Bowel obstruction Flashcards
What is bowel obstruction?
Impaired flow of normal intestinal contents
Where do bowel obstructions happen?
80% small bowel
20% large bowel
What ate the 2 classes of cause of bowel obstruction?
Dynamic
Adynamic
What is a dynamic bowel obstruction?
Bowel obstruction with increasing peristalsis working against an obstructing agent
What are the causes of bowel obstruction in a newborn?
Imperforate anus
Congenital atresia or stenosis
Volvulus
Meconium ileus
What is the common cause of bowel obstruction in 2-3 month old?
Strangulated hernia
What is the common cause of bowel obstruction in 3-18 month old?
Intussuseption
What are the causes of bowel obstruction in children and young adults?
Strangulated hernia
Post op adhesions
What are the common causes of obstruction in adults?
Strangulated hernia
Post op adhesions
Maligancy
Volvulus
What is the most common cause of small bowel obstruction?
Adhesions
What is the most common cause of small bowle obstruction in a virgin abdomen?
Tumour
What is the most common cause of large bowel obstruction?
Tumour
What is an adynamic bowel obstruction?
Bowel obstruction with cessation of peristalsis and absence of true propulsive waves
What are the causes of adynamic bowel obstruction?
Mesenteric vascular occlusion
Paralytic ileus
Large bowel pseudo-obstruction
Who is mesenteric vascular occlusion seen in?
Those with PCV, atherosclerosis, AF
People who aren’t very well
What is the presentation of mesenteric vascular occlusion?
Pain of sudden onset, severe and out of proportion with physical signs
Co-morbidities
Very unwell
What investigations are done for mesenteric vascular occlusion?
CT angio
hat is paralytic ileus?
Cessation of peristalsis due to failure of neuromuscular mechanism
What are the common triggers of paralytic ileus?
Post op
Infection
Fluid and electrolyte abnormalities
Reflex to trauma
What is the presentation of paralytic ileus?
NO pain
Vomiting and distension
What is large bowel pseudo-obstruction?
Signs, symptoms and AXR appearance of LBO but no identifiable mechanical cause
What is the presentation of large bowel pseudo-obstruction?
Older person with co-morbidities, with progressive abdominal distension and absolute constipation
What investigations are done for large bowel pseudo-obstruction?
AXR
CT- bowel dilated but no transition point or identifiable obstruction
What is a simple bowel obstruction?
Obstruction of intestinal lumen without interference of its blood supply
What causes a simple bowel obstruction?
Gallstones Impacted faeces Strictures Adhesions Tumours
What is the pathophysiology of a simple bowel obstruction?
Proximal- increased peristalsis, distension with gas and fluid
Transition point
Distal= collapsed and immobile bowel
What are the effects of simple bowel obstruction?
Dehydration from vomiting and third space losses
Electrolyte imbalances
Translocation of bacteria –> peritonitis
What are the causes of death in simple bowel obstruction?
Peritonitis
Fluid and electrolyte imbalance
What is a strangulating bowel obstruction?
Intestinal obstruction with persistent interference of blood supply
What are the causes of strangulated bowel obstruction?
Strangulated hernia Intussusception Adhesions Volvulus vascular occlusion
What is the pathophysiology of strangulated bowel obstruction?
Venous return impaired first- dark and congested bowel
Serosanguinous fluid build up and increases pressure
Increased pressure impairs arterial supply, causing necrosis
What are the causes of death in strangulated bowel obstruction?
Short segment= peritonitis
Long segment= peritonitis, hypovolaemia
What is a closed loop obstruction?
Affected bowel segment obstructed at both proximal and distal end
What can cause closed loop obstruction?
Obstructed hernia
Volvulus
Obstructed colon with competent ileocaecal valve
What is the presentation of an obstructed bowel with competent ileocaecal valve?
Abdo pain and distension, with vomiting after 24-36 hours
Caecum becomes dilated and can perforate
When are we worried about perforation of the caecum and why?
Thinnest part of bowel
When approaching 10cm
What is a Richter’s hernia?
Incomplete obstruction due to partial herniation of bowel through small hernia, commonly femoral hernias
What are the features of small bowel obstruction, in order of appearance?
Pain
Vomiting
Abdo distension
Absolute constipation
What are the features of large bowel obstruction in order of appearance?
Absolute constipation
Abdo distension
Pain
Vomiting
Describe the pain in simple bowel obstruction?
Generalised colicky, relief between attacks
Attacks increase in frequency, severity and duration
What is the rule with vomiting in bowel obstruction?
The higher the obstruction, the worse and earlier the vomiting
When is vomiting seen in large bowel obstruction?
Faecal vomiting after 24-36 hours if incompetent ileocaecal valve
Describe the distension in a small bowel obstruction
The later the obstruction, the worse the distension
Ileal= central abdo distension
Describe the distension in large bowel obstruction
Distension in flanks
What is the presentation of a strangulated obstruction?
Pain is severe and never completely absent between attacks
Tender rigid abdomen
Temperature, tachycardia, unwell
Early raised WCC
NG suction for 1-2 hours doesn’t relieve pain
What bloods are done in bowel obstruction?
FBC- low Hb= think cancer -High WCC early= strangulation -High WCC late= peritonitis U&Es LFTs ABG if unwell- metabolic acidosis in strangulation
What imaging is done for bowel obstruction?
AXR
CT
What s the AXR appearance in small bowel obstruction?
Transverse complete regular striations
Small bowel distension
What is the AXR appearance in large bowel obstruction?
Haustrations
Distension
What is the AXR appearance in a sigmoid volvulus?
Coffee bean sign
What is diagnostic of a bowel obstruction?
CT with transition point
What is the general management of bowel obstruction?
Drip and suck
NG tube- symptomatic relief and reduce aspiration risk
Resus fluids and electrolytes
Treat cause
What are the indications for surgery in bowel obstruction?
Obstructed herna Suspected strangulation SBO in virgin abdomen Failure of conservative management in 48 in adhesions Obstructing tumours on CT
Where does intussusception normally occur?
Ileo-colic
What is the management of an intussusception?
Paeds- air enema
Adults- normally organic cause, surgical excision
What is the management f a volvulus?
Caecal= right hemicolectomy Sigmoid= emergency endoscopic decompression
What is the management of adhesive obstruction?
Conservative- NG, fluids, pain relief
Surgery if failure of conservative management after 48 hours or suspected strangulation
What is the management of gallstone ileus?
Enterotomy and removal of stone
What is the management of mesenteric vascular occlusion?
Young= surgery
Older, co-morbid= palliate
What is the management of paralytic ileus?
Treat underlying cause
Supportive
What is the management of large bowel pseudo-obstruction?
Supportive
Treat any remediable underlying cause