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Gastro > liver > Flashcards

liver Flashcards

1
Q

component parts of the porta hepatis

A
  1. portal vein: blood from gut, pancreas, spleen
  2. hepatic artery: oxygenated from heart
  3. common hepatic duct: brings bile from liver to GB
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2
Q

what are kupffer cells?

A

= ‘stellate reticuloendothelial cells’ = modified macrophages
destroy old RBC and WBC
on the inner walls of sinusoids

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3
Q

describe the acinar lobule model of thinking about the liver

A
  • loosely, an elliptical zone with central veins on either side and sinusoid in the middle
  • Physiological context: different zones have different oxygenation and metabolic function
  • Zone 1 is high in O2, high in toxins, high in nutrients - Closer to the portal triad
    i- Zone 3 is low in O2, low in toxins, low in metabolites - Closer to the central vein
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4
Q

when do hepatocytes first start producing bile acids?

A

12 weeks gestation

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5
Q

how does the GB contract?

A

fat in duodenum > CCK > GB contracts + sphincter of oddi relaxes > bile released into D2

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6
Q

diff between conjugated and unconjugated bilirubin

A
  • Conjugated = water soluble  CANNOT CROSS BBB
  • Unconjugated = fat soluble
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7
Q

describe bilirubin from synthesis to excretion

A

-heme >(heme oxygenase)>biliverdin
- biliverdin >(biliverdin reductase) >unconj bili
- unconj bili bound to albumin via hepatic bile duct to liver
- in hepatocyte: unconj > (UGT)> conj bili i.e. direct
- conj bili > excreted in bile > (gut bacteria) urobilinogen
- 80% in faeces: stercobilinogen > stercobilin
- 2% in urine: urobilinogen > urobilin
- 18% urobilinogen back to enterohepatic circulation

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8
Q

describe the conjugation of unconj bilirubin to conj bilirubin

A

unconj bilirubin + glucuronide (from UDP), by BUGT enzyme i.e. bilirubin uridine glucuronsyl transferase > bilirubin diglucuronide

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9
Q

AST vs ALT:
- which is more liver specific
- in CLD, which is usually greater?
- AST/ALT ratios: >2 when? <1 when? >20 when?

A
  • ALT more liver, AST also in muscle, kidney, pancreas etc.
  • CLD: ALT > AST, but may reverse as disease progresses
  • AST / ALT >2 = alcoholic liver disease
  • AST / ALT <1 = fatty liver disease
  • AST / ALT >20 and isolated - extra-hepatic source
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10
Q

GGT vs ALP: which is more liver specific?

A

GGT from hepatocytes + bile ducts predominantly; ALP from liver + bone

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11
Q

how to tell if GGT elevated from obstruction vs induced?

A

GGT + ALP = obstruction
GGT only = induced

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12
Q

why does GGT rise in biliary obstruction?

A

GGT is an ectoenzyme > when obstruction occurs, bile acids destabilize membrane and GGT is leached out and enters the serum

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13
Q

transient hypophosphotaemia:
- what kind of ALP levels
- what age
- when
- resolves when

A
  1. Usually ALP >5x ULN
  2. Child <5 years
  3. Usually follows viral infection
  4. Resolves in 3 months
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14
Q

why are neonates predisposed to developing jaundice anyway?

A
  1. Increased production – shorter RBC survival (Fetal Hb) and higher RBC mass (high Hb)
  2. Decreased metabolism - Deficiency of UGT1A1, does not reach adult levels until 14 weeks of age
  3. Ethnic variation in conjugation (east asian, mutation in UGT1A1)
  4. Increased enterohepatic circulation – decreased gut motility, less conversion to stercobilinogen (sterile gut)
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15
Q

how does phototherapy work in jaundice?

A
  1. structural isomerisation to lumirubin - more soluble
  2. photooxidation to polar molecules - slow
  3. photo-isomerisation of 45,15Z to 45,15E isomer - less toxic, soluble. Also reversible cf lumirubin
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16
Q

breastfeeding jaundice vs breast milk jaundice
- when
- pathogenesis

A

breastfeeding
- starts D2-5
- insufficient feed
- peaks in 2 weeks, and progressively declines over 3-12 weeks

breastmilk jaundice
- later, D7-10
- breastmilk stuff e.g. metabolites of progesterone> inhibit UGT

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17
Q

causes of unconjugated hyperbili

A

increased production
1) haemolysis: Rh, ABO, G6PD def, PK def, sepsis
2) non-haemolytic: cephalohaematoma, polycythaemia

