A 38-year-old man who had been working in an automotive parts manufacturing plant for 5 years developed jaundice in the middle of January 2022.
The patient visited a local hospital on January 28, 2022. The patient's aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were very high (AST 1,140 IU/L, ALT 2,650 IU/L), gamma glutamyl transpeptidase was 215 IU/L, and total bilirubin (TB) and direct bilirubin (DB) were 9.41 mg/dL and 6.77 mg/dL, respectively. Abdominal computed tomography revealed acute hepatitis with mild hepatosplenomegaly (Fig. 1). The patient was immediately transferred to the department of gastroenterology for further evaluation and treatment.
The patient had not recently taken hepatotoxic medications such as herbal medicines, antifungal drugs, anti-tuberculosis drugs, or anti-inflammatory drugs and did not have a history of drug allergies. He had no specific familial or genetic problems and had never smoked. He drank a bottle of soju twice per week. He was diagnosed with acute hepatitis; however, the exact cause of hepatitis was not identified. The patient's general condition was tolerable; therefore, he was treated on an outpatient basis. Though he was diagnosed with acute hepatitis, he continued to work until hospitalization.
One week later, on February 4th, the patient visited the hospital for follow-up treatment. The jaundice improved and there were no other symptoms. In addition, the liver enzyme values showed a tendency to decrease (AST 662 IU/L, ALT 482 IU/L, TB 5.5 mg/dL, DB 2.7 mg/dL).
He visited the department of occupational and environmental medicine of the same hospital on February 9th. The patient reported that his condition was tolerable and jaundice and other symptoms continued to improve.
On February 15th, during an outpatient examination, the patient reported that abdominal discomfort and jaundice had recurred 4-5 days earlier. He was hospitalized in the gastroenterology department due to poor general condition and increased liver enzymes (AST 937 IU/L, ALT 409 IU/L, TB 18.8 mg/dL, DB 9.9 mg/dL). The complete blood count was normal, and coagulation factors were also normal (prothrombin time 23.3 seconds, prothrombin time/international normalized ratio 2.00, 32.7%, and activated partial thromboplastin time 41.4 seconds). Antibody tests were performed to exclude viral and autoimmune hepatitis, and the results were as follows: anti-HAV IgG (-), anti-HAV IgM (-), HBs Ag (-), anti-HCV (-), HIV Ag/Ab (-), ANA (IF) (1:320 dilution), anti-smooth muscle Ab (-), ANCA (-), AMA (-), anti-LKM Ab (-), and anti-dsDNA IgG (20.6, within normal range). Abdominal ultrasonography findings were compatible with acute hepatopathy and reactive gallbladder wall thickening. For a more accurate differentiation of acute hepatitis, elastography was performed. The mean shear wave velocity was 3.26 +- 0.24 m/s, suggesting stage 4 fibrosis (> 1.86 m/s) (Fig. 2). Although stage 4 fibrosis indicates liver cirrhosis, it was determined to be a change due to acute inflammatory findings based on the clinical correlation with other symptoms and test results. The laboratory findings during the hospitalization period are summarized in Table 1. The patient's general condition and liver function were restored after hydration and conservative treatment. He was discharged on the 8th day of hospitalization. The AST and ALT levels 20 days after discharge were 33 and 13 IU/L, respectively.
On February 9th, the patient visited the occupational and environmental medicine department for consultation regarding occupational accidents. The patient's liver function was normal during regular health check-ups conducted in May 2021. The patient worked for an automotive parts manufacturer that produced powertrain mounting products, chassis, hoses, and dampers. He had worked on coating using organic solvents on spot 10 in Fig. 3 since June 2016, and he always wore the provided personal protective equipment including respirator, gloves and apron while working. He worked two shifts. The two groups worked in shifts at weekly intervals and worked five days a week. The day shift was from 8 am to 8 pm, and the night shift was from 8 pm to 8 am the next day. His actual working time during a 12-hour shift was 10 hours 40 minutes and the remaining time was used for meals and rest (50 minutes for lunch and 30 minutes for dinner, including the time for rest). The main process consists of six parts: sanding, shotting, washing, coating, refining, and adhesive application. After washing the manufactured goods, the patient worked on the coating part. Organic solvents are mainly used in washing and coating processes. The patient reported that the residues of the washing agent used in the washing process were almost always present in the coating process. In addition, some solvents were changed a month before the onset of jaundice (December 2021). The patient showed us several material safety data sheets (MSDSs), but none of them showed hepatotoxicity. He said that the material had recently changed, but he did not see the data. He promised to bring it to the next visit, but he was hospitalized five days later.
The Ministry of Employment and Labor conducted the workplace inspections. As a result of analyzing the sample for the washing agent, it was found that it contained chloroform, which was not mentioned in the MSDS, and the content was very high (28%-38%). A time-weighted average (TWA) was used to measure the workplace environment, and 8 individual samples and 2 area samples were analyzed. The measurement time was approximately 360 minutes. They reported that the washing agent contained chloroform, and that concentrations in the workplace were up to 4.7 times the TWA when corrected (based on the Korean occupational exposure limit; 10 ppm for 8 hours TWA). However, as workers worked more than 8 hours in this case, it was necessary to calculate the corrected exposure limit according to actual working hours (7.5 ppm for 10 hours 40 minutes TWA). It has been determined to be the main cause of toxic hepatitis.
Consent for publication of this case report and any accompanying data was obtained from the study participant on July 1, 2022. This study was approved by the Institutional Review Board of Dong-A University Hospital (DAUHIRB-22-134).