Gastro Flashcards
(128 cards)
acute intermittent prophyria pathophysiology and triggers
auto dom
porphobilinogen deaminase deficiency
PBGD on chromo 11
latent in most heterozygotes
block in haem synthesis at PBGD reaction stage
> increased ALA and PBG synthesis
> increased urinary excretion of porphyrin precursors and porphyrins
precipitating factors:
- ALAS1 induction
- P450 enzymes
- alcohol
- barbiturates, sulfonamides, enzyme inducers (carbamaz, phenytoin, OCP, rifampicin)
- fluctuations in female sex hormones
- infections
- starvation
manifestations of acute intermittent porphyria
- autonomic neuropathy
> abdo pain, constipation, vomiting, tachyc, HTN, postural hypot, peripheral neuropathies - dark/red urine
- bulbar paresis > resp failure
- cerebellar signs
- hypothalamic dysfunction > SIADH
- hyponatraemia (SIADH, GI and renal loss)
- confusion, agitation, disorientation, hallucinations
managing acute intermittent porphyria
IV fluids
IV haemin
alternatively 300g dextrose IV
prophylaxis:
non cyclic- haem arginate IV once or twice weekly (risk of iron overload)
cyclic attacks in women- preventative GnRH
liver transplant
complications of acute intermittent porphyria
HTN
CKD
hepatocellular ca
types of acute pancreatitis
mild- no complications or organ dysfunction
mod- local complications and/or organ dysfunction that resolves within 48h
severe- persistent organ dysfunction leading to local complications (necrosis, abscess, pseudocysts), potentially fatal
causes of pancreatitis
Gallstones
Ethanol
Trauma
Steroids
Mumps, coxsackie B
Autoimmune
Scorpion sting
Hyperlipidaemia, hypercalcaemia, hypertriglyceridaemia,
ERCP
Drugs (azathioprine, OCP, steroids, antiretrovirals, fibrates, thiazides)
pathophysiology of pancreatitis
intrapancreatic activation of enzymes due to outflow obstruction or acinar cell injury
> autodigestion of parenchyma
> inflammatory cells go to parenchyma and release cytokines
> inflammation
enzymes also cause vascular injury
> vasodilatation and increased permeability
> third space loss
> hypotension, tachyc, shock, multi organ dysfunction
acute vs chronic pancreatitis investigation findings
acute:
raised amylase 3x, lipase (lipase remains raised longer)
sentinel loops of adynamic bowel next to pancreas on AXR
CT may confirm inflammation if amylase/lipase levels are not raised
chronic:
speckled calcification on XR, CT
irregular dilatation and stricturing of pancreatic ducts on ERCP, MRCP
endoscopic USS
PABA testing (exocrine function)
faecal elastase (exocrine insufficiency)
OGTT
surgical management of gallstone pancreatitis
consider early ERCP for decompression
cholecystectomy during same admission or within 2/52 of discharge once acute symptoms have settled
poor prognostic factors of acute pancreatitis
age > 55
WCC > 15
urea > 16
pO2 < 8
calcium < 2
albumin < 32
glucose > 10
LDH 600
AST 200
pathophysiology of alcoholic fatty liver disease
alcoholic dehydrogenase concerts alcohol to acetaldehyde to acetic acid to CO2 + H20
> reduces NAD to NAD + H
increases NADH : NAD ratio
increases fatty acid synthesis decreased fatty acid oxidation
pathophysiology of alcoholic hepatitis
acetaldehyde binds to macromolecules in hepatocytes
> immune system detects complexes
> neutrophil infiltration
> hepatocyte necrosis and inflammation
dilutional anaemia blood test
reduced haematocrit
SAAG and portal hypertension
serum albumin minus ascitic albumin
> 1.1 g/L suggests portal HTN
increased SAAG:
cirrhosis, alcoholic hepatitis, schisto, budd chiari, portal v obstruction, cardiac disease, SBP
low or normal SAAG:
nephrotic syndrome, protein losing enteropathy, peritoneal carcinomatosis, TB peritonitis, pancreatic duct leak, biliary ascites
autoimmune hepatitis genetics and environmental triggers
HLADR3 and HLADR4 (type 1)
HLA DQB1 and HLA DRB (type 2)
viruses, nitrofurantoin, diclofenac, atorvastatin
type 1 and type 2 autoimmune hepatitis
1: most common
antiSMA and ANA
increased IgG
good response to immunosuppression
2: often in children
commonly > cirrhosis
less treatable
ALKM-1, ALC-1
ANA and aSMA neg
autoimmune hepatitis histopathology
piecemeal necrosis
mononuclear infiltration of portal and periportal areas
may see fibrosis
pharmacalogical management of autoimmune hepatitis
for mod/severe inflammation (serum AST 5x upper limit, serum globulins 2x upper limit normal, necrosis on biopsy)
4/52 prednisolone
alternatively budesonide
steroid + immunosuppressant e.g. azathioprine
budd chiari vs veno-occlusive disease
both cause hepatic venous outflow obstruction
BC: any level from small hepatic veins to junction of IVC and RA
VOD: occlusion of terminal hepatic venules and sinusoids
BC associated w/ myeloprolfierative disorders, hypercoagulable disorders, behcet, SLE, sjogrens, mixed CTD, IBD, sarcoid, pregnancy and post portum
secondary BC: external compression or invasion by abscess, tumour or trauma
causes of venous occlusive disease
haematopoietic cell transplant
ctx e.g. oxaliplatin
pyrrolizidine alkaloids jamaican bush tea
high dose rtx to liver
post liver transplant
preventing veno-occlusive disorder
given ursodeoxycholic acid or heparin to patients undergoing haematopoietic cell transplant
complications of chronic pancreatitis
pancreatic duct obstruction
pseudocysts
neuropathic pain
pancreatic ascites, pleural effusion
diabetes
exocrine insufficiency
pancreatic cancer
pancreatic pseudocysts
necrotic/haemorrhagic material and enzymes within or near pancreas
no epithelial lining
found on CT
confirmed w/ EUS and FNA
larger cysts > obstruction, vomiting
occur following acute/chronic pancreatitis or trauma
pancreatic divisum
congenital
dorsal and ventral ducts do not connect
> dorsal duct drainage is disrupted
asymptomatic or recurrent pancreatitis
dx w/ MRCP or ERCP