liver failure Flashcards
def liver failure
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
aetiology liver failure
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
RF liver failure
- chronic alcohol abuse
- poor nutritional status
- female
- >40yrs
- pregnancy
- chronic hep B
- chronic pain and narcotic use
- complementary and alternative med hepatotoxicty
epi liver failure
Paracetamol overdose accounts for 50% of acute liver failure in the UK
sx liver failure
may be asymptomatic
fever
nausea
possible jaundice - reduced secretion of conjugated BR
signs liver failure
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
ecephalopathy
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
grading of encephalopathy
- Altered mood/behaviour; sleep disturbance (eg reversed sleep pattern); dyspraxia (‘Please copy this 5-pointed star’); poor arithmetic. No liver flap
- Increasing drowsiness, confusion, slurred speech ± liver flap, inappropriate behaviour/personality change (ask the family—don’t be too tactful)
- Incoherent; restless; liver flap; stupor
- Coma.
identifying cause of liver failure
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
blood liver failure
- 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
ix liver failure
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
cautions with liver failure
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
liver failure resus
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.
treatment/prevention of complications of liver failure
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
treat renal failure
haemofiltration, nutritional support
