Colorectal Cancer Flashcards
What is irritable bowel syndrome (IBS)?
A chronic illness characterised by abdominal pain/discomfort and disturbed bowel habit in the absence of causative disease.
Which gender is more prevalent for IBS?
Women.
What criteria is used to diagnose IBS?
The Rome Criteria.
What are the diagnostic criteria for IBS according to the Rome Criteria?
12 weeks of abdominal discomfort or pain with:
* Relief by defaecation
* Associated with change in stool frequency and appearance.
What are common symptoms supporting the diagnosis of IBS?
- Bloating
- Abdominal distention
- Passing mucus
- Abnormal stool frequency and form.
long history with relapse and remitting course, exacerbations aretirggered by life events, co-morbidity of anxiety/depression and symptoms worsened by eating.
What is a major pathophysiological aspect of IBS?
Increased contractility of intestinal muscles with increased sensitivity to visceral stimulation and underlying inflammation linked to stress. Gut mucosa in IBS shows chronic inflammatory cells mas cells and IBS-D (diarrhoea) will have more mucosal T lymphocytes than IBS-C.
What are common triggers for IBS exacerbations?
- Life events
- Co-morbidity of anxiety/depression
- Symptoms worsened by eating.
What are alarm features of IBS?
- Onset after age 50
- Progressive deterioration
- Weight loss
- Fever
- Rectal bleeding
- Steatorrhoea
- Dehydration
- Family history of organic gastrointestinal disease.
What investigations are recommended for IBS?
- FBC with metabolic panel
- Inflammatory markers
- Stool culture for C-diff, giardiasis, cryptosporidium
- Testing for coeliac with tissue transglutaminase antibody
- Colonoscopy.
What treatment options are available for IBS?
- Non-stimulant osmotic laxatives (e.g., macrogol)
- Anti-spasmodics (e.g., mebeverine, hyoscine butylbromide)
- Anti-diarrhea agents (e.g., loperamide)
- Anti-depressants (e.g., tricyclics and SSRIs)
- Dietary management (FODMAPs)
- Rifaximin.
True or False: There is a strong association of IBS with anxiety and depression.
True.
What is small bowel obstruction (SBO)?
A surgical emergency characterised by a triad of abdominal pain, vomiting, and abdominal distention which disrupts intestinal flow.
What are the categories of small bowel obstruction?
- Simple obstructions
- Functional obstruction
- Strangulated obstructions.
What is the cause of simple obstruction?
gallstone ileus (At ileocaecal valve))intramural lesion or extrinsic adhesion, causing proximal bowel distention and distal bowel decompression which increases intraluminal pressure alternative causes include volvulus, strictures and tumours
What is the cause of functional obstruction?
peristalsis due to metabolic disturbances like hypothyroidism or phaechromocytoma, neural inhibiton or inflammation.
What causes strangulated obstruction?
Bowel ischaemia
Hernia
Malignancy from cancer, typically carcinoid, adenocarcinoma and gastro-intestinal stromal tumour
Inflammation from conditions like Crohn’s disease with intestinal fistula and abscess
Endometriosis of the intestine
Intestinal reduced motility
What is the pathophysiology of SBO?
there will be bowel wall oedema, hyperaemia, fluid loss, and increased permeability to bacteria with risk of ischaemia and infarction and systemic effects of fluid loss. Prolonged ischaemia can lead to necrosis of the wall and result in liquefactive necrosis and vascular thrombosis in mesenteric vein.
What are common causes of small bowel obstruction?
- Post-operative adhesions
- Gallstone ileus
- Intramural lesions
- Extrinsic adhesions
- Volvulus
- Strictures
- Tumours.
What are the clinical presentations of small bowel obstruction?
- Acute abdominal pain
- Vomiting
- Dehydration
- Abdominal distention
- Tenderness over obstruction site.
How does proximal SBO present?
significant vomiting, rapid dehydration/electrolyte imbalance and minimal abdominal distention.
How does distal SBO present?
Distal SBO will have extreme abdominal distention, delayed vomiting and slower onset of systemic electrolyte imbalances.
What diagnostic tests are used for SBO?
- FBC for leukocytosis
- Hydration status and electrolytes
- ABG for metabolic alkalosis or lactic acidosis
- Upright chest radiograph
- CT scan.