Decreased conjugation - Gilbert, C-N

Reduced excretion - breastfeeding jaundice

Other
- physiological jaundice, breastmilk, HYPOthyroid

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18
Q

causes of conjugated hyperbili / neonatal cholestasis

A
  1. infection (TORCH, sepsis)
  2. structural
    - extra-hepatic: biliary atresia, choledochal cyst
    - intra-hepatic: Alagille, PSC/PBC, PCKD
    - functional: hepatitis
  3. metabolic
  4. endocrine - hypothyroid
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19
Q

3 main causes of conjugated hyperbili

A

A1AT def
neonatal hepatitis
biliary atresia

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20
Q

what would these most likely represent if found on a liver biopsy?
ii. Bile duct paucity
iii. RAS positive diastase resistant granules
iv. MRD3 staining

A

ii. Bile duct paucity -> Alagille
iii. RAS positive diastase resistant granules -> A1AT def
iv. MRD3 staining -> PFIC3

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21
Q

consequences of chronic cholestasis

A
  • growth failure
  • ADEK vitamin def -> MBD, degen neuromusc syndrome (esp. vit E def)
  • pruritus/xanthomas - can use urso
  • portal HTN, ascites
  • upper GI bleeding
  • cirrhosis
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22
Q

causes of neonatal hepatitis (4)

A

1) idiopathic neonatal hepatitis (25%)
2) Aagenaes syndrome
3) zellweger syndrome
4) neonatal haemochromatosis

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23
Q

aaegenaes syndrome
- pathogenesis
- inheritance
- presentation

A
  • cholestasis lymphoedema syndrome from lymphatic vessel hypoplasia
  • AR
  • episodic cholestasis; asymptomatic in between
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24
Q

zellweger syndrome
- what
- inheritance
- presentation
- prognosis

A
  • peroxisome disorder > accumulation of VLCFA > cerebrohepatorenal syndrome
  • AR
  • severe, generalised hypotonia and markedly impaired neurologic function with psychomotor retardation
  • fatal between 6-12 months
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25
Q

PFICs: compare type 1, 2,3, 4

A

PFIC1: ATPB81 gene, liver more susceptible to bile acids. low GGT
PFIC2: ABCB11 gene, reduced bile acid transport. low GGT. most common.
PFIC3: MDR3 gene, impaired phospholipid secretion, high GGT
PFIC4: TJIP gene, tight junctions leaky. normal/mild high GGT

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26
Q

Alagille syndrome: features

A

facies: triangular face, wide set eyes, broad nose bridge
butterfly vertebrae
JAG1
embryoxoton
pulmonary artery stenosis
tof
paucity of bile ducts and cholestasis

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27
Q

tx for pruritus 2nd to cholestasis

A

cholestyramine / rifampicin

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28
Q

biliary atresia: US findings

A

US: triangular cord sign = tubular echogenic cord of fibrous tissue, at bifurcation of portal vein

29
Q

most close DDx of biliary atresia and how to distinguish

A

idiopathic neonatal hepatitis:
- INH FHx 20%
- BA may have other abnormalities e.g. asplenia/situs invertus
- BA won’t have pigmented stools, and won’t have bile stain duodenal suction
- BA more common to have weirdly palpable live

30
Q

when does kasai have best outcome for biliary atresia?

A

if done <30 days of life

31
Q

compare Crigler-Najjar Type 1 and Type 2, and Gilbert’s syndrome

A

C-N type 1 = complete lack of UDPGT (BUGT)
C-N type 2 = incomplete lack of UDPGT (BUGT)
Gilbert’s = TA insertion into the promoter region of UGT1A1 -> decreased activation

32
Q

Crigler-Najjar type 1:
- inheritance + mutation
- Rx
- distinguishing from type 2

A
  • AR + premature stop codon on UGT1A1 gene
  • phototherapy daily
  • cholestyramine + agar + CaCO3 all acts as binders so can use as adjuvants
  • orlistat rarely used`
  • phenobarbital is CYP450 inducer; type 1 will have no response
33
Q

compare Dubin Johnson and Rotor syndrome

A

DBJ:
-MRP2 mutation&raquo_space; canniculi transporter: impaired secretion of conjugated bili + other bile salt anions
-GB not visualised on cholecystogram
- total urinary corporphyrin normal, most corporphyrin I
- liver: black stained with melanin

Rotr:
- SLCO1B1&raquo_space; code for bilirubin transporters for hepatocyte reuptake
- GB visualised
- total urinary corporphyrin high
- liver: normal

both don’t need treatment both mixed hyperbili.

