Hepatitis B: Clinical sciences

Chapters:

Watch video only

Introduction0:00–0:42

Hepatitis B virus, or HBV for short, is a bloodborne DNA virus transmitted through blood or sexual contact. Once inside the body, hepatitis B virus circulates through the blood, eventually reaching the liver, where it infects hepatocytes.
After the acute phase of the infection, many patients fully recover as their immune system clears the virus. But, if the virus sticks around long enough in the body, acute infection can progress to chronic infection, which can lead to the development of cirrhosis, and even hepatocellular carcinoma.Now, if your patient presents with a chief concern suggesting hepatitis B infection, perform an ABCDE assessment to determine if they are unstable or stable.

Unstable Patient0:42–1:51

Unstable patients may have signs like altered mental status, asterixis, upper GI hemorrhage, and ascites. In this case, immediately stabilize their airway, breathing, and circulation.
Next, obtain IV access and put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry.
Here’s a clinical pearl! In some individuals, acute hepatitis B infection can lead to fulminant hepatic failure, which is a life-threatening condition that's often associated with hepatic encephalopathy!
Labs usually reveal coagulopathy, with INR equal to or greater than 1.5, as well as elevated AST, ALT, and bilirubin. In this situation, stabilize your patient and consider consulting both your hepatology and surgery teams for further management, including a liver transplant.Okay, let’s go back and discuss stable patients.

Stable Patient 1:51–3:24

First, obtain a focused history and physical examination. Patients will usually report systemic symptoms, such as fatigue, anorexia, and low-grade fever; and gastrointestinal symptoms, like nausea, vomiting, and right upper quadrant pain.
Additionally, your patient might report a history of needlestick injury, intravenous substance use, unprotected sexual intercourse, or receiving a non-sterile tattoo.
The physical exam typically reveals jaundice and abdominal tenderness. Additionally, you might notice hepatomegaly, and inflammatory skin changes, like psoriasis or urticaria, as well as signs consistent with thrombocytopenia, such as petechiae.Now, another clinical pearl!
Individuals with hepatitis B can be asymptomatic, with no significant history or exam findings. So, for all patients, you should ask thorough questions about risk factors, such as IV drug use and high-risk sexual practices, and remember that all adults should be screened at least once!Once you are done with a focused history and physical exam, order labs, including CBC, CMP, PT/INR, and PTT.
Labs might reveal thrombocytopenia, as well as elevated ALT, AST, bilirubin, PT, INR, and PTT! At this point, you should suspect hepatitis B infection, so proceed with serologic testing, which include hepatitis B surface antigen, hepatitis B surface antibody, and hepatitis B core antibodies, both IgM and IgG.Here’s another clinical pearl!

Serologic testing3:24–4:35

After exposure to HBV, the first marker of infection detectable in blood is the hepatitis B surface antigen. The body responds to the virus by producing surface antibodies, which bind to the surface antigen and clear it from the blood.
In the bound state, the surface antigen and the antibody are not measurable! This creates a window period between 6 and 8 months after exposure, during which these markers are undetectable.
Fortunately, the body also produces the IgM core antibody during this time, making the virus detectable during the acute infectious period.
This is the reason why hepatitis B infection is screened with the triple test panel, which includes the surface antigen, the surface antibody, and the IgM core antibody!Okay, let’s take a look at the possible results of the serologic testing!

Alternative Diagnosis4:35–5:00

If the surface antigen, surface antibody, and core antibodies are all negative, your patient doesn’t have a hepatitis B infection.
In this case, consider an alternative diagnosis and be sure to provide infection transmission counseling!Next up are vaccinated individuals.

Immunity Due to Vaccination 5:00–5:47

If you see a negative surface antigen, a positive surface antibody, and negative core antibodies, that suggests immunity to HBV from prior vaccination.
This is because currently available vaccines only contain the surface antigen. Keep in mind that the presence of HBsAg can be transiently positive within 30 days after a dose of the Hepatitis B vaccine.
Now, even though your patient is immune to HBV, they’re still at risk for other viral infections, so provide infection transmission counseling, like avoiding IV substance use and following safer sex practices!Now let’s discuss individuals with prior infection.

Immunity Due to Prior Infection 5:47–6:16

If the surface antigen is negative, the surface antibody is positive, and the IgG core antibody is positive, this represents a prior, resolved infection and conferred immunity.
Again, even though immune, these patients are still at risk for other viral infections, so be sure to provide counseling on infection transmission!Next we have patients with acute infection.

