described previously and there is a need for further research in this field.

Imaging of small airways and emphysema

High-resolution chest computed tomography (CT) is one of the most useful techniques available for imaging bronchiolitis because it shows highly specific direct and indirect imaging signs. The distribution and combination of these various signs can further classify bronchiolitis as either cellular/inflammatory or fibrotic/constrictive. Emphysema is characterized by destruction of the airspaces, and a brief discussion of imaging findings of this class of disease is also included. Typical CT findings include destruction of airspace, attenuated vasculatures, and hyperlucent as well as hyperinflated lungs.

Toxic lung injury in a patient addicted to "legal highs" - case study

Background

Toxic lung injury may manifest itself in many different ways, ranging from respiratory tract irritation and pulmonary edema in severe cases to constrictive bronchiolitis, being a more distant consequence.

It is most often the result of accidental exposure to harmful substances at work, at home, or a consequence of industrial disaster.

Case Report

This article presents a case of toxic lung injury which occurred after inhalation of legal highs, the so-called “artificial hashish” and at first presented itself radiologically as interstitial pneumonia with pleural effusion and clinically as hypoxemic respiratory insufficiency. After treatment with high doses of steroids, it was histopathologically diagnosed as organizing pneumonia with lipid bodies.

Conclusions

Due to the lack of pathognomonic radiological images for toxic lung injury, information on possible etiology of irritants is very important. As novel psychoactive substances appeared in Europe, they should be considered as the cause of toxic lung injury.