Acute liver failure associated with occupational exposure to tetrachloroethylene

Oxidative stress and pro-inflammatory cytokines following perchloroethylene exposure in young female dry-cleaning workers

BACKGROUND

The involvement of Perchloroethylene (PCE) in the development of autoimmune diseases has been reported. However, few studies investigated immunotoxicity in PCE-exposed workers.

OBJECTIVE

To study changes in the oxidative stress and cytokine profile of young female dry-cleaning workers exposed to PCE.

METHODS

Thirty-eight exposed workers and 38 unexposed controls were recruited. All the participants were young nonsmoker females. Individual interviews were conducted by a physician. Blood samples were collected and hematological tests were performed by an automated Coulter Counter. Plasma PCE levels were determined using gas chromatography/flame ionization detection. Plasma total antioxidant capacity (TAC), Catalase (CAT), Superoxide dismutase (SOD), and Malondialdehyde (MDA) levels were measured using the colorimetric method. The levels of plasma cytokines interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-8, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) were measured by commercially kits.

RESULTS

The levels of plasma PCE averaged 561±96 ng/ml in the exposed group compared with 1.3±0.5 ng/ml in the controls. The hematological tests failed to find abnormalities in the exposed workers. Exposed workers presented significantly increased plasma levels of MDA, SOD and CAT. There were no significant differences between the two groups for level of plasma TAC. Significantly increased plasma IL-1β and TNF-α and decreased IL-2 and IL-8 levels were seen in the exposed workers. There were no significant differences between the two groups for IL-4, IL-6, and IFN-γ.

CONCLUSION

PCE exposure resulted in changed cytokine profile in dry-cleaning workers, suggesting the potential immunotoxicity of PCE at low exposure levels.

Acute perchloroethylene intoxication in an elderly woman: a case report

BACKGROUND

Perchloroethylene is a colorless, strong-smelling substance commonly used for dry cleaning. Liver and kidney toxicities and carcinogenicity are well-known occupational hazards caused by chronic perchloroethylene exposure. Acute intoxication by ingestion of nondiluted perchloroethylene is rare in the adult population owing to its strong smell and taste. Very few data are available to physicians managing patients in this situation.

CASE PRESENTATION

An 89-year-old Caucasian woman accidentally drank perchloroethylene while visiting her laundry, leading to a coma within a few minutes. The poison control center provided little information about perchloroethylene toxicity after ingestion, including an estimated long biological half-life (144 hour) and detrimental effects to liver and kidneys. A long intensive care unit stay was thus expected, potentially leading to several complications. After intubation, transitory hypoxemia appeared and rapidly resolved, while mild hemodynamic instability was managed with fluid resuscitation and anti-arrhythmic drugs. Twelve hours after perchloroethylene ingestion, the patient suddenly woke up and self-extubated. Less than 24 hours after ingestion, she was discharged from the intensive care unit, and 4 days later she was discharged home.

CONCLUSION

The patient drank perchloroethylene from a bottle, which prevented her from smelling it, and owing to its taste, only a small sip was likely drunk. However, a much larger intake was presumed, given her rapid and profound central nervous system depression. This case was challenging owing to the paucity of information available regarding acute perchloroethylene ingestion and the duration and magnitude of its effect. The present report will hopefully be of support for clinicians managing patients with this rare acute intoxication.

Therapeutic plasma exchange in liver failure

The multi-organ failure syndrome associated with acute and acute-on-chronic liver failure (ACLF) is thought to be mediated by overwhelming systemic inflammation triggered by both microbial and non-microbial factors. Therapeutic plasma exchange (TPE) has been proven to be an efficacious therapy in autoimmune conditions and altered immunity, with more recent data supporting its use in the management of liver failure. Few therapies have been shown to improve survival in critically ill patients with liver failure who are not expected to survive until liver transplantation (LT), who are ineligible for LT or who have no access to LT. TPE has been shown to reduce the levels of inflammatory cytokines, modulate adaptive immunity with the potential to lessen the susceptibility to infections, and reduce the levels of albumin-bound and water-bound toxins in liver failure. In patients with acute liver failure, high volume TPE has been shown to reduce the vasopressor requirement and improve survival, particularly in patients not eligible for LT. Standard volume TPE has also been shown to reduce mortality in certain sub-populations of patients with ACLF. TPE may be most favorably employed as a bridge to LT in patients with ACLF. In this review, we discuss the efficacy and technical considerations of TPE in both acute and acute-on-chronic liver failure.

