Bowel Obstruction Flashcards
What are the causes of dynamic bowel obstruction?
Outside wall
- adhesions
- hernia
- volvulus
- intussusception
In wall
- tuberculous stricture
- Crohn’s disease
- Malignancy
In lumen
- Gallstones
- round worms
- inspissated feces
- meconium ileus
What are the causes of adynamic bowel obstruction?
- cessation of peristalsis (paralytic ileus)
- mesenteric ischemia
- post-op
- electrolyte imbalance (hypokalemia)
- spinal injuries
- uremia
- diabetes
- retroperitoneal hematomas & surgeries
What is the classification of types of obstruction?
ACUTE -> small bowel CHRONIC -> large bowel ACUTE ON CHRONIC -> large bowel SUBACUTE -> Crohn's closed loop obstruction
What is the presentation depending on sites of obstruction?
PROXIMAL SMALL BOWEL -> vomiting
DISTAL SMALL BOWEL -> bilious vomitus -> feculent vomitus
LARGE BOWEL -> constipation
What is the pathogenesis of bowel obstruction?
PROXIMAL TO OBSTRUCTION collection of fluids from saliva,stomach, pancreas, & intestines
1) hyper peristaltic phase
2) anti peristaltic phase
3) flaccid, paralyzed, dilated bowel
DISTAL TO OBSTRUCTION
- collapsed
What causes a decrease in the absorption in the bowel?
- edema & inflammation -> decreased absorption -> sequestration of fluids in lumen -> bacteria multiplies -> toxemia
this leads to severe dehydration & electrolyte imbalance
Air accumulates proximal to collected fluid from?
- swallowed air (70%)
- diffusion from blood into lumen (20%)
- digested product & bacterial action (10%)
How does necrosis & gangrene develop in bowel obstruction?
dilation of bowel wall -> increase intraluminal pressure -> exceed bowel wall venous pressure -> ischemia -> further dilatation & ischemic injury -> blockage of arterial perfusion -> bowel wall necrosis & gangrene
What are the clinical features of bowel obstruction?
- abdominal pain
- vomiting
- distention
- absolute constipation
- dehydration
- features of toxemia & septicemia
- abdominal tenderness
- features of strangulation
- fever -> inflammation hypothermia -> septicemia
- borborygmi
- empty, dilated rectum with tenderness
What is the character of abdominal pain in case of bowel obstruction?
- initially colicky & intermittent ——-> continuous & severe
- sudden & severe pain
- colicky -> obstruction —————–> diffuse persistent -> strangulation
What is the character of vomiting in obstruction depending on location?
- jejunal -> early & persistent
- ileal -> recurrent bilious then faeculent
- large bowel -> laaate vomiting
What are the exceptions of absolute constipation?
- Richter’s hernia obstruction
- gallstone obstruction (ball & valve)
- mesenteric vascular obstruction
- intestinal obstruction with pelvic abscess
What does dehydration lead to?
oligouria -> renal failure
What is the character of abdominal tenderness in obstruction?
- initially localized then diffuse -> obstruction
- rebound tenderness & guarding -> strangulation
What are the features of strangulation?
- continuous severe pain
- shock
- rebound tenderness (Blumberg’s sign)
- guarding & rigidity
- absence of bowel sounds
What are the investigations that should be done in suspected bowel obstruction?
1) X-RAY (supine & erect posture) > 3 fluid levels
- jejunum -> concertina
- ileum -> characterless
- large bowel -> haustrations
2) LAB
- hematocrit
- blood urea
- serum creatinine
- electrolytes
- leucocytic count
3) gastrograffin enema in mild or subacute CT
4) ultrasound abdomen
5) doppler US to detect strangulation
How is intestinal obstruction treated?
1) NGT to decompress
2) IV fluids & electrolytes
3) antibiotics -> ampicillin + metronidazole
4) if strangulated -> FFP
5) ICU till stabilized then laparotomy
6) CVP
How do you check for viability of bowel?
- peristalsis
- pulsations
- bleeding in mesentery & bowel wall
- friability in ischemic
- color pink or black
- serosal shining
if bowel is not viable -> resection & anastomoses + peritoneal wash + drainage of abdomen
What causes a pistol shot perforation?
- closed loop obstruction -> increase pressure in the cecum -> ileocecal valve competence
What is the most common cause of obstruction?
adhesions & bands
What is the cause of adhesions?
- previous surgery
- infection
- TALC powder from gloves
- ischemia of bowel/sepsis
- gynecological infections
- bowel injury
- radiation induced enteritis
- Crohn’s disease
- TB or malignancy
How should adhesive obstruction be treated?
if good general condition -> conserve for 48-72hrs
-ryle
if patient doesn’t get better & doesn’t pass stool
- open surgical adhesiolysis using fingers
- laparoscopic adhesiolysis
What is the commonest site of volvulus?
sigmoid colon 65% -> anticlockwise (has long mesentry & is loaded by stool)
- common in patients with chronic constipation with laxative abuse
cecum second commonest -> clockwise
What are the clinical features of volvulus obstruction?
