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PA24.1-9 | Hepatobiliary System — PBL Case

CLINICAL SETTING

Preethi, a 22-year-old final-year engineering student from Chennai, is brought to a government medical college casualty by her hostel warden. She has been jaundiced for ten days, has been vomiting repeatedly for three days, and this afternoon became confused and could not recognise her roommate. She is not known to have any prior liver disease, does not drink alcohol, and has no family history of liver disease. Two months ago, she was started on anti-tuberculosis treatment (isoniazid, rifampicin, pyrazinamide, ethambutol) at a nearby DOTS centre for pulmonary tuberculosis. On examination: deeply jaundiced, drowsy and disoriented (Glasgow Coma Scale 12/15). Asterixis present bilaterally. Fetor hepaticus noted. Liver: not palpable (possibly shrunken). Spleen: not enlarged. Vitals: BP 98/62 mmHg, pulse 112/min, temperature 37.4°C. The hostel warden produces a WhatsApp message from two weeks ago in which Preethi had written: 'My eyes have gone yellow since last Friday. The doctor at the dispensary said it is common with TB medicines and asked me to continue.'

Trigger 1: Jaundice, Confusion, and a White Pill

LFT panel: total bilirubin 18.4 mg/dL (conjugated 14.2, unconjugated 4.2). ALT 3,840 IU/L (ULN 40). AST 2,960 IU/L. ALP 110 IU/L (ULN 120). GGT 88 IU/L. Albumin 2.4 g/L. Prothrombin time 28 seconds (control 12 seconds); INR 2.8. Serum ammonia 112 μmol/L (normal <50). Urine: dark brown, bile salts 3+, bile pigment 3+, urobilinogen absent. Stool: pale. Serum IgG markedly elevated (2,800 mg/dL).

DISCUSSION POINTS

  • Interpret the LFT panel systematically: identify the dominant pattern (hepatocellular vs cholestatic vs mixed), classify the jaundice mechanistically, and explain why Preethi's urine is dark and her stool is pale.
  • Preethi is confused with asterixis and elevated ammonia. Name the specific complication of liver failure she is developing, and explain the pathophysiological mechanism linking hepatocellular failure to neurological dysfunction.
  • Her prothrombin time is markedly prolonged and albumin is very low. Explain how these two findings together reflect hepatic synthetic failure — and which parameter is a more acute marker of deterioration?
  • The LFT pattern plus her anti-TB drug history strongly suggests a specific cause. What are the two main mechanisms by which anti-TB drugs cause liver injury, and which specific agent in her regimen is most hepatotoxic?
Click to reveal Trigger 2: Viral Hepatitis Serology and a Gallstone Surprise (discuss previous trigger first!)

Trigger 2: Viral Hepatitis Serology and a Gallstone Surprise

Viral hepatitis serology: HBsAg negative; anti-HBs positive; anti-HBc IgM negative; anti-HAV IgM negative; HCV RNA not detected; anti-HEV IgM negative. Anti-smooth muscle antibody (ASMA) 1:320 (positive). Anti-nuclear antibody (ANA) 1:160 (positive). Abdominal ultrasound: liver small and hyperechoic. No focal lesion. Bile duct not dilated. Incidental finding: gallbladder contains multiple echogenic foci with posterior acoustic shadowing (calculi) — patient is asymptomatic regarding gallbladder. In the ICU, Preethi develops haematemesis from an orogastric tube; upper GI endoscopy shows no varices — haemorrhage is from a Mallory-Weiss tear.

DISCUSSION POINTS

  • Interpret Preethi's viral hepatitis serology panel step by step. What does the anti-HBs positive, anti-HBc IgM negative pattern tell you? Could HEV be contributing — what is the demographic and epidemiological context for HEV in India?
  • The positive ASMA and ANA alongside markedly elevated IgG raises an additional diagnosis. What is this condition, how does it overlap with DILI in presentation, and why does it matter for management?
  • Preethi's gallbladder contains multiple stones, but she is asymptomatic. Classify the likely type of gallstone, explain the pathogenesis of each type, and identify the risk factors in Preethi's demographic and background that could predispose her to each type.
  • Acute cholecystitis was not diagnosed in Preethi — what are the pathological sequence of events from gallstone impaction in the cystic duct to acute cholecystitis, and what are the potential complications if untreated?
Click to reveal Trigger 3: Liver Biopsy, Recovery, and Long-Term Surveillance (discuss previous trigger first!)

Trigger 3: Liver Biopsy, Recovery, and Long-Term Surveillance

Preethi is managed with N-acetylcysteine, lactulose, rifaximin, vitamin K, and careful fluid management. Anti-TB drugs are withdrawn. Her hepatic encephalopathy improves gradually over 10 days. Liver biopsy (performed once INR improves): 'Centrilobular hepatocyte necrosis (zone 3); ballooning degeneration; cholestasis (bile plugs in canaliculi); acidophilic bodies (apoptotic hepatocytes); lymphoplasmacytic portal inflammation with interface hepatitis; bridging necrosis connecting central-central zones. Congo red negative. Special stain for iron: negative. Periodic acid-Schiff with diastase (PASD): negative.' A 58-year-old auto driver in the same ward, Suresh, was admitted two weeks ago with progressive abdominal distension (ascites), marked jaundice, and a 5 cm hyper-enhancing liver lesion on CT. He has been a heavy drinker for 25 years. His serum AFP is 1,480 ng/mL (normal <10 ng/mL).

