diease

Hepatitis-B


Hepatitis-B overview and Definition

Hepatitis B is a liver infection caused by hepatitis B virus (HBV). Chronic hepatitis B increases your risk of liver failure, liver cancer and liver cirrhosis. Most adults with hepatitis B recover completely. Infants and children develop a chronic hepatitis B infection. There is no cure for hepatitis B. A vaccine can prevent hepatitis B.

Clinical Clarification/Definition

Hepatitis B virus (HBV) is a hepadnavirus with a double-stranded DNA. The virus is also called as Dane particles. There are eight different genotypes A–H. HBV is transmitted by infected blood or sexual contact. Men are at greater risk than women. Infection caused by HBV may be associated with serum sickness, glomerulonephritis, and polyarteritis nodosa.


Classification of Hepatitis-B

Classification

Based on duration of hepatitis B it can be

  1. Acute hepatitis –infection occurs for upto 6 months
  2. Chronic hepatitis – infection that occurs for more than 6 months

Based on clinical presentation hepatitis B can be

  1. Pre- icteric
  2. Icteric
  3. Post – icteric


Epidemiology

According to epidemiological study on 2017, 5% of the world's population have had chronic HBV infection. Over 7,50,000 people die of hepatitis B each year.


Factors associated with Hepatitis-B

Causative factor

·       Having unprotected sex.

·       Using contaminated needles by drug users, tattoos or piercing.

·       Sharing items like razors, toothbrushes, jewelry for piercings and nail clippers that contain blood

·       Being bitten by someone with hepatitis B

·       Mother to child - born to pregnant woman hepatitis B

Hepatitis B doesn’t spread through kissing, water, food, coughing, sneezing. 


Risk Factor

·       High risk sexual behavior

·       drug users

·       living with untreated infected patients

·       mother to child during delivery 

  • occupational exposure


Pathophysiology

Hepatitis B virus is not cytopathic. Liver injury is immune mediated. Antigen cytotoxic T cells play a role in cell injury. cytokines produced by cytotoxic and other T cells also have antiviral effects that causes viral clearance and doesn’t cause cell death. Chronic infection occurs more commonly due to lack of CD8+ cytotoxic T cell and CD4+ helper T cell response. spontaneous seroconversion from HBeAg to anti-HBeAb during chronic hepatitis B is immune mediated.


Routes of Transmission

Routes Of Transmission/Spread

Horizontal transmission –

  • Injection by drug users
  • Infected unscreened blood products
  • Contaminated Tattoos and acupuncture needles
  • Sexual - homosexual and heterosexual

Vertical transmission –

              HbsAg-positive mother


Clinical signs & symptoms

The onset of symptoms is abrupt with general malaise, myalgia, arthralgia, fatigue and anorexia.

Nausea, vomiting, and diarrhea or constipation are frequent

Serum sickness seen early in acute hepatitis B.

Fever is low-grade.

There is a fall in pulse rate with the onset of jaundice.

Abdominal pain is present in right upper quadrant or epigastrium.

Hepatomegaly, Liver tenderness, and Splenomegaly is seen in 15% of patients

Jaundice occurs after 5–10 days of infection

The acute symptoms subside within 2–3 weeks.

< 1% will have a fulminant course and results in fulminant hepatitis

Hepatitis B may become chronic

It increases risk of hepatocellular carcinoma of liver


Clinical Examination/tests – 

·       General – fever, night sweats

·       Skin – icteric skin, urticaria rash in skin

·       Oral cavity – yellowing mucosa of oral cavity

·       Eyes – icteric sclera

·       Neurological – Dementia, mental confusion, coma

·       Abdomen cavity – hepatosplenomegaly, lymph node enlargement


General Essentials of Diagnosis:

 

·       Prodrome period of anorexia, nausea, vomiting, malaise and dislike the taste of smoking

·       Fever, enlarged and tender liver, jaundice.

