acute liver failure

1. Acute Liver Failure

2. Acute Liver Failure
• Acute liver failure describes the clinical syndrome of severe
impairment of liver function Encephalopathy
Coagulopathy
 jaundice
• Within 6 months of the onset of symptoms.

3. DEFINITION (PALF study group)
1.The acute onset of liver disease with no known evidence of chronic
liver disease.
2. Biochemical and/or clinical evidence of severe liver dysfunction:
• Hepatic-based coagulopathy – prothrombin time [PT] ≥15 seconds or
international normalized ratio [INR] ≥1.5 that is not corrected by
parenteral vitamin K in presence of clinical hepatic encephalopathy
• PT is ≥20 seconds or INR is ≥2.0 in presence or absence of HE .

4. Classification

5. • An alternative classification
 fulminant and sub-fulminant • liver failure - time from jaundice to encephalopathy less or more than
2 weeks
Late onset liver failure describes encephalopathy developing more
than 8 weeks (but lessthan 24 weeks) after the first symptoms

6. Acute vs acute on chronic liver failure
Acute liver failure
Acute on chronic liver failure
History
Short
Long
Nutrition
Good
Poor
Liver
Increased /normal
Hard / increased
Spleen
Increased /normal
Increased
Spiders naevi
Absent
Present

7. Causes

8. Causes
Neonates
Infectious
Herpes Virus , Hepatitis B virus
Inborn Error of Metabolism
Hereditary Fructose Intolerance , Galactosemia
(Common)
Immune Mediated
Neonatal Hemochromatosis
Ischaemia
CHD , Cardiac Surgery , Myocarditis
Infants
Infectious
Hep A , Hep B , Herpes Virus , NANB Hepatis
(Common)
Drugs
Valproate , Isoniazide , Paracetamol (Common)
Inborn Error of metabolism
Hereditary Fructose Intolerance
Immune Mediated
Autoimmune Hepatitis

9. 2-18 years old
Infectious
NANB Hepatitis ,Hep A , Hep B (common)
Drugs
Same As Infants
Immune mediated
Autoimmune
Ischaemia
Budd Chiari Syndrome
Metabolic
Wilson’s Disease

10. • In India , infectious hepatitis is the most important cause of ALF
• In Infants , main causes are inherited metabolic disorders and
infections

11. Pathogenesis
• Massive destruction of hepatocytes – direct cytotoxic effect or
immune response to antigens
• Contributing factors to liver failure – impaired hepatocyte
regeneration , altered parenchymal perfusion , endotoxemia

12. Clinical features
• The patient, previously having been well, typically develops non-specific
symptoms such as nausea and malaise.
• Progressive Jaundice.
• Vomiting is common
• Abdominal pain .
• Rapid decrease in liver size without clinical improvement is an omnious
sign
• Ascites
• Tachycardia, hypotension, hyperventilation and fever are later features
• Later coma & encephalopathy features

13. Signs of Liver cell failure
• Progressive Jaundice

14. Fetor hepaticus
• Sweetish, slightly faecal smell of the breath
• Of intestinal origin
• Normal demethylating processes being inhibited by liver damage.
• Methyl mercaptans excreted through lungs
• Frequent in patients with an extensive portal-collateral circulation
• Often precedes coma

15. Skin changes - Vascular spiders
• Found in the vascular territory of the superior vena cava.
• Common sites are the necklace area,the face, forearms and dorsum
of the hand
• An arterial spider consists of a central arteriole, radiating from which
are numerous small vessels resembling a spider’s legs

16. • Pressure on the central prominence with a pinhead causes blanching of the
whole lesion
• Disappear with improving hepatic function, whereas the appearance of fresh
spiders is suggestive of progression.
• A few spiders are not sufficient to diagnose liver disease, but many new ones,
with increasing size of old ones, should arouse suspicion.

17. Palmar erythema (liver palms)
• The hands are warm and the palms bright red in colour,especially the
hypothenar and thenar eminences and pulps of the fingers
• The mottling blanches on pressure and the colour rapidly returns.

