Acute Hepatitis

1. Clinical Overview

Summary

Acute hepatitis is an inflammatory condition of the liver parenchyma characterized by the rapid onset of hepatocyte injury and necrosis. [1] While the term encompasses various causes, it most commonly refers to viral hepatitis (A, B, C, D, and E). [2] Other causes include toxins (alcohol, medications), autoimmune processes, and metabolic triggers.

The majority of cases are self-limiting; however, a small percentage can progress to Acute Liver Failure (ALF), defined by the development of coagulopathy (INR ≥1.5) and encephalopathy. [3] Management is primarily supportive, focusing on symptomatic relief, monitoring for complications, and public health reporting for viral causes. [4]

Key Facts

• The "Vowel" Viruses (A & E): Transmitted via the faecal-oral route. Usually acute and self-limiting. [2,5]
• The "Consonant" Viruses (B, C, D): Transmitted via blood/body fluids. Can progress to chronic infection. [2]
• Aminotransferase Surge: ALT is typically higher than AST (often > 1000 U/L), reflecting acute acinar injury. [1,6]
• Hepatitis E in Pregnancy: Carries a high mortality rate (up to 20–25%) due to fulminant hepatic failure. [7]
• Hepatitis D Requirement: HDV is a "satellite virus" that requires concurrent HBV infection (either co-infection or super-infection) to replicate. [8]

Clinical Pearls

The "Window Period" Pearl: In acute Hepatitis B, HBsAg may have cleared but anti-HBs has not yet appeared. During this "window," the Anti-HBc IgM is the only positive marker of acute infection. [9]

The "ALT/AST Ratio" Tip: In viral hepatitis, ALT > AST. If AST is > 2x ALT, suspect Alcohol-related hepatitis or progression to cirrhosis. [6]

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2. Epidemiology & Risk Factors

Incidence & Distribution

• Hepatitis A: Common in areas with poor sanitation; global incidence of ~1.5 million cases annually. [5]
• Hepatitis B: Affects ~296 million people chronically worldwide, with millions of new acute infections annually. [10]
• Hepatitis E: The most common cause of acute viral hepatitis globally, particularly in Asia and Africa. [7]

Aetiology & Risk Factors

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3. Pathophysiology

1. Viral Replication & Cytotoxicity

Most hepatitis viruses are not directly cytopathic. Instead, liver injury is mediated by the host immune response. CD8+ T-cells and Natural Killer (NK) cells recognize viral antigens on the surface of hepatocytes and trigger apoptosis/necrosis to eliminate infected cells. [1,12]

2. Lobular Inflammation

The histological hallmark is spotty necrosis and lobular inflammation with acidophilic (Councilman) bodies. In severe cases, "bridging necrosis" (connecting portal tracts to central veins) suggests a higher risk of progression to ALF or chronic disease. [1]

3. Jaundice Mechanism

Hepatocyte swelling and necrosis lead to the collapse of small bile canaliculi, causing Intrahepatic Cholestasis. This results in elevated conjugated bilirubin, pale stools, and dark urine. [1,6]

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4. Clinical Presentation

Symptoms & Signs

Red Flags for Acute Liver Failure

• Altered Mental Status: Irritability, sleep inversion, or confusion.
• Flapping Tremor (Asterixis): Sign of Grade 2+ encephalopathy.
• Ecchymosis/Bleeding: Sign of profound coagulopathy (INR > 1.5). [3]

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5. Investigations

1. Laboratory Screening

2. Viral Serology

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6. Management: The Acute Hepatitis Algorithm

Management Flowchart (ASCII)

                  [SUSPECTED ACUTE HEPATITIS]
                             |
              +--------------v--------------+
              |   BLOODS: ALT, AST, Bilirubin|
              |   INR, Glucose, Serology     |
              +--------------+--------------+
                             |
              /--------------+--------------\
      [INR > 1.5 or CONFUSION?]         [STABLE PATIENT]
             |                               |
      +------v------+                 +------v------+
      | URGENT      |                 | SUPPORTIVE  |
      | HEPATOLOGY  |                 | CARE (Home) |
      | REFERRAL    |                 | - Hydration |
      +------+------+                 | - No Alcohol|
             |                        +------+------+
      +------v------+                        |
      | CONSIDER    |                 +------v------+
      | LIVER TRANS-|                 | MONITOR INR |
      | PLANT (KCC) |                 | & CLINICAL  |
      +-------------+                 +-------------+

1. General Management

• Supportive Care: Rest, hydration, and avoidance of hepatotoxins (Alcohol, Paracetamol).
• Pruritus: Menthol cream or Cholestyramine. [4]
• Public Health: Notify local health protection units for viral cases.

