Liver failure Flashcards
define liver failure?
severe liver dysfunction leading to jaundice, encephalopathy and coagulopathy
can occur suddenly in a previously healthy liver ( acute liver failure) but more often occurs as a result of decompensation of chronic liver disease ( acute- on-chronic hepatic failure)
what is the typical presentation of liver failure?
cirrhosis + acutely ill/jaundice
how is liver failure classified? and what are the classifications?
based on the time interval between onset of jaundice and development of hepatic encephalopathy
Hyperacute = < 7 days
Acute = 1-4 weeks
Subacute = 4-12 weeks
what is acute- on-chronic liver failure?
acute deterioration ( decompensation) in patients with chronic liver disease
summarise the epidmemiology of liver failure?
paracetamol overdose counts for 50% of acute liver failure in the UK
what are the main causes of liver failure?
viral
- hepatitis A , B,C, D and E
Drugs
- paracetamol overdose
- idiosynchronatic drug reactions eg anti-TB therapy
- St Johns wort
what are the less common causes of liver failure?
autoimmune hepatitis
Budd-chiari syndrome ( occlusion of hepatic veins)
pregnancy- related
malignancy ( Lymphoma)
haemochromatosis ( iron levels in the body build up over many years)
mushroom poisoning ( amanita phalloides)
Wilson’s disease
explain the pathogenesis of the manifestations of liver failure?
jaundice- due to decreased secretion of conjugated bilirubin
encephalopathy
- nitrogenous products ( ammonia) is absorbed in the gut via the portal circulation to the liver
- a normal liver would be able to extract these harmful substances
- However, if the liver is failiing-> toxic products can go through the liver and reach the brain and have its effects
Coagulopathy
- reduced synthesis of clotting factors
- reduced platelets
- platelet functional abnormalities associated with jaundice or renal failure
what are the presenting symptoms of liver failure?
may be asymptomatic
fever
nausea
jaundice ( not always)
what are the signs of liver failure on physical examination ?
jaundice
encephalopathy
asterixis
clubbing
Fetor hepaticus (smell of pear drops)
Ascites and splenomegaly (less common if acute or hyperacute)
- Ascites as low albumin therefore lower oncotic press and so more fluid leak
Bruising or bleeding
Signs of secondary causes (e.g. bronze skin colour, Kayser-Fleisher rings)
Pyrexia - may indicate infection or liver necrosis
what investigations should you do to find the cause of liver failure?
viral serology
paracetamol levels
autoantibodies ( ASM, Anti-LKM)
ferritin ( haemochromatosis)
caeruloplasmin and urinary copper ( Wilson’s disease)
what are the appopriate investigations for liver failure?
investigations for cause
bloods
Dopper scan of hepatic or portal veins- check for Budd-chiari sydrome
MRI of liver is much better than CT
ECG- monitor encephalopathy
Describe the bloods for liver failure?
FBC
- Low Hb (if GI bleed)
- High WCC (if infection)
U&Es
- May show renal failure (hepatorenal syndrome)
Glucose
LFTs
- High bilirubin
- High AST, ALT, ALP, GGT
- Low albumin
ESR/CRP
Coagulation screen
- Prolonged PT
- Prolonged APTT
- Prolonged bleeding time
- Reduced plts
ABG - to determine blood pH
Group and save
- Liver US/CT
- Ascitic Tap
Send for MC&S
- If neutrophils > 250/mm3 = spontaneous bacterial peritonitis
outline a management plan for liver failure?
Resuscitation - ABC
Treat the cause if possible:
- N-acetylcysteine - treatment for paracetamol overdose
Treatment/prevention of complications (invasive ventilation and cardiovascular support is often required)
- Monitor - vital signs, PT, pH, creatinine, urine output, encephalopathy
- Manage encephalopathy: lactulose and phosphate enemas
- Antibiotic and antifungal prophylaxis
- Hypoglycaemia treatment
- Coagulopathy treatment - IV vitamin K, FFP, platelet infusions
- Gastric mucosa protection - PPIs or sucralfate
- AVOID sedatives or drugs metabolised by the liver
- Cerebral oedema - decrease ICP with mannitol
Renal Failure
- Haemodialysis
- Nutritional support
Surgical - liver transplant
what are the possible complications of liver failure?
Infection
Coagulopathy
Hypoglycaemia
Disturbance of electrolyte balance and acid-base balance
Disturbance of cardiovascular system
Hepatorenal syndrome
Cerebral oedema (causing raised ICP) – as liver fails, nitrogenous waste builds up and passes to the brain where astrocytes clear it by processes involving conversion of glutamate to glutamine. This excess glutamine causes an osmotic imbalance and a shift of fluid into the cells – cerebral oedema
Respiratory failure