18. • Vascular spiders and palmar erythema - attributed to oestrogen
excess.
• Oestrogens have an enlarging, dilating effect on the spiral arterioles
of the endometrium, and such a mechanism may explain the closely
similar cutaneous spiders
• Liver inactivates oestrogen– in liver failure it leads to increase in
oestrogen levels – leads to cutaneous manifestations of liver failure

19. Endocrine changes - Hypogonadism
• Diminished libido and potency are frequent
• The testes are soft and small. Seminal fluid is abnormal in some cases.
• Secondary sexual hair is lost
• The female has ovulatory failure.
• Loses feminine characteristics, particularly breast and pelvic fat.
• Gynaecomastia - Alcoholic liver disease is the commonest
association.

20. • Steroid hormones are conjugated in the liver.
• Derivatives of oestrogens, cortisol and testosterone are conjugated as a
glucuronide or sulphate
• So excreted in the bile or urine.
• Failure of hormone metabolism in liver failure results in a rise in blood
hormone levels.
• This alters the normal homeostatic balance between secretion rates of
hormones and their utilization.

21. Investigations
Haematology
• The prothrombin time (together with the degree of encephalopathy) refractory to vitamin K treatment central to the assessment of the severity of the clinical situation, and its progress.
• Haemoglobin and white count are obtained.
• A falling platelet count may reflect disseminated intravascular coagulation.

22. Biochemistry
• Blood Glucose
• Blood Urea
• Serum Electrolytes
• Serum Creatinine
• Serum bilirubin
• Serum Albumin – initially normal but later low albumin carries poor
prognosis
• Transaminases – of little prognostic values as levels tends to fall as
condition worsens

23. Etiological Work Up
• Virological markers –
Serum HBsAg
IgM Anti HBc
IgM anti HAV
Anti HCV
HCV RNA

24. EEG
• The Guidelines now used for decision on management no longer
depend on EEG
• Continuous EEG has shown 50% of patients with subclinical seizure
and epileptiform activities
• Recommended for Grade 3 and 4 Encephalopathy

25. Liver Biopsy & CT Brain
• Hepatic Parenchymal necrosis more than 50% indicates poor prognosis
• Hepatic Regenerative changes on histology (<50% Necrosis ) indicates good
Prognosis
• From Practical point of view – clinical & laboratory data rather than biopsy
are used for decision making
• CT – unreliable in detecting early cerebral oedema so movement of patient
to radiology carries the risk of deterioration

26. General measures
• Volume resuscitation should be carried out aggressively
• Fluids should be glucose based with infusion rate at least 6-8
mg/kg/min
• Strict input output charting

27. Associations / complications

28. Hepatic encephalopathy
• The brain is exposed to increased levels of ammonia,
neurotransmitters and their precursors because of failed hepatic
clearance.
• Neurological and psychiatric components.
• Features of encephalopathy can be separated into changes in
consciousness, personality, intellect and speech.

29. • Disturbed consciousness with disorder of sleep is usual.
• Hypersomnia appears early and progresses to reversal of the normal
sleep pattern.
• Reduction of spontaneous movement, a fixed stare, apathy, and
slowness and brevity of response are early signs.
• Further deterioration results in reaction only to intense or noxious
stimuli.
• Coma at first resembles normal sleep, but progresses to complete
unresponsiveness.

30. Personality & intellect changes
• Irritability and loss of concern for family.
• Intellectual deterioration varies from slight impairment of organic mental function to gross confusion.
• Isolated abnormalities appearing in a setting of clear consciousness relate to disturbances in visual spatial
gnosis.
• Most easily elicited as constructional apraxia, shown by an inability to reproduce simple designs with
blocks or matches
• Writing is oblivious of ruled lines and a daily writing chart is a good check of progress
• Failure to distinguish objects of similar size, shape, function and position
• Micturating and defaecating in inappropriate places

32. Speech
• Speech is slow and slurred and the voice is monotonous.

33. Asterixis
• The most characteristic neurological abnormality is the ‘flapping’
tremor (asterixis).
• This is due to impaired inflow of joint and other afferent information
to the brainstem reticular formation resulting in lapses in posture.

34. • It is demonstrated with the patient’s arms outstretched and fingers
separated or by hyperextending the wrists with the forearm fixed .
The rapid flexion–extension movements at the metacarpophalangeal
and wrist joints are often accompanied by lateral movements of the
digits.

