Hepatotoxicity With Elevated Bilirubin Secondary to Prophylactic Doses of Unfractionated Heparin: A Case Report and Review of Heparin-Induced Hepatotoxicity

Molecular Idiosyncratic Toxicology of Drugs in the Human Liver Compared with Animals: Basic Considerations

Drug induced liver injury (DILI) occurs in patients exposed to drugs at recommended doses that leads to idiosyncratic DILI and provides an excellent human model with well described clinical features, liver injury pattern, and diagnostic criteria, based on patients assessed for causality using RUCAM (Roussel Uclaf Causality Assessment Method) as original method of 1993 or its update of 2016. Overall, 81,856 RUCAM based DILI cases have been published until mid of 2020, allowing now for an analysis of mechanistic issues of the disease. From selected DILI cases with verified diagnosis by using RUCAM, direct evidence was provided for the involvement of the innate and adapted immune system as well as genetic HLA (Human Leucocyte Antigen) genotypes. Direct evidence for a role of hepatic immune systems was substantiated by (1) the detection of anti-CYP (Cytochrome P450) isoforms in the plasma of affected patients, in line with the observation that 65% of the drugs most implicated in DILI are metabolized by a range of CYP isoforms, (2) the DIAIH (drug induced autoimmune hepatitis), a subgroup of idiosyncratic DILI, which is characterized by high RUCAM causality gradings and the detection of plasma antibodies such as positive serum anti-nuclear antibodies (ANA) and anti-smooth muscle antibodies (ASMA), rarely also anti-mitochondrial antibodies (AMA), (3) the effective treatment with glucocorticoids in part of an unselected RUCAM based DILI group, and (4) its rare association with the immune-triggered Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) caused by a small group of drugs. Direct evidence of a genetic basis of idiosyncratic DILI was shown by the association of several HLA genotypes for DILI caused by selected drugs. Finally, animal models of idiosyncratic DILI mimicking human immune and genetic features are not available and further search likely will be unsuccessful. In essence and based on cases of DILI with verified diagnosis using RUCAM for causality evaluation, there is now substantial direct evidence that immune mechanisms and genetics can account for idiosyncratic DILI by many but not all implicated drugs, which may help understand the mechanistic background of the disease and contribute to new approaches of therapy and prevention.

Liver toxicity of intravenous heparin treatment in patients with acute ischemic stroke

OBJECTIVE

Serum alanine aminotransferase (ALT), which is an indicator of liver dysfunction, may increase during treatment in patients in the acute phase of stroke. However, the cause of the ALT elevation is unclear, as multiple medications are often being used. We investigated the relationship between medications used in acute ischemic stroke, including cerebral infarction and transient ischemic attack, and ALT elevation.

METHODS

The subjects were 230 patients who had been diagnosed with cerebral infarction or TIA and treated at the Stroke Care Unit of Fukuoka University Hospital. We investigated ALT abnormalities that occurred from the start of the treatment over the subsequent 14 days. We also followed patients for an additional seven days to confirm the peak ALT levels. A binomial logistic regression analysis was performed to evaluate the association between medications used during the period and ALT elevation.

RESULTS

The incidence of ALT abnormality was 23.9% (55/230). ALT elevation was mostly mild and peaked within 21 days of treatment initiation in 93.2% of the patients, excluding indeterminate patients. A binary logistic regression analysis showed that unfractionated heparin (odds ratio [OR] 2.759, 95% confidence interval [CI] 1.328-5.729, p = 0.007) was extracted as a cause of ALT elevation. In a receiver operating characteristic (ROC) analysis for the administration period of unfractionated heparin, the cut-off value (area under the ROC curve) for ALT elevation was 6 days (0.575). Significant factors contributing to ALT elevation caused by unfractionated heparin included an unfractionated heparin administration period of ≥ 6 days (OR 2.951, 95% CI 1.244-7.000, p = 0.014) and edaravone combination (OR 2.594, 95% CI 1.159-5.808, p = 0.021).

CONCLUSION

In the acute phase of stroke, we believe that unfractionated heparin discontinuation is not necessary when hepatotoxicity of unfractionated heparin is suspected. However, physicians should be aware of the risk of liver toxicity when unfractionated heparin is administered for more than six days or when edaravone is used in combination.

Hepatotoxicity with cholestatic pattern secondary to enoxaparin treatment

Objectives

Treatment with low-molecular-weight heparins is very common in clinical practice. Exceptionally, some patients develop hepatitis within a few days of starting treatment, and rapid discontinuation of the drug is decisive to avoid chronification.

Case presentation

These episodes usually present themselves only with elevated transaminases. We describe the case of a patient who presented a cholestatic pattern, which is very uncommon with this type of drug.

Conclusions

Hepatitis secondary to heparin therapy is an underdiagnosed entity. The laboratory plays a fundamental role in its diagnosis, given that it initially presents itself without a clear clinical profile.