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Diseases of the liverIntroduction Examination of the liver is greatly concerned with an Examination of the liver is greatly concerned with an investigation of the symptoms and signs of disturbance of liver investigation of the symptoms and signs of disturbance of liver functions. functions.

It is a large organ in the body and probably possesses the It is a large organ in the body and probably possesses the greatest number and variety of functions. e.g. secretion of bile, greatest number and variety of functions. e.g. secretion of bile, protein metabolism, deamination of amino acids, formation of protein metabolism, deamination of amino acids, formation of urea, conversion of glucose, ketone bodies and other materials urea, conversion of glucose, ketone bodies and other materials used in metabolism. used in metabolism.

The liver uses the amino acids to form plasma protein (albumin, The liver uses the amino acids to form plasma protein (albumin, globulin and fibrinogen), prothrombin, choline estrase, tissue globulin and fibrinogen), prothrombin, choline estrase, tissue protein and also it stores proteins. protein and also it stores proteins.

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The liver also play an important role in also play an important role in – CHO metabolism, CHO metabolism, – formation of lipids, formation of lipids, – vitamins metabolism & storage (vitamins A, D, E, K, vitamins metabolism & storage (vitamins A, D, E, K,

thiamine, riboflavin), thiamine, riboflavin), – detoxicative metabolism, detoxicative metabolism, – erythropoesis, erythropoesis, – fat metabolism and sfat metabolism and s– torage of blood with the spleen.torage of blood with the spleen.

Primary diseases of the liver occur in farm animals as a result Primary diseases of the liver occur in farm animals as a result of poisoning. of poisoning. Secondary diseases occur as a part of generalized diseases Secondary diseases occur as a part of generalized diseases process or spread from another organ, are more common. In process or spread from another organ, are more common. In primary diseases the clinical manifestations are caused only by primary diseases the clinical manifestations are caused only by the liver lesions while in secondary involvement the syndrome the liver lesions while in secondary involvement the syndrome may include clinical signs unrelated to the hepatic lesions.may include clinical signs unrelated to the hepatic lesions.

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Manifestations of liver and biliary diseasesA) Dermatological signs:A) Dermatological signs: a- a- Icterus (jaundice):Icterus (jaundice): It is common in horses with acute It is common in horses with acute

liver diseases while in ruminants biliary obstruction is liver diseases while in ruminants biliary obstruction is the most likely cause of icterus.the most likely cause of icterus.

b- b- Photodermatitis:Photodermatitis: Phylloerythrin which acts as a Phylloerythrin which acts as a

photodynamic agent accumulates in the circulation photodynamic agent accumulates in the circulation and binds to the skin in patient with cholestasis. and binds to the skin in patient with cholestasis.

C- C- Pruritus:Pruritus: It is attributed to accumulation of bile salts It is attributed to accumulation of bile salts

in the skin has been reported in horses with liver in the skin has been reported in horses with liver failure.failure.

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B) Neurological signs:B) Neurological signs:Signs of hepatoencephalopathy may occur and it may be Signs of hepatoencephalopathy may occur and it may be attributed toattributed to– Hypoglycemia, Hypoglycemia, – HyperammonemiaHyperammonemia– Increased concentration of mercaptan, sulfur-containing Increased concentration of mercaptan, sulfur-containing

amino acids and short chain fatty acids in the plasma.amino acids and short chain fatty acids in the plasma.

C) Gastrointestinal signs:C) Gastrointestinal signs:Weight loss is attributed to anorexia and failure of hepatic Weight loss is attributed to anorexia and failure of hepatic metabolic function.metabolic function.Diarrhea is common in cattle with chronic liver diseases Diarrhea is common in cattle with chronic liver diseases attributed to increase hydrostatic pressure associated with attributed to increase hydrostatic pressure associated with portal hypertension.portal hypertension.Tenesmus followed by rectal prolapses is observed in some Tenesmus followed by rectal prolapses is observed in some cattle with liver diseasescattle with liver diseases

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Ascites is common findings in cattle with liver Ascites is common findings in cattle with liver cirrhosis. Hyperalbuminemia may be possible cause.cirrhosis. Hyperalbuminemia may be possible cause.Recurrent subacute abdominal pain has been reported Recurrent subacute abdominal pain has been reported in horses with liver failure.in horses with liver failure.

