Liver failure Flashcards
Define acute liver failure.
Rapid decline in hepatic function characterised by…
- jaundice
- coagulopathy INR>1.5
- hepatic encephalopathy
… in patients with no prior liver disease.
Define liver failure.
Severe liver dysfunction leading to jaundice, encephalopathy and coagulopathy.
Can be classed as hyperacute, acute, subacute and acute-on-chronic.
Define chronic liver failure.
Deterioration in liver function superimposed on chronic liver disease. Stable chronic liver disease is defined by:
- Palmar erythema
- Dupyutren’s contracture
- Spider naevi
- Gynaecomastia
May also be called ‘decompensation’.
What are the 4 main biochemical features of liver failure?
Failure of:
- Synthetic function
- Clotting factor and albumin
- Clearance of bilirubin
- Clearance of ammonia → encephalopathy → asterixis
How do you classify acute liver failure?
Hyperacute - jaundice with encephalopathy occurring in <7 days.
Acute - jaundice with encephalopathy occurring from 1 to 4 weeks of onset
Subacute - jaundice with encephalopathy occurring within 4-12 weeks of onset
Acute-on-chronic- acute deterioration (decompensation) in patients with chronic liver failure
Name 2 main causes of liver failure and list some less common causes.
Viral - hepatitis A, C, D, E, “non A-E hepatitis”
Drugs - paracetamol overdose, idiosyncratic drug reactions (e.g. anti-TB therapy_
Less commonly - autoimmune hepatitis, Budd-Chiari syndrome, pregnancy-related malignancy (e.g. lymphoma), haemochromatosis, mushroom poisioning (Amanita phalloides), Wilson’s disease
What is the pathogenesis of acute liver failure?
Jaundice - decreased secretion of conjugated bilirubin
Encephalopathy - increased delivery of gut-derived products into the systemic circulation and brain from reduced extraction of nitrogenous products by liver and portal systemic shunting . Ammonia may play a part.
Coagulopathy - decreased synthesis of clotting factors, decreased platelets (hypersplenism if chronic portal hypertension) or platelet functional abnormalities associated with jaundice of renal failure
What is the most common aetiology of liver failure?
Paracetamol overdose accounts for 50% of acute liver failure in the UK
What are the symptoms of liver failure?
- May be asymptomatic
- Fever
- Nausea
- Jaundice
What are the signs of liver failure on examination?
- Jaundice, encephalopathy, liver asterixis (negative myoclonus), fetor hepaticus (smell of “pear drops”)
- Ascites and splenomegaly (less common if acute/hyperacute)
- Bruising or bleeding from puncture sites of GI tract
_Look for secondary cause_s: e.g. bronze skin colour, Kayser-Fleischer rings
Pyrexia may reflect inflection or liver necrosis
What investigations would you do to identify the cause of liver failure?
- Viral serology
- Paracetamol levels
- Autoantibodies (e.g. ASM, LKM antibody, immunoglobulins)
- Ferritin
- Caeruloplasmin
- Urinary copper (low and high respectively in Wilson’s)
What investigations should you do for liver failure?
Bloods:
- FBC - low Hb if GI bleed, high WCC in infection
- U&E - hepatorenal failure
- Glucose
- LFT -high bil, transaminases, Alkphos, GGT and low albumin,
- ESR/CRP (inflammatory markers)
- Coagulation screen (high PT and INR)
- ABG (to determine pH)
- Group and save
Imaging:
- US liver, CT scan to image liver
- Doppler of hepatic and portal veins - exclude Budd Chiaru syndrome
- EEG - monitor encephalopathy
Invasive:
- Ascitic fluid tap - MC&S, biochemistry (glucose, protein), cytology, >250neutrophils/mm3 indicates SBP
Why would you do a Doppler of hepatic/portal veins in liver failure?
Doppler of hepatic and portal veins - exclude Budd Chiaru syndrome
How do you treat paracetamol overdose?
N-acetylcysteine
How do you manage liver failure (and its complications)?
Resuscitation - ABCDE, ITU care and specialist care unit support
Treatment/prevention of complications - invasive respiratory and cardiovascular support often required
- Monitor - vital signs, pH, creatinine, urine output, encephalopathy
- Encephalopathy - lactulose and phosphate enemas
- Antibiotic and antifungal prophylaxis
- Hypoglycaemia treatment
- Coagulopathy treatment - IV Vit K, FFP, platelet infusions if required
- Gastric mucosa protection - PPI or sulcralfate
- Avoid - sedatives and drugs metabolised by liver
- Cerebral oedema - nurse patient at 30 degrees C, lower intracranial pressure by IV mannitol, hyperventilate
Which scoring system is used to assess prognosis of liver disease and required strength of treatment/liver transplantation necessity?
The Child-Pugh score is a system for assessing the prognosis — including the required strength of treatment and necessity of liver transplant — of chronic liver disease, primarily cirrhosis.
