Hepatitis B, C and D Flashcards
Hepatitis B virus
(a) Family
(b) Genus
(c) Genotypes, serotypes
(e) Genome type
(f) Enveloped/Non-enveloped?
(g) Structure
(a) Family: Hepadnaviridae
(b) Genus: Orthohepadnavirus
(c) Genotypes, serotypes: 10 genotypes (A – J), one serotype
(e) Genome type: Circular DNA, partially double-stranded
(f) Enveloped/Non-enveloped? Enveloped
(g) Structure: spherical or filamentous [latter is less common]
Briefly discuss HBV transmission.
(a) Sexual contact: predominant mode among adults
(b) Close contact: household members, institutions
(c) Vertical transmission: during delivery
(d) Blood: unscreened blood transfusions, sharing toothbrushes, needles, razors, renal dialysis etc
Briefly discuss HBV risk factors.
🩺 Multiple sexual partners
🩺 Intravenous Drug Use (PWIDs)
🩺 MSM
🩺 Household members of an infected person
🩺 Crowding/institutionalization
🩺 Occupational risk - health workers
Discuss the pathogenesis of Hepatitis B.
🩺 The virus enters the body through body fluids e.g. blood, semen, and vaginal fluids [parenteral].
🩺 Once in the bloodstream, HBV attaches to heparan sulfate proteoglycans on the surface of hepatocytes (liver cells). This attachment is crucial for the virus to enter the cells.
🩺 Inside the hepatocytes, HBV replicates its DNA. The newly formed viral particles are then released into the bloodstream, leading to viremia.
🩺 The host’s immune system recognizes and targets the infected hepatocytes. This immune response is aimed at clearing the infection but also causes inflammation and damage to the liver tissue.
🩺 In some cases, the immune system fails to completely clear the virus, leading to a chronic infection. Chronic HBV infection can persist for years or even a lifetime.
🩺 Ongoing inflammation due to chronic infection can lead to fibrosis (scarring of the liver tissue), cirrhosis (severe liver scarring), and an increased risk of hepatocellular carcinoma (HCC), a type of liver cancer.
Hepatitis B incubation period
long: 30 - 180 days
Briefly discuss the symptoms of acute hepatitis.
🩺 Non-specific symptoms: Malaise, Myalgia, Fever, Fatigability, Nausea or vomiting, Anorexia
🩺 Abdominal pain – Right upper quadrant (abdomen)
🩺 Dark urine/pale stools
🩺 Jaundice
Further notes:
How does Hepatitis cause pale/clay colored stool?
â—¾ The liver produces bile, a yellow-brown fluid that helps digest fats. Bile contains bilirubin, which gives stool its brown color.
â—¾ When the liver is damaged by hepatitis, its ability to produce and secrete bile is impaired.
â—¾ The inflammation and damage caused by hepatitis can disrupt the normal flow of bile from the liver to the intestines. The disruption can lead to a decrease in bile reaching the intestines.
â—¾ Without sufficient bile and bilirubin in the intestines, stools lose their normal brown color and becomes pale or clay-colored.
Fulminant hepatitis is a severe and rapid form of liver failure that can develop in people with Hepatitis B. This condition can progress quickly, often within days or weeks, and can be life-threatening. Discuss its symptoms. [CNS, GIT, Hematological]
Central Nervous System
🩺 Hepatic encephalopathy: This is a decline in brain function due to severe liver disease. The liver is unable to remove toxins from the blood, leading to brain damage.
🩺 Somnolence/altered sleep pattern: Patients may experience excessive sleepiness or changes in their sleep patterns.
🩺 Confusion: Mental confusion and disorientation are common.
🩺 Coma: In severe cases, patients may fall into a coma.
Gastrointestinal Tract/Abdomen
Bleeding: Due to impaired liver function, there can be an increased risk of bleeding.
Ascites: This is the accumulation of fluid in the abdomen, often due to liver failure.
Hematological
Coagulopathy: This is a condition where the blood’s ability to clot is impaired, leading to excessive bleeding or bruising.
Further notes:
What is the relationship between hepatitis and ascites?
â—¾ Liver failure, often due to cirrhosis, leads to increased pressure in the portal vein, which carries blood from the digestive organs to the liver. This condition is known as portal hypertension. The high pressure causes fluid to leak out of the blood vessels and accumulate in the abdominal cavity, leading to ascites.
â—¾ The liver produces albumin, a protein that helps maintain the oncotic pressure in the blood vessels. In liver failure, the production of albumin decreases, leading to a drop in oncotic pressure. This causes fluid to leak out of the blood vessels and accumulate in the abdominal cavity.
â—¾ Liver failure can trigger the release of inflammatory mediators that increase the permeability of blood vessels, allowing more fluid to leak into the abdominal cavity.
symptoms of chronic Hepatitis
🩺 Malaise, fatigue, weakness
🩺 Weight loss
🩺 Peripheral edema
🩺 Ascites
🩺 Extra-hepatic manifestations [e.g. joint pain, kidney problems, and skin rashes]
List extra-hepatic manifestations of HBV.
🩺 Pleural effusions: accumulation of fluid in the pleural cavity
🩺 Hepatopulmonary syndrome
🩺 Arrhythmias: irregular heartbeats
🩺 Pericarditis: inflammation of the pericardium, the sac surrounding the heart
🩺 Myocarditis: inflammation of the heart muscle
🩺 Encephalopathy
🩺 Somnolence
🩺 Confusion
🩺 Arthralgia
🩺 Glomerulonephritis
🩺 Bone marrow aplasia
Briefly discuss occult Hepatitis B.
Occult Hepatitis B infection refers to the presence of replication-competent hepatitis B virus DNA in the liver and/or blood of individuals who test negative for the hepatitis B surface antigen (HBsAg) using standard assays. This condition can occur due to epigenetic or immune control mechanisms that suppress the expression of HBsAg.
Such a patient is still infectious.
Hepatitis B Serology
What does the presence of Hepatitis B Surface Antigen (HBsAg) indicate?
Indicates an active HBV infection, either acute or chronic. If HBsAg is present for more than six months, it suggests chronic infection.
Hepatitis B Serology
What does the presence of Hepatitis B Surface Antibody (Anti-HBs) indicate?
Indicates recovery and immunity from HBV infection or successful vaccination. Absence suggests susceptibility to HBV infection if other markers are negative.
Hepatitis B Serology
What does IgM Anti-HBc indicate?
Indicates recent acute infection.
Hepatitis B Serology
What does IgG Anti-HBc indicate?
It indicates past or ongoing infection. It remains positive fro life, even after recovery.
