Hepatitis

Hepatitis is a condition that causes inflammation of the liver due to various reasons. Inflammation is the swelling that occurs when body tissues are injured or infected. Your liver's ability to function may be affected as a result of the swelling and damage. Hepatitis is classified as either an acute (short-term) or chronic (long-term) infection. It can manifest itself in various ways, ranging from a complete lack of symptoms to severe liver failure. Hepatitis treatment differs depending on the kind of hepatitis, whether acute or chronic and the severity of the condition.

Causes of hepatitis are broadly categorized into two types:

1. Infectious causes
2. Non-infectious causes

Infectious Causes are the most common cause of hepatitis, caused by viruses, bacteria, fungi, and parasites. Amongst them, more than 50% of cases are caused by viruses.

Non-Infectious Causes include alcohol, drugs, metabolic diseases, and autoimmune diseases.

Following are the types of hepatitis:
1. Viral Hepatitis

• Hepatitis A is an acute (short-term) infection caused by the hepatitis A virus (HAV).
•  Hepatitis B: Hepatitis B is caused by the hepatitis B virus (HBV). This is often a chronic (long-term) condition. According to the Centers for Disease Control and Prevention (CDC), approximately 826,000 people in the United States and 257 million people globally have chronic hepatitis B.
• Hepatitis C: The hepatitis C virus (HCV) causes hepatitis C. In the United States, HCV is one of the most common bloodborne viral infections, and it usually manifests as a long-term condition.
• Hepatitis D: This is a rare type of hepatitis that only develops when hepatitis B infection is present. Hepatitis D virus (HDV) produces liver inflammation the same way as other strains do, but it can only be contracted if a person already has a hepatitis B infection.
• Hepatitis E:  Hepatitis E is a waterborne infection caused by the hepatitis E virus (HEV). It is primarily present in places with poor sanitation, and it is usually contracted by ingesting contaminated food and water.

2. Alcoholic Hepatitis: excessive alcohol use is a significant cause of alcoholic hepatitis and the leading cause of cirrhosis in the United States. The quantity and duration of alcohol consumption are the most critical risk factors for the development of alcoholic hepatitis.
Ischemic Hepatitis: Ischemic hepatitis is caused by a reduction in blood flow to the liver, which can occur due to shock, heart failure, or vascular insufficiency. Heart failure is the most common cause of the disease, but it can also be caused by shock or sepsis.
Autoimmune Hepatitis: Autoimmune hepatitis is liver inflammation caused by your immune system attacking liver cells. The specific cause of autoimmune hepatitis is unknown, but it appears that genetic and environmental factors interact over time to develop the condition.

Following are the routes of transmission for viral hepatitis that constitute most hepatitis cases:

• Fecal-oral transmission- virus is shed in infected person’s feces and transmitted through contaminated food or water. Hepatitis A and E mainly spread through this route.
• Parenteral transmission- through fluids of inflected persons such as blood, saliva, semen, breastmilk. Hepatitis B mainly spreads via this route
• Sexual transmission- hepatitis B, D, and C spread through sexual contact.
• Perinatal transmission- virus travels from infected mother to the child. Hepatitis B, C, and D spread through perinatal transmission.
• Sporadic transmission- other than that, hepatitis B and C also spread through unknown mechanisms.

• Healthcare individuals are at increased risk of hepatitis B and hepatitis C infections.
• Intravenous and intranasal drug users are at increased risk of developing hepatitis C infection.
• Hepatitis A and E are more prevalent in less developed countries, where water contamination due to improper sewage disposal is an important issue.

Infectious hepatitis presents in the following phases:

Phase 1- patients are asymptomatic, but serologic testing done for such patients is positive.

Phase 2- patients develop symptoms of anorexia, nausea, vomiting, bad taste in the mouth, generalized weakness, and body pains and might be misdiagnosed as gastroenteritis.

Phase 3- signs and symptoms of jaundice are apparent in this phase, including pallor, dark-colored urine, pale stools, and weakness. On clinical examination, liver enzymes are markedly raised, and liver inflammation can also be observed. These signs help in the diagnosis of hepatitis.

Phase 4- patients return to normal. Jaundice and other clinical symptoms resolve. Liver enzymes return to normal levels.

The incubation period for various types varies. For hepatitis A, the incubation period is 2 to 7 weeks. Signs and symptoms are like those of gastroenteritis. The incubation period for hepatitis B is around one month to three months (30-180 days). Hepatitis B can rapidly progress, causing fulminant liver failure. The incubation period for hepatitis C is 15-150 days. Most patients with this type remain asymptomatic and exhibit a few clinical signs. The incubation period for hepatitis D is around 35 days. It is an acute self-limiting type. The incubation period for hepatitis E is 2-9 weeks.
General signs and symptoms of the most common types of hepatitis include:

• Fatigue
• Nausea
• Vomiting
• Fever
• Anorexia
• Dehydration
• Hepatomegaly
• Jaundice
• Rash
• Joint swelling and pains

Following are the complications of hepatitis, most seen in the cases of hepatitis B and C:

• Hepatic Necrosis
• Chronic Active Hepatitis
• Chronic Hepatitis
• Cirrhosis
• Hepatic Failure
• Hepatocellular Carcinoma (HCC)

Following investigations are done to diagnose hepatitis and its various forms:

• Liver function tests- show increased levels of ALP, AST, and bilirubin.
• Urine analysis for the presence of bilirubin
• Deranged prothrombin time (PT) because of impaired coagulation function by the liver
• Increased blood urea nitrogen (BUN) due to renal involvement
• IgM for hepatitis A infection indicates acute infection. The presence of IgG antibodies indicates lifelong immunity has been achieved against hepatitis A infection. 
• IgM for hepatitis B antigen (HBsAg) in acute hepatitis. Increased levels of HBsAg after six months of infection indicate chronic infection 
• For hepatitis C, serologic tests are done for anti-HCV antibodies. Rapid test kits can detect Anti-HCV. PCR is done for a quantitative assay to know about the viral load of hepatitis C infection.
• For hepatitis D and E, IgM antibody assays are done.
• For chronic hepatitis after B or C infections, a liver biopsy might be indicated.

Differential diagnoses of hepatitis include:

• Liver abscess
• Drug-induced hepatitis
• Auto-immune hepatitis
• Hepatocellular carcinoma
• Gallstones
• Acute pancreatitis
• Acute gastroenteritis
• Peptic ulcer disease
• Small bowel obstruction

• Rehydration with oral and intravenous fluids is recommended in patients with severe nausea and vomiting with electrolytes replacement.
• Liver abscess is treated with parenteral antibiotics according to the causative organism and might require surgical drainage.
• The use of hepatotoxic drugs, the most common of which is acetaminophen, also commonly known as paracetamol, is restricted.
• For acute hepatitis B, lamivudine can be used.
• Patients with acute hepatitis C are treated with interferon-alpha 2b type.
• Patients with chronic hepatitis B and C are put on antiviral or interferons therapy.

The prognosis of hepatitis varies depending upon the causative agent.

• Hepatitis A is a mild form of infection, and the prognosis is usually good. One-time infection confers life-long immunity against the disease.
• Hepatitis B and C can progress to chronic forms causing hepatic failure and hepatocellular carcinoma (HCC). The outcome for patients with chronic disease is generally not good.
• Hepatitis E infection like hepatitis A is also self-limiting. Prognosis in pregnant women is not good where it can cause death during pregnancy.