The digestive system Flashcards
What is the caecum?
The start of the large intestine
What is the hepatic flexure?
The angle, edge where the ascending colon then becomes the transverse.
What is the splenic flexure?
The angle, edge where the transverse colon becomes the descending colon.
Biliary tree
What happens here?
What path does the bile take?
The biliary tree conducts bile and pancreatic digestive enzymes to the duodenum.
The gross anatomy of the biliary tree begins with the right and left hepatic ducts that drain bile from the two halves of the liver. These become the common hepatic duct that is joined by the cystic duct from the gallbladder.
The union of the common hepatic and cystic ducts form the common bile duct. The common bile duct is about 7.5 cm long. It passes posterior and often through the pancreas to join the main pancreatic duct.
The union of the main pancreatic duct and common bile duct form a short ampula called the hepatopancreatic ampula (a.k.a. ampula of Vater). The ampula inserts on the major duodenal papilla.
Function of the spleen?
Similar in structure to a large lymph node, it acts primarily as a blood filter.
Spleen plays important roles in regard to red blood cells and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron.
It metabolizes haemoglobin removed from erythrocytes. The globin portion of haemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin which is removed in the liver.
IR(ME)R 2017 rules, how does it apply in placement?
For making enquiries of females of childbearing age to establish whether the individual might be pregnant.
Check local policy
Age range ~11-55
Check local protocol
Ask the patient the date of the start their last period
Record it and get the patient the sign to confirm
You may now proceed
Patients outside 28 day rule, what happens?
- Justification of the examination should be assessed by referring practitioner
- Pregnancy test
- Reschedule examination after period
- Consider performing another investigation not involving radiation
- If the practitioner authorizes the exposure to go ahead they must sign the form
Plain film abdo pros and cons?
Reducing role
Advantages
Cheap (compared to CT/Fluoro)
Non invasive- Low Risk
Reasonable assessment of acute abdominal pain in the hospital setting, if correctly requested!
Disadvantages
Limited yield
Limited sensitivity and specificity
Gastrografin
What is it and how is it used
Gastrografin
Oral contrast administered in the cases of adhesional bowel obstruction/ileus
Effective tool for demonstrating whether surgical intervention is necessary or not
Adhesional obstruction – due to previous surgery – preventing more surgery = good thing
If there is passage of contrast through to the right colon in 24hrs – the obstruction does not require surg. Intervention
Gastrografin acts as both a gentle laxative and anti-inflammatory
How do we image the Biliary system?
Endoscopic Retrograde Cholangio Pancreatography (ERCP)
Patient usually Prone/oblique
Endoscope passed through mouth>oesophagus>Stomach>Duodenum
Once at ampulla of vatar, guidewire passed into biliary tree
Able to perform a cholangiogram, remove/break up stones and insert stent
Pooled Sens. For Gallstones 83%
Pooled Spec. for GS 99% (NICE 2018)
Fluoroscopy Abdo pros and cons
Advantages
Relatively cheap
Relatively non invasive (compared to surgery)
Dynamic
Disadvantages
Less sensitive than CT
Poorly tolerated by patients
(Note slide)
Endoscopy uses a small thin tube with contains a camera to enable us to look inside the human body
Flexible Sigmoidoscopy = to look inside the rectum and the lower part of the bowel (sigmoid colon). Biopsies can be taken at this point should any abnormalities be seen.
Colonoscopy = to look at the lining of the whole large bowel. Biopsies can be taken and simple polyps can also be removed during this procedure.
Colon capsule endoscopy = this involves the patient swallowing a capsule, which then takes thousands of pictures as it travels through the bowel, these pictures are send to a digital recording stored in a bag that you wear during the procedure. Usually takes a day or two. The images are later examined by a specialist known as a colonoscopist, they will decide if further investigations are required or any treatment. This is being offered on the NHS however it is still in its pilot stages.
Virtual Colonoscopy, CT colonoscopy- A CT examination that produces images of the inside of the large intestine to look for pathology, such as cancer and polyps.
Endoscopy uses a small thin tube with contains a camera to enable us to look inside the human body
Flexible Sigmoidoscopy = to look inside the rectum and the lower part of the bowel (sigmoid colon). Biopsies can be taken at this point should any abnormalities be seen.
Colonoscopy = to look at the lining of the whole large bowel. Biopsies can be taken and simple polyps can also be removed during this procedure.
Colon capsule endoscopy = this involves the patient swallowing a capsule, which then takes thousands of pictures as it travels through the bowel, these pictures are send to a digital recording stored in a bag that you wear during the procedure. Usually takes a day or two. The images are later examined by a specialist known as a colonoscopist, they will decide if further investigations are required or any treatment. This is being offered on the NHS however it is still in its pilot stages.
Virtual Colonoscopy, CT colonoscopy- A CT examination that produces images of the inside of the large intestine to look for pathology, such as cancer and polyps.
How is VC done?
CT colonography (CTC) = Virtual colonography
Patient receives full bowel preparation plus one dose of oral contrast 12 hours before
Rectal catheter, CO2 insufflation of bowel
Prone and supine acquisition on scanner
Good global overview of intrabdominal pathology
Very reliable for detecting small colonic tumours and ‘significant’ polyps as the colon is preped and distended
Can ‘fly through’ colon similar to standard colonoscopy
WHEN MIGHT WE DO A VIRTUAL COLONOSCOPY?
Can be used as a screening or a diagnostic tool
Look for polyps or cancer of the large intestine
Clinical Indications;
Known history of polyps
Family history of colon cancer
Persistent change in bowel habits
Blood in stool
Abdominal pain
Feeling of being bloated
Unexplained weight loss
PATIENT PREPARATION for VC
Day prior to scan;
Patient takes a laxative, e.g. Gastrografin (undiluted), before breakfast (c. 8am)
A second dose of laxative should be taken at c. 4pm
Patient should follow a low-residue diet (soft foods, low in fibre – white/clear foods) and drink plenty of fluids to remain hydrated
Evening before, patient should fast from c. 9pm until after scan
Day of scan;
Patient is changed into a gown
Consent obtained, CT safety checks done
Cannula inserted into arm for contrast examination
