CAUSES :
CAUSES
1. Shunting of intestinal blood through the severely diseased liver without the intervention of viable liver cells. TIPS (transjugular intrahepatic portacaval shunt), a widely used radiologically inserted shunt to lower portal
pressure, produces liver encephalopathy.
2. Shunting of such blood through collateral circulation or surgically constructed portacaval shunts
3. Most common in long standing cirrhosis of the liver with spontaneous shunting of intestinal blood through collaterals.
4. Failure of liver to detoxify agents noxious to CNS, eg, ammonia, mercaptans, fatty acids
5. Increased aromatic and reduced branched chain amino acids in blood
6. Precipitation of acute event, search for:
*- New overt or occult infection including spontaneous peritonitis
*. Potassium, magnesium or other electrolyte depletion
*. Use of opiate, sedative, tranquilizer, drugs
*. Gastrointestinal bleeding
7- ACUTE YELLOW ATROPHY
8- INFECTIVE HEPATITIS
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DIFFERENTIAL DIAGNOSIS
β’ Head trauma, concussion, subdural hematoma
β’ Alcohol withdrawal syndrome
β’ Toxic confusion due to medication
β’ Toxic confusion due to illicit drug use
β’ Meningitis
β’ Metabolic encephalopathy related to anoxia, hypoglycemia, hypokalemia, hypo- or hypercalcemia, uremia
β’ Screening blood, sputum and urine cultures to identify infection
β’ Hematology to identify anemia and signs of infection
β’ Standard biochemistry profi le to identify hypokalemia, bilirubinemia, altered calcium status, hypomagnesemia, urea, hypoglycemia
β’ Arterial blood gases
β’ Liver tests to evaluate severity of underlying liver disease
β’ Prothrombin and partial thromboplastin time
β’ Toxicology screen for illicit drugs
β’ Elevated ammonia often present
* SGPT - > 300 UNITS ARE UNUSUAL & MAY BE DUE TO SOME OTHER CAUSE THAN ALCOHOL
* AST / ALT RATIO > 2 ( SGOT / SGPT ) , S. ALBUMIN DECREASED, GLOBULIN INCREASED, PROTHROMBIN TIME INCREASED
* S. AMMONIA - NORMAL OR INCREASED
* PERCUTANEOUS NEEDLE BIOPSY OF LIVER
* ANTI-MITOCHONDRIAL ANTIBODIES - POSITIVE IN BILIARY CIRRHOSIS
* PERIPHERAL ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES - + IN SCLEROSING CHOLANGITIS
* ANA , SMOOTH MUSCLE & LIVER-KIDNEY MICROSOMAL ANTIBODIES - + IN AUTOIMMUNE HEPATITIS
SPECIAL TESTS
β’ Electroencephalogram shows symmetrical slowing of basic (alpha) rhythm in common with other forms of metabolic encephalopathy
β’ Visually-evoked potential specific in stages 2, 3 and 4
IMAGING
β’ Useful only to rule out other diagnoses
β’ CT scan of head most useful
β’ Brain MRI shows increased glutamine in basal ganglia
DIAGNOSTIC PROCEDURES
β’ Clinical setting and fi ndings adequate in 80% of cases
β’ Venous ammonia of great aid in patients with chronic liver disease when the clinical findings are confusing
β’ EEG is useful to a limited extent, but fi ndings are similar in other forms of metabolic encephalopathy
β’ Treatment response often confirms diagnosis
β’ Trail marking test and other psychometric tests of value in alert, ambulatory patients with slight slowing down or changed behavior