gi middle tier Flashcards
which part of the bowel gets obstructed more (small/large)
small
where is volvulus obstruction v common
south africa
LIC
4 different causes of intestinal obstruction (vague)
- something in lumen
- something in gut wall - intramural
- something outside of gut
- pseudo obstruction
something in lumen - causes of obstruction
Tumour
Diaphragm disease
- narrowed lumen of small bowel
- Fibrous
- Associated with NSAIDs
Gallstone ileus
- Large gallstone in small bowel (couldn’t have fit (bile duct/sphincter of oddi) → erodes through to small bowel)
- rare
intramural - causes intestinal of obstruction
Inflammation
Ulcerative colitis
Crohn’s disease
- Can affect anywhere
- Fibrous, granulomas make up cobblestone mucosa
Diverticular disease
- Inflammation of pockets/ cul-de-sacs in the colon (usually sigmoidal colon). Can rupture → faecal peritonitis
- These form as mucosa goes through weak spots in muscularis due to high gut pressure (low fibre diet)
Tumours
Hirschprung’s disease
- Birth defect, usually neonatal presentation
- Rectum is aganglionic (cant contract due to lack of innervation) so proximal bowel fills with faeces (backlog) and dilates
- Functional mechanism (rather than mechanical)
- Abscence of contractions = adynamic, paralytic
Intussusception
- One hollow structure in another like a telescope
- Seen more in children as bowel is softer
whats is hirschprung’s disease
- Birth defect, usually neonatal presentation
- Rectum is aganglionic (cant contract due to lack of innervation) so proximal bowel fills with faeces (backlog) and dilates
- Functional mechanism (rather than mechanical)
- Abscence of contractions = adynamic, paralytic
something outside of gut causes of intestinal obstruction
Adhesions
- Between bowel bits, causing obstruction by pulling odd-ly. Prevent free movement
- Often post-op – surgeREHH
- Common
- Easily corrected - lysis
Volvulus
- Sigmoidal colon less attached- long mesentery. So it twists on itself to create a volvulus (mesentry required)
- 360 degrees = total obstruction
- LIC
- Closed loop obstruction (type)
Peritoneal tumour
- Peritoneal cancer eg ovarian cancer, spreads to peritoneum where it grows easily
- Hard to treat - can’t remove the peritoneum
Hernias
- Abnormal protrusion of organ/tissue through a cavity
- Strangulation (type)
causes of psuedo obstruction (intestinal)
Intra abdominal trauma/sepsis Fractures Pneumonia Drugs (opiates, antidepressants) Malnutrition Parkinson’s
which intestinal obstructions happen in small/large bowel
small
- Mainly adhesions (previous surgery)
- Hernias - especially LIC
- Malignancy
- Crohn’s
large
- volvulus
- less common than small bowel obstructions
effects of blockage small/large bowel
dilation proximal to blockage
small bowel
- increased secretions
- Swallowed air
- Decreased absorption
- Wall oedema
- Increased pressure → vessel compression → ischaemia, perforation
large bowel
- Wall oedema
- Increased pressure → vessel compression → ischaemia, perforation (esp caecum
- Electrolyte imbalance
- Bacterial translocation (through wall!) - lots of them – sepsis
presentation of intestinal obstruction
- Anorexia, nausea,
- vomiting (profuse)
—Faecal -like = more large than small bowel (more digested) - Pain
— More constant in large, than small bowel - Constipation (obstipation = more severe, complete)
- No farting (esp small bowel)
- stool blood
- Distension
— The more distal, the greater the distension - Bacteria overgrowth
- Tenderness suggests strangulation
- Increased bowel signs
fluid/electrolyte imbalance due to increased secretions - Palpable mass (hernia, tumour, distended loop/caecum)
psuedoobstruction presentation
Rapid abdominal distention
Rapid onset pain and getting worse
investigations into intestinal obstruction
Bloods
- Low hb - blood loss
- Rule out other causes ?
Abdominal X ray
- Gas shadows proximal to blockage
- Distended loops proximal to obstruction
- Fluid levels
CT
- Can locate well
Digital rectal exam PR
- Empty rectum, hard stool, blood
intestinal blockage management
inc what NOT to give
Nasogastric tube - ‘drip and suck’ - sucks out contents
IV fluids to rehydrate and correct electrolyte imbalance
Analgesia
Antiemetics
Antibiotics
Surgery
NO laxative – cause bowel to perforate
where does diverticulus mainly occur?
diverticulus age
sigmoidal colon mainly (or descending). can be anywhere in bowel (mainly large bowel)
over 50y. rare in young
