Colorectal surgery Flashcards
what types of vitamins do the bacteria in the colon produce?
vitamin K and B
What structures make up the foregut?
Oesophagus Stomach Proximal duodenum liver gall bladder pancreas
What structures make up the midgut?
Distal duodenum ileum cecum appendix ascending colon proximal 2/3 of transverse colon
What structures make up the hindgut?
distal 1/3 of transverse colon descending colon sigmoid colon rectum proximal anus
Where is the anastomoses located that connects the left and right side of the colon?
splenic flexure
Define the term ‘watershed’
an area that receives dual blood supply from the most distal branches of two large arteries, such as the splenic flexure of the large intestine
Which vein drains the ascending colon?
superior mesenteric vein then into the portal vein
Which vein drains the descending colon?
inferior mesenteric vein into the splenic vein
Colorectal cancer info
very common
M>F but depends on risk factors
How are patients screened for colorectal cancer?
Quantitative faecal immunochemical test (qFIT) - less hassle, more sensitive to haemoglobin, more uptake from patients
Replaced Faecal occult blood test (FOBT)
Almost every case of colorectal cancer develops from what?
an adenoma
hence why screening is important - want to detect adenoma at early stage
Typical symptoms of patient with suspected colorectal cancer (7)
Abdominal pain - colicky (starts and stops abruptly)
Rectal bleeding – anorectal pain?, colour?, mixed in stool?
Change in bowel habits (diarrhoea, constipation)
Weight loss
Tenesmus – sensation of having something in their rectum
Fatigue
Vomiting
High risk features that indicate diagnosis of colorectal cancer (6)
Persistent change in bowel habit (>6 weeks)
Persistent rectal bleeding without anal symptoms
Right sided abdominal mass (higher up the GI tract - more serious)
Palpable rectal mass
Unexplained iron deficiency anaemia – consider menopausal women?
Patients in whom there is clinical doubt
Investigations for colorectal cancer
Colonoscopy +/- biopsies (gold standard)
Radiological imaging
- CT colonography
- Plain CT abdo/pelvis with contrast
Staging CT if confirmed CRC (CT chest)
Pre-op MRI in confirmed rectal cancer
Others i.e PET scan
CT Chest abdomen pelvis (CAP) is used for what?
to stage colorectal cancer
Which part of the colon does the tumour most commonly lie in?
Proximal 43%
Distal 30%
True or false?
Colon and rectal cancer treated as 2 separate entity
true
How does colon cancer management differ to rectal cancer
almost always straight to surgery if no metastatic disease and patient is fit
not straight to surgery - pre-op MRI important in rectal cancer - may need neodjuvant chemo, radiotherapy or both followed by surgery
What is the fatty enevelope that surrounds the rectum called? and why does it need to be removed sometimes?
mesorectum
contains all the draining lymph nodes of the rectum
what is a total mesorectal excision and why is it done
To reduce local recurrence rate as if cancer has spread to the mesorectal fascia surgery would be pointless
the rectum and it’s surrounding mesorectum has to be excised all together
almost all colorectal cancer patients will have this done
What is the circumferential resection margin
Area between the tumour and peritoneum - need clear resection margin to be able to operate
If tumour has invaded the peritoneum then surgery would be pointless as would likely reoccur
Neoadjuvant treatment + rectal cancer
Should give Neoadjuvent therapy first – chemo or radio or both to try and decrease tumour size and make clear resection margin
restage 6-8 weeks later after treatment
What things do you have to consider before surgery for rectal or colon cancer?
Resection - removing whole tumour
Restoration intestinal continuity
Faecal diversion: Stoma
Preservation of function
Difference between ileostomy and colostomy
ileostomy - usually R iliac fossa, liquid or looser stools and spouted out of the skin
Colostomy - usually in left iliac fossa, solid stools, no spout, flush with skin
Complications of general resection surgery
Bleeding
Infection (superficial & deep)
Anastomotic leak
Stoma problems (ischaemia, retraction, prolapse, hernia, high output)
Complications of low Anterior Resection (LAR) (surgery to treat rectal cancer)
Damage to pelvic nerves – bowel, urinary, sexual dysfunction
Possible impaired fertility in younger women
Post-op management
Dependent on pathological staging
Adjuvant chemotherapy may be required
Post-operative complications might hinder or delay adjuvant treatment
Surveillance CT CAP, colonoscopy
In NHS Grampian alternate USS liver + CT CAP every 6 months
Cardinal signs and symptoms of bowel obstruction (4)
Abdominal pain Vomiting Absolute constipation (flatus and solids) Abdominal distension
What serious problems can bowel obstruction cause
hypovolemic shock or septic shock due to fluid shifts in the body and/or excessive vomiting.
how is septic shock caused by bowel obstruction?
bowel distension - venous compression - decreased oxygenation - bowel cells die - increased toxins in circulation (lactic acids and bacterial toxins)
Benign causes of large bowel obstruction
Strictures (diverticular, ischaemic)
Volvulus
Faecal impaction
Intussusception
Pseudo-obstuction
what is volvulus
when a loop of intestine twists around itself and the mesentery that supports it
what is intussusception
one segment of intestine “telescopes” inside of another, causing an intestinal obstruction
Causes of small bowel obstruction (2)
adhesions
hernias
Immediate management of bowel obstruction
ABC
Fluid resuscitation
Nil By Mouth and consider nasogastric tube if vomiting
Analgesia and antiemetics
Consider IV antibiotics
Investigations for bowel obstruction
Bloods (FBC, U&Es, G&S, Coagulation screen)
Blood gas (Lactate, pH, BE)
CT abdo/pelvis
When would you not perform an anastomosis?
if patient has felt really unwell
if patient has no reservoir, rectal compliance, previous traumatic birth
risk of anastomotic leak
