Gastronintestinal Investigations

Question 1

What do erect CXR show and what causes this

Answer 1

AIr under the diaphragm - perforation

Question 2

What can be seen in an AXR

Answer 2

Dilated bowel loops and fluid level = obstruction or ileus

Calcification - chronic pancreatitis or gallstones (rare)

Question 3

What percentage of gallstones are radio-opaque

Answer 3

10%

Question 4

What is used as a radio-opaque contrast

Answer 4

Insoluble salt such as barium sulphate

Question 5

What indicates for a contrast swallow

Answer 5

Dysphagia (upper endoscopy may be too dangerous due to pharyngeal pouch)
Suspected dysmotility
Size of hiatus hernia

Question 6

What are the limitations of barium swallow

Answer 6

Does not show as good image as endoscopy or allow biopsy

aspiration is a risk

Question 7

What are the indications for a contrast meal

Answer 7

Epigastric pain with normal upper GI endoscopy
Vomiting with normal upper GI endoscopy
Suspected perforation

Question 8

Waht are the limitations of a contrast meal

Answer 8

Poor at detecting early cancer

Upper GI endoscopy shows better mucosal detail and allows for biopsy

Question 9

What are the indications for a contrast follow-through

Answer 9

Crohn’s disease
Diarrhoea or abdominal pain with normal endoscopy and histology
Suspected small bowel obstruction

Question 10

What are the limitations of a contrast follow through

Answer 10

Ionising radiation exposure

Expertise dependent

Question 11

What are the indications for a contrast enema

Answer 11

Altered bowel habit
Suspected diverticulosis where colonoscopy may be dangerous or difficult
Suspected megacolon

Question 12

What are the limitations of a contrast enema

Answer 12

Uncomfortable for the patient
Does not visualise rectal mucosa well
Ionising radiation exposure
poor mucosal definition and cannot biopsy lesions compared to colonoscopy

Question 13

What are the indications for an ultrasound

Answer 13

Abdominal masses, tumour abscess cyst 
Organomegaly
Jaundice
Gallstones
Biliary tract dilatation
Ascites
Guided procedures

Question 14

What are the limitations of ultrasound

Answer 14

Low sesnitivity for lesions
poor views if obstructed or obese
expertise dependent
poor for imaging retroperitoneal structures

Question 15

What helps muscosal definition in CT scanning

Answer 15

Oral contrast

Question 16

What helps show vascular lesions in CT scanning

Answer 16

IV contrast

Question 17

What are the indications for a CT scan

Answer 17

Tumour staging
Crohn's disease 
pancreatic disease 
bile duct stones hepatic tumour staging
guided procedures 
CT colonography

Question 18

What are the limitations of CT scanning

Answer 18

Ionising radiation exposure
May under-stage tumours
Expertise dependent

Question 19

What are the indications for MRI scanning

Answer 19

Tumour staging
Crohn's disease
Suspected neuroendocrine tumours
Suspected chronic pancreatitis
Hepatic tumour staging 
MR cholangiopancreatography (MRCP)

Question 20

What are the limitations of MRI scanning

Answer 20

Expertise dependent
Claustrophobia for some patients
time consuming
not feasible if metal prostheses in situ

Question 21

What are the indications for mesenteric angiography

Answer 21

GI haemorrhage with normal upper and lower GI endoscopy
Recurrent iron deficiency
Suspected arterio-venous malformation
Suspected mesenteric ischaemia

Question 22

What are the limitations of mesenteric angiography

Answer 22

Contrast induced nephropathy

Requires sufficiently brisk bleeding to document source

Question 23

What does a video-endoscope enable

Answer 23

Passage of flexible instruments into the upper and lower extremes of the gut

Question 24

How is Upper GI endoscopy performed

Answer 24

Under sedation with IV benzodiazapine or local anaesthetic throat spray

Question 25

When should upper GI be avoided

Answer 25

If perforation is suspected

Question 26

What are the indications for Upper GI endoscopy

Answer 26

``` Abdominal pain Haematemesis or melaena Dysphagia Weight loss Iron-defieciency anaemia vomiting gastric ulcer follow up balloon enteroscopy Dilatation of stricture Insertion of stenet to palliate strictures Placement of PEG tube Edoscopic treatment of oesophageal varices ```

Question 27

What are the complications of endoscopy

Answer 27

Perforation Over-sedation resulting in respiratory depression Aspiration pneumonia

Question 28

What is examined during a flexible sigmoidoscopy

Answer 28

The left colon and rectum

Question 29

Is sedation given for a flexible sigmoidoscopy

Answer 29

No

Question 30

What are the indications for a flexible sigmoidoscopy

Answer 30

Fresh rectal bleeding | Quantify activity in known UC patient

Question 31

What are the complications of Flexible sigmoidoscopy

Answer 31

Perforation and haemorrhage

Question 32

When is a colonoscopy performed

Answer 32

After a full bowel perparation and with conscious sedation

Question 33

What is examined during a colonoscopy

Answer 33

The whole colon

Question 34

What are the indications for a colonoscopy

Answer 34

``` Altered bowel habit rectal bleeding iron - deficiency anaemia suspected IBD Follow up of abnormal barium enema Colorectal cancer screening Polypectomy Dilatation or stent insertion ```

Question 35

What are the complications fo a colonoscopy

Answer 35

Incomplete examination - depending on expertise Perforation Haemorrhage Cariorespiratory depression if over-sedated Infective endocarditis

Question 36

What are the indications for an endoscopic ultrasound

Answer 36

Staging of cancers of oesophagus, rectum and pancreas Drainage of pancreatic pseudocysts Lymph node biopsy Assessment of anal sphincters in faecal incontinence

Question 37

What can be used to visualise the distal small bowel

Answer 37

Disposable video-capsule

Question 38

What are the indications for a video-capsule enteroscopy

Answer 38

Obscure GI bleeding | Recurrent anaemia

Question 39

What are the limitations of video capsule enteroscopy

Answer 39

Caution required if structures are suspected as the capsule can cause an obstruction Expensive

Question 40

What are the limitations of video capsule enteroscopy

Answer 40

Caution required if structures are suspected as the capsule can cause an obstruction Expensive

Question 41

How is lactose intolerance diagnosed

Answer 41

The lactose hydrogen breath test

Question 42

What is the medical term for lactose intolerance

Answer 42

Hypolactasia

Question 43

What is used to diagnose small intestine bacterial overgrowth

Answer 43

Glucose Hydrogen breath test