Hepatic Failure Flashcards
what two things is liver failure recognised by?
1) encephalopathy
2) coagulopathy (INR > 1.5 - in healthy people an INR of 1.1 or below is considered normal)
what is liver failure that occurs suddenly in previous healthy liver called?
acute liver failure.
what is classed as acute liver failure?
8-21 days
what is classes as hyper acute liver failure?
7 days or less
what is classed as sub acute liver failure?
4-26 weeks
when does chronic liver failure occur?
on the background of cirrhosis
what is fulminant hepatic failure?
clinical syndrome resulting from massive necrosis of liver cells leading to severe impairment of liver function
what are the infective causes of liver failure? (3)
- viral hepatitis (esp, B, C and CMV)
- Yellow fever
- leptospirosis
what are the drug causes of liver failure? (3)
- paracetamol overdose
- halothane
- isoniazid
what toxin can cause liver failure?
amanita phalloides mushroom disease
what are the other causes of liver failure? (10)
- alcohol
- fatty liver disease
- primary biliary cholnagitis
- primary sclerosis cholangitis
- hemochrombtosis
- autoimmune hepatitis
- A1 - antitrypisn deficiency
- Wilson’s disease
- fatty liver of pregnancy
- malignancy
what are the signs of liver failure?
- jaundice
- hepatic encephalopathy
- fetter hapticus (smells like pear drops)
- Asterix / flap
- construction apraxia (cannot copy a 5 pointed star)
- signs of chronic liver disease suggest acute-on-chronic hepatic failure
what blood tests would your request?
- FBC
- U&E
- LFT
- clotting (increased PT / INR)
- Glucose
- Paracetamol level
- Hepatits
- CMV and EBV serology
- Ferritin
- alpha 1 antitrypsin
- caruloplasmin autoantibodies
what microbiology tests would you ask for?
- Blood culture
- Urine culture
- Ascitic tap for MC&S of ascites – neutrophils more than 250/mm3 indicates spontaneous bacterial peritonitis
what radiology test would you ask for?
- CXR
- Abdominal ultrasound
- Doppler flow studies of the portal vein (and hepatic vein in suspected Budd-Chiari syndrome)
what neurophysiology tests would you ask for?
- EEG
* Evoked potentials (and neuroimaging) have a limited role
what should you be aware of before managing the patient?
sepsis
hypoglycaemia
GI bleeds / varices
encephalopathy
management of hepatic failure?
- Nurse with a 20-degree head-up tilt in ITU. Protect the airway with intubation and insert an NG tube to avoid aspiration and remove and blood from stomach.
- Insert urinary and central venous catheters to help assess fluid status
- Monitor T degree respirations, pulse, BP, pupils, urine output hourly. Daily weights
- Check FBC, U&E, LFT, and INR daily
- 10% glucose IV, 1L/12h to avoid hypoglycaemia. Do blood glucose every 1-4 hours.
- treat the cause, if known (e.g GI bleeds, sepsis, paracetamol poisoning)
- if malnourished, get dietary help: good nutrition can decrease mortality. Give thiamine and folate supplements.
- Treat seizures with phenytoin
- Hemofiltration or haemodialysis, if renal failure develops
- Try to avoid sedatives and other drugs with hepatic metabolism
- Consider PPI as prophylaxis against stress ulceration, e.g. omeprazole 40mg/d/IV/PO
- Liaise early with nearest transplant centre regarding appropriateness
what are the complications of hepatic failure?
- cerebral oedema
- ascites
- bleeding
- blind treatment of infection
- decreased blood glucose
- encephalopathy
when is prognosis worse?
if grade III-IV encephalopathy age > 40 years albumin < 30g/L increased INR drug induced liver failure late-onset liver failure worse than fulminant failure
what drugs should you avoid in hepatic failure? (3)
- drugs that constipate (increase risk of encephalopathy)
- oral hypoglycaemic
- saline containing IVs
effects of what drugs are enhanced in hepatic failure?
warfarin
what are examples of hepatic drugs?
- paracetamol
- methotrexate
- isoniazid
- azatrhiopine
- phenothiazine
- oestrogen
- 6-mercaptropurin
- salicylates
- tetracycline
- mitomycin
how does hepatic encephalopathy occur?
As the liver fails, nitrogenous waste (as ammonia) builds up in the circulation and passes to the brain, where astrocytes clear it (by process involving the conversion of glutamate to glutamine)
This excess glutamine causes an osmotic imbalance and shift of fluid into these cells – hence cerebral oedema.
how do you grade hepatic encephalopathy?
I = altered mood/behaviour, sleep disturbance (e.g. reversed sleep pattern), dyspraxia (please copy this 5-pointed star), poor arithmetic, no liver flap.
II = increasing drowsiness, confusion, slurred speech +- liver flap, inappropriate behaviour/personality changes (ask the family – don’t be too tactful)
III = incoherent, restless, liver flap, stupor
IV = coma
what else could be clouding consciousness?
- hypoglycaemia
- sepsis
- trauma
- postictal
what criteria can you sue to grade acute liver failure?
King’s college criteria
what is the kings college critter in paracetamol induced liver failure?
- Arterial pH <7.3 24 hours after ingestion
- Or all of the following
- Prothrombin time (PT) >100s
- Creatinine >300umol/L
- Grade III or IV encephalopathy
what is the king’s college criteria in non-paracetamol induced liver failure?
PT>100s
Or 3 out of 5 of the following:
- Drug undiced liver failure
- Age <10 or >40 years old
- < 1 week from 1st jaundice to encephalopathy
- PT > 50s
- Bilirubin >300umol/L
what does fulfilling the king’s criteria mean?
poor outcome in acute liver failure and should prompt consideration for transplantation
