11/14/24, 10\:58 AM Iron Deficiency Anaemia

Iron De

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Anaemia\: Hb \<130g/L for men, \<120g/L for non-pregnant women.
Iron de
million a
Causes\: reduced iron absorption (dietary, malabsorption, drugs), increased iron utilisation (pregnancy, growth spurts), blood
loss (menorrhagia, GI conditions, trauma, NSAIDs).
Risk factors\: pregnancy, menorrhagia, vegetarian/vegan diet, hookworm infection, haemodialysis, coeliac disease,
gastrectomy, NSAID use.
Symptoms\: dyspnoea, fatigue, headache, palpitations, pale skin/conjunctiva, restless leg syndrome, pica, tinnitus, pruritus,
hair loss, mouth ulcers, vertigo.
Examination
tachycardia, murmurs, cardiomegaly, heart failure signs.
Investigations\:
FBC\: low Hb, MCV, MCH, MCHC, high RDW.
Ferritin\: low in iron de
Transferrin saturation/TIBC\: low transferrin saturation, high TIBC.
Blood
B12/folate\: to rule out macrocytic anaemia.
Faecal immunochemical test (FIT)\: to guide referral of suspected colorectal cancer
Management\:
Referral\: urgent for suspected colorectal cancer; non-urgent for men and postmenopausal women with no GI bleed,
severe IDA >50 years old, premenopausal with colorectal cancer risk factors.
Iron supplementation\: oral (e.g. ferrous sulphate 200 mg daily), continue 3 months post-correction. Side e
irritation, constipation/diarrhoea.
IV iron\: for intolerance/non-response to oral iron; rapid response, risk of anaphylaxis.
Complications\: cognitive/behavioural impairment in children, reduced exercise capacity, high-output heart failure,
immunode
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A comprehensive topic overview

Introduction

Anaemia is de
women.
Iron de
IDA is the most common cause of anaemia globally, a
1
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Aetiology

The three major causes of iron de
2
Reduced absorption of iron
Increased utilisation of iron
Blood loss

Reduced absorption of iron

Causes of reduced absorption of iron include\:
Dietary\: the main sources of dietary iron include meat, leafy green vegetables, and forti
bread. Vegans, vegetarians, and those with poor or restricted diets are at risk.
2
Malabsorption\: most iron absorption occurs in the small intestine. Malabsorption of iron can occur at the pre-mucosal
level when digestive enzyme activity is disrupted, for example after gastrectomy or in patients with cystic
Coeliac disease and in
absorption. Intestinal resection and jejuno-ileal bypass cause inadequate absorption in the small intestine. Post-mucosal
malabsorption occurs due to lymphatic obstruction in conditions such as lymphoma.
3
Drugs\: drugs which reduce absorption include tetracyclines/quinolones (chelate iron) and proton pump inhibitors
(decrease gastric acid that is necessary for iron absorption).
2

Increased utilisation of iron

Causes of increased utilisation of iron include\:
5
Pregnancy\: increased demand due to increased blood volume as well as the needs of the fetus
Growth spurts in children

Blood loss

Every 2.5 mL of whole blood or 1 mL of packed red blood cells contains 1 mg of iron.
In comparison, only 1 mg on average of iron is absorbed daily from the diet, so even modest blood loss over time can lead
to iron de
4
In women, menorrhagia is a major cause of blood loss.
Conditions causing blood loss from the gastrointestinal system can include gastro-oesophageal re
ulcers, in (IBD), malignancy, hookworm/schistosomiasis in tropical countries, and drugs (NSAIDs).
Other potential causes include trauma, haematuria, recurrent nose bleeds, blood donation and haemolysis.
4,5

Risk factors

Risk factors for iron de
5
Pregnancy
Menorrhagia
Vegetarian/vegan diet
Hookworm infection
Haemodialysis\: caused by blood loss in dialysis and poor oral absorption
Coeliac disease
Gastrectomy and achlorhydria (absence of gastric acid production)
Non-steroidal anti-in

Clinical features

Iron de
gradually in otherwise healthy individuals who are able to compensate.
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History

Common symptoms of iron de
1,5
Dyspnoea
Fatigue
Headache
Palpitations
Pale skin or conjunctiva
Less common symptoms of iron de
1,5
Restless leg syndrome
Pica (a craving non-food substances, such as ice or dirt - commonly seen in children and pregnant women)
Tinnitus
Pruritus
Hair loss
Mouth ulcers
Vertigo/dizziness
Symptoms of underlying diseases associated with iron de
2
Dysphagia\: oesophageal malignancy, oesophageal webs associated with Plummer Vinson syndrome (a triad of atrophic
glossitis, oesophageal strictures, and iron de
5
Dyspepsia\: gastric cancer, peptic ulcer disease
Abdominal pain\: coeliac disease, intrabdominal malignancy, in
Change in bowel habit\: bowel cancer, coeliac disease, in
Rectal bleeding\: anal
Weight loss\: in
Other important areas to cover in the history include\:
Last menstrual period
Drug history\: especially the use of NSAIDs