35. • ‘Flapping’ tremor is not specific for hepatic pre-coma.
• It can also be observed in uraemia, in respiratory failure and in severe heart
failure
• Deep tendon reflexes are usually exaggerated.
• Increased muscle tone is present at some stage and sustained ankle clonus is
often associated with rigidity.
• During coma , patients become flaccid and lose their reflexes.
• The clinical course fluctuates, and frequent observation of the patient is
necessary.
• Clinical grading should be used as a part of the clinical record

36. Staging

37. Pathogenetic mechanisms
• The basic processes are failure of hepatic clearance of gut derived
substances, either through hepato-cellular failure or shunting, and
altered amino acid metabolism
• Result in changes in cerebral neurotransmission.
• Several neuroactive toxins, in particular ammonia, and
neurotransmitter systems are thought to be involved and inter-relate.

38. Portal systemic Encephalopathy

39. • In patients with poor hepato-cellular function, such as acute hepatitis,
the shunt is through the liver itself.
• The damaged cells are unable to metabolize the contents of the portal
venous blood completely so that they pass unaltered into the hepatic
veins
• In patients with more chronic forms of liver disease the portal blood
bypasses the liver through enlarged natural ‘collaterals’.
• The portal– hepatic vein anastomoses, developing around the damaged
liver, act as shunt.

40. • Patients going into hepatic coma are suffering from cerebral
intoxication by intestinal contents which have not been metabolized
by the liver - portal-systemic encephalopathy

41. Pathogenesis
• Ammonia is produced from the breakdown of proteins,amino acids, purines and
pyrimidines.
• Ammonia arising from the intestine is synthesized by bacteria, dietary protein and
glutamine.
• The liver normally converts ammonia to urea and glutamine through the urea cycle.
• Liver failure causes disorder of the urea cycle lead to an encephalopathy.
• Blood ammonia levels &Brain levels are also increased
• Increase in the cerebral metabolic rate for ammonia and an increase in the blood–
brain barrier permeability to ammonia

42. Effects of ammonia on brain
• The primary mechanisms proposed for ammonia in hepatic
encephalopathy - direct effect on neural membranes or on postsynaptic inhibition
• An indirect neuronal dysfunction due to disturbance of glutamate
neurotransmission.

43. Brain- Glutamate
• No urea cycle in the brain
• Ammonia removal involves a different pathway.
• In astrocytes, glutamine synthetase converts glutamate plus ammonia to glutamine .
• With excess ammonia, glutamate (an important excitatory neurotransmitter) is depleted, and
glutamine accumulates.

44. GABA
• Principal inhibitory neurotransmitter
• GABA is synthesized by gut bacteria, and that entering the portal vein
is metabolized by the liver.
• Liver failure or portal-systemic shunting - enters the systemic
circulation.
• There are increased GABA levels in the plasma of patients with liver
disease and hepatic encephalopathy – neuroinhibition

45. • Receptor is part of a larger receptor complex which also has binding sites for
benzodiazepines and barbiturates.
• The binding of any of these ligands - opens a chloride channel - hyperpolarization
of postsynaptic membrane - neuroinhibition.
• Endogenous benzodiazepines are present in patients with hepatic
encephalopathy - interact with the receptor complex and cause neuroinhibition.

46. • No unifying mechanism explains hepatic encephalopathy.
The brain controls neuropsychiatric behaviour through multiple inhibitory and stimulatory
receptor mediated pathways.

47. Investigations
• Cerebrospinal fluid - usually clear and under normal pressure , cell
count is normal
• Electroencephalogram(EEG) - bilateral synchronous slowing of the
wave frequency.
• EEG changes occur very early even before psychological or
biochemical disturbances.
• CT scan to show cerebral oedema and cortical atrophy even in those
with subclinical portal-systemic encephalopathy.

48. EEG changes

49. Treatment of Hepatic Encephalopathy
• Treatment broadly divides into three areas.
1 Identification and treatment of the precipitating cause.
2 Intervention to reduce the production and absorptionof gut-derived ammonia
and other toxins.
• Involves reduction and modification of dietary protein,
• Alteration of enteric bacteria and the colonic environment antibiotics,lactulose/lactilol
• Stimulation of colonic emptying - enemas, lactulose/lactilol.
3 Agents to modify neurotransmitter balance directly- bromocriptine, flumazemil limited clinical value at present.

