Liver Failure Flashcards
What is the epidemiology of liver failure?
<6.5 people per million per year
Globally - viral infections = most common
UK - paracetamol overdose = most common
Liver transplants are rising
What are the potential causes of liver failure?
Toxins:
- Paracetamol poisoning
- Chronic alcohol abuse
- Drug toxicity e.g. co-amoxiclav, ciprofloxacin, doxycycline, erythromycin, isoniazid, nitrofurantoin; statins; cyclophosphamide, methotrexate; disulfiram, propylthiouracil, halothane
- Certain mushroom species
- Chemicals e.g. carbon tetracholride, organic solvents, phosphorus
- Illicit drugs - cocaine, ecstasy
Infections:
- Viral hepatitis
- Adenovirus, Epstein-Barr, CMV, viral haemorrhagic fevers
Neoplastic:
- Hepatocellular carcinoma
- Metastases
Metabolic:
- Wilson’s disease
- a1-antitrypsin deficiency
Vascular:
- Ischaemia, veno-occlusive disease
- Budd-Chiari syndrome
Others:
- Acute fatty liver of pregnancy
- Autoimmune liver disease
- Idiopathic (15%)
What is the pathophysiology and classifications of liver disease?
Pathophysiology:
- Liver has sustained sever damage = loss of function/necrosis of 80-90% of hepatocytes and unable to repair itself
- Zones of the liver affected vary depending on cause e.g. Zone 1/periportal is affected in eclampsia whereas zone 3/cenrtiloulbar (with the most CYP450 enzymes) is affected in paracetamol OD and ischaemia
Fulminant hepatic failure:
- Failure occurring within 8wks of onset of underlying illness
Late-onset hepatic failure:
- Failure occurring between 8-26wks
- Underlying disease may have thus been present for a while but undiagnosed
Chronic decompensated hepatic failure:
- When the latent period is >6m
How does liver failure present?
Hx relating to the cause e.g.:
- Foreign travel
- Toxin ingestion
- Alcohol/drug use etc.
Jaundice:
- Often one of the first signs
Varices:
- Bleeding is a common acute presentation
Coagulopathy:
- Impaired synthesis of clotting factors
- Thrombocytopaenia
- Possible DIC
Hepatic encephalopathy:
- Altered mental state from confusion to hallucinations and coma
- Also cerebral oedema and subsequent raised ICP (possibly leading to herniation + death)
Ascites and peripheral oedema:
- Due to fluid redistribution and hypoalbuminaemia
Metabolic derangements:
- Hyponatraemia
- Hypoglycaemia (depleted hepatic glycogen + hyperinsulinaemia)
- Lactic acidosis in paracetamol overdose
Kidney failure:
- Possibly due to direct toxin insult or hyperdynamic circulation
- Leads to hepatorenal syndrome (usually fatal - failure of both systems)
Systemic inflammation:
- Possibly leading to multi organ failure + sepsis
Palmar erythema
Liver flap/asterixis
How do you investigate liver failure?
Bloods:
- FBC - iron deficiency anaemia (75% of CLD), thrombocytopaenia
- Clotting - INR raised
- LFTs - transaminases very high; alk phos normal/slightly raised; bilirubin raised; albumin low
- U+E - varying dysfunction depending on causes and renal involvement; high ammonia, lactate
- Glucose - very low
- Blood cultures - as co-infection = likely
- Viral serology = possible cause
- Paracetamol or toxin level testing
- Free copper = Wilson’s
Imaging:
- Doppler USS - hepatic vein patent? (Budd-Chiari) Primary/secondary carcinoma? Ascites?
- CT/MRI (non-contrast) - hepatic anatomy/pathology; head (cerebral oedema)
How do you manage liver failure?
Early diagnosis + management of any specific underlying causes and con-concomitant problems + transfer to specialist centre/relevant teams (ITU, general surg, neuro etc) +/- liver transplant
Good ABCDE is essential
General management of:
- Med review of hepatotoxic (+ nephrotoxic) drugs
- Fluid monitoring - catheters, IV colloid
- Infection/sepsis
- GI/variceal/other bleeds (F-FP, platelet concentrates, antifibrinolytics etc)
- Hypoglycaemia - large amounts of IV glucose may be required
- Nutritional status + electrolyte imbalances
- Raised ICP (use mannitol, dex)
