liver failure

LIVER FAILURE

الدكتور خلدون ذنون- كلية طب نينوى
المرحله الرابعة
Objectives
The following facts must be focused on:
Causes of liver failure including drugs, viral hepatitis is the most common.
Clinical features which ranges from poor concentration to coma.
Investigations to discover the cause and assess prognosis.
Management inside intensive care unit with close monitoring.

ACUTE (FULMINANT) HEPATIC FAILURE It is a rare syndrome which is due to sudden severe impairment of hepatic function, manifested as hepatic encephalopathy(confusion, stupor&coma) .hyperacute (<7days), acute (8-28days), subacute (4-12 week).

Aetiology

Acute viral hepatitis ( hepatitis A,B,D & non A-E ) , it is the most
common cause worldwide.
Drugs: paracetamol, halothane, aspirin, anti-TB drugs, it accounts for 75% of causes in the UK especially paracetamol.
Poisons: amanita phalloides, carbon tetrachloride.
Others: acute fatty liver of pregnancy, Wilsons disease, shock & heart failure, Budd-Chiari syndrome, leptospirosis, extensive malignant disease of the liver.
10% cause unknown.


Clinical features
Cerebral disturbance (hepatic encephalopathy) is the cardinal feature:
- Grade 1: poor concentration, slurred speech, slow mentation,
disordered sleep rhythm .
- Grade 2: drowsy, occasional aggressive behavior, lethargic.
- Grade 3: marked confusion, sleepy but responds to painful
stimuli &voice , disoriented.
- Grade 4: unresponsive to voice, may or may not respond to
Painful stimuli, coma.
Yawning, hiccup & convulsion may occur, asterixis is
characteristic but may be absent.
Cerebral oedema lead to ( intracranial pressure : unequal or abnormally reacting pupils , fixed pupils , hypertension & bradycardia , hyperventilation , sweating , myoclonus , focal fits , decerebrate posturing , papilloedema is a late sign .
Weakness, nausea, vomiting, fetor hepaticus.
Progressive & deep jaundice absent in Reyes syndrome.
Hepatomegaly may occur initially but later the liver is impalpable .
Ascites & oedema are late features.
Features of complications: infection, bleeding, renal failure, hypoglycemia, respiratory failure etc.

Complications of acute liver failure

( Encephalopathy & Cerebral oedema ( Multiorgan failure (Hypotension, Respiratory & renal failure)
( Infection ( Hypoglycemia ( Metabolic acidosis


Investigations
A- To determine the cause:
Toxicology screen: blood & urine e.g paracetamol etc.
Viral study: IgM anti-HBc, IgM anti-HAV, anti-HCV etc..
Ceruloplasmin, serum & urinary copper.
Autoantibodies: ANF, AMA, ASMA, LKM.
Ultrasound of the liver & doppler of hepatic veins.
Percutaneous liver biopsy is contraindicated because of severe coagulopathy, may be done through transjugular route for malignancy.
B- To determine the prognosis
Prothrombin time or factor v level: the laboratory test of greatest prognostic value must be done at least twice daily.
S.bilirubin, s.creatinine, PH of the blood.
Plasma aminotransferases: particularly high after paracetamol poisoning 100-500 times the normal level but it is not helpful in the prognosis.
Plasma albumin remains normal unless the course is prolonged.

Prognosis

Adverse prognostic criteria carries > 90% mortality, these are:
A- Paracetamol overdose: PH < 7.3 , s.creatinin > 300( mol/ L
PT > 100 seconds , encephalopathy grade 3 or 4.
B- Non-paracetamol cases:
PT >100 seconds or any three of the following :
Jaundice to encephalopathy time > 7 days.
Age < 10 years or > 40 years
Unknown or drug induced causes.
Bilirubin > 300( mol / L .
PT > 50 second or factor v level <15%.
Encephalopathy grade 3-4.


Management
Management should be inside intensive care unit.
Neurological observation : conscious level , pupils , planters,
Papilloedema.
Cardiorespiratory: pulse, B.P, CVP, respiratory rate.
Fluid balance : input & output of fluid (oral , i.v), urine output,
vomiting, dirrhoea .
Blood analysis : blood gases , full blood count , urea , s.creatinin ,
electrolytes ( K ,Na,Mg,HCO3 ,Ca ) , glucose , PT .
Infection screen : culture → blood , urine , throat , sputum , canula
Site, chest x-ray, temperature.
Early transfer to a specialised transplant unit must be considered.
N-acetyl cysteine in paracetamol overdosage.
Exclude protein from diet , i.v glucose , lower blood ammonia by
lactulose & evacuate blood from the bowel by enema-laxative, i.v
antibiotics, fluid electrolyte acid-base balance.
Liver transplant: 1year survival is 60%,without transplant is<10%.










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