liver failure

Question 1

def liver failure

Answer 1

development of coagulopathy (INR>1.5) and encephalopathy

may be sudden in previous healthy liver = acute

(hyperacute = onset ≤7d; acute =8–21d; subacute =4–26wks.)

on background of cirrhosis = chronic

fulminant hepatic failure - syndrome from necrosis of liver cells = severe impairment of liver func

Question 2

aetiology liver failure

Answer 2

Viral

• hep A-E, non-A-E hep
• CMV
• yellow fever

leptospirosis (bacteria)

drugs

• paracetamol OD
• idiosyncratic drug reactions eg anti-TB therapy (isoniazid)
• halothane

less common

• autoimmune hep
• Budd-Chiari syndrome
• veno-occlusive disease
• pregnancy related
• malignancy - lymphoma
• haemochromatosis
• mushroom poisoning (amanita phalloides)
• Wilson’s disease
• carbon tetrachloride

alcohol

fatty liver

primary biliary cholangitis

primary sclerising cholangitis

a1-antitrypsin deficiency

Question 3

RF liver failure

Answer 3

• chronic alcohol abuse
• poor nutritional status
• female
• >40yrs
• pregnancy
• chronic hep B
• chronic pain and narcotic use
• complementary and alternative med hepatotoxicty

Question 4

epi liver failure

Answer 4

Paracetamol overdose accounts for 50% of acute liver failure in the UK

Question 5

sx liver failure

Answer 5

may be asymptomatic

fever

nausea

possible jaundice - reduced secretion of conjugated BR

Question 6

signs liver failure

Answer 6

jaundice - hepatic

spider naevi - increased oestrogen

gynaecomastia - increased oestrogen

palmer erythema

fetor hepaticus - pear drops

caput medusa - dilation of veins around the umbilicus

oesophageal varices - high risk of upper GI bleeding

ascites

splenomegaly

bleeding or brusing from puncture sites of GIT

asterixis

constructional apraxia (cant copy 5 pointed star)

hepatic encephalopathy - increased delivery of gut products into systemic circ and brain from reduced extraction of nitrogenous products by liver and portal system shunting. Ammonia may play a part

signs of chronic liver disease and acute-on-chronic hepatic failure

coagulopathy - reduced synthesis of clottiong factors, reduced platelets (hyposplenism of chronic portal hypertension) or platelet functional abnormalities associated with jaundice or renal failure

Look for secondary causes (e.g. bronze skin colour, Kayser–Fleischer rings).Pyrexia may reflect infection or liver necrosis

Question 7

ecephalopathy

Answer 7

as liver fails nitrogenous waste (eg ammonia) builds up in circ - pass to brain - astrocytes clear it - convert glutamate to glutamin e

excess glutamine = osmotic imbalance and shift of fluid into thee cells = cerebral oedema

Question 8

grading of encephalopathy

Answer 8

1. Altered mood/behaviour; sleep disturbance (eg reversed sleep pattern); dyspraxia (‘Please copy this 5-pointed star’); poor arithmetic. No liver flap
2. Increasing drowsiness, confusion, slurred speech ± liver flap, inappropriate behaviour/personality change (ask the family—don’t be too tactful)
3. Incoherent; restless; liver flap; stupor
4. Coma.

Question 9

identifying cause of liver failure

Answer 9

viral serology - CMV/EBV

paracetamol levels

autoAb - ASM, LKM Ab, Ig

ferritin

a1-antitripsin

caeruloplasmin low, and raised urinary copper in Wilson’s

urine culture

Question 10

blood liver failure

Answer 10

• low Hb if GI blled
• raised WCC = infection
• UE - hepatorenal failure
• glucose
• LFT - high BR, transaminases, alkPhos, GGT and reduced albumin
• ESR/CRP
• coag screen - raised PT and INR
• ABG - pH
• G&S

Question 11

ix liver failure

Answer 11

US liver and CT

ascitic fluid

• tap ascites
• culture for MC&S
• biochem - glucose and protein
• cytology >250 neutrophil/mm3indicates spontaneous bacterial peritonitis
• doppler scanning of hepatic/portal veins - exclude Budd-Chiari syndrome

electroencephalogram - monitor encephalopathy

Question 12

cautions with liver failure

Answer 12

Beware sepsis, hypoglycaemia, GI bleeds/varices, & encephalopathy

Avoid drugs that constipate (increase risk of encephalopathy), oral hypoglycaemics, and saline-containing IVIs.