Exposure to organic solvents and hepatotoxicity

The purpose of this study was to identify the long-term effect of chemical exposure on the liver. Laboratory tests included alanine aminotransferase (ALT) dosage and oxidative stress tests, such as thiobarbituric acid reactive substances in plasma and superoxide dismutase (SOD) and glutathione S-transferase analysis in erythrocytes. The cross-sectional study comprised 70 workers, 30 of them exposed to organic solvents and 40 not exposed. All those exposed presented at least 5 years of exposure to solvents. Hepatitis B and C, known hepatic disease, comorbidities, use of alcohol, illicit drugs or hepatotoxic medications, smoking, body mass index >30, female sex and age (<18 or >65) were excluded from the sample. Results indicated that elevated ALT was more frequent in the exposed group compared to controls: 33% vs. 10.5%, with a statistical significance (p < 0.05). Thiobarbituric acid reactive substances were significantly elevated (p < 0.01) in the exposed group in comparison to controls. Antioxidant enzymes were more elevated in the exposed group compared to controls: SOD 7.29 (4.30-8.91) USOD/mg of protein vs. 3.48 (2.98-5.28) USOD/mg of protein and GST 2.57 µmol/min/mg of protein (1.80-4.78) vs. 1.81 µmol/min/mg of protein (1.45- 2.30) µM/min/mg of protein. The results suggest an association between exposure to organic solvents and hepatotoxicity.

Plasma exchange in patients with acute and acute-on-chronic liver failure: A systematic review

BACKGROUND

Acute liver failure (ALF) and acute-on-chronic liver (ACLF) carry high short-term mortality rate, and may result from a wide variety of causes. Plasma exchange has been shown in a randomized control trial to improve survival in ALF especially in patients who did not receive a liver transplant. Other cohort studies demonstrated potential improvement in survival in patients with ACLF.

AIM

To assess utility of plasma exchange in liver failure and its effect on mortality in patients who do not undergo liver transplantation.

METHODS

Databases MEDLINE via PubMed, and EMBASE were searched and relevant publications up to 30 March, 2019 were assessed. Studies were included if they involved human participants diagnosed with liver failure who underwent plasma exchange, with or without another alternative non-bioartificial liver assist device.

RESULTS

Three hundred twenty four records were reviewed, of which 62 studies were found to be duplicates. Of the 262 records screened, 211 studies were excluded. Fifty-one articles were assessed for eligibility, for which 7 were excluded. Twenty-nine studies were included for ALF only, and 9 studies for ACLF only. Six studies included both ALF and ACLF patients. A total of 44 publications were included. Of the included publications, 2 were randomized controlled trials, 14 cohort studies, 12 case series, 16 case reports. All of three ALF studies which looked at survival rate or survival days reported improvement in outcome with plasma exchange. In two out of four studies where plasma exchange-based liver support systems were compared to standard medical treatment (SMT) for ACLF, a biochemical improvement was seen. Survival in the non-transplanted patients was improved in all four studies in patients with ACLF comparing plasma exchange vs SMT. Using the aforementioned studies, plasma exchange based therapy in ACLF compared to SMT improved survival in non-transplanted patients at 30 and 90-d with a pooled OR of 0.60 (95%CI 0.46-0.77, P < 0.01).

CONCLUSION

The level of evidence for use of high volume plasma exchange in selected ALF cases is high. Plasma exchange in ACLF improves survival at 30-and 90-d in non-transplanted patients. Further well-designed randomized control trials will need to be carried out to ascertain the optimal duration and amount of plasma exchange required and assess if the use of high volume plasma exchange can be extrapolated to patients with ACLF.

Aliphatic Halogenated Hydrocarbons: Report and Analysis of Liver Injury in 60 Patients

Background and Aims: Intoxications by aliphatic halogenated hydrocarbons (AHH), used as effective solvents, are rare and may cause life-threatening liver injury. Patients with acute intoxications by AHH received an innovative treatment. Methods: Analyzed were data of 60 patients intoxicated by AHH, such as dichloromethane (n = 3), chloroform (n = 2), carbon tetrachloride (n = 12), 1,2-dichloroethane (n = 18), 1,1,2-trichloroethane (n = 2), trichloroethylene (n = 2), tetrachloroethylene (n = 13) or mixed AHH chemicals (n = 8), who received a new treatment consisting of CO₂-induced hyperventilation to accelerate toxin removal via the lungs. Results: Added to the inspiration air at a flow rate of 2-3 Liter min^-1, CO₂ increased the respiratory volume up to 25-30 Liter min^-1, ensuring forced AHH exhalation. This CO₂-induced hyperventilation therapy was commonly well tolerated by the 60 patients and lasted for 106.0±10.5 hours. In most cases, initially increased liver test results of aminotransferases normalized quickly under the therapy, and liver histology obtained at completion of the therapy revealed, in the majority of patients, normal findings or fatty changes, and rarely severe single cell necrosis but no confluent liver cell necrosis. Despite therapy, clinical outcome was unfavorable for 4/60 patients (6.7%) of the study cohort, due to single or combined risk factors. These included late initiation of the CO₂-induced hyperventilation therapy, intentional intoxication, uptake of high amounts of AHH, concomitant ingestion of overdosed drugs, consumption of high amounts of alcohol, and history of alcohol abuse. Conclusions: For intoxications by AHH, effective therapy approaches including forced hyperventilation to increase toxin removal via the lungs are available and require prompt initiation.