·       Normal to low white blood cell count with markedly elevated aminotransferases

·       Liver biopsy shows hepatocellular necrosis and mononuclear infiltrate 


Diagnostic Test

Lab Test


·       HBsAg is the first evidence of infection

·       Specific antibody to HBsAg also called as anti-HBs appears after clearance of HBsAg and after successful vaccination

·       IgM anti-HBc detects diagnosis of acute hepatitis B

·       HBeAg is a secretory form of HBcAg that appears during incubation period


The following tests are done after confirmation of HEPATITIS B markers,

·       white blood cell count is normal to low

·       leucopenia with a relative lymphocytosis

·       Mild proteinuria is common

·       elevated AST or ALT occurs early followed by elevations of bilirubin and alkaline phosphatase

·       increase in urinary urobilinogen. A Prodromal stage; the serum bilirubin is usually normal.

·       Coombs’-positive hemolytic anemia or aplastic anemia.

·       prothrombin time (PT) is prolonged in severe cases.

·       erythrocyte sedimentation rate is raised.


Radiology

·       ULTRASOUND

hepatomegaly - most sensitive sign

gallbladder wall thickening

periportal edema

accentuated brightness of portal vein radicle walls

 

·       CT

Hepatomegaly

periportal edema

diffuse edematous change

possible periportal/hepatoduodenal lymphadenopathy

 

·       MRI

periportal edema

periportal enhancement

hepatic steatosis

 

·       ERCP

acalculous cholecystitis

cholangitis 


Differential Diagnosis


  1. Hepatitis B and C
  2. Other infections like infectious mononucleosis, cytomegalovirus infection, herpes simplex virus infection, leptospirosis, secondary syphilis, brucellosis, Q fever
  3. drug-induced liver disease
  4. ischemic hepatitis
  5. autoimmune hepatitis
  6. Cholestasis may mimic obstructive jaundice.


Treatment

Medical

The use of antivirals for Hepatitis B infection:

·       Interferon Alfa is used in treatment of Hepatitis B infection with low viral load.

·       Other medications like lamivudine, PEGylated Interferons and Adefovir are being used in treatment and control of Hepatitis B infection.

The indications for use of antivirals are:

a.       Fulminant hepatitis B

b.       Immune reactive HBeAg positive chronic hepatitis B

c.       HBeAg-negative chronic hepatitis

d.       Pregnant women with viral load more than 2,00,000 IU

e.       reactivation hepatitis B.

 

There is no specific treatment only supportive care is given:

·       rest until recovery and avoid strenuous exercise

·       replace fluid loss with ORS. Provide IV infusion only in case of severe nausea and diarrhea

·       dietary changes – avoid drinking alcohol and intake of heavy, oily and bulky foods

·       avoid taking unnecessary medications like paracetamol, acetaminophen

 

When to Admit - hospitalization is required only in case of acute liver failure

·       Encephalopathy is present.

·       INR > 1.6.

·       The patient is unable to maintain hydration.


Surgical

Hepatic transplantation is indicated in the case where chronic infection results in carcinoma or cirrhosis that causes inability of liver to function properly.

Caution is advised since there is possibility for rejection.


Prognosis

Complete recovery occurs in 90-95% of adults cases with acute HBV infection.

5-10% of cases develop into chronic infection

In children 90% of cases are due to infection passing from mother to child at birth.

Chronic infection is common in immunodeficient conditions like Down's syndrome or HIV infection. 

Recovery from acute HBV infection occurs within 6 months

The presence of HBeAg in blood after 6 months indicates chronic infection of hepatitis B

When HBV infection occurs with HDV infection the diseases is more aggressive

chronic hepatitis B patients are asymptomatic and develop complications like cirrhosis and hepatocellular carcinoma after many years.

Cirrhosis occurs in 15-20% of patients with chronic HBV in 20 years


Complications

·       cholestatic hepatitis

·       liver cirrhosis

·       hepatocellular carcinoma

·       relapsing hepatitis

·       hepatitis B carriers

·       autoimmune hepatitis

·       acute liver failure

·       death and coma


Prevention


  • screening of blood products before transfusion
  • screening of organs before being transplanted
  • educate and counsel high risk groups about risks of needle sharing and unsafe sexual habits
  • improve personnel hygiene – do not share personnel items like razors etc.
  • caution while getting tattoo
  • vaccinations:
    • to parenteral drug users
    • to patients on hemodialysis
    • patients with chronic liver disease
    • occupational – medical, garbage and sewage cleaners
    • infants born to infected mother