What is the initial treatment for small bowel obstruction?
Fluid resuscitation and broad-spectrum antibiotics.
What complications can arise from small bowel obstruction?
- Bowel ischaemia
- Perforation
- Further adhesion formation
- Malnutrition
- Peritonitis.
What are common causes of large bowel obstruction?
- Cancers
- Inflammation
- Mechanical obstruction.
What are benign causes of large bowel obstruction?
- Volvulus present more acutely, with significant distention and tympani of bowel.
- Diverticular disease present with pain, fever, palpable mass and distention proximal to obstruction
- Food blockages
- Foreign body
- Inflammation from IBD.
What is the pathophysiology of LBO
obstruction of large bowel is exacerbated by gas forming bacteria and there is reduced venous outflow with ischaemia and necrosis and perforation, greatest risk at caecum with the thinnest wall and largest diameter. there is risk of bacterial overgrowth with reduced motility, and oedema can cause bacterial translocation to small bowel, which increases the risk of sepsis. Incompetence of ileocecal valve can lead to contents entering small bowel and inducing vomiting
What are the clinical features of large bowel obstruction?
- Pain
- Abdominal distention
- Absent bowel movements
- Nausea and vomiting.
What is the treatment of large bowel obstruction?
Use of self expandable uncovered metallic Stent as a bridge prior to emergency surgery for colorectal cancer obstruction, deployed from colonoscopy.
For benign obstruction, balloon dilatation is typically used via an endoscope as there will typically be more inflammation that increases the risk for stent migration.
Covered stents have a greater risk of migration compared to non-covered. Risk of stunting includes perforation and dissemination of malignancy
What is the treatment of simple SBO?
Simple SBO is managed non-operative LH if here is no evidence of ischaemia or perforation. Complicated SBO is treated with surgery
WHAT IS A complication of SBO?
bowel ischaemia, perforation, further adhesion formation, malnutrition and peritonitis.
How to reduce SBO occurrence?
To reduce SBO occurrence, minimally invasive echinacea like laparoscopy rather than open procedure and applying sodium hyalyronate during surgery which is an adhesion barrier and vigilant for signs of a severe abdominal pain, nausea or vomiting post-surgery.
What is the criteria for referral in colorectal cancer?
Change in bowel cancer over 6 weeks in over 60s
* Rectal bleeding over six weeks in over 50 year olds
* Rectal bleeding with change of bowel habit becoming looser in over 40s
* Palpable right lower abdominal or rectal mass
* Over 60 year olds with Iron deficiency anaemia
* Positive faecal immunochemcial tst
What is the gold standard for diagnosing colorectal cancer?
Full colonoscopy evaluation.
What screening is offered for colon cancer?
Faecal immunochemical test every 2 years to adults aged 60-75 years.
What are the investigations for colorectal cancer?
Full colonoscopies evaluation is essential and the gold standard and enable biopsy and removal of polyps to reduce the risk of spread.
Barium enema: x ray with orally ingested contrast
CT scan of chest, abdomen and pelvis to identify metastases
CT colography
FBC for Hb, MCV and colonic embryonic antigen, a tumour marker for colorectal cancer.
Carcinoembroynic antigen should not be used as a diagnostic test due to poor sensitivity and specificity but can be used to monitor disease progression and treatment efficacy. Elevated baseline CEA is assoicated with worse prognosis
What are the clinical signs of right sided colorectal cancer?
Right sided colon cancer will produce a firm palpable mass in right iliac fossa. They tend to be at a worse stage of prognosis because disease advances longer due to wider side of colon before causing obstruction.
What does the Dukes staging system classify?
Staging of colorectal cancer from A (limited to mucosa) to D (widespread metastases).
What is the TNM staging system for colorectal cancer?
- T: Tumor size and depth
- N: Node involvement
- M: Metastasis.
What is T1?
T1= Into submucosa
What is T2?
Muscularois propia invasion
What is T3?
through musclaris propia into subserosa or non-periotonealised pericolic tissue
WHAT is T4A
Peneatrates visceral periotneum
What is the management for early colorectal cancer (T1-T2, N0, M0)?
Local tumour resection and adjuvant chemotherapy.
