Disease of the Small Intestine Flashcards
what is mesenteric ischaemia?
ischaemia of the mesenteric artery restricting blood flow to SI
what causes mesenteric ischaemia?
arterial occlusion e.g. atherosclerosis, non-occlusive perfusion insufficiency (shock, strangulation, obstructed venous return e.g. hernia)
types of mesenteric ischaemia…
chronic, acute
what is chronic mesenteric ischaemia
usually superior MA and presents with abdominal cramps
where does acute mesenteric ischaemia affect the most?
small bowel usually infarcted but colon survives
what is the pathogenesis of small bowel ischaemia due to Mesenteric ischaemia?
hypoxia of mucosa > mural infarct > transmural infarct > gangrene > perforation > sepsis
common complications of mesenteric ischaemia?
fibrosis, stricture, chronic ischaemia, gangrene, perforation & sepsis
presentation of SB ischaemia?
severe, poorly localised pain
shock
inc amylase
colon ischaemia presentation?
left sided pain, CVD, shock, vasculitis
why should you be weary of mesenteric ischaemia?
may be hard diagnosis - no signs on X-ray. note if pt is taking high dose of analgesia
ix for mesenteric ischaemia?
CT angiography, bloods (lactate & amylase ^), endoscopy
tx for mesenteric ischaemia?
resect, re-anastomose, embolectomy of sup. mesenteric artery
bowel obstruction is described as?
peristalsis is disrupted and dilation of bowel proximal to obstruction
types of bowel ob pointers?
upper ie. small bowel: acute epigastric pain, hours of onset, vomit
large bowel: more gradual, colicky abdominal pain, distension, vomit
true/false…
upper GI obstruction more likely to have faeculent vomit
false…
lower GI obstruction more likely to have faeculent vomit
pathophysiology of bowel obstruction?
fluid, gas > arterial & venous blockage > ischaemia > perforation > sepsis
what are the 4 aetiological factors of bowel obstruction and an example for each?
within lumen- gall stones, bezoar
within wall- tumour, crohn’s
outside wall- adhesions, hernia, intussusception
arterial: atherosclerosis
symptoms of bowel obstruction?
colicky pain, absolute constipation, vomit, burping, abdominal distension, no bowel sounds
describe vomit associated with bowel obstruction?
proximal= earlier and semi digested food with little bile distal= opposite & faeculent
signs of bowel obstruction?
abdominal distension, visible peristalsis, lack of tenderness, mass may be palpable, hyperressonant, check for hernias,
ix to see state of patient?
urinalysis, bloods
diagnosis of bowel obstruction
supine AXR, contrast CT abdomen
tx for bowel ob?
ABC, analgesia, fluids & K, NG tube drainage, anti-thromboembolic measures
what is tx for bowel ob after 72 hrs of medical tx?
surgical tx…
laparotomy & antibis
what antibiotics are given for bowel ob?
gent & metronidazole
why are fluid with K given?
pt is usually hypokalaemic and alkalotic
what should be noted about the admin for all medication in bowel ob?
must all be given IV
what are 2 main conditions can result from bowel ob?
adynamic bowel obstruction & strangulation w perforation
what are 2 types of dynamic bowel obstructions?
paralytic ileus and oglivies syndrome?
what is a paralytic ileus, symptoms and tx?
failure of peristalsis (due to surgery, diabetic keto acidosis, peritonitis)
s/s: similar to bowel ob
tx: drip & suck
what is Ogilvie’s syndrome, causes and ix?
acute dilation of colon (w/o obstruction) in acutely unwell pts
causes: coronary artery bypass grafts, pneumonia etc
ix: ACR & CT
Tx: colonic decompression
explain strangulation as a complication of bowel ob?
proportion of bowel becomes trapped so venous return obstructed
- may progress to infarct / perforation
- pain, sepsis, shock
- tx: surgery
how to check for perforation?
s/s: generalised peritonism
ix: erect CXR, CT
what is coeliac disease?
autoimmune inflammation of mucosa in response to gluten
hypersensitivity to ___ mediated by T cells that are found in intraepithelial lymphocytes (IELs) cause Coeliac’s
gliadin
pathophysiology of coeliacs?
less enterocytes due to IEL damage > loss of villous structures > loss of surface area> reduction in absorption and a flat duodenal mucosa
what is coeliac’s associated with?
dermatitis herpertiformis and childhood diabetes (T1)
histological findings of coeliacs?
villus atrophy & crypt hypertrophy
ix for coeliac?
duodenal endoscopy & biopsy*, serology (anti-TTG antibody)
s/s of coeliac?
non specific (wt loss, bloating, failure to thrive etc)
tx of coeliac disease?
gluten free diet, vitamin supplements
complications of coeliacs?
t-cell lymphomas, small bowel carcinoma, gall stones common, ulcerative-jejenoilleitis
3 microscopic signs of ulcerative-jejenoilleitis ?
fibrinopurulent debris, base of inflamed granulation tissue, fibrotic scar tissue
complications of ulcerative-jejenoilleitis?
perforation, haemorrhage, stenosis, gastric metaplasia > H.Pylori
what is intestinal failure?
inability to maintain adequate nutrition/ fluid stats via intestines
classes of intestinal failure?
- acute
- T1
- T2
- T3
type 1 intestinal failure description?
self-limiting
s: vomiting, dysphagia, diarrhoea
A: pancreatitis, obstruction
T: replace fluids, parenteral nutrition, PPIs
T2 intestinal failure description…
prolonged PN support needed (weeks, months)
A: sepsis, crohn’s, SMA, radiation, adhesions, fistulas
T: PN & enteral feeding
T3 intestinal failure description…
chronic
A: small bowel syndrome, crohn’s & SBS, dysmotility, malabsorption
T: home PN, transplant, glucagon-like-peptide2
when would you consider transplant for intestinal failure?
T3 intestinal failure with liver disease
ix for intestinal failure?
bloods (dec albumin), dec vitamins & zinc
most common aetiology for intestinal failure?
ischaemia, malabsorption, SBS
what is SBS?
<50cm of bowel
due to frequent resections (e.g. Crohn’s/infarct)
in non-occlusive ischamia most damage is as a result of…
tissue reperfusion
