Stomach, liver and pancreas Flashcards
What is alagille syndrome?
Mutation in JAG1 gene
- 15% familial
Constellation of
- Chronic cholestais secondary to Intrahepatic bile duct paucity or arteriohepatic dysplasia
- Dysmorphic facial features including broad forehead and underdeveloped mandibles
- Occular abnormalities: posterior embyrotoxon seen on slit lamp in 70%
- Peripheral pulmonary stenosis
- Butterfly vertebrae in 50% (or other vertebral abnormalities)
- Tubulointestinal nephropathy
What is Schwachman-Diamond syndrome?
Autosomal recessive condition
- unifying cause not yet found…
Exocrine pancreatic insufficiency whereby acini are replaced by fat with little fibrosis (second most common cause of exocrine pancreatic dysfunction in childhood)
Recurrent pyogenic infections
- Common and frequent cause of death (AOM, pneumonia, osteomyelitis, dermatitis, sepsis)
- Seoncdary to neutropenia / neutrophil chemotaxis defect
Thrombocytopenia in 70%
Anaemia in 50%
Short stature
Metaphyseal dysostosis
Management: pancreatic replacement therapy
Prognosis:
- 1/3 (predominantly boys), develop myeldysplastic syndrome
- 1/4 develop AML
What is the role of liver in CHO metabolism?
CHO metabolism
- store CHO as glycogen
- supply glucose by glycogenesis and glyconeongenesis
- in neonates, glycogen stores are maximal (2-3 of adults) then it gets used up postnatally until stores reaccumulate by wk 2-3
What is the significance of coagulopathy not reversible by vitamin K?
Suggests synthetic dysfunction (i.e can’t produce clotting factor)
Malabsorption-related coagulopathy will response to vit K
What is achalasia?
Achalasia is a primary oesophageal motility disorder characterised by failure of a hypertensive LOS to relax, and the absence of oesophageal peristalsis. These abnormalities cause a functional obstruction at the gastro-oesophageal junction.
What is the role of the liver in protein metabolism?
Protein metabolism
- alpha-feto protein is the dominant early fatal protein
- albumin synthesis starts from 7 weeks gestation
- Other proteins: fibrinogen / clotting factors / transferrin / lipoproteins / caeruloplasmin and complement
What is the role of the liver in lipid metabolism?
Lipid metabolism
- Fatty acid oxidation –> major source of energy in early life
- neonatal intolerance of prolonged fasting is partly due to restricted capacity for ketogenesis
What is the role of the liver in biotransformation?
Biotransformation
- oxidation / reduction / hydrolysis / conjugation
- CYP450
What is the role of the liver in bile acids synthesis / excretion?
Bile acids
- synthesized in the liver from cholesterol
- conjugated before excretion
- Enterohepatic circulation handles 90-95% of bile acids
- bile converted to bile acids by bacteria in colon –> reabsorbed
What does rise in ALT / AST suggest?
Intracellular damage
- ALT most liver specific
- AST also in RBC / muscle
If inc in AST > ALT then think extra hepatic causes like alcohol, echovirus and metabolic disease
What is the significance of raised GGT / ALP?
indicate cholestatic phenomenon
- found on cell membrane of bile duct annuli
- raised in cholestatic liver disease
- typically ALP rises then followed bbq rise in GGP once ALP improving.
Don’t forget that GGT also inducible by phenytoin, morphine, alcohol
ALP also found in bone and placenta
What markers help assess synthetic function?
Albumin (prognostic factor) and protein
- however, can be low due to acute illness an poor nutritional state
PT/INR
- reflects factor V and vit K dep factors X, IV, VII II (1972)
- most reliable
- IV vit K reverses coagulopathy due to malabsorption from cholestasis but not if due to synthetic dysfunction
Persistently low factor VII is poor prognostic factor in fulminant liver disease
What information can liver biopsy give us?
Usually percutaneous and can do as young as 1 week
Provides:
- histological diagnosis
- enzyme analysis for inborn errors of metabolism
- iron, copper and specific metabolites
- monitor therapy and assess severity
What’s the difference between SBR in neonatal vs adult hepatitis?
Not uncommon to see conj SBR in neonatal hepatitis due to defect in transportation out of cell
In adult hepatitis, more likely to be unconjugated SBR due to inability to conjugate
What is the inheritance of alpha-1-antitrypsin?
Autosomal co-dominant
SERPINA1 - Found on chromosome 14
>20 different alleles but only a few associate with defective protease inhibitors
What is alpha-1-antitrypsin?
Glycoprotein produced by the liver and some macrophages.
Functions as a protease inhibitor and is one of the acute phase proteins.
How are diseased alleles of alpha-1-antitrypsin different from normal allele?
