Small bowel & Bowel Obstruction Flashcards
Emergency conditions of small bowel?
Obstruction
Infarction
Haemorrhage
Obstruction
Due to fluid, gas, ischaemia, perforation
- – Pain (colicky, central)
- – absolute constipation
- – vomiting
- – burping
- – abdo distension
Causes//
- – within the lumen (gallstone, food, bezoar)
- – within the wall (tumour, Crohn’s, radiation)
- – outside the wall (adhesions, herniation)
Obstruction - presentation
Distension Vomiting Borborygmi (rumbling noise) Pain Faeculent vomiting
Look for cause of obstruction. Scar, hernias
Obstruction - Ix
> Urinalysis
Bloods
Gases
Confirming diagnosis//
- AXR
- Contrast CT
- gastrograffi studies
identifying those who need surgery and those who will settle
“Drip and Suck”
> ABC > Analgesia > Fluids with potassium > Usually hypokalaemic and alkalotic > Catheterise > NG tube > Antithromboembolism measures
- up to 72 hours
- intervene earlier if there is strangulation perforation, ischaemia
Surgical Management
> Laparotomy > Operative principles --- abx --- antithromboembolic measures --- usually a midline incision --- can be laparoscopic --- find obstruction by following collapsed or dilated bowel
Mesenteric ischaemia
> Embolus, thrombosis > Chronic --- SMA --- Cramps --- angina of the guts --- atherosclerosis
Acute
– small bowel usually becomes infarcted
Cause of mesenteric ischaemia
> Embolus from AF
- – forms in left atrium
- – sticks in narrow SMA
> In situ thrombosis from general gubbedness
- –virchow’s triad
- – dehydrated
- – hypercoagulable
- – compression
- – vasocoonstricting drugs
Mesenteric ischaemia - diagnosis
> Massive pain > Acidosis > Lactate elevated > WCC may be up > CRP may be normal > CT angiogram > INTERVENE
Treatment - mesenteric ischaemia
QUICK TREATMENT.
Resect if non-viable.
Re-anastomose or staple
If viable perform an SMA embolectomy
Haemorrhage
ABC Exclude upper source Vascular malformations Ulceration CT angiogram
Meckel’s diverticulum
> 60 cm from IC valve > Present before 2 years of age > Remnant of omphalomesenteric duct > Complications --- bleed --- ulcerate --- obstruction --- malignant change
Upper bowel obstruction - vomiting
> Large volumes of vomit
> Gastric, pancreatic and biliary secretions regurgitated into stomach
Distal small bowel/ large bowel obstruction
Colicky pain and distension
Vomiting - (faeculent)
Symptoms of intestinal obstruction
> Vomiting > Pain > Constipation > Distension > Complete obstruction > Incomplete obstruction
The more proximal the obstruction…
the earlier vomiting develops
Semi-digested food eaten a day or two previously suggests…
gastric outlet obstruction
copious bile-stained fluid suggests…
small bowel obstruction
Thicker, brown, foul-smelling vomit
Distal obstruction
Distension of bowel causes…
pain.
&
there are intermittent episodes of colicky pain.
Constipation
Propulsion of bowel contents is arrested.
Bowel gas is absorbed distal to the obstruction
Absolute constipation - neither faeces nor flatus
Large bowel obstruction
gradual onset of symptoms.
If oleo-caecal valve remains competent in large bowel obstruction…
Backward flow of contents is prevented.
Thin walled caecum progressively distends with swallowed air and eventually may rupture
- – closed loop obstruction.
- – at risk of perforation
COMPETENT valve is a big problem
If oleo-caecal valve becomes incompetent…
the small bowel distends, delaying onset of symptoms
Incomplete obstruction
- symptoms
- leads to
- type of pain
Clinical features may be less defined.
Intermittent vomiting & erratic bowel habit
leads to gradual hypertrophy of muscle of the bowel wall proximally.
