Hepatitis

Question 1

What are the four general mechanisms of liver injury?

Answer 1

The four mechanisms are direct cytopathic effect (viruses), immune-mediated hepatocyte injury (viral or autoimmune), direct toxic injury (drugs and alcohol), and metabolic stress such as lipid accumulation and reactive oxygen species (ROS).

Question 2

How do viruses directly injure liver cells?

Answer 2

Viruses can cause direct cytopathic effects, meaning they directly damage hepatocytes.

Question 3

What is immune-mediated hepatocyte injury?

Answer 3

It occurs when the immune system attacks hepatocytes, commonly seen in viral hepatitis and autoimmune hepatitis.

Question 4

How do drugs and alcohol cause liver injury?

Answer 4

They cause direct toxic injury to hepatocytes.

Question 5

What is metabolic stress in liver injury?

Answer 5

Metabolic stress refers to damage caused by lipid accumulation and reactive oxygen species (ROS).

Question 6

What are reactive oxygen species (ROS)?

Answer 6

ROS are highly reactive, oxygen-containing molecules produced during normal cellular metabolism.

Question 7

What beneficial role do ROS play at low levels?

Answer 7

At normal levels, ROS are essential for cell signaling and immune function.

Question 8

What happens when ROS levels are high?

Answer 8

High levels cause oxidative stress, damaging cellular components and leading to disease.

Question 9

How does liver damage usually occur in viral hepatitis?

Answer 9

Most liver damage in viral hepatitis is immune-mediated, in addition to any direct cytopathic effect.

Question 10

What is hepatitis?

Answer 10

Hepatitis is an inflammatory injury of the liver characterized by hepatocyte damage, necrosis or apoptosis, and inflammatory infiltrates.

Question 11

How can hepatitis be classified by clinical course?

Answer 11

Hepatitis may be acute or chronic, and can be self-limited or progressive.

Question 12

What are the four key pathology questions in hepatitis?

Answer 12

They are duration, etiology, pattern of injury (histopathology), and likelihood of progression to fibrosis or cirrhosis (prognosis).

Question 13

How is hepatitis classified according to duration?

Answer 13

Acute hepatitis: less than 6 months
Chronic hepatitis: 6 months or longer

Question 14

How is hepatitis classified according to etiology?

Answer 14

It may be viral, autoimmune, drug-induced/toxic, alcohol-related, metabolic dysfunction-related, or ischemic/congestive.

Question 15

How is hepatitis classified by histologic pattern?

Answer 15

Patterns include acute hepatitis, chronic hepatitis, acute-on-chronic liver disease, cholestatic pattern, and steatohepatitis pattern.

Question 16

What are the main causes and long-term concerns of viral hepatitis?

Answer 16

Viral hepatitis is caused by HAV, HBV, HCV, HDV, HEV, and other viruses. HAV and HEV are usually acute with no chronic form, while HBV, HCV, and HDV can become chronic and lead to cirrhosis and hepatocellular carcinoma (HCC).

Question 17

What characterizes alcoholic hepatitis?

Answer 17

It is caused by heavy alcohol use, with severity depending on the amount and duration of drinking, and can progress to cirrhosis if drinking continues.

Question 18

What is non-alcoholic fatty liver disease (NAFLD/NASH)?

Answer 18

It is fat accumulation in the liver unrelated to alcohol, strongly linked to obesity, diabetes, and high cholesterol, and can progress to NASH, then cirrhosis.

Question 19

What are toxic/drug-induced and autoimmune hepatitis?

Answer 19

Toxic/drug-induced hepatitis results from medications, chemicals, or herbs and may cause acute liver failure but often improves when the cause is removed. Autoimmune hepatitis is caused by the immune system attacking the liver, is more common in women, often associated with other autoimmune diseases, and untreated leads to cirrhosis.

Question 20

What is ischemic hepatitis and what is its outcome?

Answer 20

Ischemic hepatitis results from reduced blood or oxygen supply due to conditions like heart failure, shock, or sepsis, and the liver often recovers if blood flow is restored quickly.

Question 21

Can viruses that are not primarily hepatotropic cause hepatitis?