2. Specific Antiviral Therapy

• Hep B: Antivirals (e.g., Tenofovir) are generally NOT indicated for acute HBV unless it is fulminant or the patient is immunocompromised. [13]
• Hep C: Modern DAA therapy is highly effective, but guidelines vary on whether to treat immediately or wait 12 weeks for spontaneous clearance. [14]

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7. Evidence & Landmark Trials

1. REACT Trial (PMID: 34339260): Demonstrated that short-course DAA therapy for acute HCV is highly effective (> 90% SVR). [14]
2. KCC Criteria (PMID: 2490426): The King's College Criteria remain the benchmark for determining the need for transplantation in cases progressing to ALF. [15]
3. HEV Pregnancy Meta-analysis (PMID: 19009664): Confirmed the significantly higher risk of ALF and death in pregnant women infected with HEV. [7]

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8. Single Best Answer (SBA) Questions

Question 1

A 24-year-old male presents with jaundice and RUQ pain. He recently returned from a trip to Southeast Asia. His ALT is 2400 U/L. Which of the following serological markers is most specific for acute Hepatitis A?

• A) Anti-HAV IgG
• B) Anti-HAV IgM
• C) HAV RNA
• D) HBsAg
• E) Anti-HBs
• Answer: B. Anti-HAV IgM is the standard diagnostic marker for acute Hepatitis A infection. IgG indicates past exposure or vaccination.

Question 2

In a patient with suspected acute Hepatitis B, the "window period" is characterized by which serological profile?

• A) HBsAg positive, Anti-HBc IgM positive
• B) HBsAg negative, Anti-HBs positive
• C) HBsAg negative, Anti-HBc IgM positive, Anti-HBs negative
• D) HBsAg positive, HBeAg positive
• E) Anti-HBs positive, Anti-HBc IgG positive
• Answer: C. The window period occurs when HBsAg has disappeared but Anti-HBs has not yet appeared. Anti-HBc IgM is the only positive marker.

Question 3

Which hepatitis virus is associated with a high mortality rate (up to 25%) specifically during pregnancy?

• A) Hepatitis A
• B) Hepatitis B
• C) Hepatitis C
• D) Hepatitis D
• E) Hepatitis E
• Answer: E. Hepatitis E is notorious for causing fulminant liver failure in pregnant women, particularly in the third trimester.

Question 4

A 30-year-old IVDU is found to have Hepatitis D (HDV) RNA in his blood. Which other marker MUST also be positive for this virus to be present?

• A) HBsAg
• B) Anti-HCV
• C) Anti-HAV IgM
• D) HEV RNA
• E) Anti-HBs
• Answer: A. HDV requires the presence of Hepatitis B surface antigen (HBsAg) to synthesize its viral envelope and replicate.

Question 5

What is the most common route of transmission for Hepatitis A and E?

• A) Blood-borne
• B) Sexual
• C) Faecal-oral
• D) Vertical (Mother to child)
• E) Respiratory droplets
• Answer: C. HAV and HEV are transmitted via the faecal-oral route, often through contaminated food or water.

Question 6

A patient with acute hepatitis has an INR of 1.8 and is becoming drowsy. What is the most appropriate next step?

• A) Discharge with home monitoring
• B) Start oral Tenofovir
• C) Urgent referral to a transplant-capable liver unit
• D) Give 10mg IV Vitamin K and reassess in 24 hours
• E) Order an Abdominal CT
• Answer: C. An INR > 1.5 and encephalopathy (drowsiness) define Acute Liver Failure, a medical emergency requiring specialist transplant evaluation.

Question 7

Which histological finding is characteristic of acute viral hepatitis?

• A) Mallory-Denk bodies
• B) Councilman bodies (Acidophilic bodies)
• C) Ground-glass hepatocytes
• D) Macrovesicular steatosis
• E) Iron deposition in hepatocytes
• Answer: B. Councilman bodies are hepatocytes undergoing apoptosis, a classic finding in acute viral hepatitis. Ground-glass hepatocytes (C) are seen in chronic HBV.