50. Diet
Energy
150% of recommended allowance
Carbohydrates
15-20g/kg/d
Fats
8g/kg/day
Protein (non-encephalopathic
state)
2-3 g /kg/d
It promotes growth & maintain
positive nitrogen balance
Vegetable Proteins - preferred
Protein (encephalopathy)
Grade 1 & 2 – 1-2 g/kg/d
Grade 3 &4 – 0.5 g /kg/d
Further protein restriction
exacerbate HE by causing
breakdown of endogenous proteins

51. Antibiotics
• Neomycin, given orally, is very effective in decreasing gastrointestinal
ammonium formation - used for the acute case for 5–7 days
• In acute hepatic coma, lactulose is given -- neomycin added if the
response is slow or partial.
• Metronidazole seems to be as effective as neomycin.
• Rifaximin, a non-absorbed derivative of rifamycin, is effective for
grade 1–3 hepatic encephalopathy

52. Lactulose and lactilol
• Given by mouth lactulose
• Reaches the caecum where it is broken down by bacteria predominantly to lactic acid .
• The faecal pH drops.
• Faecal acidity would reduce the ionization and hence absorption of ammonia
• The growth of lactose-fermenting organisms is favoured and organisms such as bacteroides,
which are ammonia formers, are suppressed.

53. • The aim of treatment with lactulose is to produce acid stools without diarrhoea.
• The dose is 10–30ml three times a day and is adjusted to produce two semi-soft stools daily.
• The effects of lactilol compared with lactulose
 Colonic effects similar
 As effective in encephalopathy
 Quicker action
 More convenient (powder)
 Less sweet
 Less diarrhoea and flatulence
 No longer routinely available
Purgation to prevent constipation - Lactulose or lactose enemas may be used and are superior to
water . All enemas must be neutral or acid to reduce ammonium absorption.

54. Sodium benzoate and L-ornithine -L-aspartate
• Sodium benzoate promotes urinary excretion of ammonia and is as effective as
lactulose and is less expensive.
• L-ornithine-L-aspartate treatment promotes hepatic removal of ammonia by
stimulating residual hepatic urea cycle activity and promoting glutamine
synthesis, particularly in skeletal muscle

55. Recent Advances
• Flumanezil - benzodiazepine-receptor antagonist which can induce transient, variable but
distinct improvement in some patients with hepatic encephalopathy
• Clinical situation has yet to be established.
• Patients are extremely sensitive to sedatives and whenever possible these are avoided
• Zinc Supplementation – deficiency may reduce metabolism of ammonia to urea because
of the dependency on zinc of some of the enzymes involved
• Studies of zinc therapy in hepatic encephalopathy have not established benefit

56. Cerebral edema (intracranial hypertension)
• Uncommon in patients with grade 1 or 2 encephalopathy
• Develops in the majority with grade 4.
• Raised intracerebral pressure can lead to brainstem herniation and is
the most common cause of death, being found in 80% of fatal cases
• Two mechanisms have been proposed: cytotoxic and vasogenic.
o The cytotoxic hypothesis - accumulation of osmolytes such as glutamine, in astrocyte subsequent osmotic uptake of water into the cells.
o In the brain astrocytes are the site of ammonia metabolism by amidation of glutamate to
glutamine.
o In acute liver failure cerebral glutamine concentrations rise.

57. • The vasogenic hypothesis - changes in cerebral blood flow and the blood–brain
barrier
• Cerebral blood flow autoregulation (maintained blood flow despite falling or rising
blood pressure) is lost in patients with fulminant hepatic failure .
• Loss of this protective mechanism could exacerbate cerebral changes due to systemic
hypotension (giving cerebral ischaemia) and cerebral hyperperfusion- increasing
cerebral blood volume and interstitial water
• If not controlled - progresses to loss of pupillary reflexes and respiratory arrest from
brainstem herniation.

