Microbiology Conditions Flashcards
What are the 5 viruses that cause hepatitis?
Hepatitis A (HAV) - RNA
Hepatitis B (HBV) - DNA
Hepatitis C (HCV) - RNA
Hepatitis D (HDV) - RNA
Hepatitis E (HEV) - RNA
How are hepatitis A and E transmitted?
Via Faecal-oral transmission
How are hepatitis B,C and D transmitted?
Blood to blood transmission
What is acute hepatitis?
What Hepatitis viruses cause acute hepatitis?
A sudden illnesss with a mild to severe course followed by complete resolution
All hepatitis Viruses
What is chronic hepatitis
What Hepatitis viruses cause acute hepatitis?
A prolonged course of active disease or silent asymptomatic infection.
HBV, HCV, HDV
Outline Acute hepatitis
Variable incubation period
-Systemic symptoms first:
-**Fatigue, low-grade fever, muscle/joint aches, cough, runny nose, and
pharyngitis. **
Jaundice (1-2 weeks after infection)
LFTs (rise through hepatocyte death from virus)
**ALT and AST to elevate to very high **
levels, while GGT, ALP, and bilirubin are only mildly elevated
Outline Chronic Hepatitis
More difficult to Diagnose
Patient is often asymptomatic
Clinical manifestations arethe same regardlesss of virus causing hepatitis.
Describe the transmission of hepatitis A
Ingesting contaminated drinking water or food
Close person to person contact
Often infects young children
What is the pathogenesis of HAV?
-Initial immune response consists IgM antibody; important in the laboratory
diagnosis of hepatitis A.
-1 to 3 weeks later IgG antibody is produced→ lifelong protection
What are the clinical findings of HAV?
Incubation of 3-4 weeks
Fever, anorexia, nausea, vomiting and jaundice
Dark urine, pale faeces, elevated ALT and AST.
Cases often resolve spontaneously in 2-4 weeks.
What Ix are required for HAV diagnosis?
LFTs: High AST and ALT.
Bilirubin and ALP usually only mild.
Serology - Detection of anti-HAV IgM confirms the diagnosis and remails for 3-6 months.
What is the treatment for HAV infection?
Acute Infection:
Symptomatic treatment (avoid paracetamol)
Fulminant Hepatitis:
Supportive therapy - consider liver transplanation
Pre-exposure prophylaxis - Vaccination
What is Hepatitis B virus?
DNA virus that lives in all human body fluids in an infected individual.
Semen, urine, saliva, blood, breast milk
What are HBV 3 main antigens?
HBsAg - surface antigen - required for lab diagnosis and immunity
HBcAg - Core antigen
HbeAg - e Antigen - indicator of transmissibiility
How can HBV be transmitted and give examples?
Blood to blood transmission - parenteral transmission.
Needle sharing, accidental medical exposures, sexual contact Blood transfusions
Where is HBV prevalent
ASIA
How does HBV present?
3 clinical states:
Acute hepatitis
Fulminant hepatitis - severe acute hepatitis with rapid destruction of the liver
Chronic Hepatitis
How do you diagnose HBV infection?
HBsAg antigen means there is LIVE virus and infection.
Anti - HBsAg antibodies - patient is protected and immune
HBcAg - antibodies are not protective but can be used to understand length of infection.
What are the complications of HBV infection?
HDV co-infection
Hepatocellular carcinoma
End-stage liver disease/cirrhosis
What is Hepatitis C virus
RNA virus
Incubation period 6-12 weeks
What is the clinical signs of HCV infection?
Acute infection is usually asymptomatic - some patients will present with classic acute hepatitis symptoms
Up to 85% of patients of HCV will develop chronic hepatitis
HCV strongly predisposes HCC.
Outline HCV transmission
Blood-to-blood contact via blood transfusions, injecting drug use, nosocomial (needle sticks, dialysis, inadequate sterilisation of colonoscopes
What is the most common indication for liver transplantation?
Liver cirrhosis resulting from chronic HCV infection
What comorbidities arise with HCV infection?
HCV infection can lead to significant autoimmune reactions:
vasculitis, arthralgias, purpura, membranoproliferative glomerulonephritis