Acute Hepatitis B infection6:16–7:48

Serology will reveal a positive or negative surface antigen, a negative surface antibody, and positive IgM core antibody.
In this case, diagnose acute HBV infection! But remember, if you happen to test during the window period, the surface antigen could be negative!Once you diagnose acute hepatitis B infection, initiate supportive treatment with oral or IV fluids and nutritional support, as well as symptomatic treatment for nausea and vomiting.
Counsel your patient on lifestyle modifications, like avoiding hepatotoxins, including acetaminophen and alcohol. In addition, offer infection transmission counseling, and recommend the hepatitis B vaccine and immunoglobulin to any household or sexual contacts.
Finally, screen your patient for viral co-infections, like hepatitis C and D, and HIV. Next, monitor the patient’s liver function with serial CBC, CMP, and INR until recovery.
Most acute hepatitis B cases are self-limiting, resolving within 1 to 6 months, but in severe cases, consider treatment with oral antiviral medications, such as nucleoside inhibitors like tenofovir or entecavir.Okay, after 6 months following the diagnosis, you need to recheck the surface antigen and surface antibody to see if the immune system has cleared the virus.

Recovery vs Chronic Infection7:48–8:36

If the surface antigen is negative and the surface antibody is positive, then your patient has fully recovered, so make sure to provide infection transmission counseling.
On the flip side, if the surface antigen is still positive and the surface antibody is negative, diagnose chronic hepatitis B.Here’s a high-yield fact!
The risk of progression from acute to chronic infection declines with age. So a newborn with acute infection has a 90% chance of progressing to chronic infection, whereas for an immunocompetent adult, it’s only 5%!Now, let’s go back to our original serology testing one last time.

Chronic Hepatitis B infection8:36–9:03

Consider a patient who has a positive hepatitis B surface antigen, negative surface antibody, and positive IgG core antibody.
In this case, diagnose chronic hepatitis B infection! Keep in mind that acute hepatitis B is often asymptomatic, so many patients will only come to clinical attention at the stage of chronic infection.If your patient presents with chronic hepatitis B infection, you should assess them for indications for antiviral treatment.

Indications for Antiviral Treatment9:03–10:12

These include acute liver failure; cirrhosis with detectable HBV DNA; a robust immune response called the immune active stage; personal or family history of hepatocellular carcinoma; immunosuppressive therapy; pregnancy; and a hepatitis B co-infection with hepatitis C or HIV.Here’s another clinical pearl!
Before assessing indications for antiviral treatment, you should check markers of viral replication and infectivity, which include hepatitis B DNA level, hepatitis B e antigen, and hepatitis B e antibody.
When these markers are positive, it means your patient is actively infected and can transmit the virus! Additionally, in order to identify hepatic fibrosis or cirrhosis, obtain hepatic elastography, a noninvasive test that measures liver stiffness, or less commonly, a liver biopsy.First, let’s go over treatment if there are no indications for antiviral treatment.

Treatment Indications Absent10:12–11:10

Recommend lifestyle modifications like avoidance of hepatotoxins and smoking cessation. Counsel your patient on infection transmission, vaccinate them against hepatitis A, and recommend hepatitis B vaccination to close contacts.
Don’t forget to screen for co-infections, such as hepatitis C and D, and HIV; and other causes of liver disease, like hemochromatosis.
Schedule regular follow-ups for laboratory monitoring with serial CBC, CMP, and INR. You should also closely monitor viral activity with serial hepatitis B DNA and e antigen.
Finally, since individuals with chronic HBV are at risk of hepatocellular carcinoma, schedule regular liver ultrasounds and check alpha-fetoprotein levels for surveillance.Finally, let’s go over treatment if indications for antiviral treatment are present.

Treatment Indications Present11:10–11:44

Proceed with the same management, but don’t forget to include antiviral medications. The first-line treatment includes nucleoside inhibitors, such as tenofovir or entecavir, and less commonly, you can consider pegylated interferon alpha.
Keep in mind that treatment does not eradicate the virus, but decreases the risk of developing cirrhosis and hepatocellular carcinoma and improves long-term survival!
Alright, as a quick recap… Acute hepatitis B is diagnosed with a positive surface antigen, negative surface antibody, and positive core IgM antibody.

Review11:44–12:46

But remember, the surface antigen is typically negative during the window period! Management involves supportive treatment, lifestyle changes, vaccines, co-infection screening, and liver function checks, with antivirals for severe cases.
Most patients recover within 6 months, which is marked by seroconversion from surface antigen positive to surface antibody positive.
On the flip side, if the surface antigen remains positive after 6 months, diagnose chronic hepatitis B. Next, assess indications for antiviral treatment.
Finally, since individuals with chronic hepatitis B are at risk of hepatocellular carcinoma, don’t forget to schedule regular liver ultrasounds and check alpha-fetoprotein levels for surveillance.