Colon and rectum Flashcards
which layer involved in colorectal polyp?
mucosal layer
appaearances of Colo polpys?
sessile, pedunculated, flat, depressed, elevated
types of colo polyp
neopastic
non neoplastic
Name of non neoplastic polyp
hamartoma
inflammatory
hyperplastic
name of neoplastic polyp
conventional adenoma
traditional serrated adenoma
sessile serrated
commonest type of colorectal polyp
found in where?
hyperplastic polyp
distal colon
subclassification of adenomas
tubular
villous
tubulovillous
features of adenomas
asymptomatic
bleeding
anaemia
diarrhoea
hypokalaemia
Mckittrick willock syndrome
large villous adenoma causing diarrhoea and hypokalaemia
investigation for colorec polyp
colonoscopy
sigmoidoscopy
Mx of colorec polyp
segmental colonic resection
submucosal resection
endoscopic submucosal dissection
third most common cancer in males
second most common cancer in females
which one?
Colorectal cancer
what are the factors important in colorec cancer?
sporadic=
genetic=
hereditary=
Factors are genetic and environmental
sporadic= 75%
genetic= 20%
hereditary= 5%
risk factors for malignant change in colonic polyps
large size >2cm
multiple polyps
serrated polyps( excluding small rectal hyperplastic polyps
villous architecture
high grade dysplasia
pathways of genetic involvement in colorectal cancer?
chromosomal instability
microsattelite instability
CIMP (CpG island methylated phenotype)
what are the two distinct pathways of carcinogenesis of colorectal cancer?
and there precursor lesions
the adenoma carcinoma pathway
serrated neoplasia pathway
precursor lesions: adenoma, serrated polyps
Risk factors for colorectal cancer?
genetic
diet
medical conditions
others
diet factor increased risk in colorectal cancer
red meat
saturated animal fat
diet factors decreased risk of CC
dietary fiber
fruits and vegetables
calcium
folic acid
omega 3 fatty acids
medical conditions causing risk of CC
colocrectal neoplastic polyps
long standing UC or Chrons colitis
uterosigmoidoscopy
acromegaly
pelvic radiopathy
other factors increase risk of CC
decrease risk
obesity
sedentary lifestyle
smoking
alchohol
cholecystectomy
t2 Dm
aspirin
nsaids
statins
gene involvement of colorectal carcinogenesis
early:
intermediate:
late adenoma:
carcinoma
early: APC
intermediate: KRAS
late adenoma: DCC, SMAD4
carcinoma: TP53
clinical features of left colon
and right colon
rectum CC
left colon: fresh rectal bleeding and obstruction early
right colon: anemia and altered bowel habit and obstruction (late)
rectum: early bleeding, mucus discharge or feeling of incomplete emptying
common features of colorectal cancer?
colicky abdominal pain
rectal bleeding
features of obstruction and perforations
complications of CC
obstruction
perforation
peritonitis
localised abscess
fistula
investigation of CC
colonoscopy: 1st choice
if not possible: CT colonography
after diagnosis of CC which inv?
why?
CT chest, abdomen and pelvis
or MRI
for staging
for follow up and checking recurrence which investigation should be done in CC?
CEA
which is the most important determinants of CC?
TNM staging at diagnosis.
mx of CC
endoscopy:
EMR, ESMD, EFTR
surgery
adjuvant therapy:
decrease the risk of recurrence
palliative treatment:
surgical resection for symptoms
palliative chemotherapy
prevention and screening
which is the cornerstone of rx for CC
surgery
what are the hereditary syndromes predisposing to colorec cancer
Non- polyposis
polyposis
familial adenomatous polyposis
peutz jeghers syndrome
juvenile polyposis
other name of HNPCC
lynch syndrome
what is the commonest hereditary cancer syndrome
HNPCC/lynch syndrome
HNPCC
mode of inheritance
which age groups involved
mean age for cancer development
Autosomal dominant
young age
45 years
name of the criteria for HNPCC?
what are the criterias?
Modified Amsterdam criteria
criteria:
FAP excluded
3 or more relatives with CC (atleast 1 1st degree relative)
CC in 2 or more generations
at-least 1 members before 50 years of age
after criteria of HNPCC what should be done?
pedigree assessment
genetic testing
colonoscopy
prevention of HNPCC
colonoscopy every 2 years
aspirin for reduce CC risk
✳️what are the GIT polyposis syndromes?
Neoplastic
-FAP
-PJS
non neoplastic
-juvenile
-cronkhite canada
-cowden syndrome
mode of inheritance of FAP
mutation of which gene?
type of mutation and resulting protein name?
what does this protein do?
Autosomal dominant
germline mutation of tumour suppressor APC gene
loss of function mutation resulting truncated APC protein
bind and sequester B- catenin
what is the second gene that is involved in FAP?
disease name with this?
MUTYH
MAP
FAP+CNS tumours (astrocytoma, medulloblastoma)
Congenital hypertrophy of the retinal pigment epithelium? associated with?
