Obstruction Flashcards
What can obstruction be
Complete (complete constipation)
Incomplete (passage flatus / stool 6-12 hours after symptom onset)
Simple = no interference with blood supply
Exntrinsic / extra-mural
Intramural
Intraluminal
What are common causes of large bowel obstruction
Colon cancer (60%)
Diverticulitis causing post infective stricture (20%)
Volvulus (5%)
Impacted stool
What are other structural causes
IBD stricture
Hernia
Adhesions - surgery / peritonitis / intra-abdo infection
What is an ileus
Temporary obstruction due to decreased motility / absence of peristaltic contractions
Will have no bowel sounds as no movement
What causes ileus
Post-surgery Infections Electrolyte imbalances - hyponatraemia Trauma Drugs Pancreatitis Peritonitis
What is Pseudo-obstruction
Resembles mechanical but no lesion
What can cause pseudo obstruction
Parkinson's MS Nerve issue Hypothyroid Hirschprungs Meconium ileus (CF) Ogilvies
What is Olgivies and what puts you at risk
Obstruction
Raised WCC
Fever
Pelvic surgery / trauma / CVS and near disease
How does obstruction present
Severe pain Abdo distension Diarrhoea early as increased peristalsis Constipation - absolute in distal but less pronounced if high Nausea Vomitnig = late sign Decreased appetite / anorexia Borborygmi High pitched bowel if early Silent abdomen if peritonitis Signs of dehydration / shock Altered bowel PR bleed
What does intermittent obstruction suggest
Volvulus
What puts you at increased risk of obstruction
Malignancy
Surgery
How do you Dx obstruction
Bloods
DRE
AXR = key in bowel obstruction
CT abdo = definite
What bloods
FBC U+E LFT Amylase as abode pain ABG or VBG shows clinical status
What will AXR show
Dilated bowel loops
Free air under diaphragm if perforates
Haustra 1/3 accross
What do you use to get cause
CT
What are other useful tests
Gastograffin + AXR to look for perforation / anastomotic leak USS Air or barium enema Colonoscopy CT iconography if unfit
When do you caution with colonoscopy
May perforation / distension worse
Used to untwist volvulus before surgery
How do you deal with obstruction
ABCDE NBM IV fluid NGT to remove food and prevent vomiting Pain relief Anti-emetic Catheter Enema Ax if aspiration Correct electrolyte abnormalities Surgery = definite
Why can obstruction cause chest signs
Distended abdo presses on lungs
What must you do if on NG tube or obstructed
Changes meds to IV or SC
What is common cause of small bowel obstruction
Adhesions x
Hernia x
Stricture - IBD / radiation
Malignancy
When are adhesions common
Post - surgery
Sepsis
Peritonoitis
Haemorrhage
What are other causes
RT Intussception Ischaemia Gallstone ileus Paralytic ileus Foreign body TB
How does small bowel obstruction present
Same Tend to have vomiting earlier Pain higher in abdo Distension less Central distension and increases as lower down Distension in flanks if colonic
What is important when looking at vomit
Bile = suggest past gall bladder
Bright green = proximal
Dark = distal
How do you Dx
AXR plays a key role in bowel obstruction
Gastrografin for level
CT abdo if unclear
What does AXR show in small bowel
Valvulae go all the way across
Dilated bowel
What does CT show
Dilated loops of small bowel
What else is important
U+E
ECG for electrolyte imbalance
Why is oxygen impaired
Distension
Ischaemia
Sepsis
What is general management
ABC Oxygen Analgesia Correct hypovolaemia / electrolyte - IV fluid NG to reduce distension NBM
What should you do regular
Assess fluid
What should you always do if vomiting
Abdo exam
Check for hernia
Complications of small bowel obstruction
Inection Sepsis Necorsis Hypovolaemia 3rd space fluid loss Shock Increased hydrostatic pressure = oedema and ischaemia Increased mucosal permeability Fluid and Electrolyte disturbances Dehydration leading to AKI Renal failure Stragnualtion Peritonitis Perforation
What does dehydration cause
AKI
What is strangulation
Intestinal obstruction with persistent interference of blood supply
What causes strangulation
Hernia Intussception Intestinal obstruction Volvulus Vascular occlusions
What does internal strangulated hernia cause
Pain more severe than you'd expect Never goes between attacks Peritonism = cardinal sign Shcok Localised tenderness and rebound NG fails to relieve
