Hepatic Disorders PDF

Hepatic Disorders HEPATIC DISORDERS AND HEPATIC Acute illness with liver function test FAILURE abnormalities also occurs with infection by...

Hepatic Disorders HEPATIC DISORDERS AND HEPATIC Acute illness with liver function test FAILURE abnormalities also occurs with infection by other hepatotorpic viruses such as This chapter will review the epidemiology, cytomegalovirus (CMV), herpes simplex virus Pathophysiology, and clinical presentation of (HSV), Coxsackie virus, and Epstein-Barr virus acute and chronic liver failure. It will (EBV), although these agents are unlikely to summarize laboratory testing and evidence- cause clinically evident hepatitis and jaundice based emergency diagnosis and management of in otherwise healthy individual. complications of hepatic failure, including gastrointestinal hemorrhage, spontaneous Alcoholic liver disease and viral hepatitis bacterial peritonitis, hepatorenal syndrome, ad comprise the vast majority of cases of acute and hepatic encephalopathy. chronic liver disease. Other causes include a variety of toxins, idiosyncratic drug reactions ACUTE AND CHRONIC LIVER DISEASE and autoimmune and metabolic hepatobiliary diseases. Epidemiology Pathophysiology About one-third of the U.S. population has acquired immunity to hepatitis A virus (HAV). Hepatobiliary diseases are classified according There are approximately 125,000 to 200,000 to the main pathologic processes involved and cases of HAV infection reported yearly, with an include hepatocellular, cholestatic, estimated 100 related deaths. Fulminant liver immunologic, and infiltrative disorders. failure is a rare complication of HAV infection, Considerable overlap occurs among these and chronic infection does not occur. different processes, with a common result being progressive hepatic dysfunction. Vaccination against hepatitis B virus (HBV) has reduced the incidence of fulminant hepatic Hepatic cirrhosis results from fibrous scarring failure by as much as three-quarters in some mixed with hepatocyte regeneration in response studies. Chronic infection occurs in only 6 to to sustained inflammatory, toxic, or metabolic 10 percent of cases of hepatitis B. In contrast, insults. Over time, the functional anatomy of chronic hepatitis C occurs in 85 percent of the liver is replaced by scar tissue, isolating those infected, with 70 percent developing nodules of regenerating hepatocytes. These resulting chronic liver disease. isolated foci are less efficient at performing the metabolic functions of the normal, highly The hepatitis D virus (HDV) is uncommon and structured liver. In addition to causing is described as a defective agent because progressive loss of synthetic and metabolic infection depends on concomitant or pre- function, scarring increases resistance to blood existing chronic infection by HBV. In flow from the splanchnic circulation, leading to individuals with chronic HBV infection, portal hypertension and portal-systemic superinfection with HDV often results in a shunting. Reduced blood flow through the liver rapidly progressive or fulminant form of liver deprives the remaining hepatocytes of substrate disease carrying a high short-term mortality for synthesis of essential proteins and rate. This variety of infection is most degradation of toxins, worsening the metabolic commonly associated with intravenous drug deficiencies of chronic liver disease. Portal use. hypertension results in splenomegaly and the development of gastroesophageal varices. Varices are thin-walled submucosal vessels W:\Academy EMS\ACP yr1(ICP)\ACP Year One 2014-2015\Module 3 Resp_Gastro_BLS Recert\Day 9 Gastroenterology\Gastroenterology_Handouts\Hepatic Disorders.doc prone to ulceration and hemorrhage. Family history can identify some hereditary Splenomegaly contributes to anemia and conditions that cause only mild symptoms or thrombocytopenia. laboratory abnormalities (e.g., Gilbert syndrome, Dubin-Johnson, or Rotor syndrome). Ascites develops secondary to portal Other familial disorders can lead to sever, hypertension. Abnormalities in renal sodium premature, chronic liver failure. Examples and water excretion [caused by diminished include Wilson disease, hemochromatosis, or – glomerular filtration rate (GFR) and elevations antitrypsin deficiency. in both aldosterone and antidiuretic hormone] also contribute to ascites. Ascites worsens Physical findings of acute hepatitis often are chronic fatigue and compromises respiratory limited to moderate liver enlargement and function. It sets the stage for recurrent episodes tenderness, with or without jaundice. Chronic of spontaneous bacterial peritonitis. liver disease is accompanied by a host of Encephalopathy results from the accumulation physical findings, including sallow complexion, of a variety of neurotoxic substances. Each of extremity muscle atrophy, palmar erythemia, these complications will be further addressed cutaneous spider nevi, parotid gland below. enlargement, and testicular atrophy and gynecomastia. The liver may be uniformly Clinical Features enlarged and firm or, in advance cirrhosis, shrunken and grossly nodular. Splenomegaly Clinical presentation of acute liver disease is and ascites accompany portal hypertension. variable. Symptoms of hepatocellular necrosis accompanying viral hepatitis include anorexia, nausea, vomiting, and low-grade fever. Cholestatic disease is accompanied by jaundice, pruritus, clay-coloured stools, and dark urine. Cholestasis resulting from intrahepatic processes and infiltrative disease presents more insidiously with the slow development of jaundice and few other constitutional complaints. Chronic liver disease often presents with complications of advancing cirrhosis and portal hypertension that include abdominal pain, ascites, gastrointestinal bleeding, fever, and altered mental status. However, progressive generalized fatigue may be the only symptom of chronic liver disease in the absence of supervening complications. Features of history are sometimes useful: sexual behaviours, travel, volume and duration of alcohol use, illicit drug use, consumption of nutritional supplements (vitamin A), history of blood transfusions, needle-stick blood exposures, herbal remedies, mushroom ingestion, or raw oyster consumption. W:\Academy EMS\ACP yr1(ICP)\ACP Year One 2014-2015\Module 3 Resp_Gastro_BLS Recert\Day 9 Gastroenterology\Gastroenterology_Handouts\Hepatic Disorders.doc