GI + Colorectal 2 Flashcards
What are diverticula
Diverticula are small, bulging pouches that can form in the lining of your digestive system
Occur due to hypertrophy of the muscle propria, with diverticula then occurring at sites of potential weakness in the bowel wall (entry points of blood vessels)
This creates a ‘true’ diverticulum of just mucosa, without the muscular covering (as opposed to Meckel’s)
What is diverticulosis?
The presence of diverticula
What is diverticulitis?
The inflammation of diverticula
What is diverticular disease?
Symptomatic diverticula
Where are diverticula commonly found?
In the sigmoid, with 95% of the complications arising at this site
What are the causes of diverticula?
Low fibre diet (hard stools and thus higher pressure needed to move them)
Rarer associations: Marfans, Ehler’s Danlos syndrome and PKD
What are the clinical features of diverticular disease?
Mimic carcinoma of the colon:
Left sided colic, relieved by defecation
Altered bowel habit - including blood and mucus passage
Nausea
Flatulence
Severe pain and constipation if severe (causing lumina narrowing)
What investigations should be done for diverticular disease?
PR - may reveal pelvic abscess or colorectal cancer - main ddx
Sigmoidoscopy / Colonoscopy
Barium enema
CT
what is the management of diverticular disease?
Mebeverine = 1st kline medical management
What are the clinical features of Diverticulitis (infection)
Infection due to stagnation of the contents of teh diverticula
Severe left sided colic
Constipation (or overflow diarrhoea)
Symptoms mimicking appendicitis but on the left
What are the signs of diverticulitis?
Fever + tachycardia
Tenderness, guarding and rigidity on the left hand side
Can be a palpable mass in the LIF
Raised WCC and inflammatory markers
What is the management of diverticulitis?
Mild Attacks - low grade fever:
Bowel rest (fluids only) at home
Oral co-amoxiclav +/- metronidazole
Severe attacks (complicated - high grade fever)
Admit if pain cannot be controlled, or oral fluids not tolerated
Give analgesia, IV fluids, IV cefuroxime and metronidazole and keep NBM
Order erect CXR, AXR and contrast CT to assess for complications
DO not scope in acute attack
What complications can arise from diverticulitis?
Perforation Bleeding Stricutre Abscess Fistula
What does perforation lead to following diverticulitis?
Formation of paracolic or pelvic abscess, fistulae or generalised peritonitis
Presents with ileus +/- shock
Mortality = up to 40%
Management is with laparotomy +/- Hartman’s procedure
What is the presentation and management of abscess formation following diverticular disease?
Swinging fever, leucocytosis and localising signs (e.g. a boggy rectal mass)
Should be drained under CT guidance
How does bleeding following diverticular disease present?
Sudden, painless bleeding and also chronic occult loss, as a result of erosion of vessels at the fundus of the diverticulum
Large volumes can be lost, requiring transfusion
These often stop with bed rest
If they do not stop, locate the bleeding point via angiography (or colonoscopy) and then treat with embolisation (surgery rare)
Adrenaline injections and diathermy may negate the need for surgery
What kind of fistulas can form following diverticular disease?
Colovesical - leading to UTI and pneumaturia
Colovaginal - leading to foul discharge
Where does intestinal obstruction most commonly occur following diverticular disease?
Most commonly in the sigmoid after repeated episodes of diverticulitis
Chronic inflammation leads to scarring and the formation of a diverticular mass, which causes obstruction and may mimic colonic carcinoma
What is the management of asymptomatic diverticula of the colon?
Dietary advice is required for asymptomatic diverticulae
Increase unprocessed food intake and dietary fibre intake as part of a balanced diet (>20g/day of insoluble fibre)
What is the management in patients with uncomplicated by symptomatic diverticula disease?
Mebeverine first line
If there is very severe or recurrent diverticulitis, surgery may be considered
Rarely resorted to, complication rates are high
What are the indications for surgery in diverticular disease?
Small confined pericolonic abscess rarely require surgery
Any generalised peritonitis will require surgery
Emergency colonic resection required in massive haemorrhage / perforation
What are the risk factors of colorectal carcinoma?
Family history (+FAP/HNPCC) Age Western diet - low in fibre, high in fats - exercise, obesity UC (Chron's if it is in the colon) Smoking
POLYPS
What are the protective factors against colorectal carcinoma?
Fruit and vegetables / fibre consumption
Exercise
HRT
Aspirin / NSAIDs
Which gene is related to colorectal cancer?
Hereditary non-polyposis colorectal cancer (HNPCC) is responsible for <5% = arises from germline mutations in mismatch repair genes
Familial adenomatous polyposis (FAP) is responsible for <1% cancers, and occurs due to tumour suppressor gene APC mutations
Describe the morphology of colorectal cancer
Mostly adenocarcinoma with characteristic ‘signet ring’ cells on histology
What % of colorectal cancers occur in which section?
