Liver Disease Pathophysiology

Vocabulary flashcards covering the pathophysiology, clinical presentation, and physiological functions of the liver based on medical lecture notes.

Acute liver failure (Fulminant hepatic failure)

A syndrome of acute liver injury occurring in an overwhelming manner, resulting in massive liver cell death and progressive multi-organ failure.

Cholestasis

Isolated impairment of the liver’s role in bile formation and flow, which can be caused by drugs or hepatic injury.

Portal-to-systemic (Portosystemic) shunting

A phenomenon where blood flow is diverted around the liver rather than filtered through it, often due to elevated pressure in the portal vein as seen in cirrhosis.

Sinusoids

Vascular spaces that separate individual plates of hepatocytes where blood from the hepatic artery mixes with blood from the portal vein.

Kupffer cells

Specialized macrophages anchored in the sinusoidal space that perform phagocytosis and cytokine secretion.

Stellate cells (Lipocytes)

Fat-storing cells involved in vitamin A metabolism; in chronic injury, they differentiate into myofibroblasts and contribute to hepatic fibrosis by producing extracellular matrix.

Portal triads (Portal tracts)

Sheath-like structures at the corners of liver lobules containing a portal venule, a hepatic arteriole, and a bile canaliculus.

Limiting plate

The layer of hepatocytes immediately adjacent to the portal triad; its disruption is a diagnostic marker of immune-mediated liver disease.

Zone 1 hepatocytes

Hepatocytes closest to the portal venule and hepatic arteriole; they receive the highest oxygen concentrations and are active in gluconeogenesis and urea synthesis.

Zone 3 hepatocytes

Hepatocytes closest to the central vein; they receive blood with the lowest oxygen concentration and are active in glycolysis and lipogenesis.

Liver Acinus

The unit of liver tissue centered around the portal venule and hepatic arteriole, where hepatocytes are organized based on the sequence in which they contact blood flow.

Biotransformations

Metabolic processes, typically divided into Phase I and Phase II, that convert hydrophobic substances into hydrophilic forms for excretion in urine or feces.

Phase I reactions

Biotransformation reactions involving oxidation reductions that introduce a reactive chemical group (a "handle") onto a drug or toxin.

Phase II reactions

Biotransformation reactions involving the covalent attachment of a drug to a water-soluble carrier molecule such as glucuronic acid or glutathione.

Glutathione

A tripeptide ($\gamma$-glutamyl-cystinyl-glycine) that acts as the major intracellular reducing reagent to prevent oxidative damage and serves as a substrate for Phase II detoxification.

Enterohepatic circulation

The recycling process where bile acids are synthesized in the liver, secreted into the duodenum to solubilize fats, and then reabsorbed in the terminal ileum to return to the liver via portal blood.

Jaundice (Icterus)

A yellow discoloration of the sclera and skin resulting from the accumulation of bilirubin and its metabolites.

Kernicterus

A toxic syndrome affecting the developing nervous system in neonates caused by elevated unconjugated bilirubin concentrations.

Modified Child–Pugh score

A clinical grading scheme used to assess the severity of liver disease based on ascites, encephalopathy, bilirubin, albumin, and prothrombin time prolongation.

MELD score

Model for End-Stage Liver Disease; a scoring system calculated as $3.78[\ln\text{ serum bilirubin (mg/dL)}] + 11.2[\ln\text{ INR}] + 9.57[\ln\text{ serum creatinine (mg/dL)}] + 6.43$, used to prioritize patients for liver transplantation.

Bridging hepatic necrosis

A severe histologic lesion where necrosis involves contiguous groups of hepatocytes, creating necrotic zones that link adjacent portal or central areas.

Piecemeal necrosis (Interface hepatitis)

Necrosis of hepatocytes at the periphery of the lobule with erosion of the limiting plate, characteristic of severe chronic hepatitis.

Nonalcoholic Fatty Liver Disease (NAFLD)

A spectrum of liver disease associated with metabolic syndrome, ranging from simple steatosis (NAFL) to inflammation and fibrosis (NASH).

Autoimmune hepatitis

A chronic inflammatory liver disease characterized by a T cell–mediated immune response, hyperglobulinemia, circulating autoantibodies, and a plasma cell–rich inflammatory infiltrate.

Primary biliary cholangitis

An autoimmune liver disease involving the destruction of small or medium-sized interlobular bile ducts, leading to chronic cholestasis and often positive anti-mitochondrial antibodies.

Primary sclerosing cholangitis

A chronic inflammation of the biliary epithelium leading to multifocal intrahepatic and/or extrahepatic biliary strictures, frequently associated with inflammatory bowel disease.

Cirrhosis

An irreversible distortion of liver architecture characterized by hepatic injury, extensive fibrosis, and nodular regeneration.

Ascites

The accumulation of excess fluid within the peritoneal cavity, defined in liver disease by a serum-to-ascites albumin gradient (SAAG) of $\ge 1.1\,g/dL$.

Hepatorenal syndrome

A functional kidney injury in advanced liver disease caused by intense renal vasoconstriction in response to systemic arterial vasodilation.

Spontaneous bacterial peritonitis

Infection of ascitic fluid without an evident intra-abdominal source, confirmed by a polymorphonuclear leukocyte count of $\ge 250\,cells/\mu L$.

Asterixis

Flapping motions of outstretched, dorsiflexed hands; a neurologic sign of hepatic encephalopathy.

Hepatopulmonary syndrome

A triad of advanced liver failure, hypoxemia, and intrapulmonary vascular dilation and shunting.

Hepatic hydrothorax

The accumulation of fluid in the pleural space, usually on the right side, due to small diaphragmatic defects in patients with cirrhosis and ascites.

Spider angiomas

Prominent blood vessels with a central arteriole and radiating vessels seen in the skin, resulting from estrogen excess in liver disease.