Drug-Induced Liver Injury — MCQs
What is the main contraindication for performing a liver biopsy?
Acetaminophen [Paracetamol] induced liver toxicity is due to which metabolite?
Which antiepileptic drug requires regular monitoring of liver enzymes?
Which of the following statements about drug-induced SLE is NOT true?
A patient presents to the emergency department with a history of ingestion of ten tablets of paracetamol. He has developed oliguria and liver function tests show deranged values. In the context of paracetamol overdose, which of the following can be used in the management of this condition?
Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
Ulipristal acetate (progesterone receptor modulator) should not be prescribed as emergency contraceptive in women with
A female, Lalita, aged 26 years takes 100 tablets of paracetamol. Treatment of choice is:
Which of the following is the most hepatotoxic inhalational anesthetic agent?
Centrilobular fatty infiltration of the liver is commonly associated with which of the following conditions?
Drug-Induced Liver Injury Indian Medical PG Practice Questions and MCQs
Question 1: What is the main contraindication for performing a liver biopsy?
- A. Severe thrombocytopenia
- B. Liver hemangioma
- C. Presence of ascites
- D. Severe coagulopathy (Correct Answer)
Explanation: ***Severe coagulopathy*** - **Severe coagulopathy** is the main contraindication for liver biopsy due to a significantly increased risk of **hemorrhage** [1]. - A **prothrombin time (PT)** or **activated partial thromboplastin time (aPTT)** significantly prolonged beyond the normal range, or an **INR > 1.5**, should be corrected before the procedure [1]. *Severe thrombocytopenia* - While **thrombocytopenia** (platelet count <50,000/µL) does increase bleeding risk, it is often correctable with a **platelet transfusion** prior to biopsy, making it a relative rather than an absolute contraindication [1]. - The risk of major bleeding is typically lower with isolated thrombocytopenia compared to severe coagulopathy. *Liver hemangioma* - The presence of a **liver hemangioma** at the biopsy site is a contraindication as biopsying it can lead to massive hemorrhage. - However, if the biopsy can be performed safely away from the hemangioma, it is not an absolute contraindication to the procedure itself. *Presence of ascites* - **Ascites** can complicate a liver biopsy by increasing the risk of **peritoneal bleeding** and difficulty in targeting the liver [1]. - However, it is often manageable by draining the ascites or using imaging guidance, making it a relative contraindication rather than an absolute one [1].
Question 2: Acetaminophen [Paracetamol] induced liver toxicity is due to which metabolite?
- A. Co-Q
- B. Cytochrome 'C'
- C. NAPQI (Correct Answer)
- D. N-acetylcysteine
Explanation: ***NAPQI*** - **N-acetyl-p-benzoquinone imine (NAPQI)** is a highly reactive and toxic metabolite produced during acetaminophen metabolism, especially in overdose situations [1, 3]. - When glutathione stores are depleted due to excessive NAPQI formation, this metabolite covalently binds to hepatic macromolecules, causing **hepatocellular damage and necrosis** [1, 3].*N-acetylcysteine* - **N-acetylcysteine (NAC)** is the antidote for acetaminophen overdose, not the toxic metabolite itself [2, 3]. - NAC works by replenishing hepatic **glutathione stores**, which helps detoxify NAPQI and prevent liver injury [2, 3].*Co-Q* - **Coenzyme Q10 (CoQ10)** is an endogenous antioxidant and electron carrier in the mitochondrial respiratory chain. - It is not a metabolite of acetaminophen and plays no direct role in acetaminophen-induced liver toxicity.*Cytochrome 'C'* - **Cytochrome c** is a protein involved in the electron transport chain in mitochondria and plays a critical role in apoptosis. - While cellular damage from NAPQI can eventually lead to cytochrome c release and apoptosis, cytochrome c itself is not a metabolite of acetaminophen or the direct cause of toxicity.
Question 3: Which antiepileptic drug requires regular monitoring of liver enzymes?
- A. Valproate (Correct Answer)
- B. Levetiracetam
- C. Lamotrigine
- D. Phenytoin
Explanation: ***Valproate*** - **Valproate** is known to cause dose-related **hepatotoxicity**, ranging from asymptomatic enzyme elevation to fatal hepatic failure, especially in young children and those on polytherapy. - Regular monitoring of **liver function tests (LFTs)** is crucial to detect early signs of liver injury and adjust treatment. *Levetiracetam* - **Levetiracetam** is generally well-tolerated and does not typically require routine monitoring of liver enzymes due to its primary renal excretion and low potential for hepatotoxicity. - While mild, transient elevations in LFTs can occur, they are usually not clinically significant. *Lamotrigine* - **Lamotrigine** is primarily known for causing serious **skin rashes** (e.g., Stevens-Johnson syndrome) rather than significant hepatotoxicity. - Routine liver enzyme monitoring is generally not recommended unless there are other risk factors for hepatic dysfunction. *Phenytoin* - Although **phenytoin** can cause idiosyncratic liver injury, it is not as consistently associated with dose-related hepatotoxicity as valproate. - Monitoring of **phenytoin levels** is crucial [1], but routine liver enzyme monitoring is not typically mandated as strictly as for valproate.