Caecum and ascending colon: 15% Transverse colon: 10% Descending colon: 5% Sigmoid colon: 25% Rectum 45%
What is the initial appearance of colorectal cancer? How does it invade?
Usually appear as a polypod mass with ulceration, spreading initially by direct infiltration through the bowel wall
Then involves the lymphatics and blood vessels, metastasising primarily to the liver
Transcoelemic spread can also occur
How is cancer staged?
TNM
Used to be dukes
A - tumours invade submucosa +/- muscularis propria (confined to lining of bowel)
B - tumours invade past the muscularis propria (into subserosa/directly into other organ, no nodal involvement) (through wall of bowel
C - Regional lymph node involvement
D - distant mets
Describe the stages of TNM staging
T = tumour (TX - cannot be evaluated)
T1: the tumour is in the submucosa
T2: tumour has grown into muscularis propria
T3: Tumour in subserosa
T4: The tumour has grown into the surface of the visceral peritoneum - all layers
N = nodes
N1a there are tumour cells in 1 regional node N1b (2-3)
N2a: tumour cells in 4-6 LN
2b: 7+ regional LN
M0 = no mets
M1a: one other part of body
1b: more than 1 other part of the body
1c: cancer spread to peritoneal surface
Describe the grading of tumours in colorectal cancer
GX: cannot be identified
G1: the cells are more like healthy cells (well differentiated)
G2: the cells are somewhat like healthy cells - moderately differentiated
G3: the cells look less like healthy cells (poorly differentiated)
G4: The cells barely look like healthy cells (undifferentiated)
What kind of cancers are Anal cancers?
Mainly SCC
What are the risk factors for anal cancer?
Anoreceptive sex
Syphilis infection
Anal warts/cervical caner - HPV
immunosuppression
What is the pectinate line?
An embryological division between the upper 2/3 and the lower 1/3 of the anal canal
Describe the epithelium above the pectinate line
Columnar epithelium, lymph drainage to internal iliac nodes and portal venous drainage, thus hepatic metastasis
Describe the epithelium below the pectinate line
Squamous epithelium, lymph drainage to the superficial inguinal nodes, and caval venous drainage, thus pulmonary metastases
More common in men, better prognosis
What are the presentation of a colorectal tumour?
Abdominal mass, abdominal pain, haemorrhage, perforation or fistula
How do right sided tumours tend to present? (CAECUM)
Often asymptomatic and may present with IDA/weight loss
Anaemia Obstruction (ileocaecal: SBO - bilious/faeculant) Mass dyspepsia, pain - colicky Appendicitis
How do left sided tumours tend to present? (RECTAL)
PR blood/mucus, altered bowel habit tenesmus obstruction - large bowel Pain - lower bladder sx ?
mass on PR examination
What is the presentation of anal tumours?
bleeding, pain, changes in bowel habit, pruritus ani, masses or stricture
What are the indications for 2ww referral in patients >40
Rectal bleeding or change in bowel habit for >6w
Persistent rectal bleeding, in those over 45, with no obvious evidence of benign anal disease
IDA Hb <10g/dl without an obvious cause
Palpable abdominal / PR mass
What Ix are done for patients with suspected colorectal carcinoma?
FBC (microcytic anaemia), LFTs (metastatic indicator) FIT
Colonoscopy (gold standard, as allows biopsy (polypectomy)
non-contrastCT chest, abdo, pelvis (staging)
Carcino-embryonic antigen (CEA) can be used to monitor disease
MRI (rectal cancer)
?Chest mets: CT CAP
Double contrast: barium and air - cancer appears like an apple core
Describe the surgical procedures for colorectal cancer?
Wide resection of the growth and regional lymphatics Right hemicolectomy left hemicolectomy sigmoid colectomy anterior resection abdomino-perineal resection Hartmann's procedure - resection of rectosigmoid colon with closure of the anorectal stump and formation of an end colostomy Endoscopic stenting
What are the indications for a right hemicolectomy?
For caecal, ascending and proximal transverse colon tumours
may be temporary end ileostomy prior to ileo-colic anastomoses
What are the indications for a a left hemicolectomy?
For distal transverse or descending colon tumours
may be temporary end colostomy prior to coli-colic anastomoses
What are the indications for a sigmoid colectomy
high anterior resection
for sigmoid tumours
What are the indications for an anterior resection?
For low sigmoid/high rectal tumours
colorectal anstamosis achieved at first operation, although this may be covered by a temporary loop ileostomy
What are the indications for an andomino-perineal resection
for tumours low in the rectum
permanent colostomy with removal of rectum and anus
no anastomosis
What are the indications for a Hartmann’s procedure?
For bowel obstruction or palliation
Resection of recto-sigmoid colon, with temporary end colostomy and closure of the rectal stump
What is the indication for endoscopic stenting?
Palliative
