Investigation of Gastrointestinal Disease

Question 1

What are the 4 categories of causes of dysphagia?

Answer 1

• Intrinsic lesion - e.g. benign/malignant stricture, foreign body
• Neuromuscular disorders - e.g. myasthenia gravis
• Motility disorders - e.g. scleroderma, diabetes mellitus
• Extrinsic pressure - e.g. goitre, enlarged LA in mitral valve disease

Question 2

What is heartburn?

What is the pain usually difficult to distinguish from?

Answer 2

Heartburn is a retrosternal burning discomfort which spreads up towards the throat and is a common symptom of acid reflux

The pain can be difficult to distinguish from the pain of ischaemic heart disease (a careful history can usually tell them apart)

Question 3

What is meant by dyspepsia as a symptom?

Answer 3

Dyspepsia describes a range of symptoms referable to the upper GI tract

e.g. nausea, heartburn, acidity, pain or distension

Patients are more likely to use the term “indigestion” for these symptoms

Question 4

What conditions tend to cause dyspepsia (“indigestion”)?

Answer 4

• the most common cause is functional (non-ulcer) dyspepsia
• peptic ulcers
• gastro-oesophageal reflux disease
• gastro-oesophageal cancers

Question 5

What is meant by flatulence?

Answer 5

excessive wind, presenting as belching, abdominal distension and the passage of flatus per rectum

Question 6

Why does vomiting occur?

What happens in the brain?

Answer 6

Vomiting occurs as a result of stimulation of the vomiting centres in the lateral reticular formation of the medulla

This may result from stimulation of the chemoreceptor trigger zones in the floor of the fourth ventricle, or from vagal afferents from the gut

Question 7

What are the non-gastrointestinal causes of vomiting?

Answer 7

• CNS disease - e.g. raised intracranial pressure, migraine
• drugs (especially chemotherapeutic agents)
• metabolic conditions - e.g. uraemia, diabetic ketoacidosis
• pregnancy

Question 8

How is constipation defined?

Answer 8

it is hard to define due to individual variation, but it usually taken to mean infrequent passage of stool (< twice weekly) or the difficult passage of hard stools

Question 9

How is diarrhoea defined?

Why do patients often think they have diarrhoea even when they don’t?

Answer 9

Diarrhoea implies the passage of increased amounts of loose stool (stool weight >200g / 24h)

This must be differentiated from the frequent passage of small amounts of stool, which patients will often describe as diarrhoea

Question 10

What is steatorrhoea?

What GI conditions is it linked to?

Answer 10

the passage of pale, bulky stools that contain fat ( >18mmol / 24h )

the stools are often difficult to flush away and they float due to increased air content

it indicates fat malabsorption as a result of small bowel, pancreatic or biliary disease

Question 11

What is the main way of investigating GI disease?

What must be gained from the patient?

Answer 11

endoscopic investigation of the GI tract

it is usually performed as an outpatient procedure and requires explanation to the patient and written informed consent

Question 12

What happens in an oesophagogastroduodenoscopy?

What sedation may be used?

Answer 12

a flexible endoscope is passed by mouth into the oesophagus, stomach and duodenum following the administration of local anaesthetic spray to the pharynx

light sedation with intravenous midazolam may also be used

Question 13

What should patients be advised to do before an oesophagogastroduodenoscopy?

Answer 13

Patients should fast for 6 hours prior to the procedure and be warned not to drive for 24 hours afterwards if sedation is given

Question 14

What types of conditions are diagnosed using oesophagogastroduodenoscopy?

What therapeutic options does this procedure have?

Answer 14

It is used for the investigation of dyspepsia, dysphagia, weight loss and iron deficiency anaemia

duodenal biopsies can be obtained to diagnose coeliac disease

therapeutic options include arresting upper GI bleeding, oesophageal dilatation of peptic strictures and stent insertion for palliation of oesophageal malignancy

Question 15

How is sigmoidoscopy performed?

What does the patient need to take before this procedure?

Answer 15

it can be performed with a rigid instrument to examine the rectum and distal sigmoid colon

or a flexible instrument to allow for examination of the left colon

bowel preparation is achieved with one or two phosphate enemas and sedation is rarely required

Question 16

What is a colonoscopy?

What does the patient have to do beforehand and what are they not advised to do afterwards?

Answer 16

this is endoscopic examination of the entire colon and terminal ileum

full bowel preparation on the day before the examination is acheived with oral sodium picosulfate or polyethylene glycol

sedation is usually required so patients should be warned not to drive for 24 hours afterwards

Question 17

What is colonoscopy used to investigate?

