Acute Hepatitis

Question 1

What suggests ACUTE hepatitis?

Answer 1

less than 6 months

previously normal lab values

Question 2

Why is alcoholic hepatitis not in the differential of true acute hepatitis?

Answer 2

it is the result of an acute exacerbation of underlying CHRONIC liver dz

Question 3

Which antibody tests are used to look for autoimmune hepatitis?

Answer 3

anti smooth muscle antibody (SMA)
anti nuclear antibody (ANA)
LKM1

Question 4

What is the initial management approach to patients with mild acute hepatitis?

Answer 4

watchful waiting

if abnormalities persist - evaluate like severe dz

Question 5

Which causes of hepatitis are unlikely to present as acute and mild?

Answer 5

ischemia and obstruction

genetic liver diseases

Question 6

What happens in acute self-limited hepatic injury?

Answer 6

if inciting agent IDed and removed - enzymes back to normal (ALT slower than AST)
common following ischemia, choledocholithiasis, acetaminophen toxicity

Question 7

Which causes of hepatitis typically have slow returns of enzyme levels to normal?

Answer 7

viral hepatitis

drug hepatotoxicity

Question 8

What are the basics of the urea cycle?

Answer 8

metabolism of dietary AAs and excess ammonia forms urea - major source of enzymes in liver
urea cycle defects lead to ammonia accumulation

Question 9

What does acute liver failure cause in the brain?

Answer 9

hepatic encephalopathy - not seen in chronic

cerebral edema and intra-cranial HTN from excess ammonia and glutamine

Question 10

What is the most common etiology of acute liver failure in developed countries?

Answer 10

acetaminophen - level between 4-24 hrs after ingestion predicts hepatotoxicity

Question 11

How is acetaminophen metabolized by the liver?

Answer 11

3 pathways
glucoronidation and sulfation –> innocuous metabolites
third catalyzed by p450 –> potentially toxic NAPQ1
Glutathione transferase promotes NAPQ1 binding to glutathione = innocuous - less glutathione = toxicity

Question 12

What can provide a source for glutathione?

Answer 12

therapy with N-acetyl cysteine

Question 13

What factors can increase flux through the toxic pathway of acetaminophen metabolism?

Answer 13

ones that decrease glucoronidation - Gilbert’s and fasting

ones that induce p450s - alcohol, some meds

Question 14

What is the histologic hallmark of acetaminophen toxicity?

Answer 14

centrilobular necrosis (also in ischemic, heat stroke, and cocaine)

Question 15

What clinical features suggest hepatic encephalopathy?

Answer 15

disturbances of consciousness
impaired intellectual function
asterixis (hand flap)
constructional apraxia (can't sign name)
coma or delirium

Question 16

What is the requisite lab finding for the diagnosis of ACUTE liver failure?

Answer 16

prolonged PTT and INR - coagulopathy (coagulation factors have short half lives) THEN elevated ATs
prolonged INR seen first in acetaminophen overdose
prolonged, rather than spontaneous, bleeding

Question 17

What findings can differentiate a non-hepatic cause of encephalopathy?

Answer 17

arterial ammonia levels normal except in renal failure (modest increase)
lack of coagulopathy or evidence of hepatic injury

Question 18

What is the management of acute liver failure?

Answer 18

prevent problems while waiting for regeneration or transplant - IV glucose, head elevation/hyperventilation/diuretics/drug-induced coma, avoid hyperthermia, hyperglycemia, hyponatremia and hypercapnia

Question 19

What is the management of hepatic encephalopathy?

Answer 19

cathartic agents - lactulose - to decrease ammonia
aggressively treat infection, electrolyte abnormalities, GI bleeding
limit dietary protein