under good illumination, noting any abnormality. Check for

fissures, particularly if the patient reports pain during the

procedure.

• Ask the patient to strain down as you slowly withdraw the

instrument to detect any degree of rectal prolapse and the

presence and severity of any haemorrhoids.

Proctoscopic examination of the anus and lower rectum can

confirm or exclude the presence of haemorrhoids, anal fissures

and rectal prolapse. Rectal mucosa looks like buccal mucosa,

apart from the presence of prominent submucosal veins. During

straining, haemorrhoids distend with blood and may prolapse. If

the degree of protrusion is more than 3–4 cm, a rectal prolapse

may be present.

Investigations

Selecting the relevant investigation depends on the clinical problem

revealed on history and examination. Investigations are costly

and many carry risks, so choose tests capable of distinguishing

the likely diagnoses and prioritise the most decisive ones (Box

6.17 and Figs 6.26–30).

to the median lobe. A hard, irregular or asymmetrical gland with

no palpable median groove suggests prostate cancer. Tenderness

accompanied by a change in the consistency of the gland may

be caused by prostatitis or prostatic abscess. The prostate is

abnormally small in hypogonadism.

Proctoscopy

Proctoscopy is visual examination of the anal canal; it is an invasive

procedure and should only be practised after appropriate training.

Always undertake digital rectal examination first. If examination

of the rectal mucosa is required, perform flexible sigmoidoscopy

rather than proctoscopy.

Examination sequence

• Place the patient in the left lateral position, as for digital

rectal examination.

• With gloved hands, separate the buttocks with the

forefinger and thumb of one hand. With your other hand,

gently insert a lubricated proctoscope with its obturator in

place into the anal canal and rectum in the direction of the

umbilicus.

A B

Fig. 6.25 Acute pancreatitis. A Bruising over the flanks (Grey Turner’s sign). B Bruising round the umbilicus (Cullen’s sign).

6.17 Investigations in gastrointestinal and hepatobiliary disease

Investigation Indication/comment

Clinical samples

Stool:

Faecal occult blood Gastrointestinal haemorrhage; sensitive but not specific; used as population screening tool

for colorectal cancer

Faecal calprotectin Inflammatory bowel disease – raised

Urine: dipstick or biochemistry Jaundice (see Box 6.7)

Acute abdominal pain

Ascitic fluid: diagnostic tap Clear/straw-coloured – normal

Uniformly blood-stained – malignancy

Turbid – infection

Chylous – lymphatic obstruction

High protein (exudate) – inflammation or malignancy

Low protein (transudate) – cirrhosis and portal hypertension

Continued

114 • The gastrointestinal system

6.17 Investigations in gastrointestinal and hepatobiliary disease—cont’d

Investigation Indication/comment

Radiology

Chest X-ray Suspected acute abdomen, suspected perforated viscus or subphrenic abscess

Pneumonia, free air beneath diaphragm, pleural effusion, elevated diaphragm

Abdominal X-ray Intestinal obstruction, perforation, renal colic

Fluid levels, air above liver, urinary tract stones

Barium meal Rarely indicated unless gastroscopy not possible and there is suspicion of pharyngeal or

gastric outlet obstruction on clinical symptoms (dysphagia or vomiting)

Oesophageal obstruction (endoscopy preferable, especially if previous gastric surgery)

Small bowel follow-through Subacute small bowel obstruction, duodenal diverticulosis

Small bowel magnetic resonance imaging or magnetic

resonance enteroclysis (real-time imaging of liquid

moving through the small bowel)

Crohn’s disease, lymphoma, obscure gastrointestinal bleeding

CT colonography Altered bowel habit, iron deficiency anaemia, rectal bleeding: alternative to colonoscopy in

the frail, sick patient, if colonoscopy is unsuccessful or if not acceptable to patient to

diagnose colon cancer, inflammatory bowel disease or diverticular disease; useful in colon

cancer screening

Abdominal ultrasound scan Biliary colic, jaundice, pancreatitis, malignancy

Gallstones, liver metastases, cholestasis, pancreatic calcification, subphrenic abscess

Abdominal CT Acute abdomen, suspected pancreatic or renal mass, tumour staging, abdominal aortic

aneurysm

Confirms or excludes metastatic disease and leaking from aortic aneurysm

MR cholangiopancreatography (MRCP) Obstructive jaundice, acute and chronic pancreatitis

Pelvic ultrasound scan Pelvic masses, inflammatory diseases, ectopic pregnancy, polycystic ovary syndrome

Pelvic structures and abnormalities

Ascitic fluid

Invasive procedures

Upper gastrointestinal endoscopy Dysphagia, dyspepsia, gastrointestinal bleeding, gastric ulcer, malabsorption

Gastric and/or duodenal biopsies are useful

Lower gastrointestinal endoscopy (colonoscopy) Rectal bleeding, obscure gastrointestinal bleeding, altered bowel habit, iron deficiency

anaemia

Able to biopsy lesions and remove polyps

Video capsule endoscopy Obscure gastrointestinal bleeding with bidirectional negative endoscopies, suspected small

bowel disease (vascular malformations, inflammatory bowel disease)

Endoscopic retrograde cholangiopancreatography (ERCP) Obstructive jaundice, acute and chronic pancreatitis

Mainly therapeutic role

Stenting strictures and removing stones

Endoscopic ultrasound ± fine-needle aspiration (FNA) or

Tru-Cut needle biopsy

Staging of upper gastrointestinal or pancreatobiliary cancer

Drainage of pancreatic pseudocysts

Laparoscopy Suspected appendicitis or perforated viscus, suspected ectopic pregnancy, chronic pelvic

pain (e.g. due to endometriosis or pelvic inflammatory disease), suspected ovarian disease

(e.g. ruptured ovarian cyst), peritoneal and liver disease

Ultrasound- or CT-guided aspiration cytology and biopsy Liver metastases, intra-abdominal or retroperitoneal tumours

Liver biopsy Parenchymal disease of liver

Tissue biopsy by percutaneous, transjugular or laparoscopic route

Others

Pancreatic function tests Stool elastase, pancreolauryl test

CT, computed tomography.

Investigations • 115

6

A

B

C

Fig. 6.26 Radiography in gastrointestinal disease. A Air under the

diaphragm on chest X-ray due to a perforated duodenal ulcer. B Dilated

small bowel due to acute intestinal obstruction. C Dilated loop of large

bowel due to sigmoid volvulus.

A

B

Fig. 6.27 Ultrasound scan of the gallbladder. A, Thick-walled

gallbladder containing gallstones. B, Posterior acoustic shadowing.

B

A

Fig. 6.28 Gastrointestinal endoscopy. A Gastric ulcer. B Gastric

varices.

116 • The gastrointestinal system

Fig. 6.29 Colonoscopy. Colon cancer.