D) Hematological signs:D) Hematological signs:a- Bleeding diathesis, coagulopathy leading to a- Bleeding diathesis, coagulopathy leading to

hemorrhage as in epistaxis, bleeding from hemorrhage as in epistaxis, bleeding from venipuncture sites may accompany severe terminal venipuncture sites may accompany severe terminal liver failure and is caused by inadequate hepatic liver failure and is caused by inadequate hepatic synthesis of clotting factors. Beside decreased synthesis of clotting factors. Beside decreased absorption of fat soluble vitamin K which is required by absorption of fat soluble vitamin K which is required by the liver for production of certain factors.the liver for production of certain factors.

b- Hemolytic crisis: which may be attributed to increased b- Hemolytic crisis: which may be attributed to increased RBCs fragility has been reported in horses with liver RBCs fragility has been reported in horses with liver failure.failure.

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Diagnosis1-1- Clinical signsClinical signs as mentioned above. as mentioned above.

2-2- Laboratory testsA) Liver enzymes such asA) Liver enzymes such as– Gamma-glutamyl transferase (GGT)Gamma-glutamyl transferase (GGT)– Alkaline phosphatase (AP)Alkaline phosphatase (AP)– DehydrogenasesDehydrogenases

- Sorbitol dehydrogenases (SDH)- Sorbitol dehydrogenases (SDH)- Lactate dehydrogenases (LDH)- Lactate dehydrogenases (LDH)- Glutamate dehydrogenase (GDH)- Glutamate dehydrogenase (GDH)

B) Serum bilirubin assessment.B) Serum bilirubin assessment.C) Bile acid concentration.C) Bile acid concentration.D) Dye excretion tests.D) Dye excretion tests.

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33- - Other diagnostic modalities

A) Hepatic ultrasound to diagnose hepatomegaly A) Hepatic ultrasound to diagnose hepatomegaly and space-occupying lesions in the liver.and space-occupying lesions in the liver.

B) Percutaneous liver biopsy to determine the B) Percutaneous liver biopsy to determine the presence and causes of liver diseases.presence and causes of liver diseases.

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Treatment1- For management of hepatic encephalopathy.

Sedation: for convulsing animal and restless, xylazine (0.5-1 mg/kg) and diazepam 0.4 mg/kg are effective sedatives.Minimize production and absorption of toxic metabolites using minerals and lactulose (0.3 ml/kg) to decrease ammonia absorption from the gut and neomycin (10-100 mg/kg) orally to decrease production of ammonia by gut microflora.Diet: in form of low protein with high energy feeds rich in amino acids.

2- IV fluid therapy: 5% dextrose (2 ml/ kg hour) should be used for first 24 hours in animals with hypoglycemia, after 24 hours, 2.5 dextrose in lactated ringer solution should be substituted.

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3- Vitamins supplementationsVitamin K1 (40 mg/ 450 kg. once weekly) is indicated to prevent coagulopathies.Vitamin B1 and folic acid, once weekly.

4- Antimicrobial therapy based on culture and sensitivity including administration of B-lactam and an aminoglycosides or trimethoprim-sulfanamides. Metronidazole should be added if anaerobic infection suspected.

5- Corticosteroids may benefit animals with chronic active hepatitis (0.5-1.5 mg / Kg twice daily).

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Diffuse diseases of the liverHepatitis

It is include all diffuse degenerative and inflammatory It is include all diffuse degenerative and inflammatory diseases which affect the liver.diseases which affect the liver.

Etiology:1) Toxic hepatitis1) Toxic hepatitis: The lesion may be mild manifested : The lesion may be mild manifested by cloudy swelling or severe accompanied by by cloudy swelling or severe accompanied by extensive necrosis leading to fibrosis. The common extensive necrosis leading to fibrosis. The common causes are:causes are:– Inorganic poison such as copper, phosphorus, arsenic & Inorganic poison such as copper, phosphorus, arsenic &

selenium, orselenium, or– Organic poison such as carbon tetrachloride, Organic poison such as carbon tetrachloride,

hexachloroethan & chloroform.hexachloroethan & chloroform.– Poisonous plants, fungi (such as aspergillus, penicillium & Poisonous plants, fungi (such as aspergillus, penicillium &

fusarium) and algae.fusarium) and algae.

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2) Infectious hepatitis2) Infectious hepatitis: It may occur in cases : It may occur in cases of:of:

– SalmonellosisSalmonellosis– LeptospirosisLeptospirosis– Systemic mycoses (histoplasmosis) andSystemic mycoses (histoplasmosis) and– Infectious necrotic hepatitis due to infection with Infectious necrotic hepatitis due to infection with

clostridium novyiclostridium novyi..

3) Parasitic hepatitis3) Parasitic hepatitis: It occur in cases of:: It occur in cases of:– Massive liver fluke infestationMassive liver fluke infestation– Migration of ascaris larvae.Migration of ascaris larvae.

