Bowel Scenario Flashcards
What is the pathophysiology of the large bowel?
Large intestine consists of:
Vermiform appendix
Caecum
Ascending, transverse and descending sigmoid colon.
Most nutrients already absorbed by small intestine.
What is the main function of the large bowel?
Remove remaining water and solidify the material into faeces.
Contains bacteria to aid digestion.
Colon intermittently contracts pushing waste material into the rectum.
What is the function of the rectum and anus?
Defecation takes place, excreting waste products.
Occurs under neurological voluntary control in adults.
What are the 4 major functions of the large bowel?
Reabsorption of water and mineral ions such as sodium and chloride.
Formation and temporary storage of faeces.
Maintaining a resident population of over 500 species of bacteria.
Bacterial fermentation of indigestible materials.
What is bacterial fermentation in the large bowel?
the bacteria that inhabit the large intestine can further digest some material creating gas.
Bacteria also make some important substances such as Vitamin K (important role in blood clotting).
What are the clinical features of bowel cancer?
Anaemia Change in bowel habit Rectal blood loss General malaise Anorexia/weight loss Colicky pain Bowel obstruction
What is chemotherapy?
Chemotherapeutic drugs target rapidly dividing cells and cause cell death in 2 ways:
- interfering with the cell’s genetic information
-disrupting the normal process of cell division
The drugs can be used singularly or in combination (most common).
Usually given in cycles with a rest period in between.
What is radiotherapy?
Ionised particles (electrons, protons and gamma rays) are used to attack cancer cells and damage their DNA. Given via external beam to a targeted point, occasionally placed inside tumour (brachytherapy). Usually given daily for up to 7 weeks.
What are the side effects of radiotherapy?
Skin reactions: usually in 2nd/3rd week of treatment, local to site of radiotherapy, skin very vulnerable.
Pruritus (itch): caused by decreased production of sweat and sebaceous glands, excessive drying causes itching.
Erythema: inflammatory rection in epidermis.
Alopecia
Dry + moist desquamation(peeling of skin)
What are the investigations and screening for bowel cancer?
Digital rectal exam and abdominal examination. Colonoscopy Sigmoidoscopy depending on surgeon's choice. May have barium enema to show tumours. CT scan and ultrasound of liver Stool specimen and FOB/FIT test. Staging of cancer. FBC.
What is an FOB and/or FIT test?
FIT test now used in Scotland.
One sample of poo collected to be checked.
FOB test detects tiny amounts of hidden blood in poo (occult blood).
Bowel cancers/polyps sometimes bleed but there can be other causes.
If blood is detected by FOB/FIT then further testing will be offered, usually a colonoscopy.
What is a colonoscopy?
A thin, flexible tube (colonoscope) is inserted into the rectum to examine the lining of the bowel.
Small camera on the end of the tube is used to take pictures and samples may be collected.
Requires bowel preparation to clear the bowel, given in the form of laxatives and a specific diet the day before.
How is cancer staged?
TMN staging
T(Tumour) staging is the size of the primary tumour.
N(Nodes) describes presence of lymph node involvement.
M(Metastasis) describes presence/or lack of metastasis.
What is combined chemotherapy and radiotherapy used for?
Preparation for surgery.
Agressive cancer management.
Symptom control in palliative care.
How does chemotherapy affect normal cells and what areas are affected?
Chemotherapeutic drugs attack rapidly replicating cells which means normal cells are also at risk of damage.
Areas affected include: Bone marrow Digestive system Hair and nails Reproductive system Peripheral nervous system