Bowel Obstruction + Ischaemia Flashcards
what is a simple bowel obstruction
occlusiion of bowel without vascular compromise
what is a strangulated obstruction
occlusion of bowel with vascular compromise
most common cause of small bowel obstruction
adhesions
strangulated hernias also common
what needs to be ruled out in large bowel obstruction
Colorectal cancer
other causes of bowel obstruction
luminal:
- foreign body , impacted faeces, intussusception, gallstones
intramural:
-tumours, strictures, crohns, diverticulitis
extrinsic:
- adhesions, volvulus, hernia, tumour compression
cardinal symptoms of bowel obstruction
colikcy abdominal pain
vomiting
absolute constipation
abdominal distention
signs of bowel obstruction on examination
abdominal tenderness
tympanic percussion
tinkling bowel sounds
imaging choice for bowel obstruction
CT now 1st line
supine CXR still frequently done
Difference between large + small bowel obstruction on XRAY
small:
- central, valvulae conniventes transverse entire thickness of the bowel
large:
- peripheral, haustra partially cross thickness of the bowel
what type of bowel obstruction is this
large
- haustra
- peripheral
what type of bowel obstruction is this
small
- central
- valvulae conniventes cross entire bowel width
what other imaging may be required in bowel obstruction
erect CXR if perforation suspected- shows air under diaphragm if perforated
management of bowel obstruction
Trial of ‘Drip + suck’: NG tube, nil by mouth, IV fluids.
analgesia.
Surgery: laparotomy. absolute indications if:
- peritonitis
- perforation
- irreducible hernia
- caecal volvulus
what is paralytic ileus
reduced small bowel motility in the absence of obstruction
what usually causes paralytic ileus
post abdo surgery
what are bowel sounds like in paralytic ileus compared to obstruction
ileus = silent
obstruction = tinkling
management of paralytic ilieus
IV fluids, NG tube if vomiting, mobilise to stimulate peristalsis
what is a pseudo-obstruction
reduced motility of the large bowel in the absence of obstruction
what causes pseudo-obstruction
increased sympathetic tone
what is a volvulus
twisting of a loop of intestine around its mesenteric attachment
- results in bowel obstruction
- affected loop can become ischaemic due to compromised blood supply
most common sites for volvulus
sigmoid colon
- counterclockwise twisting
caecum (2nd)
- clockwise twisting
coffee bean sign
sigmoid volvulus
management of sigmoid volvulus
decompression by sigmoidoscope + flatus tube insertion
management of a caecal volvulus
laparotomy with ileocaecal resection
what structures make up the foregut?
what is the blood supply?
stomach, biliary system, liver, pancreas
Celiac artery
what structures make up the midgut?
what is the blood supply?
duodenum to first half of transverse colon
-superior mesenteric artery
what structures make up the hindgut?
what is the blood supply?
2nd half of transverse colon to rectum
- inferior mesenteric artery
what is acute mesenteric ischaemia
acute reduction in blood flow through the superior mesenteric artery (most commonly) or coelic artery, injuring the small bowel
risk factors for acute mesenteric ishaemia
Atrial fibrillation
Post MI
Atherosclerosis
Coagulation Disorders
what is chronic mesenteric ichaemia due to
atherosclerosis of the superior mesenteric artery / inferior mesenteric artery / coeliac artery
aka intestinal angina
presentation of acute mesenteric ischaemia
sudden onset abdominal pain disproportionate to exam findings
progressess to peritonism
how is mesenteric ishaemia diagnosed
CT angiogram
blood gas in mesenteric ishaemia
metabolic acidosis
high lactate
management of acute mesenteric ischaemia
IV fluids + Abx
Papaverine - opiod antispasmodic which causes vasodilation
Thrombolysis
In perforation/peritonitis: urgent laparoscopy/laparotom for embolectomy and resection of any infarcted bowel
management of chronic mesenteric ishaemia
systemic mesenteric bypass
- percutaneous angioplasty if unfit for open surgery
what is ishaemic colitis
large bowel ishaemia, typically transient, leading to inflammation
- usually due to atherosclerosis
- splenic flexure most commonly affected
what is fulminant ishaemic colitis
ishaemic colitis with necrosis, perforation and sepsis
presentation of ishaemic colitis
abdominal pain, onset over hours, tenderness over affected area
PR bleeding + diarrhoea
diagnostic test for ischaemic colitis
colonoscopy
- sloughing, friability, ulceration
