Colorectal Flashcards
What are the clinical features of Gardner syndrome?
- Form of FAP (familial adenomatous polyposis chromosome 5)
- Caused by APC gene mutation
- Autosomal Dominant (50% chance of passing onto offspring)
- Multiple colorectal polyps (benign & malignant)
- Soft tissue tumours: sebaceous cysts, Desmoid tumours, Fibromas
- Osteomas of mandible, supernumary teeth, osteomas of skull
- Adrenal masses
- Associated with papillary carcinoma of thyroid
- Early age colon cancer
- Congential hypertrophy of retinal pigment (@neonates)
- Mainly diagnosed on gene testing of APC
- 30-40 yrs life expectancy
What is the diagnosis of Gardner’s syndrome based on polyp count?
- > 100 colorectal polyps /
- - <100 colorectal polyps & immediate FH of FAP or gardner’s syndrome
Risk factors for CRC?
NON-MODIFIABLE
1) Age>40
2) FH
3) Genetic syndromes (FAP/HNPCC)
4) Prev history
5) Chronic IBD
MODIFIABLE
1) Exposure to pelvic irradiation
2) Dietary factors - alcohol, obesity, smoking
Main differences between Turcot & Gardners syndrome?
Turcot: Primary brain lesion with colonic polyps
(glioblastoma/medulloblastoma)
Either associated with FAP/HNPCC
Gardners: associated with FAP
No brain involvement??
What are the clinical features of Li-Fraumeni syndrome?
- Leukaemia
- Breast Cancer
- Sarcomas
- Soft tissue sarcomas
- Adrenocortical carcinoma
**SUSPECT ANYONE WITH SARCOMA <45YRS
Which type of polyp has the highest risk of developing into CRC?
Villous adenoma
How far deep can the proctoscope look into the anal canal?
5cm
How far deep can the rigid sigmoidoscope look into the anal canal?
15cm
What would the FBC show for a patient with CRC?
Hb/MCV: low - hypochromic, microcytic anaemia with low serum ferritin
What are the guidelines for CRC urgent referral?
- ANY RECTAL/ABDO MASS
>40 YRS - unexplained weight loss & abdo pain >50 YRS - unexplained rectal bleeding >60 YRS - iron-deficiency anaemia / - changes in their bowel habit / - tests show occult blood in their faeces
<50 YRS W/ RECTAL BLEEDING & UNEXPLAINED
- abdominal pain /
- change in bowel habit /
- weight loss /
- iron-deficiency anaemia
What are the most/least common positions of the appendix in relation to the cecum?
- *MOST COMMON**
1) Retrocecal (74%)
2) Pelvic (21%)
3) Paracecal (2%)
4) Subcecal (1.5%)
5) Pre ilial (1%)
6) Post ilial (0.5%) - *LEAST COMMON**
What is the diagnostic criteria for Lynch syndrome?
AMSTERDAM CRITERIA
- 3 relatives with an associated cancer
- Colon/endometrium/intestine/ureter/renal Ca
- 1 relative must be 1st-degree relative of other 2
- 2 successive generations involved
- 1 of the cancers diagnosed <50 YRS
- FAP must be excluded
- Tumours verifed on pathology exam
What is the mechanism of Hirschbrung’s disease?
Absence of ganglionic cells & dysfunction of autonomic nervous system in large bowel at:
1) Meissners (submucosal) plexus
2) Myenteric plexus - important in peristalsis
What are the indications for elective surgery in Crohn’s?
1) Fistula (with or without abscess)
2) Obstruction
3) Failed medical therapy
4) Malignancy
What are the indications for emergency surgery in Crohn’s?
1) Perforation
2) Haemorrhage
3) Toxic colitis / megacolon