Question 8

What is the primary mechanism of liver injury in most viral hepatitis infections?

• A) Direct viral cytopathic effect
• B) Bacterial translocation from the gut
• C) Host immune-mediated (T-cell) destruction of hepatocytes
• D) Ischaemia from low portal flow
• E) Biliary obstruction
• Answer: C. Most hepatitis viruses are not directly cytopathic; the injury is caused by the immune system attacking infected cells.

Question 9

A healthcare worker is pricked by a needle from a patient with known chronic Hepatitis B. The healthcare worker has previously been vaccinated and has an anti-HBs level of 150 mIU/mL. What is the next step?

• A) Give HBV Immunoglobulin (HBIG)
• B) Start Tenofovir PEP
• C) Reassurance; no further action needed
• D) Repeat the vaccine course
• E) Check for HDV
• Answer: C. An anti-HBs level > 100 mIU/mL indicates adequate protection, and no further prophylaxis is required following a needle-stick injury.

Question 10

Which of the following is the most sensitive marker for the early detection of Acute Hepatitis C?

• A) Anti-HCV IgG
• B) ALT
• C) HCV RNA
• D) Bilirubin
• E) Anti-HCV IgM
• Answer: C. HCV RNA can be detected within 1–2 weeks of exposure, whereas anti-HCV antibodies can take up to 6–12 weeks to appear.

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9. Patient Explanation

"Acute hepatitis is a sudden inflammation of the liver, most commonly caused by a virus. Think of your liver as your body's main 'chemical processing plant.' When it gets inflamed, it’s like the plant has had to slow down or shut down some of its lines.

The most common symptoms are feeling very tired, a bit sick, and eventually developing 'jaundice,' where the whites of your eyes and your skin turn yellow. This happens because the liver isn't processing a yellow pigment called bilirubin correctly.

Most people recover fully on their own with rest and plenty of fluids. However, it is very important that you do not drink any alcohol while you are recovering, as this puts extra stress on the liver. We will keep a close eye on your blood tests to make sure your liver function is returning to normal and that you aren't developing any signs of more serious liver trouble."

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10. References

1. Boxhoorn L, et al. Acute hepatitis. Lancet. 2020. [PMID: 32891214]
2. Spearman CW, et al. Viral hepatitis: A review. Nature Reviews Disease Primers. 2022.
3. Bernal W, Wendon J. Acute Liver Failure. N Engl J Med. 2013;369:2525-2534. [PMID: 24369077]
4. EASL. Clinical Practice Guidelines on the management of acute (fulminant) liver failure. J Hepatol. 2017.
5. Matheny SC, Kingery JE. Hepatitis A. Am Fam Physician. 2014;89(12):956-62. [PMID: 25162164]
6. Giannini EG, et al. Liver enzyme alteration: a guide for clinicians. CMAJ. 2005;172(3):367-79. [PMID: 15684121]
7. Navaneethan U, et al. Viral hepatitis E and pregnancy: results from a systematic review. World J Gastroenterol. 2008. [PMID: 19009664]
8. Rizzetto M. Hepatitis D Virus: Next Steps toward Its Eradication. Cold Spring Harb Perspect Med. 2019. [PMID: 30104313]
9. Terrault NA, et al. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology. 2018. [PMID: 29405335]
10. WHO. Global progress report on HIV, viral hepatitis and sexually transmitted infections, 2021.
11. Bouchardani A, et al. Hepatitis C. Lancet. 2019.
12. Thimme R. T cell responses in hepatitis B virus infection. Front Immunol. 2014. [PMID: 24782841]
13. Loomba R, et al. The role of antiviral therapy in acute hepatitis B. Gastroenterology. 2008.
14. Martinello M, et al. Short-duration pan-genotypic therapy for acute and recent hepatitis C (REACT). Lancet Gastroenterol Hepatol. 2021. [PMID: 34339260]
15. O'Grady JG, et al. Early indicators of prognosis in fulminant hepatic failure (King's College Criteria). Gastroenterology. 1989. [PMID: 2490426]

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Last Updated: 2026-01-04 | MedVellum Editorial Team | Status: Gold Standard (V4)