Causes
In a small proportion of cases, the encephalopathy is caused directly by liver failure; this is more likely in acute liver failure. More commonly, especially in chronic liver disease, hepatic encephalopathy is caused or aggravated by an additional cause, and identifying these causes can be important to treat the episode effectively.
| Type | Causes |
|---|---|
| Excessive nitrogen load |
Consumption of large amounts of protein, gastrointestinal bleeding e.g. from esophageal varices (blood is high in protein, which is reabsorbed from the bowel), renal failure (inability to excrete nitrogen-containing waste products such as urea), constipation |
| Electrolyte or metabolic disturbance |
Hyponatraemia (low sodium level in the blood) and hypokalaemia (low potassium levels)—these are both common in those taking diuretics, often used for the treatment of ascites; furthermore alkalosis (decreased acid level), hypoxia (insufficient oxygen levels), dehydration |
| Drugs and medications |
Sedatives such as benzodiazepines (often used to suppress alcohol withdrawal or anxiety disorder), narcotics (used as painkillers or drugs of abuse) and sedative antipsychotics, alcohol intoxication |
| Infection | Pneumonia, urinary tract infection, spontaneous bacterial peritonitis, other infections |
| Others | Surgery, progression of the liver disease, additional cause for liver damage (e.g. alcoholic hepatitis, hepatitis A) |
| Unknown | In 20–30% of cases, no clear cause for an attack can be found |
Hepatic encephalopathy may also occur after the creation of a transjugular intrahepatic portosystemic shunt (TIPSS). This is used in the treatment of refractory ascites, bleeding from oesophageal varices and hepatorenal syndrome. TIPSS-related encephalopathy occurs in about 30% of cases, with the risk being higher in those with previous episodes of encephalopathy, higher age, female sex and liver disease due to causes other than alcohol.
Read more about this topic: Hepatic Encephalopathy