Acute live failure Flashcards
How is a patient with acute liver failure diagnosed?
Acute Liver failure is diagnosed by demonstrating ALL of the following:
- Elevated aminotransferases (often with abnormal bilirubin and ALP levels)
- Hepatic encephalopathy: clinical, based on West-Haven Classification
- Prolonged PT (INR >1.5)
What are the causes of acute liver failure in <7 days?
Fulminant/ Hyperacute LF e.g. Paracet OD, ischemia (Budd Chiari etc)
What are the causes of acute liver failure in 8 - 28 days?
Acute LF – Viral Hepatitis (A, E, B)
What are the causes of acute liver failure in >28 days?
Subacute LF e.g. Wilson’s
How do patients with encephalopathy present and how do we test them?
Presentation
- Sleep Disturbances (Hyper/Insomnia occurs before overt neuro findings!)
- Neuro Findings = asterixis, hyperactive reflexes etc
How will we test?
- Constructional Apraxia
- Asterixis
- Orientation to time and place
What are the different grades of hepatic encephalopathy (West haven criteria for semi quantitative grading of mental status)?
Grade 1
- trivial lack of awareness
- euphoria or anxiety
- shortened attention span
- impaired performance of addition
Grade 2
- lethargy or apathy
- minimal disorientation for time or place
- subtle personality change
- inappropriate behaviour
- impaired performance of subtraction
Grade 3
- somnolence to semi stupor, but responsive to verbal stimuli
- confusion
- gross disorientation
Grade 4: coma (unresponsive to verbal or noxious stimuli)
What are the causes of acute liver failure?
Viral hepatitis, mainly:
- Hep A & E: intake of undercooked food (seafood esp)
- Hep B: minority p/w ALF; majority are subclinical in acute phase & p/w CLF
- Hep C: more commonly p/w CLF
- Hep D: p/w CLF and is contracted in pt who are Hep B +ve
Drugs
- Paracetamol (most common): Hyperacute Liver Failure
- TB drugs (all causes hepatitis, esp isoniazid)
- Antiepileptic drugs
- TCM
Ischemic
- Acute hepatic vein thrombosis i.e. Budd Chiari syndrome
- cocaine use
- Sepsis
Toxin exposure
Autoimmune hepatitis
Metabolic:
Wilson’s disease
Diffused malignant infiltration of liver
Acute fatty liver of pregnancy/HELLP
What is the relevant history to take in a patient with acute liver failure?
History of alcohol use
History of prior episodes of jaundice or known liver disease
Drug history
- Paracetamol OD?
- TCM / supplements
- Including blood transfusions and immunosuppressants
Toxin exposures
Pregnancy
Travel history
- Risk factors for acute viral hepatitis
- Hep A/E: consumption of undercooked food, esp seafood
- Hep B: Sexual Contact, Blood Transfusion, Tattoos, IVDU
- Hep B Status, Hep B Vaccine
Sexual history
Family history of hep B, liver disease
What would you examine for in a patient with acute liver failure?
General examination - Mental state - Uremic, anuric: Hepatorenal Syndrome 🡪 AKI - Cold peripheries: Sepsis Cachectic?
Neurologic examination
- Presence of encephalopathy
- Hepatic flap
Signs of CLD: to determine if this is ALF / AoCLD
Hepatomegaly
What are the complications (cause of death in ALF)?
- Multiorgan failure (most common)
- Sepsis
- Intracranial hypertension (rare)
- Bleeding (rare)
What are the investigations to be performed in acute liver failure?
Laboratory
- FBC
- LFT
- Other components to liver function: Bilirubin, PT/INR , Albumin
- Renal panel : TRO Hepatorenal Syndrome
- ABG + lactate
- +/- Arterial ammonia
- +/- CBG (patient may be hypoglycaemic)
Depending on Aetiology
- Viral hepatitis serologies (hep A IgM, HBsAg, HBc antibody IgM, HCV antibody)
- Toxicology screen: Acetaminophen level – for Paracetamol OD
- Autoimmune markers: ANA, anti-smooth muscle 🡪 for AI Hepatitis
- Pregnancy test
- HIV screen
Imaging
- Liver ultrasound + doppler -> for Budd Chiari and IVC thrombosis
- CXR
- CT brain (if patient has AMS)
- CT/MRI abdo (if USS unremarkable)
Others
- Liver biopsy (if lab and imaging tests fail to identify an etiology)
What is the supportive/ empiric therapy given to patients with acute liver failre?
GW vs ICU
- Patients with grade l encephalopathy may be managed in a GW
- Any patient with grade ll encephalopathy or higher needs ICU admission
Vitals Monitoring and GCS charting (CLC) to monitor HE
Glucose monitoring Q6hrly to monitor possible glycaemic Δs
Serum PT monitoring Q6hrly to monitor coagulopathy
IV NAC : Improves transplant survival in early stage (Grade 1 or 2 HE) in non-paracet DILI (Drug-induced-liver-injury) ALF
Nutrition
- Severe protein restrictions should be avoided to prevent protein catabolism
- Enteral feeding should be given in patients with grade lll or lV encephalopathy
Avoid sedation unless necessary as it may mask the signs of worsening encephalopathy or cerebral edema in the patient
Other medications to avoid: hepatotoxics and nephrotoxics
Consider early referral to transplant
How would you manage the complications in acute liver failure?
Cerebral edema
- Liver transplantation
- Raised ICP measures: Nurse w/ head elevated, Permissive Hyperventilation, Keep normothermic, Mannitol
Hepatic encephalopathy is due to ↑ Serum Ammonia
- Patient MUST BO at least twice a day 🡪 helps clear ammonia
- Consider Laxatives e.g. Lactulose to ↑ clearance of ammonia from gut lumen
2’ hyperaldosteronism (from hepatorenal) leading to hypernatremia/hypokalaemia
- Low Na diet, IV hypotonic fluids if patient is dehydrated e.g. D5W, 0.45% saline
- Frequent electrolyte monitoring and correction when necessary
Metabolic abnormalities eg: glycaemic derangements
Coagulopathy
- IV omeprazole for bleeding prevention
- Vitamin K infusion, blood products if required
Watch for sepsis
Keep only essential medications
How do you treat the underlying cause of ALF?
- paracetamol
- hep B
- Wilson’s
- Autoimmune hepatitis
- Budd Chiari:
- Herpes/ Varicella
- Acute fatty liver of pregnancy
- Paracetamol: NAC
- Hep B: nucleoside analogue (e.g. entecavir, tenofovir)
- Wilson’s: liver transplant
- Autoimmune hepatitis: prednisone
- Budd Chiari: anticoagulation / thrombolysis / shunts / transplant
- Herpes/ Varicella: IV acyclovir
- Acute fatty liver of pregnancy: emergent deliver
What’s the king college hospital criteria for liver transplantation in patients with acute liver due to paracetamol overdose?
- H+ > 50nmol/l
Or all of the following
- prothrombin time >100s
- creatinine >300 umol/l
- grade 3-4 encephalopathy