Question 4: Which of the following statements about drug-induced SLE is NOT true?
- A. Female: Male ratio=1:9 (Correct Answer)
- B. CNS involvement not common
- C. Renal involvement not common
- D. Anti-histone antibodies are negative
Explanation: ***Female: Male ratio=1:9*** - Drug-induced lupus erythematosus (DILE) typically has no significant **gender predilection**, unlike idiopathic SLE which has a marked female predominance (9:1 female: male ratio) [1]. - This statement is incorrect because the male:female ratio is closer to 1:1, or even male predominance, making the given ratio of 1:9 (female:male) false. *Anti-histone antibodies are negative* - **Anti-histone antibodies** are positive in 95% of patients with drug-induced lupus, making this statement incorrect. - The presence of anti-histone antibodies is a hallmark diagnostic feature of drug-induced lupus. *CNS involvement not common* - **Central nervous system (CNS) manifestations** are indeed uncommon in drug-induced lupus erythematosus. - This statement accurately reflects a key differentiating feature from idiopathic systemic lupus erythematosus (SLE), where CNS involvement can be significant [1]. *Renal involvement not common* - **Renal involvement** is rare in drug-induced lupus erythematosus. - This statement is true and helps distinguish drug-induced lupus from idiopathic SLE, where renal disease (lupus nephritis) is a frequent and serious complication [1].
Question 5: A patient presents to the emergency department with a history of ingestion of ten tablets of paracetamol. He has developed oliguria and liver function tests show deranged values. In the context of paracetamol overdose, which of the following can be used in the management of this condition?
- A. N-acetylcysteine (Correct Answer)
- B. Dopamine
- C. Ursodeoxycholic acid
- D. Furosemide
Explanation: **Correct: N-acetylcysteine** - **N-acetylcysteine (NAC)** is the specific antidote for **paracetamol overdose**, working by replenishing **glutathione** stores in the liver. - Replenishing **glutathione** helps detoxify the toxic metabolite **N-acetyl-p-benzoquinone imine (NAPQI)**, preventing further **hepatic damage** and facilitating recovery in cases of **liver failure** and potential **renal damage** (oliguria). - Most effective when given within **8 hours** of ingestion, but remains beneficial even with **established hepatotoxicity** (as in this case with deranged LFTs). *Incorrect: Dopamine* - **Dopamine** is a **vasopressor** primarily used to increase **blood pressure** and **cardiac output** in conditions like **shock**. - While it might be used to support circulation in severe overdose complications, it does not directly treat the **paracetamol toxicity** itself. *Incorrect: Ursodeoxycholic acid* - **Ursodeoxycholic acid (UDCA)** is a **cholagogue** used in the management of **cholestatic liver diseases** (e.g., primary biliary cholangitis) by improving bile flow. - It has no role in the direct management of **acute liver failure** due to **paracetamol overdose**. *Incorrect: Furosemide* - **Furosemide** is a **loop diuretic** used to increase **urine output** in conditions like **fluid overload** or **heart failure**. - While **oliguria** is present, it is often a sign of **acute kidney injury** requiring supportive care, and furosemide would not address the underlying **toxic mechanism** of paracetamol.
Question 6: Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
- A. A-1, B-3, C-2, D-4
- B. A-4, B-1, C-3, D-2 (Correct Answer)
- C. A-3, B-2, C-4, D-1
- D. A-2, B-4, C-1, D-3
Explanation: ***A-4, B-1, C-3, D-2*** - **Morphine** is contraindicated in **head injury** as it can increase intracranial pressure and mask neurological symptoms. - **Amiodarone** is contraindicated in patients with **QT prolongation** due to its risk of inducing more severe arrhythmias like Torsades de Pointes. - **Vigabatrin** is contraindicated during **pregnancy** due to its potential for teratogenicity and adverse effects on fetal development. - **Estrogen preparations** are contraindicated in patients with a history of **thromboembolism** due to their increased risk of blood clot formation. *A-1, B-3, C-2, D-4* - This option incorrectly matches **Morphine** with QT prolongation and **Estrogen preparations** with head injury, which are not their primary contraindications. - It also incorrectly links **Vigabatrin** with thromboembolism and **Amiodarone** with pregnancy. *A-3, B-2, C-4, D-1* - This choice incorrectly associates **Morphine** with pregnancy and **Vigabatrin** with head injury, which are not the most critical or direct contraindications. - It also misaligns **Amiodarone** with thromboembolism and **Estrogen preparations** with QT prolongation. *A-2, B-4, C-1, D-3* - This option incorrectly matches **Morphine** with thromboembolism and **Amiodarone** with head injury, which are not their most significant contraindications. - It also incorrectly links **Vigabatrin** with QT prolongation and **Estrogen preparations** with pregnancy.