What does external strangulated hernia cause
Tense
Tender
Irreducible
No expansible impulse
What causes intussception in adult
Polyp
Lipoma
Adhesions
Malignant tumour
How do you Dx and Rx
Target sign on USS
Laparotomy and resection
When is paralytic ileus common
Post-surgery
Drug
Electrolyte
What suggest ileus and how do you Rx
Lack of bowel sounds N+V Distension Abdo tenderness Dilated loops of bowel Previous surgery now no bowel sounds Fluid and electrolyte on bloods
Rx = NBM, NG tube, start IV fluid and recommence oral slowly
Mobilise to stimulate
TPN if long term
What are complications of strangulation
Bowel ishcaemia Gangrene Perforation Peritonitis Sepsis Hypovolaemic shock Dehydration
What is best nutrition
Going through gut is always best
Try most natural
When might enteral or parenteral nutrition be needed
Severe vomitnig or obstruction
What does TPN require
Daily bloods - U+E
PICC or peripheral
Complications of TPN
Infection Refeeding Fluid balance Phlebitis / thrombosis Sepsis Abnormal LFT
How do you decrease risk of abnormal LFT
Lipid free days
Decreased duration
Altered content of bags but only do this in chronic
Watch glucose as liver may not cope
What type of jaundice does TPN cause
Painless
Non-obstructive
What is dioralyte used for
Dehydration and to increase salt content i.e. if high volume fistula / stoma
Pulls out electrolytes
What is NG tube used for
Gastric outlet obstruction
Pseudo-obstrution / ileus
What is refeeding syndrome
Body switching from catabolism to carb when food introduced
What does it cause
Low phosphate Low K Low Mg Low B12 Abnormal fluid Organ failure
What can low Mg cause
Torsade de points
How do you treat
Slow introduction
Who is high risk
Low BMI Weight loss Poor intake Metabolic disturbance prior Alcohol
What occurs above obstruction
Peristalsis and distension
Increases the higher up
What can occur at level
Perforation
What occurs below obstruction
Immobile and pale bowel
What type of distension if jejunal
Minimal
Distension in ileal
Central
Distension in colonic
Central
Flanks - colonic only
When would obstruction present without constipation
Hernia
Pelvic abscess
Mesenteric vascular occlusion
What do you do in examination
Look for scars - adhesions? Hernia PR Palpation Ausculate
What do you hear on auscultation
Loud and high pitched in early
Silent if peritonitis
What may erect CXR show
Free air if late perforation
How much dilatation in SBO
> 3cm
Does normal AXR exclude
No
Summary high SBO
Early vomiting
Minimal distension
Minimal small bowel loops
Summary low SBO
Late vomitng
Pain and distension
Dilated loops
Symmary LBO
Lots of distension
Pain and vomit late
What confirms the Dx of bowel obstruction
CT
What is CT good for
Determining level
Find cause
Detecting ischaemia and perforation
What will confirm resolution of SBO
Contrast in caecum in gastrograffin
What always has absent bowel
Paralytic as no movement
What is Olgivie associated with
Elderly Recent surgery Infection - WCC / fever Severe pulmonary / CV disease Severe electrolyte imabalnce Drugs
How can you get hypovolaemic -> AKI but have overall +ve fluid balance
Fluid lost into 3rd space
In obstruction what occurs before signs
Fluid an electrolyte dsiturbance
Hypovolaemia
What is a volvulus
Bowel twist abnormally
Where does it occur
Sigmoid
Can occur in caecal
What are RF
Psychiatric disorder Neuro disorder Nursing home Chronic constipation Pelvic mass Adhesion
How does it present
Colicky pain
Constipation
Distension - asymmetric
Tender
What are complications
Obstruction
Ischaemia
Perforation
How do you Dx
Presents like obstruction
AXR - coffee bean sign
CT to confirm
How do you Rx
Endoscopy decompression
Laparotomy
- Hartmann’s for sigmoid
- R-hemi-Colectomy for caecal
What is an incisional hernia
Hernia that occurs at site of incision due to inadequate closure
What increases risk
Bigger incision = bigger risk
Comorbid which cause poor heeling
To Dx obstruction what is used
Will get AXR as quick
- Good for toxic megacolon
Almost always CT to define location
What are other measures in obstruction
Octeoride as reduces gastric secretion and associated N+V
Steroid as stimulates bowel but can cause increased hunger when want NBM
