acute liver failure Flashcards
(47 cards)
what is acute liver failure?
clinical condition characterised by biochemical evidence of liver injury/damage (raised ALT), impaired liver function (long PT, high billi), and hepatic encephalopathy setting in <8w (subacute <28w) of the first symptoms, in the absence of pre-existing liver disease.
what is it called if a patient has all the features of acute liver failure but no hepatic encephelopathy?
acute liver injury (ALI)
what are the early signs of hepatic encephalopathy (HE)?
irritability
lack of coordination
how is HE graded?
grades 1-4: 1=most mild, 4=comatose
what are the consciousness levels of each stage of HE?
1-sleep reversal, restless
2-lethargy, slowing
3-sleepy, confused
4-comatose
how does the patient act in each stage of HE?
1-forgetful, agitated, irritable
2-disorientated, loss of inhibition, inappropriate behaviour
3-disorientation, aggression
4-comatose
what are the neurological signs of each stage of HE?
1-tremor, apraxia, impaired coordination, impaired handwriting
2-asterexis, dysarthria, ataxia, hyporeflexia (LMN signs)
3-asterexis, muscular rigidity, extensor plantars, hyperreflexia (UMN signs)
4-decerebration
what is apraxia?
loss of ability to execute or carry out skilled movement and gestures, despite having the physical ability and desire to perform them and understanding the command.
how does liver injury progress?
elevated transaminases due to acute liver insult and asx -> acute liver injury with jaundice, coagulopathy, deranged LFTs -> ALF with all criteria and HE -> multi system failure -> death
what are the classifications of acute, hyperacute, and subacute liver failure?
from jaundice to hepatic encephalopathy:
hyperacute =within a week
acute =1-4 weeks
subacute -now accepted up to 28 weeks.
what is an example of a cause of hyperacute liver failure?
paracetamol OD
what is an example cause of acute timescale ALF?
hep B
what is an example cause of subacute ALF?
non paracetamol drug induced liver failure
what are the differences in characteristics between acute hyperacute and subacute liver failure?
hyperacute: greater chance of transplant free survival
acute: more jaundiced, moderate chance of transplant free survival
subacute: deeper jaundice, lower transmaminases, less marked coagulopathy, splenomegaly, ascites, shrinking liver volume, extremely poor survival without transplantation
what is the most common cause of ALF worldwide?
viruses
what is the most common cause of ALF in the UK?
paracetamol overdose
what are the causes of ALF?
-drugs
-viral -hep B, A, E (not C!), (CMV, HSV, VZV, dengue -less common)
-toxins -mushroom poisoning, phosphorus
-vascular -budd-chiari syndrome, hypoxic hepatitis
-pregnancy
-wilson disease
-malignant infiltration of liver
-other eg autoimmune, HLH
which drugs can cause ALF?
paracetamol
isoniazid
statins
NSAIDs
phenytoin , carbamazepine
cocaine and MDMA
flucloxacillin, nitrofurantoin, co-amox
ketoconazole
some chemo
what malignancies typically can migrate to the liver and cause ALF?
breast
lymphoma
how do you diagnose non paracetamol drug induced ALF and what do you need to rule out?
currently a diagnosis of exclusion
need to especially rule out hep E -hep E IgM should be in acute liver screen
why is ruling out hep E important with ALF?
hep E if missed will progress to chronic hep E which can lead to cirrhosis if untreated
how do cocaine and MDMA cause liver injury and what is the typical presentation and prognosis?
induce liver injury via circulatory collapse and hypoperfusion
present with hyperacute ALF
usually will survive on medical management alone but some will need transplants
what viral cause of ALF has the highest mortality?
hep B
what are the subtypes of hep E and which ones cause ALF?
1 and 2 cause ALF and they’re associated with travelling to endemic regions eg india
3 and 4 cause chronic hep E esp in immunosuppressed are acquired in the UK
