This module covers the essential knowledge of liver diseases crucial for the PLAB 1 exam. We will explore common etiologies, pathophysiology, clinical manifestations, diagnostic approaches, and management principles.

Before delving into diseases, a solid understanding of the liver's anatomy and its vital functions is paramount. The liver performs over 500 functions, including detoxification, protein synthesis, bile production, and metabolism of carbohydrates, fats, and proteins.

Liver diseases can stem from various causes, broadly categorized as infectious, toxic, metabolic, autoimmune, and genetic. Understanding these categories helps in differential diagnosis.

Viral hepatitis is a major cause of liver disease worldwide. Understanding the transmission, clinical course, and management of Hepatitis A, B, C, D, and E is critical.

Alcohol is a significant hepatotoxin. ALD encompasses a spectrum from fatty liver to alcoholic hepatitis and cirrhosis.

NAFLD is increasingly prevalent, strongly associated with metabolic syndrome, obesity, type 2 diabetes, and dyslipidemia. It ranges from simple steatosis to non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis.

Cirrhosis is the end-stage of many chronic liver diseases, characterized by irreversible scarring and nodule formation, leading to portal hypertension and liver failure.

Symptoms can be nonspecific or absent in early stages. As disease progresses, patients may present with jaundice, fatigue, abdominal pain, ascites, edema, pruritus, and signs of hepatic encephalopathy.

Diagnosis involves a combination of history, physical examination, laboratory tests (LFTs, viral serology, autoantibodies, coagulation profile), imaging (ultrasound, CT, MRI), and sometimes liver biopsy.

Management focuses on treating the underlying cause, managing complications, and supportive care. This may include antiviral therapy, immunosuppression, lifestyle modifications, and in severe cases, liver transplantation.