Iron-Deficiency Anaemia — When It Points to a GI Source
TL;DR — Iron-deficiency anaemia (IDA) is the most common preventable cause of anaemia worldwide. In adult men, post-menopausal women, and many pre-menopausal women, IDA can be the first — and only — sign of a slowly bleeding gastrointestinal lesion, including bowel cancer. The standard investigation is bidirectional endoscopy (gastroscopy + colonoscopy under one sedation) plus coeliac serology. If both scopes are normal, the small bowel is examined with capsule endoscopy (PillCam). Dr Goutham performs the complete pathway across Brisbane, Redland and Logan.
Patient PDF available: Iron-Deficiency Anaemia — GI Work-Up Pathway 2026.
What is iron-deficiency anaemia?
Iron deficiency happens when iron intake or absorption fails to keep up with iron loss. The body produces fewer red blood cells, and the cells it does produce are smaller and paler than normal (a microcytic, hypochromic anaemia on the blood film). Confirmed iron deficiency requires a low ferritin (the iron-storage protein) or a low transferrin saturation in the absence of other causes.
Why “just take an iron tablet” is not the right answer
Iron tablets do correct the anaemia — but they do nothing about the cause. If the cause is a slow-bleeding bowel cancer, angiodysplasia or coeliac disease, the lesion continues to cause harm. The first task in IDA is to find and stop the source — then replace the iron.
Symptoms
- Fatigue, reduced exercise tolerance, breathlessness on exertion
- Pallor, especially of the conjunctivae and tongue
- Brittle nails, hair thinning
- Cold hands and feet
- Restless legs, particularly at night
- Pica (craving for ice or non-food items) — uncommon but specific
- Glossitis or angular cheilitis
- In severe cases: chest pain, palpitations, syncope
Many patients have no symptoms and the deficiency is found incidentally on routine blood testing.
Causes
- GI blood loss — bowel cancer, large polyps, angiodysplasia, gastric or duodenal ulcer, oesophagitis, hookworm (uncommon in AU), Meckel’s diverticulum
- Malabsorption — coeliac disease (around 5–6% of IDA patients), inflammatory bowel disease, prior gastric surgery, H. pylori
- Menstrual blood loss — common in pre-menopausal women; the most likely explanation when no other cause is found
- Inadequate intake — restrictive diets, vegan/vegetarian diets without iron-rich plant foods, infants on cow’s milk
- Increased requirements — pregnancy, growth spurts in adolescents
Who needs a GI work-up?
Current Australian and international guidelines recommend GI investigation in the following groups, even without GI symptoms:
- All adult men with iron-deficiency anaemia
- All post-menopausal women with iron-deficiency anaemia
- Pre-menopausal women with IDA that is severe, unresponsive to iron, recurrent, or accompanied by any GI symptom or family history of bowel cancer / coeliac
- Anyone with IDA plus rectal bleeding, weight loss, change in bowel habit, abdominal pain
How is the GI work-up done?
The standard pathway is bidirectional endoscopy under single sedation — gastroscopy plus colonoscopy on the same day. Coeliac serology is checked beforehand where possible; if not, duodenal biopsies at gastroscopy can establish the diagnosis.
| Test | What it looks for |
|---|---|
| Coeliac serology (tTG-IgA, total IgA) | Coeliac disease — the most common reversible cause |
| Gastroscopy + duodenal biopsies | Peptic ulcer, oesophagitis, gastritis, H. pylori, coeliac disease, occult upper GI cancer |
| Colonoscopy | Bowel polyps, cancer, IBD, angiodysplasia of the colon |
If both scopes are normal — which happens in about 25–30% of cases — capsule endoscopy (PillCam) is the standard next step. You swallow a vitamin-sized capsule that photographs the small bowel as it passes through. The capsule is single-use; you don’t feel it; you wear a recorder belt for 8–10 hours; the capsule passes naturally. PillCam identifies a source — typically angiodysplasia, a small-bowel polyp, or Crohn’s disease — in around half of cases that reach this step.
How is iron-deficiency anaemia treated?
Iron replacement is usually started in parallel with the work-up — you do not need to wait for scopes to be done.
- Oral iron (Ferro-grad C, Ferro-tab, Maltofer) — 1 tablet daily or every second day. Take with vitamin C; avoid taking with tea / coffee / dairy.
- Every-second-day dosing is often better tolerated than daily and just as effective.
- IV iron (Ferinject, Monofer) — faster, useful when oral iron is not tolerated, not absorbed, or when haemoglobin needs to come up quickly.
- Continue iron for at least 3–6 months after the haemoglobin normalises — to refill iron stores (ferritin), not just blood.
When to see a specialist
- Confirmed iron-deficiency anaemia in an adult man
- Confirmed iron-deficiency anaemia in a post-menopausal woman
- Iron deficiency in a pre-menopausal woman that is severe, recurrent, or unresponsive to oral iron
- Iron deficiency plus any GI symptom (bleeding, change in bowel habit, weight loss)
- Iron deficiency plus a family history of bowel cancer or coeliac disease
What to expect at your appointment with Dr Goutham
Dr Goutham will review your blood results, GI symptoms, family history and current iron replacement. Most patients are booked for bidirectional endoscopy under one sedation — this means a single fasting period, single bowel prep (for the colonoscopy component), and one recovery. The procedure takes 30–50 minutes; total time at the facility is 3–4 hours. Findings are explained on the day; pathology and surveillance recommendations follow in 7–14 days. If capsule endoscopy is needed, it is scheduled separately as a 30-minute appointment to swallow the capsule and fit the recorder belt.
Frequently asked questions
My ferritin is low but my haemoglobin is normal — does that count?
Yes. Low ferritin without anaemia is iron deficiency without anaemia — a precursor stage. It still warrants investigation in the same risk groups (adult men, post-menopausal women), particularly if unexplained or unresponsive to oral iron.
I’m vegan — can dietary iron deficiency alone explain it?
Diet can contribute, but should not be assumed to be the only cause without investigation — particularly in adult men and post-menopausal women, where a dietary explanation alone is rarely sufficient.
How long after starting iron will I feel better?
Energy usually improves within 2–4 weeks. Haemoglobin rises by about 10–20 g/L per month. Ferritin (iron stores) take 3–6 months to refill — don’t stop iron the moment the anaemia corrects, or the deficiency recurs.
Book a consultation
Phone 07 3733 1551 or send a referral via the contact form. Download the patient PDF: Iron-Deficiency Anaemia — GI Work-Up Pathway 2026. See about Dr Goutham or the cost page.
Draft v1. Schema (MedicalCondition + MedicalAuthor + FAQPage) to be added on publish per §13.4 Brief I.
