Session 9: Group Work Flashcards
What is the most likely type of cancer to be found in the colon?
Adenocarcinoma
State four risk factors for developing large bowel cancer.
Obesity
Alcohol
High red meat intake
IBD
FAP
Why do distal colon cancers present with rectal bleeding more frequently than lesions in more proximal locations?
Higher up the blood will be digested and the stool will present as malaena.
Higher up it will also be more disguised in the faeces.
State five other common causes of rectal bleeding not related to colon cancer.
Diverticulitis
Ulcerative colitis
Haemorrhoids
Crohn’s
Anal fissure
In contrast to this patient, briefly describe how an upper GI cancer that was bleeding into the lumen might affect a patient’s stool colour/consistency.
Malaena which is very black and tarry stool.
Describe two reasons why a cancer in the sigmoid colon is more likely to result in bowel obstruction than one in the ascending colon.
Left will have more dense stool.
Left sided cancer tends to be annular and stenosing leading to a narrower lumen.
Further tests are used to determine the extent of the tumour. The stage is given as T3N2M1.
Explain what this means.
T3 - size (big)
N2 - Metastasised to lymph nodes (4-6)
M1 - Distant metastases from blood
A CT scan has revealed liver metastasis.
If the primary cancer had metastasised via venous route, name the major veins the cancer would have to move through to arrive in the liver from the sigmoid colon.
The sigmoid colon is drained by the inferior mesenteric vein.
IMV -> Splenic vein -> portal vein -> liver
A 34 year old mand presents to his GP after noticing that there was occasionally right red blood on the toilet paper after passig stool. This was painless and not associated with any other symptoms. He is subsequently diagnosed with haemorrhoids.
Based on the history the location of the haemorrhoids could be determined as lying above the pectinate line.
What is the pectinate line?
A shift between columnar epithelium to stratified squamous that divides upper 2/3 and lower 1/3 of the rectum.
It is the junction of the hindgut and the proctodaeum (ectoderm)
What in the history suggests the haemorrhoids lie above the pectinate line?
Explain.
Painless and no other symptoms.
This is because there is no somatic innervation above the pectinate line and the sensation that is felt is stretch.
Haemorrhoidal tissues are a normal part of the human ano-rectal region.
What is their function?
Faecal continence
Prevents water from passing through the anal canal.
Protects muco from hard stool by cushioning.
Are haemorrhoids the same as anorectal varices?
Explain
Anorectal varices are due to portal hypertension
Haemorrhoids are dilation of the venous plexus around the anorectal canal (anal cushions)
An 85 year old woman is admitted to hospital with lower left abdominal pain. She has previously had episodes of diverticulitis.
What are diverticula and where do they commonly develop?
Outpouchings of mucosa and submucosa through the muscularis layers of the large intestines.
This is most commonly found in the sigmoid colon (85%) and due to increased intraluminal pressure.
Briefly explain how diverticulitis develops.
Diverticulitis means inflammation of the diverticula and is symptomatic.
It is generally due to a faecolith that gets stuch and blocks the entrance to the diverticula. Inflammation ensues and bacteria can invade.
This can lead to perforation.
Describe the common clinical features of a patient presenting with diverticulitis.
Abdo pain
Fever
Bloating
Haematochezia
Constipation
