Disorders Of The Hepatobiliary System: Dr. Mehzabin Ahmed

Disorders of the Hepatobiliary system

Dr. Mehzabin Ahmed

Normal functions The liver is an important organ involved primarily for metabolism. It has varied functions like: 1. Carbohydrate metabolism: it serves as a storage organ for glycogen and is the source of plasma glucose 2. Fat metabolism: it converts dietary fats into lipoproteins 3. Protein metabolism: it is involved in the synthesis of plasma proteins like albumen, coagulation proteins as well as the catabolism of proteins resulting in the formation of urea. 4. Bile synthesis: the liver secretes bile, which contains bilirubin, cholesterol, electrolytes and bile salts. 5. Storage organ for glycogen, iron, copper and fat soluble vitamins 6. Detoxification organ: it serves to metabolize nitrogenous compounds, hormones and drugs.

General clinical features of liver disorders 

Jaundice: yellowish discoloration of sclera and skin. 

Causes: increased hemolysis (increased formation of bilirubin), liver disease ( impaired conjugation and/or excretion), or biliary obstruction

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Dark urine due to increased Urobilinogen

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Pale faeces in case of biliary obstruction due to lack of bile pigments

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Steatorrhoea passage of fatty stools due to malabsorption of fat due to lack of bile in biliary obstruction

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Ascites and edema due to decreased oncotic pressure (decreased albumen synthesis). Ascites may also be due to portal hypertension.

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Xanthelasma are lipid deposits in the

skin due to increased

cholesterol in the blood in biliary obstruction 

Pruritis: itching due to bile salt accumulation

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Easy bruising and bleeding disorders due to impaired synthesis of clotting factors

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Hepatomegaly increased size of the liver in hepatitis, tumor or fat/ amyloid infiltration

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Haematemesis due to ruptured esophageal varices due to portal hypertension

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Encephalopathy results due to failure of the liver to remove exogenous or endogenous substances mimicking or altering the balance of the neurotransmitters.

Major causes of the diseases of the liver 

Toxic substances: drugs and alcohol

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Infections: viruses, bacteria, parasites

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Vascular disorders: results in the disturbances in the blood flow

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Disturbances in the bile secretion

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Neoplasms of the liver parenchyma or the biliary architecture

Clinical conditions produced by hepatic disorders      

Acute /Chronic hepatitis Alcoholic liver disease Chronic liver disease Acute hepatic failure Cirrhosis Cholestasis

Hepatitis 

Inflammation of the hepatocytes is called hepatitis.

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Causes: 

Infectious agents - Hepatitis virus- five types A, B, C, D & E. - spread by the feco-oral route (A, E) or by blood (B, C). - The hepatitis B, C and D infections cause chronic hepatitis and frequently present as carriers

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Drugs

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Alcohol

Clinical features: They produce symptoms like fever, nausea and vomiting, jaundice (yellowish discoloration of the skin, sclera and the increased yellowish discoloration of the urine) and tender hepatomegaly (increases in the size of the liver, tender means painful when palpated).

Hepatitis 

Lab investigations: reveal an increase in bilirubin levels in the blood, and increased levels of ALT & AST (liver enzymes).

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Non- viral infections may present as 

abscesses- bacterial, protozoal (amoebic-the suppurative material is of brown color or is called anchovy sauce color),

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Cysts: hydatid cysts- due to the dog tape worm (parasite) infestation.

ALCOHOLIC LIVER DISEASE 

It is due to chronic alcohol consumption.

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The first changes noted are the fatty liver (accumulation of fat globules in the hepatocytes/ also seen in malnutrition and hypoxic conditions),

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Acute hepatitis (inflammation of the liver) and

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Alcoholic liver cirrhosis (fibrosis of the liver with regeneration of nodules of the hepatocytes).

Chronic liver disease

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Some follow an acute liver injury or may remain silent for a long time.

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Seen in 

Chronic hepatitis B &C virus infection,

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Chronic alcoholism

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Inborn metabolic disorders

Metabolic diseases affecting the liver 

Hemochromatosis: metabolic error resulting in accumulation of iron as hemosiderin 

Liver cirrhosis + Hemosiderin deposition in the endocrine organs like the pancreas resulting in the destruction of the islets cells & gives a brown color in the organs- Bronze Diabetes.

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It may b primary (congenital) or secondary (due to repeated blood transfusions or high iron intake in the diet)

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Wilson’s disease: inherited disorder of copper metabolismaccumulation of copper in the liver, brain (in the basal ganglia) and cornea (Kayser- Fleischer ring in the cornea)

ACUTE HEPATIC FAILURE 

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It results in 

jaundice,

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hepatic encephalopathy (delirium, followed by coma- due to failure to eliminate the toxic nitrogenous waste), and

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bleeding disorders due to deficient synthesis of coagulation factors like II, VII, IX and X.

