Hepatic encephalopathy

What it is

Hepatic encephalopathy is a neuropsychiatric syndrome with symptoms ranging from mild cognitive changes to coma. With variceal bleeding, ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, jaundice and HCC, it is one of the complications of cirrhosis that make it decompensated cirrhosis, and portal hypertension is responsible for most of these complications. In the liver form there is ammonia intoxication, since the liver can't detoxify.

Causes and risk

The precipitating factors are infection, including SBP; low-K alkalosis; renal impairment; GI bleeding; and sedative drug use. A second list is given as infection, volume depletion, GI bleeding, or sedating medications. TIPS is a cause of its own: the shunt converts the blood from the portal vein directly to the systemic vein by bypassing the liver, so the toxins that the liver would remove, ammonia among them, will bypass it too, and portosystemic encephalopathy is the primary complication of TIPS.

How it presents

Symptoms range from mild cognitive changes to coma. Lethargy with asterixis points to it, but asterixis is not specific to the liver: its common causes are hepatic encephalopathy, uremic encephalopathy and hypercapnia. In uremic encephalopathy the kidney can't excrete urea and the BUN is high, against a normal urea of 9-20.

A 45-year-old man with chronic hepatitis B infection has an altered mental status: a waxing and waning attention span, mumbling his words and making no sense. On examination he is disoriented, jaundiced, and his hands shake when he holds them outstretched. The clinical sign has a name: flapping tremor, that is asterixis. Two differentials are given for that sign alone: CO2 retention and uremia. This picture is hepatic encephalopathy at stage III. Its acute plan is Rx precipitating factors, which it lists as GI bleeding, SBP and drug side effects, then lactulose titrated to achieve about 4 BM/d, with oral rifaximin.