DISCUSSION POINTS

  • Interpret Preethi's liver biopsy findings, identifying which features indicate acute hepatocellular necrosis and which features suggest a chronic/autoimmune component. Name each morphological finding and explain its pathological mechanism.
  • Using Suresh's findings (25 years of heavy alcohol use, ascites, jaundice, hyper-enhancing 5 cm liver lesion, AFP 1,480 ng/mL), construct the pathological progression from hepatic steatosis through alcoholic hepatitis to cirrhosis to hepatocellular carcinoma — naming the key molecular pathways at each transition.
  • AFP is elevated in Suresh to 1,480 ng/mL. Describe the hepatocellular carcinoma screening protocol recommended for high-risk patients in India, what the AFP threshold for diagnosis is, and what microscopic patterns of HCC you would expect on biopsy.
  • Preethi is recovering but needs long-term surveillance. Construct an evidence-based plan for her follow-up: when to restart anti-TB treatment (and which agents to use), how to monitor for autoimmune hepatitis, and what the long-term implications of this acute injury are for her liver function.

Group Task Assignments

Group 1: Bilirubin metabolism and jaundice classification

  • Draw a labelled diagram of the complete bilirubin metabolic pathway from haem to faecal stercobilinogen, marking each step, the enzymes involved, and where obstruction at each step would cause prehepatic, hepatic, or posthepatic jaundice.
  • Prepare a table of four hereditary hyperbilirubinaemia syndromes (Gilbert, Crigler-Najjar Types I and II, Dubin-Johnson) covering: which step is disrupted, which bilirubin fraction accumulates, key clinical distinguishing feature, and treatment.

Competencies: PA24.1

Group 2: Hepatitis — viral, toxic, and autoimmune

  • Compare HAV, HBV, HCV, HDV, and HEV across: transmission route, incubation period, risk of chronicity, serology marker used for acute diagnosis, and at-risk population in India.
  • Create a differential diagnosis flowchart for acute hepatitis based on LFT pattern, serology, drug history, and autoimmune markers — distinguish viral hepatitis, DILI, autoimmune hepatitis, and alcoholic hepatitis with one distinguishing lab feature for each.

Competencies: PA24.3, PA24.6

Group 3: Hepatic failure — mechanisms and clinical consequences

  • List all the clinical manifestations of hepatic failure (jaundice, encephalopathy, coagulopathy, hypoalbuminaemia, hepatorenal syndrome, infection susceptibility) and explain the mechanism of each, linking it to the specific hepatic function that has failed.
  • Apply the Child-Pugh scoring system to two case scenarios provided by the tutor: classify each patient as Child-Pugh A, B, or C and estimate 1-year survival, then explain what each parameter in the score measures functionally.

Competencies: PA24.2, PA24.4

Group 4: Portal hypertension and HCC

  • Draw a diagram of the porto-systemic collateral circulation, marking the four major sites of anastomosis, the clinical consequence of each (oesophageal varices, haemorrhoids, caput medusae, retroperitoneal veins), and the mechanism of ascites formation in portal hypertension.
  • Describe the pathogenesis of hepatocellular carcinoma from cirrhosis to HCC, including the role of AFP as a tumour marker, the diagnostic threshold for AFP, and the three gross morphological patterns of HCC.

Competencies: PA24.5, PA24.7

Group 5: Cholelithiasis, cholecystitis and microscopic liver pathology

  • Describe the pathological sequence from cholesterol supersaturation to gallstone formation, then from cystic duct obstruction to acute cholecystitis, empyema, and perforation — using a stepwise diagram.
  • Review the histological features of four liver diseases identifiable on light microscopy: alcoholic hepatitis (ballooning + Mallory-Denk bodies + neutrophilic infiltrate), viral hepatitis (acidophilic bodies + lobular disarray), cholestasis (bile plugs + feathery degeneration), and cirrhosis (regenerative nodules + bridging fibrosis) — describe each feature and its pathological mechanism.

Competencies: PA24.8, PA24.9

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [PA24.1] What is the complete pathway of bilirubin metabolism from haem to excretion, and how do disruptions at prehepatic, hepatic, and posthepatic levels produce different patterns of jaundice on clinical and biochemical testing?
  2. [PA24.2] What are the pathophysiological mechanisms underlying the clinical manifestations of hepatic failure (encephalopathy, coagulopathy, hypoalbuminaemia, hepatorenal syndrome), and how are acute and chronic hepatic failure distinguished?
  3. [PA24.3] What are the distinguishing features of HAV, HBV, HCV, HDV, and HEV infection in terms of transmission, serology, pathological mechanism of hepatocyte injury, chronicity risk, and complications?
  4. [PA24.4] What is the three-stage spectrum of alcoholic liver disease, and what are the pathological mechanisms and morphological features of hepatic steatosis, alcoholic hepatitis, and alcoholic cirrhosis?
  5. [PA24.5] What is portal hypertension, how is it classified by anatomical site, and what are the mechanisms and clinical consequences of porto-systemic collaterals, splenomegaly, ascites, and hepatic encephalopathy?
  6. [PA24.6] How are LFT panels interpreted systematically to distinguish hepatocellular, cholestatic, and mixed patterns, and how is viral hepatitis serology interpreted to diagnose acute versus resolved versus chronic infection?
  7. [PA24.7] What are the aetiology, pathogenesis, gross and microscopic morphology, and key diagnostic markers of hepatocellular carcinoma, including the role of AFP and the fibrolamellar variant?
  8. [PA24.8] What are the pathophysiology and pathological changes of cholelithiasis and acute cholecystitis, including the classification of gallstone types, their pathogenesis, and the complications of untreated disease?
  9. [PA24.9] What are the microscopic features that distinguish the major liver diseases (viral hepatitis, alcoholic hepatitis, cholestasis, cirrhosis, HCC), and how are special stains (PAS, iron, Congo red, Masson trichrome) used in liver biopsy interpretation?