Thyrotoxicosis is often accompanied by secretory diarrhoea or

steatorrhoea and weight loss.

Low-volume diarrhoea is associated with irritable bowel

syndrome. Abdominal pain, bloating, dyspepsia and non-alimentary

symptoms commonly accompany irritable bowel symptoms.

Criteria have been developed to define irritable bowel syndrome

more precisely, taking account of the duration of symptoms, the

presence of abdominal pain and its relationship to defecation,

and the frequency and consistency of stools (see Rome IV criteria

for irritable bowel syndrome).

Constipation

Clarify what the patient means by constipation. Use the Bristol

stool form scale (Fig. 6.7) to describe the stools. Constipation

is the infrequent passage of hard stools.

Ask about:

• onset: lifelong or of recent onset

• stool frequency: how often the patient moves their bowels

each week and how much time is spent straining at stool

• shape of the stool: for example, pellet-like

• associated symptoms, such as abdominal pain, anal pain

on defecation or rectal bleeding

• drugs that may cause constipation.

Constipation may be due to lack of dietary fibre, impaired

colonic motility, mechanical intestinal obstruction, impaired

rectal sensation or anorectal dysfunction impairing the process

of defecation. Constipation is common in irritable bowel syndrome.

Other important causes include colorectal cancer, hypothyroidism,

Formerly Reader in Medicine at the University of Bristol.

Fig. 6.7 Bristol stool form scale. Reproduced with kind permission of

Dr KW Heaton, formerly Reader in Medicine at the University of Bristol.

©2000, Norgine group of companies.

The history • 101

6

colorectal cancer or colonic polyps, inflammatory bowel disease,

ischaemic colitis and colonic angioectasias.

Jaundice

Jaundice is a yellowish discoloration of the skin, sclerae (Fig. 6.8)

and mucous membranes caused by hyperbilirubinaemia (Box 6.6).

There is no absolute level at which jaundice is clinically detected

but, in good light, most clinicians will recognise jaundice when

bilirubin levels exceed 50 µmol/L (2.92 mg/dL).

Ask about:

• associated symptoms: abdominal pain, fever, weight loss,

itching

• colour of stools (normal or pale) and urine (normal or dark)

• alcohol intake

• travel history and immunisations

• use of illicit or intravenous drugs

• sexual history

• previous blood transfusions

• recently prescribed drugs.

Unconjugated bilirubin is insoluble and binds to plasma albumin;

it is therefore not filtered by the renal glomeruli. In jaundice from

unconjugated hyperbilirubinaemia, the urine is a normal colour

(acholuric jaundice; Box 6.7).

Bilirubin is conjugated to form bilirubin diglucuronide in the

liver and excreted in bile, producing its characteristic green

colour. In conjugated hyperbilirubinaemia, the urine is dark brown

due to the presence of bilirubin diglucuronide. In the colon,

conjugated bilirubin is metabolised by bacteria to stercobilinogen

and stercobilin, which contribute to the brown colour of stool.

Stercobilinogen is absorbed from the bowel and excreted in the

urine as urobilinogen, a colourless, water-soluble compound.

Melaena

Melaena is the passage of tarry, shiny black stools with a

characteristic odour and results from upper gastrointestinal

bleeding. Distinguish this from the matt black stools associated

with oral iron or bismuth therapy.

Peptic ulceration (gastric or duodenal) is the most common

cause of upper gastrointestinal bleeding and can manifest with

melaena, haematemesis or both. Excessive alcohol ingestion

may cause haematemesis from erosive gastritis, Mallory–Weiss

tear or bleeding oesophagogastric varices in cirrhotic patients.

Oesophageal or gastric cancer and gastric angioectasias (Dieulafoy

lesion) are rare causes of upper gastrointestinal bleeding.

The Rockall and Blatchford scores are used to assess the

risk in gastrointestinal bleeding (Box 6.5). A profound upper

gastrointestinal bleed may lead to the passage of purple stool

or, rarely, fresh blood.