Question 7: Ulipristal acetate (progesterone receptor modulator) should not be prescribed as emergency contraceptive in women with
- A. liver dysfunction (Correct Answer)
- B. glaucoma
- C. coagulopathy
- D. kidney failure
Explanation: ***Correct: liver dysfunction*** - **Ulipristal acetate** is extensively metabolized in the **liver** by the CYP450 enzyme system, predominantly CYP3A4. - In individuals with **severe hepatic impairment**, the metabolism of ulipristal acetate can be impaired, leading to increased plasma concentrations and potential adverse effects. - **Severe liver dysfunction** is a documented contraindication in product labeling. *Incorrect: glaucoma* - There is **no known contraindication** for ulipristal acetate use in individuals with **glaucoma**. - Its mechanism of action primarily involves progesterone receptors and does not directly impact intraocular pressure. *Incorrect: coagulopathy* - Ulipristal acetate does **not significantly affect blood coagulation** parameters or platelet function. - It is not contraindicated in individuals with **coagulopathy**, unlike some estrogen-containing contraceptives. *Incorrect: kidney failure* - While urinary excretion of ulipristal acetate metabolites occurs, the **primary elimination pathway is fecal** (approximately 90%). - **Kidney failure** is not considered a contraindication, and dose adjustments are generally not required.
Question 8: A female, Lalita, aged 26 years takes 100 tablets of paracetamol. Treatment of choice is:
- A. Lavage with charcoal
- B. Dialysis
- C. Alkaline diuresis
- D. Acetylcysteine (Correct Answer)
Explanation: ***Acetylcysteine*** - **Acetylcysteine** is the **antidote of choice** for paracetamol (acetaminophen) overdose, replenishing **glutathione stores** and detoxifying toxic paracetamol metabolites. - Early administration (within 8 hours of ingestion) is crucial for preventing **hepatic damage**, as it inhibits the binding of the toxic metabolite **NAPQI** to liver proteins. *Lavage with charcoal* - **Gastric lavage** and **activated charcoal** are primarily used for **decontamination** in the early stages (within 1-2 hours) of acute overdose, to prevent absorption. - Given the ingestion of **100 tablets**, a significant amount of paracetamol has likely already been absorbed, making these less effective as the sole treatment. *Dialysis* - **Dialysis** is generally reserved for severe cases of paracetamol overdose complicated by **acute liver failure** or other severe organ dysfunction, which requires elimination of paracetamol and its metabolites from the blood. - It is not the **first-line treatment** for acute paracetamol overdose itself, but rather a supportive measure for complications. *Alkaline diuresis* - **Alkaline diuresis** is sometimes used to enhance the elimination of **acidic drugs** like salicylates (aspirin) from the body. - Paracetamol is primarily metabolized by the liver into glucuronide and sulfate conjugates, which are then excreted, and its elimination is not significantly enhanced by **alkaline diuresis**.
Question 9: Which of the following is the most hepatotoxic inhalational anesthetic agent?
- A. Halothane (Correct Answer)
- B. Sevoflurane
- C. Desflurane
- D. Enflurane
Explanation: ***Halothane*** - **Halothane hepatitis** is a rare but potentially fatal complication characterized by severe liver damage, especially after repeated exposure. - The mechanism involves the formation of **trifluoroacetylated liver proteins** acting as neoantigens, triggering an immune-mediated hepatotoxic reaction. *Sevoflurane* - **Sevoflurane** is generally considered to have a very low risk of hepatotoxicity. - It is known for its **rapid tissue uptake and elimination**, and its metabolism does not produce significant hepatotoxic intermediates. *Desflurane* - **Desflurane** is also considered to have a very low risk of hepatotoxicity, similar to sevoflurane. - It undergoes **minimal hepatic metabolism**, with most of the drug being eliminated unchanged through pulmonary excretion. *Enflurane* - While enflurane has been associated with a slightly higher incidence of hepatic dysfunction compared to newer agents, it is **less hepatotoxic than halothane** and primarily linked to renal toxicity. - Its metabolism produces **fluoride ions**, which were a concern for renal toxicity, rather than severe immune-mediated hepatitis.
Question 10: Centrilobular fatty infiltration of the liver is commonly associated with which of the following conditions?
- A. Malnutrition
- B. Tetracycline
- C. Viral hepatitis
- D. Alcoholism (Correct Answer)
Explanation: ***Viral hepatitis*** - Periportal fatty infiltration is commonly associated with **viral hepatitis**, showing characteristic findings in liver histology [1]. - This condition is linked with **increased hepatocellular damage** and inflammation, contributing to fat accumulation around portal areas. *Tetracycline* - Tetracycline typically causes **hepatotoxicity**, but it does not lead to **periportal fatty changes** specifically. - Adverse effects might include **cholestasis** rather than the fatty infiltration seen with viral infections. *Alcoholism (may cause diffuse fatty liver but not specifically periportal changes)* - Alcoholism mainly results in **diffuse fatty liver** (steatosis) rather than localized periportal changes [1]. - It produces a characteristic **macrovesicular steatosis** throughout the liver rather than sparing the portal areas. *Malnutrition (can cause fatty liver with periportal changes in severe cases)* - Malnutrition can lead to fatty liver, but the changes are typically more **diffuse** and less specifically **periportal**. - While severe malnutrition can show fatty infiltrates, it is not as commonly associated with the **periportal pattern** seen in viral hepatitis. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 388-389.
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