What is the treatment for stage 3 (T1-T3, N1-2, M0) colorectal cancer?
invovles short-course radiotherapy and:
* capecitabine with oxaliplatin for 3 months
* Second line is oxaliplatin with 5-fluorouracil and foil IC acid
What is oxaliplatin?
alkylating agent for cross-linking
What is capecitabine?
inhibits DNA synthesis by reducing thymidine production
What is fluoropyrimiine?
inhibits thymidylate synthase
What is the role of chemotherapy in colorectal cancer treatment?
Indicated for advanced disease.
What is a common site of metastasis from colorectal cancer?
Liver.
What is the principle of tumour removal in colorectal cancer?
removing the tumour and the vessels supplying it and the lymphatics and resection of any structures atttached to the tumour, with a 5cm margin of bowel on either side of the tumour to mini site he possibility of an anastomotic reccurence
What is laparoscopic surgery?
Laparoscopic surgery is a minimally invasive surgery through the abdomen with small incisions using a camera to assess the contents like the reproductive organs and bowel and bladder. laparoscopic colostomy creates an incision in the bowel to create an opening for faeces to enter a bag.
What is a colostomy?
A stoma created from the colon.
What is the purpose of a surgical drain?
To remove pus, blood, or fluids from a body cavity to reduce the risk of infection.
Fill in the blank: The surgical procedure to remove the entire colon is called a _______.
Colectomy.
How does surgery differ from chemotherapy and radiation therapy in terms of kinetics?
Surgery operates via zero order kinetics to kill 100% of excised cells, while chemotherapy and radiation therapy operate by first-order kinetics, killing only a fraction of tumor cells.
What is a colectomy?
Removal of the entire bowel.
What is a colostomy?
Creation of a stoma from the colon.
What is an ileostomy?
Creation of an opening from the ileum.
What is a proctocolectomy?
Removal of the large bowel and rectum, requiring a J pouch to be created.
What is a J pouch?
An ideal pouch that acts as a replacement for the rectum, connected to the anus using a surgical stapler.
What is an anterior resection indicated for?
Anterior resection is ideal for high rectal tumours over 5cm from anus to leave rectal sphincter intact
What is a high resection?
High resection is removal of the sigmoid colon and the upper region of the rectum. The remaining descending colon is joined to the remaining rectum as an anastomosis, with the use of a circular stapler device.lymph nodes in the region are also removed. It is unlikely that a stoma will be needed, but if necessary, a temporary stoma called ileostomy will be made.
What is a low resection used for?
Low anterior resection is used to remove some or all of the sigmoid colon and part of the lower region of the rectum, typically via laparoscopic surgery and an anastomosis is made. Preparations include a low-fibre diet. There is a higher risk of anastomic leak, so a de functioning ileostomy is often used.
What is an ultra-low resection?
Ultra-low resection involves removing sigmoid Colon and all or up to the lower portion of the rectum, along with nearby lymph nodes and surrounding fatty tissue.
What is the risk associated with low and ultra-low anterior resection?
Risk of low anterior resection syndrome, characterized by fecal incontinence, tenesmus, diarrhea, and incomplete bowel movements.
What is a left hemicolectomy?
Removal of the descending colon, splenic flexure, and part of the sigmoid colon.
What does a left hemicoloectomy involve?
Ideal for descending colon tumours, with removal of the left branch of the middle colic vessels, inferior mesenteric vein and left colic vessels from inferior mesenteric artery and inferior mesenteric vein.
What is Hartmann’s procedure used for?
Hartmann’s procedure is used in emergency bowel surgery, such as bowel obstruction or perforation wit complete resection of the recto-sigmoid colon with the formation of an end colostomy and closure of rectal stump. Bowel obstruction can also be treated with a decompressing colostomy (stoma) or endoscopic stunting.
Name a complication of abdominoperineal resection.
- Bleeding
- Damage to local structures
- Resection of other organs
- Anaesthetic risk With teeth damage, nausea, vomiting an cardiovascular complications
What are early complications post-surgery?
- Pain
- Risk of wound infection
- UTI
- Scarring
- DVT
What does the reversal of stomas involve?
Dissecting around the stoma at the trephine site and rejoining to the colon by staples anastomosis or handsewing.