Answer 21

Yes, non-hepatotropic viruses can cause hepatitis, but this is rare and is almost always acute.

Question 22

Which non-hepatotropic viruses can cause acute hepatitis?

Answer 22

These include cytomegalovirus (CMV), Epstein–Barr virus (EBV), adenovirus, varicella zoster virus, herpes simplex virus (HSV-1 and HSV-2), HIV, parvovirus B19, dengue fever virus, and yellow fever virus.

Question 23

What is Parvovirus B19?

Answer 23

Parvovirus B19 is a common, generally mild childhood viral illness caused by human parvovirus B19.

Question 24

What disease is classically caused by Parvovirus B19?

Answer 24

It causes Fifth Disease (Erythema Infectiosum).

Question 25

How can Parvovirus B19 cause serious complications?

Answer 25

In certain populations, it can cause severe anemia due to its effects on red blood cell production.

Question 26

What is the cellular tropism of Parvovirus B19?

Answer 26

Parvovirus B19 has a strong tropism for erythroid progenitor cells in the bone marrow.

Question 27

How does Parvovirus B19 infection lead to jaundice and hepatomegaly?

Answer 27

Destruction of erythroid progenitors causes markedly increased red blood cell turnover, overwhelming the liver with hemoglobin breakdown, leading to unconjugated hyperbilirubinemia, jaundice, and hepatomegaly.

Question 28

What are the main mechanisms of hepatocyte injury in viral hepatitis?

Answer 28

Injury occurs through direct cytopathic effects, CD8⁺ cytotoxic T-cell–mediated cytotoxicity, and cytokine-induced apoptosis.

Question 29

Which cytokines are involved in cytokine-induced hepatocyte apoptosis?

Answer 29

Interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α).

Question 30

How does viral persistence affect the liver?

Answer 30

Persistence of the virus leads to chronic inflammation, which progresses to fibrosis.

Question 31

What are the gross features of severe acute hepatitis?

Answer 31

The liver is swollen, has a wrinkled capsule due to parenchymal collapse, contains small regenerative nodules, and shows no fibrosis.

Question 32

What defines acute viral hepatitis in terms of duration and general histology?

Answer 32

It lasts less than 6 months and shows lobular injury with inflammation.

Question 33

What happens to hepatocytes during acute viral hepatitis?

Answer 33

There is disappearance of individual or small clusters of hepatocytes, leaving empty spaces or a collapsed reticulin framework, and hepatocytes appear swollen and pale.

Question 34

What apoptotic features are seen in acute viral hepatitis?

Answer 34

Eosinophilic rounded fragments (apoptotic bodies) are present, seen in conditions like hepatitis B (HBsAg) and certain drug-induced injuries.

Question 35

What inflammatory changes occur in acute viral hepatitis?

Answer 35

There is loss of orderly hepatocyte cords, mononuclear (lymphocytic) infiltrates in portal tracts and lobules, periportal inflammation, inflammatory spillover into adjacent parenchyma, and canalicular bile plugs.

Question 36

What regenerative and macrophage changes are seen in acute viral hepatitis?

Answer 36

Findings include hepatocyte mitosis and binucleation, as well as Kupffer cell hyperplasia and hypertrophy.

Question 37

How do symptoms of acute viral hepatitis typically develop over time?

Answer 37

Symptoms appear after an incubation period and unfold in distinct clinical phases.

Question 38

What is the prodromal (pre-icteric) phase of acute viral hepatitis?

Answer 38

It is the early phase (days 1–7) characterized by nonspecific, flu-like symptoms.

Question 39

What systemic symptoms occur in the prodromal phase?

Answer 39

Fatigue, malaise, muscle aches, and joint aches.

Question 40

What additional symptoms are seen during the prodromal phase?

Answer 40

Low-grade fever, nausea, vomiting, loss of appetite (anorexia), and right upper-quadrant abdominal discomfort.

Question 41

When does the icteric phase of acute viral hepatitis begin?

Answer 41

It usually begins in week 2 or later.

Question 42

What is the hallmark sign of the icteric phase?