FAP in mesentery or abdominal wall, name?
Turcot syndrome
FAP
Desmoid tumours
Extra intestinal features of FAP
5⭐️
CHRPE= 70-80%
Epidermoid cyst (extremities, face and scalp)= 50%
Benign osteomas esp, skull and angle of mandibles= 50-90%
Dental abnormalities= 15-25%
Desmoid tumors= 10-15%
other malignancies (brain, thyroid, liver adenoma)= 1-3%
5⭐️
Epidermoid cyst
benign osteoma
dental abnormalities
which syndrome?
Gardner syndrome
colorectal cancer+ bleeding+ extra intestinal features
colonic polyps
FAP
pigmentation+bleeding+ intusucception+ bowel and other cancers
small bowel polyps
PJS
hair loss+ pigmentation+ nail dystrophy+ malabsorption
gastric polyps and colorectal polyps
Cronkhite canada syndrome
many congenital anomalies+ oral and cutaneous hamartomas+ thyroid+ breast tumuors
gastric polyps
Cowden disease
investigation for FAP
sigmoidoscopy
genetic testing if diagnosed
genetic testing to all 1st degree relatives
Rx for FAP
total proctocolectomy with ileal pouch anal anastomosis
Multiple hamartomatous polyps in small intestine and colon + melanin pigmentation of the lips, mouth and digits
other features?
PJS
anaemia, bleeding, intusuception
mode of inheritance
gene mutation in pjs?? 🌟🌟
Autosomal dominant
serine-threonine kinase gene on chromosome 19p (STK11)
investigation for PJS
genetic testing
upper gi endoscopy
colonoscopy
small bowel and pancreatic imaging
Diverticulosis site??
Sigmoid
Descending colon
Common age group for diverticulosis
Middle age group
name the laxatives class
bulk forming: ishapgula husk, methylcellulose
stimulants: Bisacodyl, denton, decusate, senna
faecal softeners: docusate, arachis oil enema
osmotic laxatives: lactulose, lacitol, magnesium sulphate
serotogenic agents: prucalopride
prosecretory agents: linaclotide, lubipristone, plecanatide
others: polyethylene glycol, phosphate enema
melanosis coli
specific mucosa finding?
rx
long term consumption of stimulants laxatives leads to accumulation of liposfuscin pigment in macrophages of lamina propria
tiger skin
stop laxatives
complication of melanosis coli
and their barium enema finding
megacolon or cathartic colon
featureless mucosa, loss of haustra, shortening of the bowel.
✳️
hirschprung’s disease
cause
Constipation and colonic dilatation
congenital absence of ganglion cells in the large intestine
✳️Hirschprung disease mode of inheritance
affecting genes
type of mutation
autosomal dominant
RET- proto oncogene
loss of function mutation
pathogenesis of hirschprung disease
rectal finding during DRE
ganglion cell are absent from nerve plexuses, most commonly in a short segment of the rectum and/or sigmoid colon causing internal anal sphincter fails to relax
rectum is empty
✳️investigation for hirschprung disease
findings
plain abdominal xray
barium enema
full thickness biopsy
anorectal manometry
a small rectum and colonic dilatation above the narrowed segments
to confirm the absence of ganglion cell
failure to internal sphincter to relax with balloon dilatation
✳️Rx of hirchprung disease
resection of the affected segments
causes of acute colonic pseudo obstruction
trauma, burn,
recent surgery
drugs: opiates and phenothiazines
respiratory failure
electrolytes and acid base disorders (hypokalaemia, hypomagnesesimea)
DM- automic dysfunction
uraemia
what is haemorrhoids
cause
degrees of piles
S/S
treatment
congestion of internal and external anal sphincters
unknown, constipation, straining, first time in pregnancy
1st degree: bleed
2nd degree: prolapse but retract spontaneously
3rd degree: manual replacement after prolapse
bright red rectal bleed +pain+ pruritus ani+ mucus discharge+ thrombosis which is very painful
Band ligation, haemorroidectomy, HALO
causes of pruritus ani??
piles, fistula, fissures, poor hygiene
threadworms, candidiasis
contact dermatitis, psoriasis, LP
Diarrhoea or any incontinence, IBS, anxiety
anal fissure
S/S
✳️Rx
traumatic and ischemic damage to the anal mucosa causing superficial mucosal tear and spasm of the anal sphincters
severe pain on defecation+ minor bleeding+ mucus discharge+ pruritus+ oedematous skin tag or sentinel pile
bulk forming laxatives
plenty of water intake
NO and 0.2% gtn: relax sphincter, alt: diltiazem cream
inj botulinum toxin: resistant case
surgery: lateral int anal sphincterectomy
or advanced anoplasty
causes of faecal incontinece
obstetric trauma
severe diarrhoea
faecal impaction
cong anorectal anomaly
anorectal disease
neurological disease
