Colin Dale Flashcards
What is a double contrast barium enema?
Uses positive contrast such as barium and negative contrast such as air/CO2
Used to visualise mucosal irregularities such as polyps
3 CIs for double contrast barium enema
Toxic megacolon
Pseudomembranous colitis
Imminent rectal biopsy within 7 days of procedure or within 7 says after rectal biopsy.
NICE guidelines for referral of suspected CRC
Refer adults using the suspected cancer pathway referral (2 week wait) for colorectal cancer if:
- Aged 40 or over with unexplained weight loss and abdominal pain or
- Aged 50 and over with unexplained rectal bleeding or
- They are over 60 with iron deficiency anaemia or changes in bowel habits
- Tests show occult blood (can’t see it with the naked eye) in their faeces
- Any patient with a rectal or abdominal mass
Px of CRC- general, right sided, left sided
General: change in bowel habit, rectal bleeding, weight loss, abdominal pain, iron deficiency anaemia.
Right sided colon cancers- abdominal pain, occult bleeding, anaemia, mass in RIF, often present late.
Left sided colon cancers- rectal bleeding, change in bowel habit, tenesmus (cramping rectal pain), mass in LIF or on PR exam.
screening for CRC
screening every 2 years to people 60-75y/o- faecal immunochemistry test uses antibodies against human haemoglobin to detect blood in faeces.
Any positive tests get referred to specialist nurse for further investigation via colonoscopy
One off colonoscopy for 55y/o
Ix for CRC
Lab tests: FBC (microcyctic anaemia), LFTs, clotting, CEA- not diagnostic but is good for monitoring disease progression and as screening for recurrence.
Imaging- gold standard is colonoscopy with biopsy. If not suitable can use flexible sigmoidoscopy or CT colonography.
Once diagnosed- CT chest/abdo/pelvis, a full colonoscopy of CT colongram is required to check for a 2nd tumour if not used initially, MRI rectum to assess death of invasion and need for pre-operative chemo, endo-anal ultrasound for early rectal cancers (T1 or 2) to assess for trans-anal resection.
5 risk factors for CRC
family Hx increasing age smoking high alcohol intake low fibre diet
what is CEA and is it still used?
o Cardioembryonic antigen test
o Used to monitor progress during treatment but not as a diagnostic test due to the sensitivity and specificity.
o Marker for various cancers: rectal, lung, breast, liver, pancreatic, stomach an ovarian cancer.
o Can also be raised in non-cancerous conditions such as liver disease and inflammatory bowel disease e.g. Crohn’s and ulcerative colitis.
o Low sensitivity and specificity
Benzodiazepine MOA
increase the activity of GABA, producing the sedative effect, relaxes the muscles, induces sleep, anaesthesia and amnesia. Bind to the benzodiazepine site on GABA-A receptors which increases the frequency of Cl- opening, thus increasing firing of these neurons.
Cautions for benzos
avoid prolonged use due to withdrawal, elderly, history of alcohol dependence or abuse, MG, personality disorder as it may increase the risk of addiction, respiratory disease.
CI for benzos
risk of fatal respiratory depression when taken with opioids, CNS depression, compromised airway, severe respiratory depression.
6 cancers that might occur in the large bowel
o Squamous cell tumours
o Carcinoid tumours- slow growing neuroendocrine tumour, growing in hormone producing tissue
o Sarcomas- cancer of the muscle tissue- leiomyocarcinomas (start in SM cells)
o Lymphomas
o Adenocarcinoma- mucinous and cygnet ring
o Melanoma of the anus- retrograde spread
6 systemic factors affecting wound healing
o Age and Sex
o Nutrition
o Vitamin and trace element deficiencies - vitamin C, vitamin A, zinc
o Drugs – steroids, chemotherapy, immunosuppression
o Systemic disease – diabetes, jaundice, malignancy
o Hypoxia
5 local factors affecting wound healing
o Infection o Foreign bodies o Surgical techniques o Blood supply o Tension
MOA for 5FU
inhibition of the formation of thymidylate from uracil, which leads to the inhibition of DNA and RNA synthesis and cell death. Fluorouracil can also be incorporated into RNA in place of uridine triphosphate (UTP), producing a fraudulent RNA and interfering with RNA processing and protein synthesis.