Colicky pain due to peristalsis
Physical signs of intestinal obstruction
Dehydration
Abdo distension
Visible peristalsis
Relative lack of abdominal tenderness
Mass may be palpable
Centre of abdomen tends to be resonate due to gaseous distension
groins examined for hernia
Bowel sounds?
High pitched, tinkling.
Absent, echoing.
Water lapping against a boat
Bowel obstruction - investigations
Supine abdo xray**
Bowel proximal to obstruction is distended
Small bowel on Xray
“lines” go all the way across the bowel
Large bowel xray
Haustra
What is performed after supine AXR?
CT scan to confirm diagnosis
transition point between collapsed and distended bowel.
Initial management
Nil by mouth
Insert IV cannula and send bloods
Resus with IV fluids
Replace electrolyte loss
Pass a nasogastric tube to decompress the stomach
Drip and suck
Adhesions/bands
Mechanical cause of obstruction.
Congenital/iatrogenic
Small bowel loops should be free to move about
Can become stuck to each other and twist on each other
Collapse lumen
Incarcerated abdominal wall hernias
Mechanical cause of obstruction
Volvulus
A mobile loop of bowel rates causing obstruction at its neck.
sigmoid volvulus
closed loop structure
massively distended
caecal volvulus - hypermobile caecum.
Tumour
Most common - colonic cancer
Hypokalaemia/ hypocholaemic metabolic alkalosis
Losing chloride through vomiting
Losign H+ ions
Losing potassium as well
Inflammatory stricture
- Crohn’s disease - due to proximal hypertrophy
- Diverticular disease
incomplete usually
Bolus obstruction
- Food bolus
- Impacted faeces
- impacted gallstone ileus
- Trichobezoar - hair ball
What is a trichobezoar?
Hair ball
Intussusception
a segment of bowel wall becomes telescoped into the segment distal to it
Usually initiated by a mass in the bowel wall - tumour
Overacvie lymphatic tissue
Bowel Strangulation
> A segment of bowel becomes trapped
Venous return is obstructed
↑local intra vascular pressure, arterial inflow compromised
Infarction–> perforation
Pain over a hernia
indicates bowel strangulation
surgical intervention.
can occur in external hernia or volvulus
Paralytic ileus
Disruption of normal propulsive activity of GI tract
No peristalsis
Reent GI surgery
Inflammation w/ peritonitis
Diabetic keto acidosis
Symptoms and signs//
pain and high pitched sounds less common
Everything will be uniformly distended with no obvious point of obstruction
Ogilvies Syndrome
Acute dilatation of colon in absence of colonic obstruction in ACUTELY UNWELL patients
hip replacement CABG Spinal Pneumonia Frail/elderly
gaseous distension to distal rectum.
no “cut-off” point
Colonoscopic decompression if causing pain or resp compromise.
Most common cause of bowel ischaemia?
Mesenteric artery occlusion
- atherosclerosis
- thromboembolism (AF)
Other case of small bowel ischaemia?
Non-occlusive perfusion insufficiency
- shock
- strangulation obstructing venous return
- drugs
- hyper viscosity
What is the most metabolically active part of the bowel wall?
Mucosa
Longer time of ischaemia
greater the depth of damage
In non occlusive ischaemia, what causes most tissue damage?
REPERFUSION INJURY
Meckel’s diverticulum
Tubular structure - 2 inches long, 2 foot above IC valve in 2% of people.
May mimic appendicitis
True diverticulum (includes all layers)
Commonest site of carcinoid tumours?
Appendix
(Primary) Small bowel carcinoma associated with
Crohn’s disease and coeliac disease
late presentation
What must acute inflammation invlove?
The muscle coat
Appendicitis - complications
Peritonitis Rupture Abscess Fistula Sepsis and liver abscess
Classic coeliac disease rash?
Dermatitis herpetiformis
sub epithelial IgA deposition
What is the component of gluten suspected to be the toxic agent in coeliac disease?
