Hepatitis D

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Hepatitis D
File:Hepatitis-d-virion-Pathogens-04-00046-g001-1024.png
Synonyms	Hepatitis delta
Pronounce	N/A
Specialty	N/A
Symptoms	Jaundice, fatigue, abdominal pain, nausea, vomiting
Complications	Cirrhosis, liver failure, hepatocellular carcinoma
Onset	Typically 2 to 8 weeks after exposure
Duration	Acute or chronic
Types	N/A
Causes	Hepatitis D virus (HDV) infection
Risks	Hepatitis B infection, intravenous drug use, unprotected sex
Diagnosis	Serology, liver function tests, HDV RNA detection
Differential diagnosis	Hepatitis B, Hepatitis C, Hepatitis E
Prevention	Hepatitis B vaccination, avoiding risk factors
Treatment	Antiviral drugs, interferon therapy, liver transplant
Medication	N/A
Prognosis	Variable; worse with co-infection or superinfection
Frequency	Approximately 15-20 million people worldwide
Deaths	N/A

Hepatitis D is a form of hepatitis that only causes symptoms when the individual is already infected with hepatitis B

Other names

Hepatitis D is also known as “delta hepatitis and is caused by hepatitis D virus.

Summary

• Hepatitis D is a liver infection caused by the hepatitis D virus (HDV).
• Hepatitis D only occurs in people who are also infected with the hepatitis B virus.
• Hepatitis D is spread when blood or other body fluids from a person infected with the virus enters the body of someone who is not infected. Hepatitis D can be an acute, short-term infection or become a long-term, chronic infection.
• Hepatitis D can cause severe symptoms and serious illness that can lead to life-long liver damage and even death.
• People can become infected with both hepatitis B and hepatitis D viruses at the same time (known as ‚Äúcoinfection‚Äù) or get hepatitis D after first being infected with the hepatitis B virus (known as ‚Äúsuperinfection‚Äù).
• There is no vaccine to prevent hepatitis D.
• Prevention of hepatitis B with hepatitis B vaccine also protects against future hepatitis D infection.

Hepatitis viruses A,E,B,C,D.

Hepatitis viruses A,E,B,C,D.

Coinfection and superinfection

• HBV/HDV coinfection occurs when a person simultaneously becomes infected with both HBV and HDV, whereas HDV superinfection occurs when a person who is already chronically infected with HBV acquires HDV.
• Although acute HBV/HDV coinfections can resolve, HDV superinfection can lead to rapid progression of the already present HBV infection, resulting in liver cirrhosis and liver failure.
• These outcomes occur within 5–10 years in 70%–80% and within 1–2 years in 15% of people with chronic HBV/HDV infection.

Incidence

HDV infection is uncommon in the United States, where most cases occur among people who migrate or travel to the United States from countries with high HDV endemicity. Hepatitis D is most common in Eastern Europe, Southern Europe, the Mediterranean region, the Middle East, West and Central Africa, East Asia, and the Amazon Basin in South America.

Genotypes

• Eight different HDV genotypes can be found across the globe, all of which share the same transmission routes and risk groups.
• HDV genotype 1 circulates mainly in North America, Europe, the Middle East, and North Africa.
• HDV genotypes 2 and 4 can be found in East Asia; genotype 3 is found exclusively in the Amazon Basin in South America, and
• HDV genotypes 5, 6, 7, and 8 are found in West and Central Africa.

Histopathology of acute hepatitis

Histopathology of acute hepatitis

Transmission and Exposure

HDV is mainly transmitted through activities that involve percutaneous (i.e., puncture through the skin) and to a lesser extent through mucosal contact with infectious blood or body fluids (e.g., semen and saliva), including

• sex with an infected partner;
• injection-drug use that involves sharing needles, syringes, or drug-preparation equipment;
• birth to an infected mother (rare);
• contact with blood from or the open sores of an infected person;
• needle sticks or exposures to sharp instruments; and
• sharing items (e.g., razors and toothbrushes) with an infected person.
• HDV is not spread through food or water, sharing eating utensils, breastfeeding, hugging, kissing, hand holding, coughing, or sneezing.

Risk groups

The following populations are at increased risk for becoming infected with HDV:

• People chronically infected with HBV
• Infants born to mothers infected with HDV
• Sex partners of persons infected with HDV
• Men who have sex with men
• People who inject drugs
• Household contacts of people with HDV infection
• Health care and public safety workers at risk for occupational exposure to blood or blood-contaminated body fluids
• Hemodialysis patients

Signs and Symptoms

HDV causes infection and clinical illness only in HBV-infected people. These include:

• Fever
• Fatigue
• Loss of appetite
• Nausea
• Vomiting
• Abdominal pain
• Dark urine
• Clay-colored bowel movements
• Joint pain
• Jaundice

These signs and symptoms typically appear 3–7 weeks after initial infection.

Interface hepatitis -- very high mag

Interface hepatitis -- very high mag

Clinical course and complications

Chronic HDV generally causes a more aggressive and rapid progression of liver disease than chronic HBV infection alone. This is especially evident in patients infected with genotype HDV-3, which is common in the Amazon Basin Of people with chronic HDV superinfection, cirrhosis and liver failure occur within 5–10 years in 70%–80% and within 1–2 years in 15%. Comparatively, the mean age of onset of cirrhosis for people who acquire chronic hepatitis B in childhood is 40 years.

Diagnosis

• Because cases of hepatitis D are not clinically distinguishable from other types of acute viral hepatitis, diagnosis can be confirmed only by testing for the presence of antibodies against HDV and/or HDV RNA.
• HDV infection should be considered in any person with a positive hepatitis B surface antigen (HBsAg) who has severe symptoms of hepatitis or acute exacerbations.

Treatment

• No treatment is available for HDV infection specifically.
• Pegylated interferon alpha has shown some efficacy, but the sustained virologic response rate (a measure of viral clearance) is low (25%).
• In cases of fulminant hepatitis and end-stage liver disease, liver transplantation may be considered.

Prevention

Although no vaccine is available for hepatitis D, vaccination with the hepatitis B vaccine can protect people from HDV infection.