What is the recommended surgical approach for malignant obstruction in patients under 70?
Single stage operation including washout, resection, and primary anastomosis.
What is an ileus?
stasis of bowels which lasts 24 hours but may be longer. It may be necessary to drain the stomach contents until the bowel is resumed functioning. To avoid this, minimise contamination and bowel handling and correct electrolyte imbalances post-operatiely.
What is an anastomotic leak?
A leak from the anastomosis created during surgery, which can lead to peritonitis.
What is an incisional hernia?
Incisional hernia, where perforation of the bowel occurs due to an incompletely-healed surgical wound. Indications include coughing producing a bulge at the site of incision and there is increased risk of obstruction, strangulation of the bowe and incarceration, where the bowel conten becomes trapped in the opening which can result in adhesions forming.
To prevent this, ensure fascia is tightly closed with the small bites technique, by making incisions between 5-8mm and interval of 5mm. this technique improves wound healing and strength and reduces risk of infection.
What are adhesions?
Irregular bands of scar tissue that may form between abdominal tissues and organs. Imaging may show “fat-bridging sign” where cord forms connection across the periotneum. Treatment is adhesolysis.
What is acute diarrhea?
Diarrhea that lasts less than one week and typically self-resolves.
What is chronic diarrhea?
Diarrhea that lasts at least 4 weeks.
What causes lactose intolerance?
Decreased or absent lactase enzyme leading to malabsorption of lactose. Lactose is osmotically active, and it retains and attracts water, leading to watery diarrhea. Patients typically have symptoms of bloating and flatulence along with watery diarrhea.
What is the cause of fatty diarrhoea?
Fatty diarrhoea is typically caused by malabsorptive diseases like coeliac disease andd chronic pancreatitis and Symptoms often include upper abdominal pain, flatulence, and foul-smelling, bulky, pale stools due to malabsorption of fats.
What is the cause of secretory diarrhoea?
Secretory diarrhoea is caused by bacterial and viral infections, the watery stool results from injury to the gut epithelium. Epithelial cells line the intestinal tract and facilitate water absorption, electrolytes, and other solutes. Infectious etiologies cause damage to the epithelial cells, which leads to increased intestinal permeability. The damaged epithelial cells cannot absorb water from the intestinal lumen, leading to loose stool.
Which medications cause secretory diarrhoea?
Medications can cause secretory diarrhoea such as quinine, antibiotics, colchicine, calcitonin.
What is the cause of osmotic diarrhoea?
Osmotic diarrhoea occurs due to laxative use, carbohydrate malabsorption, coeliac disease or surgery alcohols.
What are common pathogens for diarrhea in daycare settings?
- Rotavirus
- Shigella
- Campylobacter
- Cryptosporidium
When is anti-diarrhoea medication contraindicated?
Anti-diarrhoea therapy is contraindicated with bloody diarrhoea or high fever because it may worsen severe intestinal infections .
What causes diarrhoea from dairy?
salmonella and campylobacter
What causes diarrhoea from meats?
clostridium perfirngens, campylobacter, aeromonas and salmonella
What causes diarrhoea from vegetables?
clostridium perfingens
How can rotavirus be tested?
Rotavirus is tested with enzyme immunoassay and agglutination of stool.
What does the stool pH under 5.5 indicate?
Carbohydrates in the stool due to viral illness.
What are the investigations for diarrhoea?
*Complete FBC to examine for infection and anaemia
*Erythrocytes sedimentation rate and C-reactive protei, thyroid function test, searching for electrolyte abnromalities, renal function and stool occult blood, protein and albumin.
*Stool assessment, especially for recent antibiotic use
*Faecal chymotrypsin and elastase are pancreatic enzymes, indicating pancreatic infsuficicney
What is the indication for endoscopy referral?
chronic diarrhoea onset after age 50
* Rectal bleeding/melena
* Nocturnal pain or diarrhea
* Progressive abdominal pain
* Unexplained weight loss, fever, or other systemic symptoms
* Laboratory abnormalities such as iron deficiency anemia, elevated ESR/CRP, elevated fecal calprotectin, or fecal occult blood
* First degree relative with inflammatory bowel disease or colorectal cancer
What is the treatment for Clostridium difficile infection?
Oral metronidazole or vancomycin.
