GIT Flashcards
Achalasia
failure of smooth muscle fibres to relax → cause lower oesophageal sphincter to remain CLOSED
- due to failure of inhibitory ganglion cells (which normally cause oesophageal dilatation)
Clinical features
- dysphagia
- nocturnal cough
- FTT
Dx
barium swallow or endoscopy
Rx
myotomy
pneumatic dilatation of LES
Chronic diarrhoea definition
↑ frequency +/or volume of stool for AT LEAST 2 weeks
NB: chronic non-specific diarrhoea (CNSD) most common - often due to transit time “toddlers diarrhoea”
chronic non-specific diarrhoea (CNSD)
“toddlers diarrhoea”
“fruit juice diarrhoea”
“peas and carrots” diarrhoea
Child is otherwise well and thriving normally
no physical redflag signs eg: clubbing, oedema, pallor (anaemia), jaundice, wasting, pot belly etc
Normal stool microscopy
- no fat globules or fat crystals
- no blood or pus cells
- giardia or cryptosporidiae
normal coeliac screen → TTG (tissue transglutaminase Ab)
Types of diarrhoea
mechanisms
OSMOTIC - sugar malabsorption or intolerance
1’ causes
- fructose (fruit juices)
- congenital deficiencies
2’ causes(interfere w glucose transporter, bacterial overgrowth)
eg: short gut, enteropathy, bacterial overgrowth, severe allergies, immune deficiency
NB: osmotic diarrhoea stops when pt is NBM, secretory diarrhoea continues, regardless of food intake
∴ think of secretory diarrrhoea when Hx of dehydration and electrolyte disturbances
SECRETORY
infective - e.coli, cholera (rice water - will die if dont rehydrate)
fat malabsorption: fatty acids + bile acid cause colonic secretion
laxative abuse
rare tumours - VIPomas, neuroblastomas (catecholamine), medul thyroid Ca,
congenital villous atrophy
congenital chloride diarrhoea
INFLAMMATORY (tissue damage due to immune cell activation)
- infection: campylobacter, salmonella, yersinia, amoebic dysentry, c.diff
- inflammatory bowel disease: crohn’s, UC, eosinophilic enteritis, immune deficiency syndrome incl chronic granulomatous disease
BLOOD + PUS = HALLMARK FEATURE
GVHD
Causes of fat malabsorption
1) Maldigestion
pancreatic insufficiency (CF, chronic pancreatitis)
- fat globules in stool
2) inadequate micellar solubilisation of digested fat
eg: bile acid deficiency in cholestatic liver disease eg: biliary atresia
- fat globules in stool
3) impaired mucosal absorption of fat
- mucosal disease eg: coeliac
- see fatty acid CRYSTALS rather than globules
4) impaired t/f of fat from enterocytes → lymphatics
eg: lymphoma, lymphangiectasia, abetalipoproteinaemia
Consequences of fat malabsorption
Fat soluble vitamin deficiency (ADEK)
Calorie deficiency + FTT
steatorrhoea (bulky, fatty, smelly stools)
sarcopenia
osteoporosis
how to ix for fat malabsoprtion
CCK/secretin stimulation test (NJ tube measure panc fluid) → no longer available due to secretin shortage
faecal fat balance studies - 5 day food diary to determine fat intake - 72hr fat excretion measurement - >7% excretion = fat malabsoprtion → this is done in CF pts
faecal elastase assay
labelled triolein H breath test
PERT (pancreatic enzyme replacement Rx)
- improves digestion, symptoms, nutritional status + QoL
PERT dosage 5000 lipase units/kg/day\
Ix
stool MCS/OCP/fat globules or fatty acid crystals/faecal calprotectin
FBE, iron studies, B12/folate
LFT - ? low alb
coeliac serology (IgA lvls, TTG, EMA) NB: coeliac serology alone is NOT reliable in very young/pre-school age ∴ would go onto endoscopy (modified marsh criteria >1 = coeliac)
Hx/RF/Dx coeliac disease
FTT, diarrhoea, steatorrhoea, anaemia, hypoalbuminaemia, +FHx
effects 1-3% of population
RF for coeliac (ALL NEED SCREENING) 1st degree +FHx T1DM Downs syndrome autoimmune thyroiditis autoimmune hepatitis
serology (sensitive + specific):
IgA: anti-tTG (tissue transglutaminates),
4x ULN false +ve, but 10 x ULN - pretty diagnostic
IgG: DGP - deamidated antigliadin Ab
total IgA lvls
HLA DQ2 + DQ8
duodenal Bx changes
gastroenteritis definition + epi
vomiting/fever (often → then) diarrhoea
diarrhoea = 3+ loose stools/24hrs for <14 days
now less due to rotavirus vaccination
first infection @ 3-36mo likely most severe
peak in mid to late winter
Causes of gastroenteritis
VIRUS (70%)
rotavirus
- immunity not lifelong, incubation 1-3 days then profuse early vomiting, temp >39 in 1/3 of pt
- penetrates SB wall + causes villus destruction ∴ 5-7 days for bowel to reform
adenovirus (epidemics, rash may be prominent)
norovirus (epidemics, schools, camps, childcare)
-parechovirus: can cause sepsis likely illness in neonates + young infants (esp <3mo)
– macpap rash, enchephalitis, myoclonic jerks, hepatitis, distended abdo, irrititabiltiy like in pain, volvulus, intussusception, bowle ischaemia → needs ACTIVE supportive Rx
- others: enterovirus, , astrovirus)
BACTERIA (15%) Campylobacter - wide variety of animal hosts, esp chicken - abdo pain prominent Salmonella - contaminated food (summer epidemics) - mucosal invasion → colitis prominant - WCC in stool - prolonged excretion of bacteria E.coli (ETEC etc) Shigella S typhi cholera Yersinia (reputation for mimicking appendicitis)
PARASITES
giardia
cryptosporidium
others eg: entamoeba
is it viral or bacterial GE?
Viral/rotarvirus - tenders to be autumn/winter - watery diarrhoea without blood \+/- vomiting low grade temp anorexia 90% < 5yo
bacterial blood + mucous in stool \+/- vomiting high fever may have Hx recent travel foodborne? HUS - ARF, low plt, anaemia w MAHA
Dehydration clinical picture
NO single symptom reliably predicts dehydration ∴ take all info into account
- wet nappies
- fontanelle
- skin turgor
- CRT
- tachycardia
mild 3% reduced UO thirst dry MM mild tachycardia
moderate 5% body weight = NG or IV dry MM ↑ HR abnormal resp pattern lethargy reduced TT sunken eyes
severe 10% above signs plus poor perfusion - mottled, cool, slow CRT altered conscious state thready pulse + marked tachycardia
IV/IO w 20ml/kg stat dose
important DDx GE (ie: vomiting, fever, diarrhoea)
and red flag symptoms to prompt consideration of other causes
acute appendicitis strangulated hernia intususception + other causes BO (malrotation/volvulus) UTI meningitis other causes of sepsis any cause of raised ICP DKA inborn errors of metabolism inflammatory bowel disease HUS
blood in stool or vomit bile in vomit (bowel obstruction) vomiting but no diarrhoea diarrhoea then vomiting headache very high temp >39 young child esp <3mo severe abdo pain/distension
Ix in gastro if moderate to severe dehydration
bloods (FBE/UEC/CRP/LFT) + BSL +/- blood culture if >38.5
stool MCS + PCR
consider
urine MCS
CXR, AXR, USS, air enema
