​Kembara Xtra - Medicine - Hepatitis A Virus

​Kembara Xtra - Medicine - Hepatitis A Virus 
The hepatitis A virus (HAV), a species of the Hepatovirus genus, is the culprit behind hepatitis A infections. One of the most widespread viruses in the world, it mostly affects the liver. One of the hepatitis virus varieties that can harm the liver is HAV. HAV stands out from the other hepatitis viruses thanks to a number of unique characteristics.


Epidemiology HAV cases declined by 95% in the US from 1996 to 2011 following the introduction of the HAV vaccine in 1995, with an annual incidence of 1.4 million cases worldwide.
Regional outbreaks have contributed to the rise in cases that have been documented in the US.

There were 12,474 cases reported in the United States in 2018, with an incidence of about 4.0/100,000.

As much as 50% of HAV infections now present in the United States are contracted when traveling to countries where the virus is widespread. There is no variation in infection rates based on sex.
28-day incubation time (range: 15 to 50 days)
Prevalence
Roughly one-third of Americans have serologic proof of previous HAV infection. Anti-HAV prevalence varies with age, from 9% in children aged 6 to 11 to 75% in people over 70.

Child Safety Considerations
Children frequently have milder or no symptoms; as they become older, the severity increases.

 Infections are asymptomatic in 70% of children under the age of six. 
In the United States, >75% of 13 to 17-year-olds have received their vaccinations.

Considerations for Pregnancy Preterm labor, premature rupture of the membranes, antepartum hemorrhage, and placental abruption are all at increased risk. Vertical transmission has also been recorded, and fecal-oral transmission after birth is a possibility.
There is no reason not to breastfeed.


Pathophysiology and Etiology 

A member of the Picornaviridae family of enteroviruses, HAV is single-stranded linear RNA. Only hepatocytes and macrophages are infected.
HAV is primarily disseminated via excretion into the bile and ultimately the feces. Fecal-oral transfer is the main method.
can also spread through intravenous drug usage and sexual activity, especially anal-oral contact. The sole natural host is a human.
Incubation lasts between two and six weeks on average. The 2 weeks prior to and the first week following the onset of a clinical illness are the most contagious.
The majority of times, infection happens after ingesting HAV-contaminated food or drink or through direct contact.
Viruses can survive in liquids and on surfaces, but they can also be quickly destroyed by strong heat or cleaning solvents.
HAV is not a chronic disease, although shellfish (clams and oysters) that have been picked from contaminated waters may be contaminated.
Genetics
After HAV infection, HLA class II DR3 and DR4 are infrequently linked to autoimmune hepatitis.

Risk factors include: direct human contact:
- Intimate exposure, especially among guys who engage in male-to-male sex
- Institutional residential transmission
- Working in the medical field - Exposure in the home
- Daycare facilities and schools
Contaminated food or water contact: >50% of cases in North America and Europe are related to travel to poor nations.
- Eating uncooked or raw vegetables, seafood, or other things. - Eating food that has been inadequately handled Other mechanisms of transmission:
- Injecting illegal substances
- Disorders of the clotting factor, such as hemophilia
- Transfusion or exposure to blood (rare)
- In 50% of cases, no known risk factor

Prevention 
Adequate hand washing and sanitation, especially for those who handle food, provide medical care, or work in childcare Active immunization with HAV vaccines: The inactivated vaccines Havrix and Vaqta and the combination HAV and HBV vaccine Twinrix offer protection for 20+ years.

All children between the ages of 12 and 23 months, with catch-up vaccinations given until the age of 18, and all visitors to nations with a high endemic rate of hepatitis A (parts of Africa, Central and South America, and South and Southeast Asia), are advised to get the vaccine. - Guys who have sex with guys
- People who use medicines both intravenously and topically - People who face employment dangers
- Pregnant women, if there is a danger of infection or serious consequences - All HIV-positive people under the age of one
- Chronic liver illness (including people undergoing and recovering from liver transplants) - Close friends and family of children adopted from nations with a high prevalence of HAV (before to arrival) Routine vaccination is no longer always advised for people who receive blood products for the treatment of clotting problems. - People who are homeless or live in unsafe housing. - Unvaccinated people exposed during an outbreak.

 Don't wait to vaccinate HIV-positive people until their CD4 count rises beyond a specified level (3)[A].
– In those with HIV, vaccination response may be diminished. One month after the HAV series, postvaccination serologic testing should be carried out.
- People with HIV who do not respond should think about getting vaccinated again and using Ig prophylaxis.

