Small Intestine Flashcards
What are the presenting F of small bowel disease?
Diarrhoea Steatorrhoea Abdo pain Discomfort Wt loss result of accompanying anorexia.
2 most common in developed c:
Coeliac + Crohns!!
Crohns( malabs of VitB12)
What disorders of the small intestine cause malabsorption?
Coeliac Crohns Dermatitis herpetiformis Tropical sprue SB bacterial overgrowth Intestinal resection Whipples disease (infx) Radiation enteritis Parasite infx -> giardia intesrinilis (Giardiasis) .
Small intestine
Digestion + absorption
Nutrients absorbed throughout except Vit B12 + bile salts-> specific receptors at terminal ileum.
Coeliac disease
Abn jejunal mucosa that improves
CF of coeliac D
Any age but 2 peaks
Infancy - FTT, after weaning on gluten foods + 30-40s
Non specific sx- tiredness, malaise, or small bowel sx. (Diarrhoea, steatorrhoea)
.
CF of coeliac D
Any age but 2 peaks
Infancy - FTT, after weaning on gluten foods + 30-40s
Non specific sx- tiredness, malaise, or small bowel sx. (Diarrhoea, steatorrhoea)
O/E- anaemia signs and nutritional def.
Inv and mx of coeliac disease
Distal duodenal biopsies taken at endoscopies- absent or stunted small intestn vili w/ elongation of crypts (subtotal viouls atrophy)
Serum Abs
EMA- endomysial + tTG : ⬆️ specificity and sensitivity.
Can be used for non specific sx and pts assc w/ auroimmune conditions like DM1.
FBC- 50% anaemia, always folate def , commonly Fe def, rareley VitB12.
Radiology: small bowel follow-through- dilated loops of bowel + thickened folds.
Bone densitometry- DEXA- always done, due to ⬆️ risk of osteoporosis.
Mx
Gluten free diet forever + nutritional supplements.
Definite dx- ✔️ when sx resolve w/ gluten free diet. No histo biopsy needed then.
Complications/:
Malignancy assc w/ oesophageal, small bowel + intestinal lymphoma.
Incidence reduced w/ gluten free diet.
Causes of vilous atrophy in adults
Coeliac Dermatitis herpetiforms Giardiasis Malnutrition Ischaemia Whipples disease Lymphoma Tropical sprue- progressive small bowel disorder- w/ malabroption visitors of tropicalmareas- asia, caribean, puerto rico, S. America
Bacterial overgrowth
Upper small intestine almost sterile- bile salts are sterile
Bacterial overgrowth may occur if stasis of intestinal contents due to abnormal mobility- systemic sclerosis, or steuctural abn- diverticulum, prevx small bowel surgery
CF
Diarrhoea, steatorrhoea caused by deconjugation of bile salts by bacteria. Vit B12 deficiency due to bacterial metabolism can also occur.
Dx
Breath tests- hydrogen or C14 breath test- CHOICE⭐️
Depend on ability of organisms to metabolise flucose or labelled bile salts, Given bymouth, w/ production of wpeither H2 from glucose or 14CO2 from bile salts- which are then absorbed and measured in exhaled air.
Meckels diverticulum
Cong abn -2-3%
Diverticulum protrudes from ileum wall, bout 60cm from ileocaecal valve.
50% will contain gastric mucosa :( so acid secretion-> oerforation and bleeding
Mx- surgical removal
Adenocarcinoma
50% of small intestine tumours- increased incidence with coeliac and crohns,
Lymphoma
Non hodgkins lympoma- 15%
May be B or T cell origin
Carcinoid tunours
Originate from enterochromaffin cells (serotonin producing) of intestine,.
Appendix, terminal ileum and rectum.
Carcinoid syndrome: sx arising from tumour like 5-HT, kinins, histamine, prostaglandins.
Liver usually metabolises these.
Pts w/ GI carcinoid tumours have the syndrome only if they have liver metastasis cz tumour producs drain directly into hepatic vein –> no metabolism–> into systemic circulation–> effects:
Flushing, wheezing, diarrhoea, abdo pain, R cardiac valvular stenosis, regurgitation.
Inv- lots of 5-HIAA product of serotonin breakdown found in urine. + liver USS confx 2o deposists.
Mx
Sx- inhibitiom of tumour products w somatostatin analogue, octreotide, 5-HT antagonists,
Chemo, hep artery embolisation, radiofrequency ablation.. Surg resection. To reduce tumour mass