What are the therapeutic options with this procedure?

Answer 17

it is used for the investigation of patients with altered bowel habit, rectal bleeding, abdominal pain or a strong family history of bowel cancer

therapeutic options include removal of polyps (polypectomy) or diathermy of bleeding lesions such as angiodysplasia

Question 18

What are the complications of colonoscopy?

Answer 18

bowel perforation and bleeding following polypectomy are uncommon complications

Question 19

What might be seen on a plain chest / abdominal X-ray when used in investigation of the acute abdomen?

Answer 19

• free gas with a perforated viscus
• dilated loops of bowel with intestinal obstruction
• colonic dilatation in a patient with toxic megacolon (in UC)
• faecal loading in constipation

Question 20

How can chronic pancreatitis be seen on an abdominal X-ray?

Answer 20

calcification in the pancreas (just to the left of L1) indicates chronic pancreatitis

Question 21

What are the different types of barium examination?

Answer 21

Ingestion of barium followed by X-rays allows examination of:

• the oesophagus - barium swallow
• the stomach & duodenum - barium meal
• the small intestine - barium follow-through
• colon - barium enema

for examination of the colon, barium and air are inserted per rectum and the patient is rotated until barium reaches the caecum

Question 22

When are CT scans used to investigate GI disease?

Answer 22

in the staging of intra-abdominal malignancy and investigation/assessment of the acute abdomen

it is mainly used where conventional colonoscopy cannot be performed due to patient intolerance or technical difficulties

Question 23

What preparation is needed before a patient undergoes a CT scan for their abdomen?

Answer 23

full bowel preparation with oral sodium picosulfate or polyethylene glycol (as with colonoscopy) and air distension of the colon

Question 24

When does transabdominal ultrasound tend to be used in GI investigations?

Answer 24

it is useful for the visualisation of the liver, gallbladder, biliary tree and kidneys

it is used for investigations of abnormal LFTs, hepatomegaly and for characterising abdominal masses

Question 25

When is high-resolution transabdominal ultrasound used?

Answer 25

• in the diagnosis of suspected appendicitis or diverticulitis
• to identify associated complications, such as perforation and abscess formation
• to detect bowel wall thickening and to determine the extent of involved segments in Crohn’s disease (but it is not disease specific)

Question 26

What is endoscopic ultrasound?

When does it tend to be used?

Answer 26

an endoscope with an ultrasound probe at its tip that allows more accurate visualisation of the walls of the upper & lower GI tract and nearby organs such as the pancreas and gallbladder

it is used for tumour and nodal staging of oesophageal, gastric or pancreatic cancer and for non-invasive imaging of the biliary tree

Question 27

When is endoanal ultrasonography used?

Answer 27

this involves the passage of a transducer into the rectum

it is used to assess the anal sphincters, particularly in patients with faecal incontinence

Question 28

When is MRI used in GI investigations?

Answer 28

it is typically used to image the pelvis

• in the assessment of patients with perianal Crohn’s disease
• in the staging of rectal cancer

Question 29

In which groups of patients is MRI contraindicated?

Answer 29

• patients with pacemakers
• patients with prosthetic heart valves
• patients with intraorbital metallic foreign bodies

this is because MRI may cause movement of a ferromagnetic object within the body

Question 30

When is PET scanning used in the investigation of GI disease?

Answer 30

it is used with other imaging modalities to investigate suspected malignancy and for the detection of metastases in known malignancy

Question 31

What is involved in oesophageal pH monitoring?

Answer 31

a pH probe is inserted into the lower oesophagus via the nose

this allows continual monitoring of acid reflux over 24 hours

data are captured on a small device worn on a belt and transferred to a computer to calculate the frequency and duration of reflux episodes

Question 32

When is oesophageal pH monitoring used?

Answer 32

to confirm GORD prior to surgery or in difficult diagnostic cases

Question 33

What is involved in oesophageal manometry?

Answer 33

it involves the passage of a small tube containing several pressure transducers into the oesophagus via the nose

the patient is asked to swallow, allowing oesophageal peristalsis and pressure to be assessed

Question 34

When is oesophageal manometry used?

Answer 34

it is used in patients with dysphagia to establish a diagnosis of suspected achalasia or oesophageal spasm

or for detecting oesophageal motor abnormalities in patients with systemic disease e.g. systemic sclerosis