Chapter 18 – Drug- and Toxin-Induced Liver Disease Flashcards
What accounts for about 10% of adverse
drug reactions, and is the most common cause of fulminant hepatitis in the United States .
Drug-induced liver injury
The liver is subject to potential damage from an enormous array of pharmaceutical and
environmental chemicals. [39]
The incidence of liver injury induced by prescribed drugs is estimated to be between 14 and 40 per
100,000 patients.
What is the critical factor that influences the susceptibility to drug induced injury?
- (1) from direct toxicity to hepatocytes or biliary epithelial cells, causing necrosis, apoptosis, or disruption of cellular function;
- (2) through hepatic conversion of a xenobiotic to an active toxin; or
- (3) through immune mechanisms, usually by a drug or a metabolite acting as a hapten to convert a cellular protein into an immunogen
Drug reactions may either be what?
- predictable (intrinsic) or
- unpredictable (idiosyncratic).
What is a predictable drug reactions?
Predictable drug reactions can occur in anyone who receives a sufficient dose of an agent.
What is unpredictable drug reaction
Unpredictable reactions depend on idiosyncracies of the host, particularly the rate at which the
host metabolizes the agent, and the intensity of the immune response.
Idiosyncratic drug
reaction should be considered in any patient receiving what kind of drug?
a therapeutic drug who develops
evidence of liver damage.
Which age group is Idiosyncratic drug
reaction more susceptible?
Generally, adults are more susceptible than children, and women are
affected more than men.
Important examples include chlorpromazine, an agent that causes cholestasis in patients who are slow to metabolize it to an innocuous byproduct, and halothane, which can cause a fatal immune-mediated hepatitis in some patients who are exposed to this
anesthetic on multiple occasions.
What is the course of development in Drug- and Toxin-Induced Liver Disease?
It should be noted that the injury may be immediate or may take weeks to months to develop, presenting only after severe liver damage has developed. It may take the form of hepatocyte necrosis, cholestasis, or insidious onset of liver dysfunction.
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Pattern of
Injury
- Cholestatic
- Cholestatic hepatitis
- Hepatocellular necrosis
- Steatosis
- Steatohepatitis
- Fibrosis and cirrhosis
- Granulomas
- Vascular lesions
- Neoplasms
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Cholestatic
Morphologic Findings
Bland hepatocellular cholestasis, without inflammation
Examples of Associated Agents
- Contraceptive and anabolic steroids;
- estrogen replacement therapy
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Cholestatic
hepatitis
Morphologic Findings
- Cholestasis with lobular necroinflammatory activity;
- may show bile duct destruction
Examples of Associated Agents
- Numerous antibiotics;
- phenothiazines
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Hepatocellular
necrosis
Morphologic Findings
Spotty hepatocyte necrosis
Examples of Associated Agents
- Methyldopa,
- phenytoin
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Hepatocellular
necrosis
Morphologic Findings
- Submassive necrosis,
- zone 3
Examples of Associated Agents
- Acetaminophen,
- halothane
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Hepatocellular
necrosis
Morphologic Findings
Massive necrosis
Examples of Associated Agents
Isoniazid,
phenytoin
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Steatosis
Morphologic Findings
Macrovesicular
Examples of Associated Agents
- Ethanol,
- methotrexate,
- corticosteroids,
- total parenteral nutrition
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Steatohepatitis
Morphologic Findings
Microvesicular, Mallory bodies
Examples of Associated Agents
- Amiodarone,
- ethanol
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Fibrosis and
cirrhosis
Morphologic Findings
Periportal and pericellular fibrosis
Examples of Associated Agents
- Methotrexate,
- isoniazid,
- enalapril
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Granulomas
Morphologic Findings
Noncaseating epithelioid granulomas
Examples of Associated Agents
- Sulfonamides,
- numerous other agents
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Vascular
lesions
Morphologic Findings
- Sinusoidal obstruction syndrome (venoocclusive disease):
- obliteration of central
Examples of Associated Agents
- High-dose chemotherapy,
- bush teas
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Vascular
lesions
Morphologic Findings
Budd-Chiari syndromel
Examples of Associated Agents
Oral contraceptives
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Vascular
lesions
Morphologic Findings
Sinusoidal dilatation
Examples of Associated Agents
Oral contraceptives, numerous
other agents
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Vascular
lesions
Morphologic Findings
Peliosis hepatis: blood-filled cavities, not lined
by endothelial cells
Examples of Associated Agents
Anabolic steroids, tamoxifen
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Neoplasms
Morphologic Findings
Hepatic adenoma
Examples of Associated Agents
Oral contraceptives, anabolic
steroids
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Neoplasms
Morphologic Findings
Hepatocellular carcinoma
Examples of Associated Agents
Thorotrast
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Neoplasms
Morphologic Findings
Cholangiocarcinoma
Examples of Associated Agents
Thorotrast
TABLE 18-5 – Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury
Neoplasms
Morphologic Findings
Angiosarcoma
Examples of Associated Agents
Thorotrast, vinyl chloride
Among the agents listed in Patterns of Injury in Drug- and Toxin-Induced Hepatic Injury hepatic injury is considered predictable with overdoses
of what?
- acetaminophen,
- exposure to Amanita phalloides toxin,
- carbon tetrachloride, and,
- to a certain extent, alcohol.
What plays a major role in individual susceptibility to even “predictable” hepatotoxins?
However, individual genetic differences in the hepatic metabolism of xenobiotics through activating and detoxification pathways play a major role in individual susceptibility to even “predictable” hepatotoxins.
Many other xenobiotics, such as sulfonamides, α-methyldopa, and allopurinol, cause idiosyncratic reactions.
What is the leading cause of drug-induced acute liver failure the ?
acetaminophen
The most common prescription drugs causing idiosyncratic injury (that is, drug toxicity unrelated to drug
dosage) include what?
- antibiotics and, in particular,
- isonazid,
- nonsteroidal analgesics, and
- anti-seizure medications.
How does Idiosyncratic reactions evolve?
with a subacute course and are usually characterized by high bilirubin levels.
What can be responsible for both
predictable and idiosyncratic liver damage.
Herbal preparations
What is Reye syndrome?
Reye syndrome, a rare and potentially fatal
syndrome of mitochondrial dysfunction in liver, brain, and elsewhere, occurs predominantly in
childrenand ischaracterized morphologicallybyextensive accumulation of fat droplets within
hepatocytes (microvesicular steatosis).
How does Reye syndrome developed?
Its development has been associated with the
administration of acetylsalicylic acid (aspirin) for the relief of fever, but a causal relationship
between aspirin and Reye syndrome has not been established.
Nevertheless, aspirin should be
avoided in children with febrile illness.