 Freezing does not kill HAV; instead, the following things do. - Heating for 60 seconds at >185°F
- Iodine and chlorine


Accompanying Conditions 

Glomerulonephritis, cryoglobulinemia, ocular neuritis, myocarditis, pericardial effusion, Guillain-Barré syndrome, pancreatitis, pneumonia, and pleural effusion are some of the more uncommon extrahepatic symptoms that HAV can sometimes cause.

 Leukocytoclastic vasculitis, thrombocytopenia, aplastic anemia, or red cell aplasia 

Presenting History The beginning is frequently abrupt. Initial signs and symptoms frequently include nausea, emesis, diarrhea, and headache.

The intensity of the symptoms worsens with age.
Children's cases (under 6 years old) are frequently asymptomatic
Other historical facts presented include: - Joint pain, anorexia, anemia, myalgias, fever, and malaise
- Bilirubinuria, or dark urine
- Right upper abdomen discomfort - Pruritus (which may be a sign of cholestasis)


clinical assessment 
Fever is a varied
> 70% of adults and older children have icterus and jaundice.

Splenomegaly is less typical than hepatomegaly.
Tenderness in the right upper quadrant of the abdomen
Rare: arthritis, rash, or cervical lymphadenopathy
Asterixis denotes acute liver failure.

Hepatitis B, C, D, and E are the differential diagnoses. Not clinically different from other viral hepatitis types; during an outbreak, diagnosis may be suspected with usual symptoms.
AIDS infection
Alcoholic hepatitis, drug-induced hepatitis, toxin-induced hepatitis, and autoimmune hepatitis
Malaria; adenovirus infection; Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpes simplex virus, yellow fever; adult-onset hemochromatosis (Wilson disease);
Primary or secondary hepatobiliary illness (elevated AST/ALT): celiac disease, congestive heart failure, and thyroid disease Ischemic hepatitis or Budd-Chiari syndrome Primary or secondary hepatic malignancy
Leptospirosis, syphilis, Rocky Mountain spotted fever, and Q fever are examples of bacterial illnesses. Liver flukes or toxocariasis are examples of parasites. 

Initial diagnostic tests (lab, imaging)
Anti-HAV IgM is the main test used to identify acute infection and is positive at the time of symptom onset with sensitivity and specificity above 95%.
Anti-HAV IgG: develops shortly after IgM and typically lasts for years or for the rest of one's life.
AST/ALT high (500–5,000): ALT typically more than AST

 Mildly increased alkaline phosphatase
Conjugated and unconjugated fractions of bilirubin are often higher.
Typically, bilirubin increases after ALT/AST increases, which is consistent with the pattern of hepatocellular damage.

The partial thromboplastin time and prothrombin time typically stay normal or close to normal.
– Significant increases should prompt worry about concomitant chronic liver illness or abrupt hepatic failure.
CBC: aplasia, pancytopenia, and moderate leukocytosis - Thrombocytopenia may indicate the severity of an illness.
- Rare case of autoimmune hemolytic anemia
Evaluation of hepatic and renal function using albumin, electrolytes, and glucose (rare renal failure)
Urinalysis: bilirubinuria (not clinically essential).
Consider ultrasound (US) only if the lab pattern is cholestatic in order to rule out biliary blockage.

Tests in the Future & Special Considerations

Usually, 4 weeks from the start of an illness, it is over.

Repeat labs are not necessary unless symptoms worsen or acquire new symptoms.
Other/Diagnostic Procedures
Typically, a liver biopsy is not required.
US can assess additional reasons, such as concomitant cirrhosis or thrombosis.
Interpretation of Tests
Hepatitis A positive serum indicators include: Acute disease: only anti-HAV IgM positive; Recent disease (within the last six months): both anti-HAV IgM and IgG positive
- IgM negative and IgG positive for anti-HAV due to past illness or immunization If liver biopsy is performed, it reveals portal inflammation and is immunofluorescently positive for the HAV antigen. 

Management 
Continue to eat and drink sensibly.

Beware of alcohol.
Precautions taken by everyone to stop the spread
Watch out for fluid imbalances, electrolyte imbalances, acid-base imbalances, hypoglycemia, and renal dysfunction.
To the local public health department, report cases.
Laboratory testing to rule out hepatic failure, including coagulation factors
A uncommon referral for fulminant failure to a liver transplant center

Medication Preexposure vaccination in accordance with advised recommendations.
Both of the hepatitis A vaccinations available in the US (Havrix and Vaqta) call for two doses spaced at least 6 months apart.