34
Q

Galactossaemia:
- genes involved

A
  • GALT deficiency (classic)- converts galactose-1-phosphate to UDP-galactose
  • GALK def - converts galactose to galactose-1-phosphate. cataracts only manifestation
  • GALE def
35
Q

galactossaemia: manifestations

A

eyes - cataracts
jaundice - mixed hyperbili
vomiting
FTT
cholestasis
RTA
ovarian failure

36
Q

galactossaemia diagnosis - gold standard

A

nearly complete absence of galactose-1-phosphate uridyl transferase (GALT) activity in red blood cells (RBCs)

37
Q

tyrosinaemia - mutation and manifestation

A

Deficiency of fumarylacetoacetate hydrolase -> FAA build up
‘hepatorenal’ tyrosinaemia - liver failure + fanconi’s RTA

38
Q

Wilson’s disease:
- inheritance
- gene and pathogenesis
- age of onset

A
  • AR
  • ATP7B - encodes protein that transports copper in hepatocyte and binds it to apocaeruloplasmin&raquo_space; lower circulating, bound Cu&raquo_space; hepatotoxicity due to free radicals&raquo_space; free Cu impacts other organs
  • spectrum of disease: knockout of gene will be earlier
39
Q

manifestations of Wilson’s disease

A

B-PEARL:
brain - Parkinsonian: tremor, dysarthria, rigidity, choreoform
psych - depression, personality change, psychosis
eye - K-F rings: Cu deposit in descemet’s membrane
anaemia - haemolytic, Coomb’s neg: RBCs can’t cope with Cu
renal - RTA + Fanconi’s
liver - hepatomegaly (+/- spleno), hepatitis, cirrhosis etc

40
Q

Wilson’s disease: manifestations more common in younger vs older people with disease onset

A

younger: liver
older: neuro

41
Q

Wilson’s disease: serum Cu, urinary Cu and caeruloplasmin levels

A

serum Cu: high
urinary Cu: high - can use 24h collection and assess response with chelator
caeruloplasmin: low (not bound, so apo- not turned into caeruloplasmin)

42
Q

Wilson’s disease - management

A

1) low Cu diet e.g. low fish
2) chelators
- Oral D penicillamine
- Triethylene tetramine dihydrochloride (Trientine)
3) agents blocking intestinal absorption of cooper
- zinc: increases metallothionein protein in enterocytes > inc Cu uptake and trap it there
- Ammonium tetrhiomolybdate

43
Q

potential side effects of penicillamine treatment

A
  • 10-15% have worsened neuro condition
  • hypersensitivity: goodpasture, SLE, polymyositis etc.
  • low vit B6: penicillamine is an antimetabolite of vitamin B6 so need to supp with vit b6
44
Q

A1AT def:
- inheritance
- gene affected + pathogenesis
- main clinical manifestations

A
  • AR
  • SERPINA1 gene: codes for A1AT protease inhibitor inc. elastase inhibitor.
  • PiMM = normal. PiZZ = 10-20% A1AT = most comon for liver disease
  • if no A1AT protein, no liver disease!
  • COPD/emphysema: breakdown of alveolar elastin
  • liver disease: abnormal protein trapped in hepatocytes
45
Q

A1AT def: liver biopsy stains

A

periodic acid-Schiff positive, diastase resistant globules

46
Q

neonatal haemochromatosis:
- pathogenesis

A
  • maternal alloimmune injury
  • Transplacental passage of specific reactive IgG > activates foetal complement cascade > production of MAC > foetal liver injury
  • Iron deposition is a consequence rather than a cause of liver injury -> extrahepatic siderosis e.g. buccal glands with iron
47
Q

liver abscesses: which part of liver more likely to be affected?

A

solitary liver abscess in R) lobe - 70%

48
Q

Hep A / B / C
- incubation

A

HAV: 28d incubation, contagious 2wk-7days after jaundice
HBV: 1-5mo incubation
HCV: ~2mo incubation

49
Q

different types of hepatitis A presentation

A

1) Prodromal stage (VIRAEMIA) = unwell with non-specific symptoms (nausea, anorexia)
2) Icteric stage/ classic hepatitis (IMMUNE RESPONSE) = 1-2 weeks later, jaundice
3) Hepatitis A relapse after initial improvement
4) Cholestatic hepatitis = initial symptoms as in classic hepatitis A, prolonged pruritis
5) Fulminant hepatitis (1-5%) = initial presentation as in classic hepatitis A&raquo_space; rapid deterioration with confusion and decreased LOC

