Unexplained iron-deficiency anaemia

Understanding unexplained iron-deficiency anaemia

Why anaemia is a symptom, not a diagnosis

Iron-deficiency anaemia means the body lacks enough iron to make haemoglobin. The important question is never simply how low the count is, but why the iron is disappearing.

In pre-menopausal women, heavy periods and pregnancy explain most cases. In men and in women past the menopause, unexplained iron deficiency is assumed to be blood loss from the digestive tract until proven otherwise, because that is where it usually comes from.

Understanding unexplained iron-deficiency anaemia

How the gut bleeds without you seeing it

Bleeding heavy enough to see is obvious. What causes chronic iron deficiency is usually the opposite: a very slow, steady loss of a small amount of blood each day, from a source that never produces a visible change in the stool.

Over months, that quiet trickle empties the body's iron stores. The person feels tired, breathless on exertion, and looks pale, but has never once seen blood.

Understanding unexplained iron-deficiency anaemia

What we look for

Several conditions bleed slowly and silently, and they occur throughout the digestive tract:

• Colorectal cancer and large polyps, the most important to exclude
• Stomach or duodenal ulcers
• Gastritis and oesophagitis, particularly with long-term painkiller use
• Coeliac disease, which causes iron deficiency by poor absorption rather than bleeding
• Angiodysplasia, fragile abnormal blood vessels in the bowel wall
• Stomach cancer
• Inflammatory bowel disease

Understanding unexplained iron-deficiency anaemia

How it is investigated

Confirming true iron deficiency comes first, with a ferritin level and full iron studies, since not all anaemia is iron-related.

Because a source can be anywhere in the digestive tract, standard practice is to examine both ends: a gastroscopy and a colonoscopy, which may be arranged at the same visit when clinically appropriate. The team discusses the comfort plan for each examination; colonoscopy does not routinely involve sedation at Zendale. Coeliac testing is done at the same time, with small bowel biopsies at gastroscopy.

Where both examinations are normal and the anaemia persists, the small bowel between them is investigated, usually with a capsule endoscopy in which a swallowed camera photographs its length.

Understanding unexplained iron-deficiency anaemia

Treatment

Treatment has two parts, and doing only one is a common mistake. Iron replacement restores the blood count, usually with tablets taken over several months, and intravenous iron where tablets are not tolerated or absorption is poor.

The second part is treating whatever caused the loss. Iron alone, without finding the source, corrects the number while leaving the reason untouched. Anaemia that recurs after iron treatment is a particularly strong signal that the source has never been identified.