The ACIP advises giving the first dose as soon as feasible to tourists visiting endemic regions (3)[A].
– For healthy people between the ages of 12 months and 40 years, give the first dose as soon as you can and finish the series within the suggested time frame.
– If you are less than two weeks away from your scheduled departure and you are older than 40, have chronic liver disease, or are immunosuppressed, you should also think about giving Ig injections. Additionally, vaccination series should be finished within the suggested time range.
- Infants under 6 months old should get IG, with the dosage based on the distance traveled.
– Although this dose does not offer long-term protection, infants between the ages of 6 and 11 months should take one dose of the vaccine; at 12 months, the newborn will need to receive a series of vaccinations.
Give postexposure prophylaxis to people who haven't gotten the HAV vaccine before within two weeks of being exposed to the virus (3)[A].
- As soon as possible, give healthy people between the ages of 1 and 40 the hepatitis A vaccine series.
For those over 40, take into account IG. If the patient has already received at least one dose of the vaccination, a second dosage is not required.
- Give children under 1 years old IG (0.1 mL/kg).
- Individuals with substantial comorbidities (liver disease, immunosuppression, etc.) who have not yet finished the immunization series should be given the vaccine plus immunoglobulin. If the patient has already received at least one dose of the vaccine, a second dosage is not necessary. If the patient is ineligible for the vaccine, use Ig for passive preexposure prophylaxis.
- 1 and 2 months of coverage are offered by 0.1 and 0.2 mL/kg, respectively.
- For sustained risk (such as travelers), long-term (>2 months) prophylaxis should be administered with 0.2 mL/kg every 2 months.
– Infants under the age of six months, people with immune impairment, people who have chronic liver illness, and people for whom immunization is not recommended should all get one dose of 0.1 to 0.2 mL/kg.
Use Ig by itself in children under 1 year olds.
- Avoid administering Ig within six months after receiving the MMR or varicella vaccines.

Initial Line
No antiviral drugs are recommended; over 99% of patients get spontaneous remission.
Acetaminophen should only be taken in doses of no more than 2 grams per day.
Don't use hepatotoxic substances.
Second line: diphenhydramine 50 mg PO IM every six hours; consider cholestyramine 4 g BID if cholestasis; antiemetics (such as ondansetron); IV fluids; pruritus.


A high-volume liver transplant program should be referred in cases of hepatic failure, depending on the severity of the patient's sickness.

Surgical Techniques 
Rare reasons for liver transplantation in fulminant hepatic failure 

Alternative Therapies 

Barberry, comfrey, golden ragwort, groundsel, huang qin, kava kava, pennyroyal, sassafras, senna, valerian, wall germander, and wood sage are among the plants that may be hepatotoxic.

Admission 
Unless there are symptoms of liver failure, most patients get outpatient care.
Address electrolyte imbalances and dehydration.
Enteric seclusion. Masks, robes, and private spaces are not required.
Frequently cleansing hands.  A bleach solution diluted 1:100 can be used to clean surfaces. Wear gloves when handling possibly contaminated materials.

Follow-up Patients are contagious for up to 4 weeks following the commencement of their symptoms, so it's important to practice good hygiene when returning to work or school.


Monitoring of the patient includes checking for coagulation issues, fluid and electrolyte imbalances, hypoglycemia, and renal function. 

Diet
Avoid drinking, eat a balanced diet, and segregate those who handle food if they have HAV. HAV immunity lasts for years after infection.

Excellent prognosis; case-fatality ratios range from 0.1% to 5.4% depending on age and the study; risk is higher in people who have underlying chronic liver disease and in older people (1.8% mortality rate for people over 50 years old).

 Coagulopathy, encephalopathy, and renal failure are complications.
Prolonged cholestasis is characterized by prolonged periods of jaundice and pruritus (>3 months); it only resolves with supportive care. Autoimmune hepatitis can occur after HAV infection, but it responds well to steroids. Relapsing HAV is typically milder than the initial case.
Hepatic failure occurs in 1-2% of cases.
Pancreatitis, aplastic or hemolytic anemia, agranulocytosis, thrombocytopenic purpura, pancytopenia, postviral encephalitis, Guillain-Barré syndrome, vasculitis, arthritis, and cryoglobulinemia (all rare)

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