Warfarin effcts are enhanced.

Hepatotoxic drugs: paracetamol, methotrexate, isoniazid, azathioprine, phenothiazines, oestrogen, 6-mercaptopurine, salicylates, tetracycline, mitomycin

Question 13

liver failure resus

Answer 13

airway, breathing and circulation

ITU care and specialist unit support essential

20° head-up tilt in ITU. Protect the airway with intubation and insert an NG tube to avoid aspiration and remove any blood from stomach.

Question 14

treatment/prevention of complications of liver failure

Answer 14

invasive ventilatory and CVS support often needed

monitor: vital signs, PT, pH, creatinine, UO, encephalopathy, temp, respirations, pupils, daily weights

Manage encephalopathy: Lactulose and phosphate enemas.

Antibiotic and antifungal prophylaxis

Hypoglycaemia treatment 10% glucose IV, 1L/12h

Coagulopathy treatment: IV Vitamin K, FFP, platelet infusions if required.

Gastric mucosa protection: Proton pump inhibitors or sulcralfate. eg omeprazole 40mg/d IV/PO.

Avoid: Sedatives or drugs metabolized by the liver.

Cerebral oedema: Nurse patient at 30 degreesC, reduce intracranial pressure by IV mannitol, hyperventilate.

nutrition reduces mortality - thiamine and folate supplements

treat seizures with phenytoin

Question 15

treat renal failure

Answer 15

haemofiltration, nutritional support

Question 16

surgical mx liver failure

Answer 16

Kings college hospital criteria for liver transplantation

If due to paracetamol overdose:

• arterial pH<7.3, or
• PT>100s, creatinine>300 and severe encephalopathy

For other causes (three out of five):.

• age<10 or>40 years,
• bilirubin>300mM,
• .caused by non-A, non-E viral hepatitis or drugs,
• interval from jaundice onset to encephalopathy>7 days, or
• PT>100s.

Question 17

treating complications of liver failure

Answer 17

cerebral oedema - on ITU 20% mannitol IV, hypervent

bleeding - vit K 10mg/d IV 3d, platelets, FFP + blood +- endoscopy

Ceftriaxone 1–2g/24h IV, not gentamicin (increased risk of renal failure).

low Blood glucose:If <2mmol/L or symptomatic, - 50mL of 50% glucose IV;check often.

Encephalopathy: Avoid sedatives; 20° head-up tilt in ITU; correct electrolytes; lactulose 30–50mL/8h (aim for 2–4 soft stools/d) is catabolized by bacterial flora to short-chain fatty acids which reduce colonic pH and trap NH3 in the colon as NH4+ ; Rifaximin 550mg/12h is a non-absorbable oral antibiotic that reduces numbers of nitrogen-forming gut bacteria.

Question 18

complications of liver failure

Answer 18

• infection
• coagulopathy
• hypoglycaemia
• disturbances of electrolytes
• acid-base and CVS
• hepatorenal syndrome - concurrent hepatic and renal failure
• cerebral oedema
• raised intracranial pressure
• resp failure

Question 19

px liver failure

Answer 19

• Depends on the severity and aetiology
• The traditional prognostic score for surgical mortality is the Childs–Pugh score.
• worse if grade 3-4 encephalopathy
• >40yr
• albumin <30g/L
• high INR
• drug induced
• late onset hepatic failure worse than fulminant failure