Page 618 - Textbook of Pathology, 6th Edition

602 MORPHOLOGIC FEATURES. Grossly, the liver is MORPHOLOGIC FEATURES. Grossly, the liver is enlar-
enlarged and dark green. The atretic segments of biliary ged and yellowish-orange.
system are reduced to cord-like structures. Microscopically, hepatocytes show small droplets of
Histologically, the condition must be distinguished from neutral fat in their cytoplasm (microvesicular fat). Similar
idiopathic neonatal hepatitis as surgical treatment is fatty change is seen in the renal tubular epithelium and
possible in extrahepatic biliary atresia but not in the latter. in the cells of skeletal muscles and heart. The brain shows
Besides, α-1-antitrypsin deficiency also produces similar oedema and sometimes focal necrosis of neurons.
appearance in liver biopsy. The main histologic features
are as under: HEPATIC FAILURE
1. Inflammation and fibrous obliteration of the
extrahepatic ducts with absence of bile in them. Though the liver has a marked regenerative capacity and a
2. Ductular proliferation and periductular inflammation. large functional reserve, hepatic failure may develop from
3. Cholestasis and bile thrombi in the portal area. severe acute and fulminant liver injury with massive necrosis
4. Periportal fibrosis and later secondary biliary cirrhosis of liver cells (acute hepatic failure), or from advanced chronic
(page 625). liver disease (chronic hepatic failure). Acute hepatic failure
5. Transformation of hepatic parenchyma to neonatal develops suddenly with severe impairment of liver functions
(giant cell) hepatitis in 15% of cases. whereas chronic liver failure comes insidiously. The
prognosis is much worse in acute hepatic failure than that
Intrahepatic Biliary Atresia in chronic liver failure.
Intrahepatic biliary atresia is characterised by biliary ETIOLOGY. Acute and chronic hepatic failure result from
hypoplasia so that there is paucity of bile ducts rather than different causes:
their complete absence. The condition probably has its origin Acute (fulminant) hepatic failure occurs most frequently
in viral infection acquired during intrauterine period or in in acute viral hepatitis. Other causes are hepatotoxic drug
the neonatal period. Cholestatic jaundice usually appears reactions (e.g. anaesthetic agents, nonsteroidal anti-
within the first few days of birth and is characterised by high inflammatory drugs, anti-depressants), carbon tetrachloride
serum bile acids with associated pruritus, and poisoning, acute alcoholic hepatitis, mushroom poisoning
hypercholesterolaemia with appearance of xanthomas by and pregnancy complicated with eclampsia.
first year of life. Hepatic as well as urinary copper Chronic hepatic failure is most often due to cirrhosis.
SECTION III
concentrations are elevated. In some cases, intrahepatic Other causes include chronic active hepatitis, chronic
biliary atresia is related to α-1-antitrypsin deficiency. cholestasis (cholestatic jaundice) and Wilson’s disease.

MORPHOLOGIC FEATURES. The microscopic features MANIFESTATIONS. In view of the diverse functions
are as follows: performed by the liver, the syndrome of acute or chronic
1. Paucity of intrahepatic bile ducts. hepatic failure produces complex manifestations. The major
2. Cholestasis. manifestations are briefly discussed below and
3. Increased hepatic copper. diagrammatically illustrated in Fig. 21.5.
4. Inflammation and fibrosis in the portal area, 1. Jaundice. Jaundice usually reflects the severity of liver
eventually leading to cirrhosis. cell damage since it occurs due to failure of liver cells to
metabolise bilirubin. In acute failure such as in viral hepatitis,
Systemic Pathology
REYE’S SYNDROME jaundice nearly parallels the extent of liver cell damage, while
in chronic failure such as in cirrhosis jaundice appears late
Reye’s syndrome is defined as an acute postviral syndrome
of encephalopathy and fatty change in the viscera. The and is usually of mild degree.
syndrome may follow almost any known viral disease but 2. Hepatic encephalopathy (Hepatic coma). Neuro-
is most common after influenza A or B and varicella. Viral psychiatric syndrome may complicate liver disease of both
infection may act singly, but more often its effect is modified acute and chronic types. The features include disturbed
by certain exogenous factors such as by administration of consciousness, personality changes, intellectual
salicylates, aflatoxins and insecticides. These effects cause deterioration, low slurred speech, flapping tremors, and
mitochondrial injury and decreased activity of mitochondrial finally, coma and death. The genesis of CNS manifestations
enzymes in the liver. This eventually leads to rise in blood in liver disease is by toxic products not metabolised by the
ammonia and accumulation of triglycerides within diseased liver. The toxic products may be ammonia and other
hepatocytes. nitrogenous substances from intestinal bacteria which reach
The patients are generally children between 6 months and the systemic circulation without detoxification in the
15 years of age. Within a week after a viral illness, the child damaged liver and thus damage the brain. Advanced cases
develops intractable vomiting and progressive neurological of hepatic coma have poor prognosis but may respond
deterioration due to encephalopathy, eventually leading to favourably to hepatic transplantation.
stupor, coma and death. Characteristic laboratory findings 3. Hyperkinetic circulation. All forms of hepatic failure are
are elevated blood ammonia, serum transaminases, bilirubin associated with a hyperkinetic circulation characterised by
and prolonged prothrombin time. peripheral vasodilatation, increased splanchnic blood flow