Lvr
Hepatitis A
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Hepatitis A
, Hepatitis A Virus
See Also
Viral Hepatitis
Acute Hepatitis Causes
Epidemiology
Endemic in underdeveloped countries
More common in western United States
Outbreaks
Day-care centers
Residential institutions
Incidence
World: 1.4 Million/year
U.S. (esp west): 60,000/year (only 7700 reported)
Decreased >90% following
Hepatitis A Vaccine
introduction in 1995
Pathophysiology
Picornavirus (enterovirus)
Single stranded RNA genome
Size: 27 nm
Nonenveloped (resistant to bile lysis)
Only replicates in hepatocytes, GI epithelial cells
Hardy agent
Resistant to acids, detergents, freezing
Temperature
s
Survives in salt water and fresh water, soil, hands
Inactivated by heat >185 F, formalin,
Chlorine
Pathophysiology
Timing
Incubation: 15 to 50 days (mean 28 days)
Duration: 2 weeks to 3 months
Contagious status
Infectivity
peaks 2 weeks before and 1 week after symptom onset
Stool
virus concentration peaks 2 weeks before symptoms
Virus
replicates in liver and shed by bilary tract
Stool
is highly contagious
Transmission most likely in presymptomatic period
Asymptomatic children may shed virus for months
No longer contagious once significant symptoms occur
Jaundice
Liver
transaminase peak
Pathophysiology
Transmission
Oral-Fecal transmission
Household or child care centers
Sexual contact
Foodborne Illness
epidemic
Infected food handlers
Raw shellfish
Fresh produce (green onions, strawberries)
Waterborne Illness
epidemic
Blood exposure can occur but is uncommon
Symptoms
Symptom occurence depends on age
Adults: 70% have symptoms
Children under age 6: 70% do not have symptoms
Usually more mild in young children
Common symptoms (onset 5-7 days before
Jaundice
)
Fever
Severe
Anorexia
out of proportion with clinical signs
Nausea
and
Vomiting
Abdominal Pain
Malaise
Headache
Other less common symptoms
Arthralgia
s
Myalgias
Diarrhea
Cough
Constipation
Pruritus
Urticaria
Signs
Pre-icteric (starting 5-7 days before
Jaundice
)
Fever
Enlarged and tender liver (
Hepatomegaly
)
Splenomegaly
Bradycardia
Posterior cervical adenopathy
Signs
Icteric phase
Pale, clay colored stool
Dark Urine
Jaundice
(
Incidence
increases with age)
Under age 6: <10%
Adults: Up to 80%
Course
Illness usually lasts 2 months
Not uncommon to miss 1 month of school or work
Usually complete recovery within 6-12 months
No chronic carrier state
Labs
Complete Blood Count
(CBC)
Leukopenia
Liver
Transaminases elevated
Transaminases are higher than in
Alcohol
ic heptitis and similar or lower than toxic or ischemic hepatitis
Alanine Aminotransferase
(ALT) elevated (500 - 5000 U/L)
Aspartate Aminotransferase
(AST) elevated (500 - 5000 U/L)
Typically lower than the ALT
Liver Function Test
s and Cholestasis Labs elevated
Bilirubin
elevated (<10 mg/dl)
Increase typically follows the transaminase increase
Alkaline Phosphatase
minimally increased
Diagnosis
Hepatitis A Serology
Fecal HAV: present 2-6 weeks after exposure
xHAV IgM
Present 4-12 weeks (up to 6 months) post-exposure
Present 5-10 days before symptom onset
Preferred first-line test (high
Test Sensitivity
>95%)
Risk of
False Positive
in asymptomatic patients
xHAV IgG
Present from 4 weeks after exposure
Present life-long and confers
Immunity
Differential Diagnosis
Acute Hepatitis Causes
Management
Symptomatic relief
Antiemetic
s
Avoid
Alcohol
and other
Hepatotoxin
s
Diet as tolerated otherwise
Rest
Avoid return to work, school until fever and
Jaundice
resolve
Management
Post-exposure
Indications
Serologically confirmed case and
Exposure during source patient's
Incubation Period
and extending until one week after
Jaundice
onset
Administer
Vaccine
or
Immunoglobulin
within 2 weeks of exposure
Hepatitis A Vaccine
(preferred in most cases)
Offer to all outbreak exposures >age 1 years old
Exceptions
Isolated, single case exposures with casual contact (e.g. school, office)
Controlled setting with barrier precautions (e.g. hospital)
Hepatitis A Immunoglobulin
(0.02 ml/kg IM) indications
Patient <1 year old
Age over 40 years old
Serious comorbidity
Immunocompromised
Chronic Liver Disease
Severe allergy to
Hepatitis A Vaccine
Monitoring
Hepatitis A Virus
Antibody
testing is optional
References
(2007) MMWR Morb Mortal Wkly Rep 56(41): 1080-4 [PubMed]
Prevention
Gene
ral Hygiene Measures in endemic areas
Meticulous
Hand Washing
Clean surfaces with 1:100 solution household bleach
Careful food preparation
See
Prevention of Foodborne Illness
Heat foods to 185 F for 1 minute
Avoid uncooked foods
Hepatitis A Vaccine
for high risk potential exposures
Protective for 20 years or more after 2 doses
Recommended as part of
Primary Series
for child age 1 year
Hepatitis A Immunoglobulin
Preexposure for travel within 1 month
Postexposure for close contacts of known case
Complications
Most cases follow a benign, self limited course
No increased risk of
Cirrhosis
and liver cancer
No chronic form of Hepatitis A
Uncommon complications
Relapsing Hepatitis A infection (occurs in up to 15% at up to 6 months after the initial infection)
Rare liver complications
Biliary obstruction
Fulminant Hepatitis
(rare)
Rare extra-hepatic complications
Vasculitis
Arthritis
Thrombocytopenia
Acute Pancreatitis
Aplastic or
Autoimmune Hemolytic Anemia
Acute Renal Failure
Pericarditis
Guillain-Barre Syndrome
Mortality
Caused 100 U.S. deaths per year prior to routine
Hepatitis A Vaccine
Prognosis
Risk factors for serious complications
Age over 50 years
Underlying liver disease (e.g.
Hepatitis B
,
Hepatitis C
)
Pregnancy
Resources
CDC Hepatitis A faq
http://www.cdc.gov/hepatitis/hav/havfaq.htm
References
Jeong (2010) Intervirology 53(1):15-9 [PubMed]
Matheny (2012) Am Fam Physician 86(11): 1027-34 [PubMed]
Yeung (2010) Liver Int 30(1): 5-18 [PubMed]
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