Gastronintestinal Investigations Flashcards
What do erect CXR show and what causes this
AIr under the diaphragm - perforation
What can be seen in an AXR
Dilated bowel loops and fluid level = obstruction or ileus
Calcification - chronic pancreatitis or gallstones (rare)
What percentage of gallstones are radio-opaque
10%
What is used as a radio-opaque contrast
Insoluble salt such as barium sulphate
What indicates for a contrast swallow
Dysphagia (upper endoscopy may be too dangerous due to pharyngeal pouch)
Suspected dysmotility
Size of hiatus hernia
What are the limitations of barium swallow
Does not show as good image as endoscopy or allow biopsy
aspiration is a risk
What are the indications for a contrast meal
Epigastric pain with normal upper GI endoscopy
Vomiting with normal upper GI endoscopy
Suspected perforation
Waht are the limitations of a contrast meal
Poor at detecting early cancer
Upper GI endoscopy shows better mucosal detail and allows for biopsy
What are the indications for a contrast follow-through
Crohn’s disease
Diarrhoea or abdominal pain with normal endoscopy and histology
Suspected small bowel obstruction
What are the limitations of a contrast follow through
Ionising radiation exposure
Expertise dependent
What are the indications for a contrast enema
Altered bowel habit
Suspected diverticulosis where colonoscopy may be dangerous or difficult
Suspected megacolon
What are the limitations of a contrast enema
Uncomfortable for the patient
Does not visualise rectal mucosa well
Ionising radiation exposure
poor mucosal definition and cannot biopsy lesions compared to colonoscopy
What are the indications for an ultrasound
Abdominal masses, tumour abscess cyst Organomegaly Jaundice Gallstones Biliary tract dilatation Ascites Guided procedures
What are the limitations of ultrasound
Low sesnitivity for lesions
poor views if obstructed or obese
expertise dependent
poor for imaging retroperitoneal structures
What helps muscosal definition in CT scanning
Oral contrast
What helps show vascular lesions in CT scanning
IV contrast
What are the indications for a CT scan
Tumour staging Crohn's disease pancreatic disease bile duct stones hepatic tumour staging guided procedures CT colonography
What are the limitations of CT scanning
Ionising radiation exposure
May under-stage tumours
Expertise dependent
What are the indications for MRI scanning
Tumour staging Crohn's disease Suspected neuroendocrine tumours Suspected chronic pancreatitis Hepatic tumour staging MR cholangiopancreatography (MRCP)
What are the limitations of MRI scanning
Expertise dependent
Claustrophobia for some patients
time consuming
not feasible if metal prostheses in situ
What are the indications for mesenteric angiography
GI haemorrhage with normal upper and lower GI endoscopy
Recurrent iron deficiency
Suspected arterio-venous malformation
Suspected mesenteric ischaemia
What are the limitations of mesenteric angiography
Contrast induced nephropathy
Requires sufficiently brisk bleeding to document source
What does a video-endoscope enable
Passage of flexible instruments into the upper and lower extremes of the gut
How is Upper GI endoscopy performed
Under sedation with IV benzodiazapine or local anaesthetic throat spray
When should upper GI be avoided
If perforation is suspected
What are the indications for Upper GI endoscopy
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
What are the complications of endoscopy
Perforation
Over-sedation resulting in respiratory depression
Aspiration pneumonia
What is examined during a flexible sigmoidoscopy
The left colon and rectum
Is sedation given for a flexible sigmoidoscopy
No
What are the indications for a flexible sigmoidoscopy
Fresh rectal bleeding
Quantify activity in known UC patient
What are the complications of Flexible sigmoidoscopy
Perforation and haemorrhage
When is a colonoscopy performed
After a full bowel perparation and with conscious sedation
What is examined during a colonoscopy
The whole colon
What are the indications for a colonoscopy
Altered bowel habit rectal bleeding iron - deficiency anaemia suspected IBD Follow up of abnormal barium enema Colorectal cancer screening Polypectomy Dilatation or stent insertion
What are the complications fo a colonoscopy
Incomplete examination - depending on expertise
Perforation
Haemorrhage
Cariorespiratory depression if over-sedated
Infective endocarditis
What are the indications for an endoscopic ultrasound
Staging of cancers of oesophagus, rectum and pancreas
Drainage of pancreatic pseudocysts
Lymph node biopsy
Assessment of anal sphincters in faecal incontinence
What can be used to visualise the distal small bowel
Disposable video-capsule
What are the indications for a video-capsule enteroscopy
Obscure GI bleeding
Recurrent anaemia
What are the limitations of video capsule enteroscopy
Caution required if structures are suspected as the capsule can cause an obstruction
Expensive
What are the limitations of video capsule enteroscopy
Caution required if structures are suspected as the capsule can cause an obstruction
Expensive
How is lactose intolerance diagnosed
The lactose hydrogen breath test
What is the medical term for lactose intolerance
Hypolactasia
What is used to diagnose small intestine bacterial overgrowth
Glucose Hydrogen breath test