58. Treatment
• Head should be elevated to 30 degrees
• High levels of PEEP should be avoided – it may increase hepatic venous pressure
& intracranial pressure
• Mannitol bolus of 0.5 g/kg as 20 % solution over 15 minutes – can be repeated if
serum osmolality less than 320 mOsm/L
• Other methods 3% hypertonic saline
• STEROIDS ARE NOT INDICATED IN TREATMENT OF INTRACRANIAL HYPERTENSION
in ALF – as it may complicate infection & cause gastric erosions

59. Coagulopathy
• The liver synthesizes all the coagulation factors (except factor VIII) inhibitors of coagulation and
proteins involved in the fibrinolytic system.
• The coagulopathy of fulminant hepatic failure is complex
• Not only to factor deficiency, but also to enhanced fibrinolytic activity
• The platelet count may fall due to increased consumption or reduced production, and platelet
function is also abnormal in hepatic failure.
• The resulting coagulopathy predisposes to bleeding- potential cause of death
• The prothrombin time is the most widely used test to assess coagulation. It is a guide to prognosis.

60. Treatment
• Iv vitamin K to correct any reversible coagulopathy
• FFP – to be given in case of haemorrhage or if coagulopathy is severe
(PT>60sec)
• Thrombocytopenia to be corrected
• Prophylaxis for GI bleed – administration of PPI , sucralfate , ranitidine

61. Metabolic , electrolyte and acid base disturbances
• Hyponatremia
• Hypokalemia – decreased dietary intake , chronic illness , secondary hyperaldosteronism , frequent GI
losses
• Hypophosphatemia – due to amount of regenerative liver mass as phosphate be a substrate for
various kinase enzymes that phosphorylate proteins for liver regeneration
• Hypoglycemia – failure of hepatic gluconeogenesis , high plasma insulin levels due to decreased
uptake
• Respiratory alkalosis – due to hyperventilation – direct stimulation of respiratory centre by toxic
substances

62. Treatment
Hypokalemia
3 Meq (1.5 ml kcl ) if K+ >3 Meq
4 Meq (2 ml kcl ) if K+ is 2.5 - 3 Meq
5 Meq (2.5 ml kcl ) if K+ is 2 – 2.5 Meq
6 Meq (3 ml kcl ) if K+ is < 2 Meq
Hyponatremia
Restrict sodium infusion to < 2 Meq
/kg/day
Hypoglycemia
Increase GIR
Maintain blood sugar levels between 100 –
200 mg/dl

63. Infections
• Ninety per cent of patients with acute liver failure and grade 2 or
more encephalopathy have clinical or bacteriological evidence of
infection
• The majority of infections are respiratory.
• The high rate of infection can be related to poor host defences with
impaired Kupffer cell and polymorph function

64. Renal
• Hepatorenal syndrome is the most common cause of renal
insufficiency in ALF
• Secondary to renal vasoconstriction
• Type 1 – rapidly progressive in renal function , doubling of s.
creatinine to a level > 2.5 mg/dl or 50 % reduction in CrCl to < 20
ml/min in less than 2 weeks
• Type 2 – progression slow , > 2 weeks

65. Treatment
• Primarily focussed on decreasing splanchic circulation –
1. Vasoconstrictors – Terlipressin
2. Alpha agonist- nor-epinephrine , medodrine
Very effective in reversal of functional renal insufficiency

66. Prognosis
• Overall survival for those reaching grade 3 or 4 encephalopathy is 20% without
transplantation.
• If only grade 1 or 2 coma is reached, survival is around 65%.
• Aetiology is important - 66% for hepatitis A, 38.9% for hepatitis B and 50% for
acetaminophen overdose
• Decerebrate rigidity, with loss of the oculovestibular reflex and respiratory failure
are particularly ominous
• Prothrombin time is the best indicator of survival
• The association of a clotting factor V concentration of less than 15% with coma is
also ominous

67. • Liver biopsy -Hepatic parenchymal necrosis of more than 50% is
associated with a reduced survival
• The causes of death are: cerebral oedema, infection, bleeding,
respiratory and circulatory failure, renal failure, hypoglycaemia and
pancreatitis
• Hyper-acute liver failure - the chance of survival without
transplantation is more than in acute liver failure

69. Auxiliary liver transplantation
• The native liver is left in place
• Donor liver graft either placed in the right upper quadrant alongside the native liver
(heterotopic), or part of the native liver is resected and replaced with a reduced size graft
(orthotopic).
• The intention - to provide viable liver function from the graft, giving the native liver time to
recover and regenerate.
• The advantage over conventional transplantation is the temporary need for immunosuppression