Acute Liver Failure ✅ Flashcards

1
Q

What is acute liver failure defined as?

A

Development of hepatic necrosis in absence of pre-existing liver disease

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3
Q

How might acute liver failure present in infancy?

A
  • Irritability
  • Sleepiness
  • Hypoglycaemia
  • Bruising, petechiae, or bleeding/oozing from venepuncture sites/umbilical stump
  • Jaundice
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4
Q

What are the categories of causes of acute live failure in neonates/infants up to 6 months?

A
  • Infective
  • Metabolic
  • Poisoning
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5
Q

What are the infective causes of acute liver failure in neonates/infants up to 6 months?

A
  • Septicaemia
  • Hepatitis B
  • Adenovirus
  • Echovirus
  • Coxsackie B
  • Herpes simplex
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6
Q

What are the metabolic causes of acute liver failure in neonates/infants up to 6 months?

A
  • Neonatal haemchromotosis
  • Tyrosinaemia type 1
  • Mitochondrial disease
  • Fatty acid oxidation defects
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7
Q

What are the categories of causes of acute liver failure in children >6 months?

A
  • Infection
  • Autoimmune
  • Drug
  • Metabolic
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8
Q

What are the infectious causes of acute liver failure in over 6 month olds?

A
  • Hepatitis A/B/E
  • Epstein-Barr virus
  • Parvovirus B19
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9
Q

What are the types of autoimmune disorders causing acute liver failure in children over 6 months?

A

Type I or II

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10
Q

What drugs can cause acute liver failure in children over 6 months?

A
  • Paracetamol (in overdose)
  • Anti-epileptics, e.g. sodium valproate, carbamazepine
  • Isoniazid
  • Halothane
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11
Q

What metabolic conditions can cause acute liver failure in over 6 months?

A
  • Wilson’s disease

- Alper’s disease

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12
Q

What is neonatal haemochromotosis?

A

Iron storage disorder

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13
Q

In what form does iron exist in the body?

A

As transferrin

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14
Q

What is transferrin?

A

Iron bound to apotransferrin

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15
Q

Where is most of the iron used for haemoglobin production obtained from?

A

Haemoglobin breakdown of senescent red blood cells

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16
Q

How is haemoglobin released from RBCs?

A

They are phagocytosed by macrophages. Proteolytic enzymes in the macrophages degrade the ingested cells, and release haem and globin molecules as separate entities

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17
Q

Where are RBCs phagocytosed by macrophages?

A
  • Spleen
  • Liver
  • Bone marrow
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18
Q

What happens to the globin molecules released from phagocytosed RBCs?

A

They are broken down into amino acids and used for protein production

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19
Q

What happens to the haem molecules released from phagocytosed RBCs?

A

Iron is released from haem, leaving a porphyrin ring, which is converted to bilirubin

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20
Q

What can lead to accumulation of iron in the liver?

A

Failure of processes of RBC breakdown

Excessive iron absorption

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21
Q

What are the clinical features of iron accumulation in the liver?

A
  • Raised transaminases
  • Conjugated jaundice
  • Hypoalbuminaemia
  • Severe coagulopathy
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22
Q

What kind of disorder is neonatal haemochromatosis considered to be?

A

Alloimmune disorder

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23
Q

What is the pathological process behind neonatal haemochromotosis?

A

Mothers develop an abnormal immune response to fetal liver protein, which results in liver damage and a direct or indirect effect on fetal iron storage

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24
Q

How does the number of pregnancies a mother has had affect the incidence of neonatal haemochromotosis?

A

It is rare in first pregnancies, but higher in subsequent

25
Q

What will be found on iron studies in neonatal haemochromotosis?

A
  • High serum iron
  • Hypersaturation of iron-binding capacity
  • Elevated ferritin
26
Q

Describe the clinical course of neonatal haemochromotosis?

A

Progressive, with death from liver failure without transplantation

27
Q

What is the diagnosis of neonatal haemochromotosis based on?

A

Demonstrating iron storage outside of the liver, e.g. salivary glands, pancreas, or brain on MRI

28
Q

When does galactosaemia present?

A

Typically in early neonatal period

29
Q

How does galactosaemia present?

A
  • Sepsis
  • Liver failure
  • ‘Oil drop’ cataracts on opthalmoscopy
30
Q

What is the inheritance of galactosaemia?