50
Q

most common hepatitis virus in the world

A

Hepatitis A

51
Q

AST/ALT in relation to hepatitis A symptoms

A

AST/ALT rise occurs BEFORE jaundice

52
Q

How is HBV transmitted

A

1) Vertical
2) Horizontal – children in endemic country
3) Blood-borne
4) Sexual

53
Q

phases of HBV infection

A

1) immune tolerant phase months-decades long: high HBV load, normal AST/ALT
2) immune clearance: high AST/ALT as body tries to clear
3) immune control = inactive carrier: seroconversion HBeAg –ve to anti-HBe positive. LFTs normal.
4) immune escape: LFTs rise again

54
Q

neonates with HBV: how many become carriers

A

95% become asymptomatic chronic HBV carriers

55
Q

HBV serology: what does each marker mean
HBsAg
HBsAb
HBcAb
HBeAg
HBeAb
HBV DNA

A

HBsAg = active infection, first to appear
HBsAb = immunity, either vaccination or infection
HBcAb = Infection with HBV – either past or current
HBeAg = active viral infection – either acute or chronic
HBeAb = indicates Seroconversion; goal of treatment
HBV DNA = Amount of replication

56
Q

treatment options for HBV to reduce viral load

A
  1. Pegylated interferon
    - Weekly S/C injection for 48 weeks
    - AE = fever, myalgia, lethargy, depression, anaemia, thrombocytopenia, neutropenia
    - 35-40% seroconvert OR drop viral load, 8% lose surface antigen at 3 years
  2. Antivirals = entecavir + tenofovir
    - Oral tablets 1/daily
    - Well tolerated, taken long term but cannot be given with pregnancy
    - 90% drop viral load to undetectable at 12 mo, E seroconversion at 15%/year, <1% loss of surface Ag
57
Q

complications of HBV infection

A
  • fulminant hepatitis
  • cirrhosis
  • HCC
  • HBV associated GN
58
Q

HCV transmission

A

blood borne; sexual unlikely

59
Q

acute HCV infection - symptoms?

A

very vague, fatigue/nausea - so most don’t get picked up

60
Q

HBV vs HCV cure rate

A

HBV is lifelong, can’t be cured
HCV can be cured

61
Q

treatments for HCV infection (2), and what determines response to therapy?

A

PEG IFN and ribavirin
1. Genotype of virus
- IL28B genotype of the patient indicates likelihood of response to therapy

62
Q

complications of HCV infection

A

1) Cirrhosis
2) Rheum: myalgia, fatigue, arthralgias, and arthritis; Sjogren’s
3) porphyria cutanea tarda and lichen planus
4) Cryoglobulinaemia = single or mixed immunoglobulins that undergo reversible precipitation at low temperatures
5) MPGN
6) Eye complications = keratoconjunctivitis sicca (dry eyes), which may be a manifestation of Sjogren’s syndrome and Mooren ulcer (a rapidly progressive, painful ulceration of the cornea)

63
Q

HDV:
- relationship to HBV
- treatment
- prevention

A
  • need HBV for envelope
  • chronic HDV - IFN alpha
  • HBV vacc prevents HDV
64
Q

definition of acute hepatic failure

A
  1. Acute liver related illness (jaundice, elevated transaminases) with no history of known chronic disease (<8 weeks), PLUS
  2. Coagulopathy – not corrected by vitamin K
    a. INR >1.5 or PT >15s with encephalopathy
    b. INR >2.0 or PT >20s with or without encephalopathy
65
Q

definition of portal HTN

A

elevation of portal pressure >10-12 mmHg

66
Q

clinical manifestations of CLD

A

hands: leukonychia, palmar erythema, pale palmar creases, asterixis
skin: bruising, pruritus, muscle wasting, jaundice, xanthomas, spider naevi, gynaecomastia, caput medusae
hepatomegaly
portal HTN -> ascites, varices, bleeding
encephalopathy
hepatorenal syndrome
hepatopulmonary syndrome

67
Q

hepatorenal syndrome

A
  • splanchnic vasodilation, mesenteric angiogenesis, and decreased effective blood volume with resulting decreased renal perfusion
  • Hallmark is intense renal vasoconstriction with coexistant systemic vasodilation
  • Diagnosis supported by oliguria, urine electrolyte abnormalities (urine sodium <10meq/L, fractional excretion <1%, normal sediment), absence of hypovolaemia and exclusion of other causes
68
Q

hepatopulmonary syndrome

A

1) hypoxaemia 2) intrapulmonary vascular dilatation 3) liver disease

  • Intrapulmonic R to L shunting of blood resulting from enlarged pulmonary vessels that prevents RBC traveling through the center of the vessel allowing adequate exposure to oxygen-rich alveoli
  • Shunting of vasodilatory mediators from the mesentery away from the liver is thought to contribute

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