Intestinal obstruction Flashcards
Volvus
twist/rotation of segment of bowel
always at part of bowel with mesentery
narrow base + wide lumen
adhesions
sticking together
intesussuption
telescoping of one hollow structure into its distal hollow structure
atresia
absence of opening or failure of development of hollow structure
which is more common, SBO or LBO?
SBO: 70% of cases
RFs for SBO in adults
adhesions - previous surgery
hernia
Caron’s
malignancy
RFs for SBO in children
appendicitis interruption volvulus atresia hypertrophic pyloric stenosis
RFs LBO
age + race dependent
what makes up the majority of LBOs?
colorectal malignancies, distal to the transverse colon
Classification of BO
site
extent of luminal obstruction
mechanism
pathology e.g. simple, closed loop, strangulation
SBO pathology of obstruction
proximal dilatation
increased secretions + distension
untreated obstruction –> ischamia –> necrosis –> perforation
LBO pathology of obstruction
colon prox to obstruction dilates
increase in colonic pressure
decreased mesenteric BF
mucosal oedema
atrial supply compromised
mucosal ulceration
full thickness necrosis
perforation
Presentation
vomiting
nausea
anorexia
colic occurs early
active ‘tinkling’ bowel sounds
Why faceulent vomiting?
fermentation of intestinal contents in established obstruction
What would a digital rectal exam of LBO show?
empty rectum
hard stools
blood
what would sudden onset, pain, localised tenderness and distension in large bowel be?
volvulus
does vomiting follow or precede pain in SBO?
follows
resonance if theres gas and resonance if theres fluid?
tympanic - gas
dull - fluid
Plain X-ray partial SBO
gas throughout abd
in LBO what does contrast enema provide info on?
level, degree & type of obstruction
Mx
fluid resuscitation
bowel decompression
analgesia + antiemetic
non-mechanical obstruction
a dynamic obstruction
failure of peristalsis
no mechanical cause
differences in presentation of SBO and LBO
SBO: vom occurs earlier, distention is less and pain higher in the abdomen
AXR SBO
central gas shadows and no gas in large bowel
AXR LBO
pain is more constant, peripheral gas shadows proximal to blockage, but not in rectum
(unless you’ve done a PR examination!)
ileus obstruction
functional obstruction from reduced bowel motility
no pain + bowel sounds are absent
simple obstruction
1 obstructing point
no vascular compromise
closed loop obstruction
obstruction at 2 points
loop of grossly distended bowel at risk of perforation
strangulated obstruction
blood supply is compromised
peritonism is the cardinal sign
other signs of mesenteric ischamia
which types require surgery?
strangulation
closed loop
LBO
which types can be managed conservatively? (initially)
incomplete SBO
ileus
AXR with ‘inverted U’ loop of bowel that looks like a coffee bean
sigmoid volvulus
severe, rapid, strangulated obstruction
elderly, constipated + morbid pt
laparotomy
surgical procedure involving a large incision through the abdominal wall to gain access into the abdominal cavity. It is also known as a celiotomy.