A

Autosomal recessive

31
Q

What is the pathological process in galactosaemia?

A

Deficiency of galactose-1-phosphate uridyltransferase

32
Q

How is a diagnosis of galactosaemia made?

A
  • Suggested by detection of urinary reducing substances without glycosuria
  • Confirmed by demonstrating reduced enzyme activity in blood (Gal-1-PUT)
33
Q

When might misleading results be obtained when testing for galactosaemia?

A

In presence of recent blood transfusion

34
Q

What organs are particularly affected by mitochondrial disease?

A

Those that need large amounts of energy;

  • Brain
  • Heart
  • Liver
  • Renal tubules
35
Q

How might neonates with mitochondrial disease present?

A
  • Acute liver failure
  • Seizures
  • Cardiomyopathy
  • Renal failure
36
Q

How might older children with mitochondrial disease present?

A
  • Hepatic steatohepatitis
  • Cholestasis
  • Cirrhosis
37
Q

What is a key feature of mitochondrial diseases?

A

Lactic acidaemia

38
Q

Is liver transplasntation used in mitochondrial disease?

A

May be used if disease confined to liver, but contraindicated if multi-organ involvement

39
Q

How might acute liver failure present in an older child?

A
  • Jaundice
  • Encephalopathy
  • Coagulopathy
40
Q

What complications may arise from acute liver failure?

A
  • Cerebral oedema
  • Coagulopathy
  • Systemic inflammatory response syndrome
  • Hyponatraemia
  • Hypotension
41
Q

What does cerebral oedema caused by liver failure lead to?

A
  • Hepatic encephalopathy
  • Coma
  • Brain herniation
  • Death
42
Q

How severe is hepatic encephalopathy?

A

Varies from subtle deficit in higher brain function, e.g. mood, concentration in grade I encephalopathy, to deep coma in grade IV encephalopathy

43
Q

Which patients are at highest risk of developing cerebral oedema and grade IV encephalopathy?

A

Patients presenting with acute and hyperacute liver failure

44
Q

What causes cerebral oedema and encephalopathy in acute liver failure?

A

Exact pathogenesis unclear, but likely to be consequence of;

  • Accumulation of toxins, e.g. ammonia, which affects neurotransmitter levels and neuroreceptor activation
  • Impairment of autoregulation of cerebral blood flow, resulting in anaerobic glycolysis and oxidative stress
  • Inflammatory mediatiators
45
Q

Why do you get coagulopathy in acute liver failure?

A

Due to the livers role in production of coagulation factors

46
Q

What measure of coagulation is used to monitor severity of hepatic injury?

A

PT time (prolonged in acute liver failure)

47
Q

What happens to platelets in acute liver failure?

A

Platelet dysfunction, with loss of larger and more active platelets

48
Q

In what % of patients with acute liver failure is systemic inflammatory response syndrome seen in?

A

Up to 60%

49
Q

What does SIRS lead to?

A

Multi-organ failure

50
Q

What causes SIRS in acute liver failure?

A

Impaired immune function, increasing the risk of sepsis

51
Q

How is SIRS prevented in acute liver failure?

A

Patients are treated routinely with antibiotics and antifungals

52
Q

How does acute liver failure cause hyponatraemia?

A
  • Water retention in response to hypoalbuminaemia

- Shift in intracellular sodium transport from inhibition of Na/K-ATPase

53
Q

What other electrolyte abnormalities are often seen in acute liver failure?

A
  • Hypokalaemia
  • Hypophosphataemia
  • Metabolic alkalosis
54
Q

Why is hypotension seen in acute liver failure?

A
  • Peripheral vascular dilatation and reduced systemic vascular resistance
  • Tissue hypoxia and lactic acidosis
55
Q

How is hypotension in acute liver failure compensated for?

A

Cardiac output increases

56
Q

What are the indications for transplant in acute liver failure?

A
  • Worsening coagulopathy, which is unsupported by blood products and not responsive to vitamin K
  • Worsening encephalopathy
57
Q

What are the contraindications for transplant in acute liver failure?

A
  • Multisystem disease
  • Irreversible brain damage
  • Pre-existing life-limiting disorders
58
Q

What mutations have been identified as causing mitochondrial disease?

A

Mutations in nuclear genes such as SCO1, BCS1L, POLG, DGUOK, and MPV17, and deletion or rearrangement of mitochondrial DNA