Hepatic encephalopathy (HE)

(NEJM 2016;375:1660; Hepatology 2014; 60:715)

• Pathogenesis: failure of liver to detoxify NH3 + other substances (eg, ADMA; J Hepatol 2013;58:38) that cause cerebral edema, ↓ O2 consumption, ↑ ROS → brain dysfxn

• Precipitants: bleeding, infxn, med nonadherence, ↓ K, ↓ Na, dehydration, hypoxia, portosystemic shunt (eg, TIPS), meds (eg, sedatives), acute insult to liver (eg, PVT)

• Stages: see section in “Acute Liver Failure”

• Dx: serum NH3 levels have poor Se for dx & monitoring Rx; remains a clinical dx

• Rx: identify/correct precipitants; lactulose (acidification of colon: NH3 → NH4+) w/ goal 2–4 stools/d (PEG may be as effective; JAMA IM 2014;174:1727); add rifaximin 550 mg bid (↓ gut bacteria → ↓ NH3 prod) if refractory or after 2nd recurrence HE on lactulose (NNT=3) (Am J Gastro 2013;108:1458); FMT, oral branched-chain AAs, probiotics may have a role (Cochrane Reviews 2017;2; Gastro 2019;156:1921); maintain K >4, avoid alkalosis as able