Acute Liver Failure Flashcards
Define acute liver failure
Acute liver failure describes the rapid onset of hepatocellular dysfunction leading to a variety of systemic complications. (Passmed)
Acute liver failure (ALF) is a rapid decline in hepatic function characterised by jaundice, coagulopathy (INR >1.5), and hepatic encephalopathy in patients with no evidence of prior liver disease. (Idea that it would be decompensated liver disease if they already had existing liver disease)
Acute liver failure can be hyperacute, acute or subacute; describe each
- Hyperacute= onset = 7 days
- Acute= 8-21 days
- Subacute=4-26wks
State the triad of acute liver disease
- Jaundice
- Coagulapathy
- Hepatic encephalopathy
State some causes of acute liver disease
-
Infections
- Viral hepatitis
- Infectious mononucleosis
- Cytomegaolvirus
- Yellow fever
-
Drugs
- Paracetamol overdose
- Isoniazid
- Alcohol
-
Toxins
- Posionous wild mushrooms
-
Other
- Budd-Chiari sydrome
- Autoimmune hepatitis
- Wilson’s disease
Highlight the most common causes of acute liver failure
- Paracetamol overdose (UK & America)
- Acute hepatitis (most common worldwide)
- Rare adverse drug reaction (11%)
Describe the pathophysiology of acute liver disease caused by paracetamol overdose
Paracetamol is predominantly metabolised in the liver through glucuronidation and sulfation, with a small amount metabolised by the cytochrome P450 system. A toxic intermediate- NAPQI- generated via the P450 pathway is subsequently conjugated by glutathione. In the setting of paracetamol overdose, glutathione stores may become depleted, resulting in direct hepatocyte injury via NAPQI.
State some risk factors for acute liver failures
- Alcohol abuse
- Female gender
- Poor nutritional status
- Chronic hepatitis B
- Use of mutiple paracetamol preparations for chronic pain
State some signs & symptoms of acute liver disease
- Jaundice
-
Hepatic encephalopathy symptoms e.g.
- altered mood/behaviour,
- confusion
- increasing drowsiness
- Constructional apraxia (can’t copy a 5 pointed star)
- Asterixis
- Nausea & vomitting
- RUQ pain
- Malaise
- Signs associated with cerebral oedema e.g. abnormal pupillary reflexes
- Fetor hepaticus (breath smells strong & musty)
Describe the difference between the terms ‘acute liver failure’ and ‘decompensated chronic liver disease’
- Acute liver failure: rapid decline in hepatic function in pts with no evidence of prior liver disease
- Decompensated liver disease: acute deterioration in liver function in pt with underlying liver disease
Discuss what investigations you would consider in someone with suspected acute liver failure, include:
- Bedside
- Bloods
- Imaging
*For each, justify why you are doing it
Bedside
- ABG: check for acidosis- important prognostic factor
- Pregnancy test: pregnancy is a risk factor
- Urine toxicology screen: drug use?
Bloods
- FBC: WCC, anaemia, thrombocytopenia
- U&E:check kidney func
- LFTs: deranged, hypoalbuminaemia
- Ammonia
- Coagulation
- Paracetamol level
- ‘Group & save’ or ‘crossmatch’
- Liver screen
Imaging
- CXR: assess for e.g. aspiration pneumonia as many patients present with reduced alertness with hepatic encephalopathy
- Abdo ultrasound with doppler ultrasound: check for any evidence of hepatic vessel thrombosis associatd with Budd-Chiari syndrome
Discuss the key principles in the management of acute liver failure
- Early recognition
- Finding out cause so it can be treated
- Must be cared for in intensive care once signs of hepatic encephalopathy are present
- Managing nutrition
- Treat complications
- Consider liver transplantation
State some complications of acute liver failure
- Cerebral oedema
- Renal failure/AKI
- Infection/sepsis
- GI bleeding
- Metabolic disorders e.g. hypoglyceamia
Briefly discuss how pts with acute liver failure are managed in intensive care
- Nurse with 20o head up tilt (reduce cerebral oedema)
- Protect airway witih inbubation
- NG tube to prevent aspiration
- Urinary catheter
- Central venous catheter
- Regular obs, weight and bloods
- Haemofiltration or haemodialysis (if renal failure develops)
- Drugs such as omeprazole (decrease GI bleeding risk), vit K/clotting factors (prevent bleeding), antibiotics (infection)develops)
Highly supportive care which focuses on preventing complications
Discuss the prognosis of acute liver failure
- High risk of mortality
- Approximately 75% of patients with paracetamol-induced liver injury recover without liver transplantation. In contrast, ALF resulting from idiosyncratic drug-induced liver injury, acute hepatitis B, or indeterminate cause has a much lower rate of spontaneous recovery, ranging from 25% to 41%.
Compare acute liver failure and decompensated liver disease
- Acute liver failure: rapid deterioration in liver function in pt with no prior liver disease
- Decompensated liver disease: acute deterioration in liver function in a patient with cirrhosis