What is the treatment of e.coli?
E.coli infection is treated wih combination of Trimethoprim-sulfamethoxazole (TMP-SMX). Parenteral second or third-generation cephalosporins are indicated for systemic complications.
What is the treatment of aeromonas infection?
cephalosporins like cefixime.
What is the treatment of C.diff?
oral metronidazole/vancomcyin
What is the treatment of entamoeba histolytica?
metronidazole
What is the first line therapy for chronic diarrhea?
Opioid agonists like loperamide. Alternatives include an alpha 2 agonist which slows the intestinal tract and anticholinergic medication.
What pathogens cause fever?
seen with invasive pathogens Salmonella, Shigella, and Campylobacter, enteric viruses or a cytotoxic organism such as Clostridioides difficile.
What are the clinical features of dehydration?
Clinical features of dehydration include increased pulse rate, reduced skin turgor, dryness of mucous membranes, delayed capillary refill time,decreased urine output, hypotension(check for postural changes), and altered mental status and oliguria/anuria.
How should gastroenteritis that is infective be managed?
They should avoid sharing towels, wash soiled clothing and bed linen separately at high temperature to avoid contamination and avoid work until 48 hours after the last episode of diarrhoea/vmiting
What is constipation?
Reduced frequency of defecation to twice weekly or less.
List the three clinical subtypes of constipation.
- Normal transit with hard stools
- Slow colonic transit
- Inco-ordination of rectum, anus, and pelvic floor That requires digitaton to empty
What drugs can cause constipation?
- Analgesics (opiates)
- Anticholinergics
- Antipsychotics
- Anti-parkinsonian drugs
What are red flag symptoms in diarrhea assessment?
- Blood in stool
- Weight loss
- Dehydration
- Nocturnal symptoms
What is the management for gastroenteritis in adults?
Emergency hospital admission for severe dehydration or suspected sepsis.
What is the role of stool assessment?
To evaluate for recent antibiotic use and assess for infections.
What is the typical symptom of IBS?
Bouts of bloating and abdominal pain, relieved by defecation.
What are the common causes of constipation?
- Low fiber diet / Poor dietary habits
- Lack of fluid intake
- Caffeine abuse
- Overuse of alcohol
- Medications (e.g., analgesics, anticholinergics)
- Sedentary lifestyle
- Endocrine disorders
- Neurologic disease
- Psychological issues Like sexual abuse
Includes conditions such as diabetes and hormonal imbalances that affect gut motility.
What congenital conditions are associated with constipation?
- Hirschprung’s disease
- Meningococele
These conditions can affect bowel function and lead to constipation.
What symptoms should be evaluated in a patient with constipation?
- Excessive straining
- Discomfort
- Incomplete sense of evacuation
- Blockage
- Pain or bleeding
- Associated abdominal pain or bloating
- Incontinence
These symptoms help to determine the severity and underlying issues related to constipation.
What is animus?
Animus may ocause constipation, which is the failure of the pelvic floor muscles to relax during defaecation when straining, which may be seen in victims of sexual abuse
What are the complications of constipation?
- Urinary retention
- Faecal incontinence
- Rectal prolapse
- Anal fistula
- Stercoral perforation
- Volvulus
These complications can arise from prolonged constipation and may require medical intervention.
What is a faecalith?
A stone made of faeces, typically found in the descending and sigmoid colon
Faecaliths can contribute to bowel obstruction and complications such as stercoral colitis.
What is faecal impaction?
Faecal impaction is a solid immobile bulk of faeces linked to neurogenic disorders. It commonly occurs in the elderly hospitalised or in care homes, with severe constipation and mental disorders requiring antipsychotic treatment.
This causes increased intraluminal pressure and commonly occurs in the sigmoid colon, with risk of perforation and compression of bladder causing urinary retention.
Treatment includes manual disimpaction with lubrication, abdominal x-ray with catheter. Combined with Docusate or sorbit
What are the investigations for colorectal cancer?
Upright chest Radiolohraphy to assess for megacolon and Colonic dilatation
Rectal biopsy and radiology for Hirschsprung’s disease
Anorectal manometry to evaluate function of rectal and anal muscles by inserting a catheter with pressure sensors into the anu
What is the first-line treatment for constipation?