M –> normal
Disease alleles differs by single base pair substitution
E.g Substitution of glutamic acid with the amino acid lysine results in Z allele, whereas valine –> S allele
S –> slow –> SS 50% of normal alphaAT1 function
Z –> normal production but abnormal transport into circulation –> ZZ 10-20% (most common abnormality)
null –> null/null –> no production
What are the clinical implications of alphaAT1 deficiency?
Liver cirrhosis
- abnormal synthesis results in increase accumulation of product –> liver damage
- accumulation occurs in 100% ZZ phenotype
- 10-20% of ZZ develops neonatal cholestatic hepatitis (indistinguishable from other forms of neonatal hepatitis)
- 10-20% has liver cirrhosis
- null / null has no liver disease (no production)
Lung emphysema (panacinar)
- usually occurs in adulthood
- increased protease damage from dead bacterial or leucocyte
- 80% of ZZ adults develop COAD
Assoc with panniculitis
- inflammation of subcutaneous tissue
What are the investigations you would do for ? alphaAT1 deficiency?
Serum Alpha-1-antitrypsin Trypsin inhibitory capacity (reduced because aAT1 usually inhibits trypsin) Pi genotype CXR in adults (looking for COAD) Liver biopsy
What is the management of alpha-1-AT deficiency?
Medical
- Danazol: analogue testosterone which increases hepatic alphaAT1 production but can only be used in men and short term only
Replacement
- purified blood derived A1A via IV, given in USA for ZZ / null null, costly!
- recombinant available
- intra-nasal spray also available
- liver transplant
Supportive
- Bronchodilators
- Pneumococcal and flu vaccine
- Smoke-free
- prompt treatment of resp. infections
Screening for family members
What is autoimmune hepatitis?
Chronic hepatic inflammatory involving both hepatocytes and duct epithelium with incr serum transaminases and autoantibodies.
M>F
Highly variable clinical px of asymptomatic –> cirrhosis / LF
Mimics acute viral hepatitis
Px with insidious onset of malaise, anorexia before jaundice
Assoc with arthritis, vasculitis, nephritis, thyroiditis, coombs +ve anaemia, rash
What are the ix findings in autoimmune hepatitis?
Elevated transaminases 3-10x and SBR (mostly conjugated)
Hypergammaglobinaeamia
HypoAlb common
Pancytopenia
Antibodies
- titres as low as 1:40 may be significant but not that up to 20% of patients don’t have detectable antibodies
- ‘type 2’ most common type in children: Anti liver-kidney-microsomal ab (LKM)
- ‘type 1’ usually found in young women with marked hypergammaglobulinaemia and lupoid features: ANA and antiSMA
Biopsy
- plasmolymphocytic infiltrate expanding portal tracts with variable bile duct injury
- piecemeal hepatic necrosis, riding necrosis
How do you treat autoimmune hepatitis?
Steroids
+/- other immunosuppression e.g azathioprine
Ursa commonly used as cholerectic agent
Assess with biopsy prior to stopping tx in pt with biochemical remission
What are the causes of fatty liver?
obesity, insulin resistance, hyperlipidaemia, steroids, Tx, pregnancy, lipid metabolic disease, HIV, IBD
Manage by diet and weight reduction
What is haematochromatosis?
Excessive absorption and inappropriate storage of iron
Hereditary
- AR (HFE gene on chr 6)
- Increased intestinal iron absorption and deposition
- most common genetic disease almost Northern Eu descent people
- HLA A3, B7, B14
- A/N testing possible
Neonatal
- acquired due to a/n liver disease
- usually fatal w LF
Transfusion induced
- ie B thalaessaemia
- Prevent with Fe chelation (desferoxamine)
What is the presentation of haemachromatosis?
Reversible
- hepatomegaly and splenomegaly
- skin bronzing
- dilated cardiomyopathy
- DM
Irreversible
- cirrhosis –> hepatocellular carcinoma
- arthropathy (second and third MCP, knees)
- testicular atrophy
Susceptible to
- sederophilic organisms like yersina, vibrio vulnificus septicaemia
- listeria
How do you ix for haemachromatosis?
Bloods
- raised serum Fe / ferrite with low TIBC
- transferrin saturation elevated by 10yo, detected in adolescence, found in all homozygous individuals by age 40
- AbN LFTs
- Gene test (HFE gene, C282Y mutation)
Other
- fasting BSL (DM)
- ECHO (CHF)
- ECG (arrhythmias)
- Joint xrays
What’s the tx for haemachromatosis?
Phlebotomy every 1-2 weeks until ferritin < 100 then titrate
avoid excess iron (supplements, vitamin C, red meat)
Vaccinate against HBV / HAV
Monitor w 2mly iron studies, Hb w venesection
Yearly AFP and USS if cirrhotic
Screen relatives