Medically Fit For Exams
Medically Fit For Exams

Hepatitis

Definition

  • Inflammation of the liver, impacting on liver function
  • Can refer to viral hepatitis (HAV, HBV, HCV, HDV & HEV)

 

Risk factors

  • Viral hepatitis
    • Habitation or travel to high risk areas
      • Africa
      • Asia
      • South America
    • Unprotected sex (HBV mainly)
    • Needle sharing/infected blood products (HBV, HCV, HDV)
    • Eating/drinking contaminated substances (HAV, HEV)
    • Immunodeficiency
  • Alcohol abuse
  • Drug abuse

 

Differential diagnosis

  • Liver abscess
  • Pancreatic cancer
  • Hepatocellular cancer
  • Cholangitis
  • Cholelithiasis
  • Peptic ulcer

 

Epidemiology

  • Viral hepatitis
    • Hepatitis A is most common worldwide, is endemic in many countries, especially in Africa
      • In endemic areas, is very common in children, epidemics are unlikely
      • Low prevalence in many countries
    • Hepatitis B
      • Up to 20% prevalence in some parts of Africa and Asia
      • Much lower in UK
      • Spread through blood, sexual contact
    • Hepatitis C
      • Common in IV drug users
      • Very high prevalence in Egypt (spread through dodgy vaccines)
      • Low prevalence in UK
      • Very difficult to cure, likely to progress to chronic, so quite a few carriers
    • Hepatitis D relies on HBV coinfection
      • Similar demographic to HBV, especially IV drug users
    • Hepatitis E
      • Up to 40% prevalence in India
      • Similar demographic to HAV
  • 10-20% of heavy drinkers will develop alcoholic hepatitis

 

Aetiology

  • HAV – infection with hepatovirus
  • HBV – infection with hepadnavirus
  • HCV – infection with flaviridae
  • HDV – infection with deltaviridae
  • HEV – infection with hepeviridae
  • Alcoholic hepatitis causes by alcohol abuse
  • Autoimmune hepatitis – cause generally unknown, may have environmental trigger

 

Clinical features

  • Likely to be initially asymptomatic, unless rapid progression to fulminant hepatitis
  • As progresses may notice
    • Anorexia
    • Malaise
    • Weight loss
    • Pruritis
    • Nausea and vomiting
    • Smell/taste change and aversion
    • Fever
  • May progress to
    • Dark urine
    • Pale stool
    • Jaundice
    • Rash
    • GI signs
    • Hepatomegaly – firm with smooth border
  • Fulminant hepatitis
    • Very severe acute hepatitis
    • Has associated encephalopathy
    • Most patients die

 

Pathophysiology

  • Acute hepatitis
    • Likely to be little macroscopic change – insufficient time
    • May be mottled and large in mild hepatitis
    • In severe acute hepatitis liver may be necrosed and therefore red and shrunken
    • Necrosis of hepatocytes is most pronounced in zone 3 of liver lobule (closest to central vein)
    • Apoptosis also occurs
    • Eosinophilia and lots of macrophages to clear debris
    • If damage is very severe, the reticulin framework can break down, resulting in collapse and necrosis of the entire parenchyma (liver lobule)
    • Regeneration usually occurs after about a week
      • Will go pretty much back to normal if reticulin framework is preserved
      • If reticulin necrosis, regeneration is patchy, with hepatocytes forming nodules, with scar tissue, resulting in post-hepatic cirrhosis
  • Chronic hepatitis
    • Likely to occur in HCV and HDV, can also occur in HBV
    • Macroscopically, may be little change, or may appear fibroses, or nodular
    • Cirrhosis has palpable nodules
    • May progress to carcinoma
    • Portal inflammation (around the portal triad)
    • Interface hepatitis – inflammation between lobules and portal triad, rather than within the lobule (as with acute hepatitis)
    • Evidence of regeneration and scarring
      • Fibrous septa between portal tracts
  • Alcoholic hepatitis
    • Often associated with alcoholic fatty liver disease
    • Mallory bodies – tangles of filaments inside degenerating hepatocytes
    • Neutrophil infiltration

 

Investigations

  • FBC
  • LFT –
    • Raised bilirubin
    • Albumin may be normal in acute, may be raised in chronic
    • INR may be low
    • ALT is likely to be very high (up to 50x normal)
    • AST is likely to be very high (over 1000)
  • Microscopy, culture and sensitivities
  • Serology for viral antibodies
  • Liver ultrasound
  • Urinalysis (bilirubin)
  • Might take liver biopsy for chronic hepatitis

 

Management

  • Prevention is important for viral and alcoholic causes
    • Vaccinations available for HAV & HBV, but not HCV or HDV (HEV vaccine recently developed)
    • Stop risky behaviours
  • Generally no specific treatment for hepatitis, management is usually supportive
    • Chronic HBV can be treated with antivirals, but cure rate is low
    • Direct antiviral agents are used in chronic HCV
    • Interferon therapy used to prevent acute HCV progressing to chronic
    • Liver transplant possible in HDV

 

Prognosis

  • Fulminant hepatitis has very high mortality rate
  • HCV and HDV have high rate of progression to chronic hepatitis
    • Increased morbidity and mortality
Hepatitis.docx
Microsoft Word document [16.1 KB]

Get social with us.

Print Print | Sitemap
© medicallyfitforexams.co.uk