Systematic review: non A-E, seronegative or indeterminate hepatitis; what is this deadly disease?

BACKGROUND

A significant proportion of cases of acute liver failure (ALF) do not have an identifiable cause; so called "non A-E," "non A, non B, non C," "seronegative" or "indeterminate" hepatitis. However, this entity is clinically not well described.

AIM

To collate the known incidence and outcomes in indeterminate hepatitis. This systematic review sought to identify potential aetiologies that ought to be considered, and identify likely future objectives in classification and treatment strategies for indeterminate hepatitis.

METHODS

Literature review to determine aetiological factors, prevalence and outcomes relating to indeterminate hepatitis.

RESULTS

There is significant heterogeneity within the reported cases of indeterminate hepatitis in the literature. Some of the potential infective aetiologies which are reviewed here include: parvovirus B19 (PVB19), herpes simplex virus (HSV), Toga-Like Virus and the Annelloviridae (including SEN-V). Interestingly, this condition predominately affects middle aged women, with subacute progression of the liver failure. In addition, the prognosis of indeterminate hepatitis is poor, with reduced spontaneous survival compared with other causes of acute liver failure and increased need for emergency liver transplantation.

CONCLUSIONS

Whilst various pathological processes have been implicated in the development of indeterminate hepatitis, the specific cause remains elusive. There is an urgent need for general consensus on a specific definition and exclusion of confounding aetiologies with coordinated multicentre investigation of this rare condition to identify aetiology and develop therapies to reduce the significant mortality and need for emergency liver transplantation associated with this condition.

Risk of hepatocellular carcinoma in workers exposed to chemicals

CONTEXT

Studies on experimental animals have shown liver is a common target of chemical carcinogens; this might suggest that occupational exposure to chemicals is another risk factor for HCC. However, the relationship between occupation and liver cancer has not been extensively studied, with the exception of the known association between vinyl chloride and angiosarcoma of the liver.

EVIDENCE ACQUISITION

A MEDLINE and conventional search of the past 50 years of the medical literature was performed to identify relevant articles on incidence and mechanisms of HCC due to occupational exposure to chemicals. Several important edited books and monographs were also identified and reviewed.

RESULTS

While laboratory data clearly indicate that the liver is an important target of chemical carcinogenesis, epidemiological studies provide very limited evidence on occupational risk factors for HCC. Nevertheless, we found some case reports and epidemiological data showing a moderately increased risk of HCC development in people exposed to vinyl chloride, organic solvents, pesticides, polychlorinated biphenyls, and arsenic.

CONCLUSIONS

Occupational exposure to chemicals may be another risk factor for HCC development, but the interpretation of currently available findings is limited by the small number of studies, questionable accuracy of the diagnosis of liver cancer, and potential confounding or modifying factors such as chronic hepatitis virus infection and alcohol consumption. Further relevant investigations are required for clarifying the actual contribution of occupational exposure to chemicals in HCC development.

Changes of serum biochemical parameters and liver pathology in 18 patients with 1,1,2,2-tetrachloroethane-induced hepatotoxicity

OBJECTIVE

To evaluate the changes of serum biochemical parameters and liver pathology in patients with 1,1,2,2-tetrachloroethane (TTCE)-induced hepatotoxicity.

METHODS

A total of 18 patients were diagnosed as TTCE-induced hepatotoxicity with an incubation period of 11-56 days. Blood samples were obtained from all patients and liver biopsy was performed in 16.

RESULTS

All patients had fatigue, poor appetite and dark urine, 15 of whom suffered nausea, vomiting, abdominal distension and other gastrointestinal disorders. All patients had various degrees of liver function damage, and one died from liver failure. The prothrombin time was significantly prolonged in 6 patients. Histological findings showed varying degrees of necrosis, fatty degeneration and fibrosis in portal areas without cirrhosis. Patients with more severe jaundice had more severe pathologic changes, including piecemeal and bridge necrosis, and cholestasis.

CONCLUSIONS

TTCE-induced hepatotoxicity may cause the changes in serum biochemical parameters and liver pathology. Most patients might recover with regular treatment. Prevention and early diagnosis of TTCE-induced hepatotoxicity are necessary.