Bulk forming laxative like Isphagala husk with adequate fluid intake. Avoid in Coli IC atony and intestinal obstruction. May cause bronchospasm.
This approach helps to increase stool bulk and promote regular bowel movements.
What is the second line treatment?
osmotic laxative like macrogol
-> alternative is lactulose
What is 3rd line for constipation?
stimulant laxative for stools that are soft but difficult to pass or sensation of inadequate emptying
What is Docusate?
Stool softener given for constipation which increases the water and lipid content for stools. Can lead to abdominal cramps and nausea.
What is the treatment of faecal loading?
Suppository for soft stool is bisacodyl or glycerol alone
For hard stool, bisacodyl and glycerol
What is the difference between suppository and enema?
Suppository is a small solid capsule; enema is liquid medication
What is the last treatment for faecal impact ion?
enema of sodium phosphorite or arachis (peanut) oil, which may need to be repeated several times
What diagnostic tests are used for constipation evaluation?
- Colonoscopy
- Flexible sigmoidoscopy
- FBC for faecal occult blood
- Upright chest radiography
- Rectal biopsy
- Anorectal manometry
These tests help to identify structural and functional abnormalities in the gastrointestinal tract.
What dietary sources are recommended for increasing fiber intake?
- Cereals
- Breads
- Fruits
- Vegetables
- Peanuts
Increasing fiber helps to bulk up stool and promote bowel regularity.
True or False: Opioid-induced constipation should only be treated with osmotic laxatives.
True
Stimulant laxatives may also be considered, but osmotic laxatives are preferred.
What is the role of biofeedback therapy in treating constipation?
To train and normalize pelvic floor function while visually assessing sphincter function
This therapy is beneficial for patients with pelvic floor dysfunction.
What is volvulus?
twisting of the intestine and mesentery, which compromises blood supply. It typically happens at the sigmoid colon due to a long mesentery. They will present with abdominal distention and absolute constipation and abdominal pain. Abdomen will be dissented and tympanic to percussion. Risk factors are older age, male, reduced mobility, neurological disorders like Parkinson’s and people on antipsychotics.
CT imaging showing a whir sign, where sigmoid colon and mesentery are twisted. Radiograph will show coffee-bean sign in left iliac fossa
What is the management approach for volvulus?
- Fluid resuscitation
- Sigmoid colectomy with Hartmann’s procedure
These interventions are necessary to address the twisting of the intestine and restore blood supply.
What is stercoral colitis?
inflammatory colitis when faecalith impaction causes colon distention and results in faecalith/faecaloma forming which compresses on colon wall and may cause colonic necrosis, distention and ischaemia. It commonly occurs i the sigmoid colon and rectum during chronic constipation because the rectosigmoid colon is the narrowest part of the colon and stool here has decreased water content it can cause diffuse compression of veins, decreased outward blood flow and intramural oedema.
What are the signs of stercoral colitis?
- Diffuse abdominal tenderness
- Distention
- Stool present in the rectum with small amounts passed
These signs indicate inflammation due to faecalith impaction.
Fill in the blank: The ideal laxative for proximal fecal impaction is _______.
polyethylene glycol
This osmotic laxative promotes water retention in stool.
What are the risk factors for developing volvulus?
- Older age
- Male gender
- Reduced mobility
- Neurological disorders
- Use of antipsychotics
These factors increase the likelihood of intestinal twisting.
What is the treatment for faecal impact ion?
endoscopically guided disimpaction
Surgical resection of affected bowel and formation of Hartmann’s pouch
Increase fluid and fibre intake
What is the recommended dietary change for managing chronic constipation?
Increase fluid and fiber intake
Long-term management focuses on lifestyle modifications to prevent recurrence.
What is the significance of a two-week bowel diary in constipation management?
To measure colon transit time and assess bowel habits
This can help identify patterns and guide treatment.
What is T4B?
Penetrating adjacent organs
What is N1A?
Inoves one regional node
What is N1b?
2 -3 regional node
N2a
4-6 lymph nodes
What is N2b
over 7 lymph nodes
What is negative node disease?
minimum of 12 negative lymph nodes
What is M1a?
distant metastases to one organ
What is M1b?
multiple organ metastases
What is m1c?
metastasis to periotneum
