colon and rectum Flashcards
what is the definition of constipation
2 or more of the following for at least 3 months
- infrequent passage of stool (<3 a week)
- straining >25% of time
- passage of hard stools in >25% defecations
- incomplete evacuation and sensation of anorectal blockage un >25% defecations
- manual manoeuvres to facilitate >25% defecations
what are the 3 categories of constipation
- normal transit through the colon
- defecatory disorders
- slow transit
what is megacolon
used to describe a number of congenital and acquired conditions in which the colon is dilated
when does megacolon present
first years of life
what gives rise to constipation in megacolon
A ganglionic segment of the rectum (megarectum) gives rise to constipation and subacute obstruction
what is faecal incontenance
incontenance is classified as minor (inability to control flatus or liquid stool, causing soiling) or major (frequent and inadvertent evacuation of stool of normal consistency)
aetiology for feacal incontenance
- congenital
- anal sphincter dysfunction
- rectal prolapse
- faecal impaction with overflow diarrhoea
- neurological and physcological disorders
what is initial management of faecal incontenance
Minor incontinence initial management is bowel habit regulation. Loperamide is the most potent antidiarrhoeal agent, which also increases sphincter tone
what is ischemic colitis
Ischemic colitis occurs when branches of the superior mesenteric artery or inferior mesenteric artery are occluded and there is reduced blood reaching the colon. Inflammation and injury of the large intestine result from inadequate blood supply.
what are clinical features of ischaemic colitis
- sudden onset of abdominal pain
- passage of bright red blood per rectum with or without diarrhoea
- may be signs of shock and evidence of underlying cardiovascular disease
what is seen on examination of a patient with Ischemic colitis
- the abdomen may be distended and tender
- thumb printing at the splenic flexure seen on Xray
- may have lactic acidosis
what investigations are carried out for patients with ischemic colitis
- urgent CT scan to exclude perforation
- unprepared flexible sigmoidoscopy
how to manage ischaemic colitis
- most patients settle on symptomatic treatment
- surgery is perforation
what are diverticula
Diverticula are small, bulging pouches that can form in the lining of your digestive system.
what does diverticulosis mean
indicates the presence of diverticula
what does diverticulitis mean
implies that these diverticula are inflamed
what does diverticular colitis mean
refers to crescentic inflammation on the fold in areas of diverticulosis
how are diverticular formed
there is thickening of the muscle layer and because of high intraluminal pressures, punches of mucosa extrude through the muscular through weakened areas near blood vessels to form diverticula.
when does diverticulitis occur
when faeces obstruct the neck of the diverticulum, causing stagnation and allowing bacteria to multiply and produce inflammation
what can diverticulitis lead to
- bowel perforation
- abscess formation
- fistulae into adjacent organs
what are clinical features and investigations of diverticular disease
- asymptomatic in 95% of cases
- discovered accidentally on colonoscopy or barium enema
- no treatment apart from increasing dietary fibre
- in symptomatic patients intermittent left iliac fossa pain or discomfort and an erratic bowel habit commonly occur
- colonoscopy and barium enema are investigations of choice
how do you manage diverticular disease
- well balanced fibre diet with smooth muscle relaxants if required
- Hartmans procedure if perforation
- surgery if fistula
- antibiotics and drainage if abscess
what is acute diverticulitis
when diverticula suddenly become inflamed
clinical features of acute diverticulitis
- severe pain in left iliac fossa
- fever
- constipation
- febrile
- tachycardia
what does an abdominal exam show for actor diverticulitis
- tenderness
- guarding
- rigidity
- palpable left tender mass sometimes felt in the left iliac fossa
(on the left side of abdomen)
what are investigation findings for acute diverticulitis
- blood tests often revel polymorphonuclear leucocytosis. The ESR and CRP are raised
- CT colonoscopy will show colonic wall thickening, diverticula and often pericolic collections and abscesses. There is usually a streaky increased density extending into the immediate periocolic fat with thickening of the pelvic fascial planes
- US examination can demonstrate a thickened bowel and large pericolic collections
how do you manage acute diverticulitis
- oral antibiotics eg ciprofloxacin and metronidazole
- bowel rest, IV fluids and IV antibiotic therapies
what are complications of diverticular disease
- perforation
- fistula
- intestinal obstruction
- bleeding
- mucosal inflammation
what is a colonic polyp
abnormal growth of tissue projecting from the colonic mucosa
they can be single/multiple, pedunculate, sessile or flat
what are the classifications of colorectal polyps
- hyperplastic
- hamartoma
- inflammatory
- lymphoid
- adenoma
what are sporadic adenoma
an adenoma is benign, dysplastic tumour of columnar cells or glandular tissue. They have tubular, tubulovillous or villous morphology.
The vast majority are not inherited = sporadic
what are signs and symptoms of right sided cancers
- unexplained iron deficiency anaemia
- persistant tiredness
- a persistant and unexplained change in bowel habit
- unexplained weight loss
- abdominal pain (colicky in nature)
- lump in the abdomen
what are signs and symptoms of left sided colorectal cancer
- rectal bleeding
- feeling of incomplete emptying
- worsening constipation
what investigations for colorectal cancer
- barium enema (widely abandoned)
- sigmoidoscopy vs colonoscopy
- CT colonography
what are sessile polyps
Sessile polyps grow flat on the tissue lining the organ. Sessile polyps can blend in with the lining of the organ, so they’re sometimes tricky to find and treat. Sessile polyps are considered precancerous. They’re typically removed during a colonoscopy or follow-up surgery.
what are predunculated polyps
Pedunculated polyps are easier to spot and can be removed in one piece. “The head is where the precancer would be, so by snaring the stalk, we know without a doubt that it’s gone,” he says.
how do colorectal cancers develop
as a result of progression from normal mucosa to adenoma to invasive cancer
These are controlled by critical growth regulating genes and these can be grouped into 3 pathways
- chromosomal instability
- CpG island methylator phenotype 3. microsatellite instability
what is the pathology of colorectal cancer
- usually takes the form of a polypoid mass with ulceration, spreads by direct infiltration through the bowel walls
- involves lymphatics and blood vessels with subsequent spread, most commonly to the liver and lung
what are symptoms of colorectal cancer
- change in bowel habit
- looser more frequent stools
- rectal bleeding
- tenesmus and symptoms of anaemia
what are investigations for colorectal cancer
- colonoscopy
- double contrast barium enema
- endoanal ultrasound and pelvic PRI
- chest, abdominal and pelvic CT
- PET scanning
- MRI
- serum carcinoembryonic antigen
- faecal occult blood test
how do you manage colorectal cancer
- total mesolectal excision - is required for rectal cancers and removes the entire package of mesolectal tissue surrounding it. A low rectal anastomoses is then carried out
- segmental resection - and restorative anastomoses, with removal of draining lymph nodes
- surgical or ablative treatment of liver and lung metastases