Answer 42

Jaundice, which is yellowing of the skin and sclera (whites of the eyes).

Question 43

Why does dark urine occur during the icteric phase?

Answer 43

Because bilirubin is excreted by the kidneys.

Question 44

Why do patients develop pale, clay-colored stools?

Answer 44

Due to lack of bilirubin reaching the intestines.

Question 45

How do prodromal symptoms change during the icteric phase?

Answer 45

Symptoms like fatigue and nausea often persist but may start to improve.

Question 46

What skin symptom may occur during the icteric phase?

Answer 46

Pruritus (itching).

Question 47

How long can fatigue persist during recovery?

Answer 47

Weeks to months, even after other symptoms resolve.

Question 47

What happens during the convalescent phase of acute viral hepatitis?

Answer 47

There is gradual resolution of jaundice and other symptoms.

Question 48

What is fulminant hepatitis?

Answer 48

A rare but severe complication of acute viral hepatitis characterized by rapid onset of acute liver failure (ALF).

Question 49

What neurological manifestation defines severe acute hepatitis?

Answer 49

Hepatic encephalopathy, including confusion, disorientation, drowsiness, personality changes, and coma.

Question 50

Why does coagulopathy occur in acute liver failure?

Answer 50

Because the liver cannot produce clotting factors, leading to easy bruising and bleeding, measured by prolonged INR/PT.

Question 51

What other major complication can develop in fulminant hepatitis?

Answer 51

Ascites, which is fluid accumulation in the abdomen.

Question 52

How is acute liver failure diagnosed in acute viral hepatitis?

Answer 52

By the presence of hepatic encephalopathy and coagulopathy.

Question 53

How is acute liver failure managed?

Answer 53

It is a medical emergency, treated with supportive care in intensive care units, with urgent liver transplantation as the definitive treatment.

Question 54

Which viral hepatitides most commonly lead to acute liver failure?

Answer 54

Hepatitis B (HBV): Most common; associated with high HBV DNA or immune reconstitution Hepatitis E (HEV): Very high risk in pregnant women, especially third trimester (20–25%) Hepatitis A (HAV): Rare; usually elderly or chronic liver disease patients Hepatitis D (HDV): Severe in HBV superinfection Hepatitis C (HCV): Very rarely causes ALF

Question 55

What are the key histopathologic features of chronic viral hepatitis?

Answer 55

Chronic hepatitis lasts >6 months and shows ongoing injury with fibrosis, including: Portal inflammation with dense lymphocytic infiltrates Interface hepatitis (piecemeal necrosis) destroying periportal hepatocytes Lobular activity with spotty necrosis or apoptosis Progressive fibrosis from portal expansion → bridging septa → cirrhosis

Question 56

What happens at the cellular level after chronic liver injury?

Answer 56

After chronic liver injury, inflammation activates hepatic stellate cells (HSCs), causing them to trans-differentiate into myofibroblast-like cells. These activated cells acquire contractile, proinflammatory, and fibrogenic properties, leading to expansion of the myofibroblast (MFB) pool and progression toward fibrosis and cirrhosis.

Question 57

What causes can lead to activation of hepatic stellate cells (HSCs)?

Answer 57

HSC activation can be triggered by many chronic liver insults, including parasites, alcohol, alcoholic steatohepatitis (ASH), cryptogenic causes, drugs, toxins, obesity, nonalcoholic fatty liver disease (NAFLD), cholestasis, metabolic diseases, venous congestion, and chronic inflammation. Growth factors and mediators such as IGF-1, PDGF, endothelin-1 (ET-1), and reactive oxygen species (ROS) play key roles in this activation process.

Question 58

How does hepatic stellate cell activation lead to fibrosis, cirrhosis, and cancer?

Answer 58

Activated HSCs and myofibroblasts produce excessive extracellular matrix components, including collagen, elastin, glycoproteins, and proteoglycans, sometimes with contribution from bone marrow–derived fibrocytes and epithelial–mesenchymal transition (EMT). This progressive matrix deposition leads to liver fibrosis, then cirrhosis, and ultimately increases the risk of primary liver cell carcinoma.