The patient presents with 

edema,

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bleeding disorder,

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ascites, encephalopathy,

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renal failure,

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loss of secondary sex characteristics and gynaecomastia and

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appearance of spider naevi (small vascular lesions seen in the skin in pregnancy) due to hyperoestrogenism.

ACUTE HEPATIC FAILURE Lab investigations: 

The liver function tests reveal the type of liver disease. The ALT & AST are increased in necrosis of the liver cells,

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Alkaline phosphatase- increased in biliary obstruction

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Bilirubin- levels are raised

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Albumen- synthesis is decreased resulting in edema (decreased oncotic pressure)

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Hematological disorders: coagulation factors are deficient resulting in an abnormal prothrombin time (seen in chronic liver disease and failure.

CIRRHOSIS 

It is the replacement of normal liver tissue by nodules of regenerating hepatocytes separated by fibrosis.

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It is the end stage of many liver diseases like:

1.      Alcoholic liver disease 2.      Hepatitis B, C infections 3.      Idiopathic 4.      Biliary obstruction 5.      Hemochromatosis 

Classified as

1.      Morphologically as micronodular (upto 3mm diameter-alcoholic cirrhosis) or macronodular (>3mm diameter- greater risk of cancer development) 2.      Etiologically as viral, alcoholic, hemochromatosis, autoimmune, biliary obstruction, Wilson’s diseqse

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Clinically the patient presents with 

longstanding cirrhosis resulting in liver failure and portal hypertension and

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predisposes to hepatocellular carcinoma

Hepatic stellate cells are converted into collagen producing myofibroblasts, by :

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1. Disruption of the extra cellular matrix

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2. Secretion of cytokines by the Endothelial cells, Lymphocytes, Kuppfer cells, Hepatocytes

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3. Direct action of the toxins on the Hepatic stellate cells

Vascular disorders of the liver 

Passive venous congestion of the liver in right sided heart failure- nutmeg liver

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Portal hypertension: results from obstruction to blood flow in the portal system

Causes: 

Pre hepatic: portal vein thrombosis and massive splenomegaly

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Hepatic: cirrhosis is the most common cause, sarcoidosis, schistosomiasis, chronic active hepatitis

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Post hepatic: cardiac failure, constrictive pericarditis

Clinical features: The patients present with 

splenomegaly (increased size of the spleen),

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ascites (fluid collection in the peritoneum),

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dilation of the porta- systemic shunts in the lower esophagus (esophageal varices), anus (hemorrhoids) and around the umbilicus (caput medusae)

Diseases of the gall bladder & extra hepatic biliary ducts

Cholelithiasis 

Formation of stones in the gall bladder.

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There are two types of gall stones, cholesterol and pigment stones.

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The risk factors for development of cholesterol stones include female gender, obesity and diabetes mellitus.

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Pigment stones occur in hemolytic anemias (increased production of bilirubin from the hemoglobin of the hemolysed RBCs).

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Consequences of gallstones are 

cholecystitis (inflammation),

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predisposition to carcinoma,

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obstruction to the bile flow resulting in jaundice,

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infections of the static bile,

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pancreatitis and

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formation of mucocele (accumulation of mucus in the gall bladder resulting in its distension)

Cholecystitis: inflammation of the gallbladder 

Acute cholecystitis: usually due to obstruction of the bile outflow. Intense inflammation and infection can result in empyema ( collection of pus in a hollow organ or cavity)

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Chronic cholecystitis: almost always associated with gallstones. The walls of the GB are thickened due to fibrosis

Carcinoma of the gall bladder: 

Adenocarcinoma occurs almost invariably in association with gallstones.

Obstructive jaundice 

Bile duct obstruction may be due to : a. gallstones b. carcinoma of the common bile duct c. carcinoma of the head of the pancreas d. inflammatory stricture of the common bile duct e. accidental surgical ligation of the common bile duct

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The patient presents with  jaundice,  pale stools and  dark urine.  If the obstruction persists the static bile may undergo infection causing cholangitis and liver abscesses and  malabsorption of fat and fat-soluble vitamins.

Diseases of the exocrine pancreas 

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Acute pancreatitis

Results in acute abdomen,

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Usually due to duct obstruction, shock, alcohol ingestion, mumps infection, trauma and action of toxin.

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It is often hemorrhagic.

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Fat necrosis in the surrounding tissue occurs due to the action of the enzymes

Chronic pancreatitis

most commonly caused by chronic alcoholism.

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Fibrosis and exocrine atrophy occurs.

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Malabsorption may result due to loss of pancreatic secretions