Gliadin - leading to t cell mediated reaction
Coeliac disease - what happens to enterocytes
LOSS of enterocytes due to IEL mediated damage
Loss of villous structure, loss of SA
reduction in absorption
FLAT mucosal biopsy
Coeliac disease lesions are worse in?
Duodenal biopsy
What antibodies are present in coeliac disease?
anti-TTG
anti-endomesial
anti-gliadin
Coeliac leads to malabsorption of… leading to…
malabsorption of fat
–> STEATORRHOEA
Coeliac has reduced hormone production. Leading to…
Recuded pancreatic secretion and bile flow.
–> gallstones
Coeliac disease
Loss of weight Anaemia Abdominal bloating Failure to thrive Vitamin deficiencies T cell lymphomas Carcinoma Gall stones Ulcerative jejenoilleitis
Causes of malabsorption
Common//
Coeliac Crohn's Post infectious Biliary obstruction Cirrhosis
Uncommon//
Pancreatic cancer parasites bacterial overgrowth drugs short bowel
Fat malabsorption
Digestive
Absorptive
Post absorptive
a physiological defect in any of these can lead to malabsorption
Carb malabsorption
Quite uncommon
Severe oancreatic insufficiency (alpha-amylase)
What can lead to vitamin b12 deficiency?
Deficiency of gastric intrinsic factor (pernicious anaemia)
Menkes disease
“Kinky hair disease”
caused by disorder of cellular copper transport
What is lactase deficiency confirmed by?
Hydrogen breath test
Tropical sprue
Leads to malabsorption
Colonisatio of the intestine by infectious or alterations in intestinal bacterial flora
diarrhoea, steatorrhoea, weight loss, nausea, anorexia, anaemia
Crohns disease
Abdo pain and tenderness - RLQ
Diarrhoea, fever and weight loss
What are punched out lesions a sign of?
Crohn’s disease
Giardia Lamblia
parasitic infection
Water supplies that may be contaminated
diarrhoea, flatulence, abdo cramps, epigastric pain and nausea. Malabsorption w steatorrhoea an weight loss
Stool sample x 3
METRONIDAZOLE
PMHx that may indicate malabsorption
Gastric/small bowel resection
Gastrointestinal division
Radiation expsosure
Travel
Gingival hyperplasai
Scurvy
Vitamin C deficiency
weak collagen formation
Acrodermatitis Enteropathica
Imparied zinc uptake
perioral rash
Lack of iron
Glossitis
Angular stomatitis
spooning of nails
Large MCV (mean corpuscular volume) =
Macrocytic anaemia
Investigations for malabsorption
FBC Coagulation LFTs MCV Albumin Ca/Mg Stool
Endoscopy
Bacterial overgrowth causing malabsorption
diarrhoea, steatorrhoea, macrolytic anaemia
E. coli or bactericides
Evidence of - fistulas, diverticula, strictures, Crohn’s disease
High folate levels
Surgical correction
Tetracyclines
What are the intestinal glands/crypts called?
Crypts of Lieberkühn
S.I. regions
Duodenum - contains brunner’s glands
Jejunum - tallest villi. located on permanent circular folds of the mucosa and submucosa—– plicae circularis
Ileum - Peyer’s patches
What do Brunner’s glands produce?
Thin, alkaline mucous to neutralise the chyme
Jejunum has…
Plicae circularis
Closely packed folding
do not disappear when intestine is distended
Ileum has large aggregations of..
lymphoid tissue
Peyer’s patches
Cells of large intestine
Absorptive cells - removal of salts and water
Goblet cells - secret of mucous to lubricate colon
arranged in crypts
Gastro-duodenal junction
Stratified squamous to columnar epithelium
Longitudinal muscle of large intestine
3 muscular strips
Teniae coli
The appendix has a lot of …tissue
Lymphoid
Rectoanal junction
Rectum - columnar epithelium
Anus - stratified squamous
Where is the myenteric plexus?
Between the 2 muscle layers
Where is the submucosal plexus?
In the submucosa
controls muscular is mucosae and regulates secretion in the epithelium