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4) Nutritional hepatitis4) Nutritional hepatitis: liver cirrhosis caused by : liver cirrhosis caused by methionine deficiency and acute hepatic necrosis methionine deficiency and acute hepatic necrosis caused by cystine deficiency in diets of rats are not caused by cystine deficiency in diets of rats are not known to have an importance in farm animals.known to have an importance in farm animals.

5) Congestive hepatopathy5) Congestive hepatopathy: Congestive heart : Congestive heart failure cause increase pressure in sinusoids of the failure cause increase pressure in sinusoids of the liver causing anoxia and compression resulting in liver causing anoxia and compression resulting in degeneration degeneration

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Pathogenesis:Pathogenesis:The usual lesion in toxic hepatitis varies from The usual lesion in toxic hepatitis varies from cloudy swelling to acute necrosis with terminal cloudy swelling to acute necrosis with terminal veno-occlusive lesion in some plant poisoning. veno-occlusive lesion in some plant poisoning.

In infectious hepatitis the lesion vary from necrosis In infectious hepatitis the lesion vary from necrosis of local isolated cells to diffuse necrosis. of local isolated cells to diffuse necrosis.

In parasitic hepatitis, the changes depend upon the In parasitic hepatitis, the changes depend upon the number and type of migrating larvae. Massive fluke number and type of migrating larvae. Massive fluke infestation may cause acute hepatic insufficiency. infestation may cause acute hepatic insufficiency. In liver fibrosis, the signs develop more slowly.In liver fibrosis, the signs develop more slowly.

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Clinical findings:1- Anorexia accompanied by constipation punctuated by attack of diarrhea. The feces is lighter in color than normal.

2- Nervous signs such as yawing or coma to hyperexcitability with muscle tremors and convulsions may occur due to hypoglycemia and failure of detoxification mechanism of the liver.

3- Dummy syndrome with signs of animal push with head, not responding to stimuli and may be blind.

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4- Subacute abdominal pain may be present 4- Subacute abdominal pain may be present manifested by arching of the back and pain on manifested by arching of the back and pain on palpation of the liver due to distension with increase palpation of the liver due to distension with increase tension of liver capsule.tension of liver capsule.

5- Jaundice and edema particularly in horses may or 5- Jaundice and edema particularly in horses may or may not be present.may not be present.

6- Photosensitization may occur in animal fed green 6- Photosensitization may occur in animal fed green food and exposed to sunlight. food and exposed to sunlight.

7- In chronic hepatic fibrosis, the signs are similar to 7- In chronic hepatic fibrosis, the signs are similar to those of hepatitis but developed more slowly and those of hepatitis but developed more slowly and persist for months. Ascitis and the dummy syndrome persist for months. Ascitis and the dummy syndrome are more common than in hepatitis.are more common than in hepatitis.

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Focal diseases of the liverHepatic abscessHepatic abscess

It does not cause clinical signs unless they are massive and It does not cause clinical signs unless they are massive and metastatic. metastatic. Liver abscess cause significant loss in feedlot and grain-fed Liver abscess cause significant loss in feedlot and grain-fed cattle because chemical ruminitis leading to hepatic abscess.cattle because chemical ruminitis leading to hepatic abscess.Omphalophelebitis, ruminal parakeratosis or ruminitis may Omphalophelebitis, ruminal parakeratosis or ruminitis may also lead to hepatic invasions by also lead to hepatic invasions by fusobacterium necrophorumfusobacterium necrophorum or other organisms including or other organisms including actionmyces, streptococcusactionmyces, streptococcus & & staphylococcus staphylococcus spp.spp.

Tumors of the liverTumors of the liverThe commonest neoplasm in calves is lymphmatosis. The commonest neoplasm in calves is lymphmatosis. Adenoma, adenocarcinoma and metastasis through portal Adenoma, adenocarcinoma and metastasis through portal veins are not uncommon in ruminants.veins are not uncommon in ruminants.

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Diseases of the pancreaseDiabetes mellitus:

Lesions of the pancrease causing diabetes mellitus Lesions of the pancrease causing diabetes mellitus are recorded in cows, horses and monkies. are recorded in cows, horses and monkies.

Clinical signs in horses include weight loss, polydipsia, Clinical signs in horses include weight loss, polydipsia, polyuria and high blood glucose and cholesterol. It polyuria and high blood glucose and cholesterol. It occurs in old horses due to pancreatic injury related to occurs in old horses due to pancreatic injury related to migration of strongyl larvae. migration of strongyl larvae.

In cow, there is emaciation, polydipsia, ketonuria, In cow, there is emaciation, polydipsia, ketonuria, glucosuria and hyperglycemia.glucosuria and hyperglycemia.