- marked abdominal distention
- intestinal obstruction
- TYRE LIKE FEEL (diagnostic)
- features of peritonitis due to impaired blood supply
What is the DD of volvulus?
- Ogilves’ syndrome
- faecal impaction
- carcinoma rectosigmoid
- idiopathic megacolon
What are the investigations that should be done for volvulus diagnosis?
1) X-ray
- OMEGA SIGN
- CAR TIRE SIGN
- COFFEE BEAN SIGN
2) contrast enema -> line of transection
3) CT for difficult cases
How is volvulus treated?
- admit patient
- IV fluids catheterization
- antibiotics
- flatus tube or rigid sigmoidoscope -> try to detorte
- if detortion doesn’t occur -> Sigmoidopexy
- > Hartmann’s operation -> colostomy 3 months -> prepare & anastomose
right colon resection -> immediate anastomoses
left colon resection -> colostomy
-> open table preparation
What is acute intussusception?
gut becomes invaginated in adjacent segments & stretched blood supply
- hyperplasia of Peyer patches could cause it
- most common in children (3-9 months)
- if it occurs in adults -> polyp, submucosal lipoma, tumor
most common strangulating obstruction by acute intussusception?
ileocecal
What is the clinical picture of acute intussusception?
- severe attacks of pain (lasting minutes)
- RED CURRANT JELLY STOOL
- sausage shaped lump -> empty RIF -> SIGN DE DANCE
- p/r -> blood stained stool
- later -> vomit & distention
What investigations should be done for acute intussusception?
- x ray -> absent cecal gas
- barium enema -> CLAW SIGN
- CT -> target sign
How should acute intussusception be managed?
- hydrostatic reduction with enema
- operative reduction -> fixation by appendectomy or to cecal wall
Failure of neuromuscular mechanisms (Auerbach’s & Meissner’s plexus) leads to?
Paralytic ileus
What are the causes of paralytic ileus?
- peritonitis
- hypokalemia
- abdominal surgery
- spine injury
What are the clinical features of paralytic ileus?
- no passage of flatus
- no bowel sounds
- marked abdominal distention
- vomiting large volumes of fluid
- high pitched tinkling note
- dull abdominal pain (NOT COLICKY)
What investigations should be done for paralytic ileus?
rule out
- uremia
- hypokalemia
- diabetes
- DYNAMIC OBSTRUCTION
How should paralytic ileus be treated?
CONSERVING is better than opening if patient has good general condition
- don’t stimulate peristalsis
- NPO
- NGT
- measure abdominal girth
- decompress by flatus tube if possible
recovery in 3-6 days most probably
What are the causes of mesenteric vessel ischemia?
- embolism
- thrombosis -> in portal hypertension & OCP use -> atherosclerosis
- hypotension/hypoperfusion
What pathological features occur in mesenteric vessel ischemia?
- bowel & mesentery edematous, friable, discolored, & collected with fluid & blood
- within 3 hours mucosa sloughs -> ulcerates -> bleeds in lumen -> bacteria in bloodstream -> whole thickness -> exudates serosanguinous fluid in peritoneum -> functional obstruction
- can lead to extensive gangrene or focal ischemia
What is the clinical picture of mesenteric ischemia?
- acute abdominal pain (doesnt respond to narcotics or NGT)
- vomiting & obstruction like symptoms
- BLEEDING PER RECTUM
- sepsis
- shock
- signs of peritonitis (BOARD LIKE RIGIDITY)
What investigations should be made to diagnose mesenteric ischemia?
- X-ray -> increase air fluid levels
- ultrasound - CT
- arteriography
- amylase elevated
- doppler
How should mesenteric vessel ischemia be treated?
EMERGENCY LAPAROTOMY
- patient presents after 24-48 hours -> gangrene -> resection & anastomosis
- within 6 hours -> salvage bowel
Emergency SMA angiography
Heparin or thrombolytics
CLOSE MONITORING for possibility of gangrene formation
Broad spectrum antibiotics
What is the cause of chronic ischemia of mesenteric vessels?
atherosclerosis at the mouth of superior mesenteric artery
- in old males
postprandial abdominal pain starting 15 mins after meal & lasting for an hour is a sign of?
chronic ischemia
- abdominal angina
- loss of weight (afraid of eating)
- upper abdominal bruit
How should chronic ischemia be diagnosed and treated?
US, CTA & MRA
ENDARTERECTOMY (coring out thickened intema) or BYPASS GRAFT