Clinical examination

Clinical
2
Conjunctival pallor
Angular cheilitis (ulcers at the corners of the mouth)
Atrophic glossitis (painful tongue with loss of papillae)
Koilonychia (spoon-shaped nails)
Dry skin and hair
oedema.
1
In severe anaemia, there may be tachycardia, murmurs, signs of cardiomegaly, and signs of heart failure such as peripheral
An abdominal examination should also be carried out, to look for masses and lymphadenopathy.
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Figure 1. Koilonychia
7

Di

Clinical features of iron de
further investigations are essential to narrow the di
Iron de
blood
Other causes of microcytic anaemia include thalassemia, a genetic defect of haemoglobin production common in certain
parts of the world such as the Mediterranean Coast and sideroblastic anaemia, a congenital or acquired inability to
integrate iron into haemoglobin. Both diseases cause microcytosis and hypochromia.
Anaemia of chronic disease is caused by ongoing in
In
Cancer
Kidney disease
Infections (e.g. tuberculosis and HIV)
Anaemia of chronic disease usually causes normocytic anaemia, but in 20% of cases can cause normochromic microcytic
anaemia.
Hyperchromic microcytic anaemia is rare and caused by hereditary spherocytosis, a genetic red cell membrane defect.
Other rarer causes of microcytic anaemia are lead toxicity and copper de
5,8

Investigations

Con

Full blood count
Typical
1,5
Low Hb\: \<130 g/L for men, \<120 g/L for non-pregnant women
Low MCV\: \<80
Reduced mean corpuscular haemoglobin (MCH)\: \<27.5 picograms/red cell indicates hypochromia
Reduced mean corpuscular hemoglobin concentration (MCHC)
Increased red cell distribution width (RDW)\: indicates variation in the size of red blood cells
Ferritin
If the full blood count reveals a low Hb and MCV, a ferritin level should also be assessed.
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The presence of low serum ferritin can help to con
reactant (i.e. it rises in in
serum ferritin levels in the context of acute in
Transferrin saturation and total iron-binding capacity (TIBC)
Transferrin saturation and TIBC can be useful to con
infection, in
Typical
Low transferrin saturation\: as there is less iron to saturate the transferrin
Raised total iron-binding capacity (TIBC)\: there is an increased capacity to bind iron due to reduced levels of iron
Blood
Typical
2
Figure 2. Blood
hypochromic microcytic cells with anisocytosis and
poikilocytosis.
9
B12 and folate
B12 and folate are often checked in all patients presenting with anaemia to rule out B12/folate de
presents with macrocytic anaemia.
B12 and folate levels should be checked if\:
1
The anaemia is normocytic with a low or normal ferritin level
There is an inadequate response to iron supplements in proven iron de
Vitamin B12 or folate de
The person is in an older age group (more at risk of pernicious anaemia)

Investigation of an underlying cause

Investigation to identify an underlying cause of iron de
groups\:
Younger healthy patients with a clear cause for iron de
Menstruating young women with no history of gastrointestinal symptoms or family history of colorectal cancer
Pregnant women (unless the anaemia is severe, there is no response to iron therapy, or there are concerning features in
the history)
People who are terminally ill or unable to undergo invasive investigations
In all other cases, the following investigations should be performed\:
Coeliac serology\: tissue transglutaminase antibody
Urine dipstick\: to screen for haematuria
Stool examination\: to detect parasites if the patient has recently travelled to high-risk areas
Faecal immunochemical test (FIT)\: to guide referral of suspected colorectal cancer
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Management

Referral to specialist services

Referral to specialist services may be required depending on the suspected underlying pathology causing iron de
anaemia.
1
Urgent suspected cancer referral
An urgent suspected cancer referral should be made for patients with a\:
1
Positive FIT test (≥10 µg Hb/g faeces)
Negative FIT with ongoing clinical concern for malignancy (i.e. abdominal or rectal mass)
Other referral pathways may be indicated depending on the probable cause of the iron-de
urology for unexplained haematuria. Women with postmenopausal bleeding should be referred to gynaecology urgently
within 2 weeks.
1
Non-urgent gastroenterology referral
A non-urgent gastroenterology referral should be made for\:
1
All men and postmenopausal women with iron de
bleeding
All people aged 50 years or over with marked anaemia
Premenopausal women aged under 50 years and have colonic symptoms, a strong family history of gastrointestinal
cancer, persistent IDA despite treatment, or if they do not menstruate
All patients with positive coeliac serology for endoscopic biopsy
Correction of iron de1
Oral iron supplementation
The cause of anaemia should be identi
increase intake of iron-rich food and a dietitian referral may be useful.
Iron supplementation (e.g. oral ferrous sulphate 200 mg once daily) should be prescribed, and treatment continued for
three months after the iron de
Iron tablets may have side e
counsel the patient that these usually settle over time and can be managed by taking the tablet with food. Lower doses
may be better tolerated.
Changing the formulation may also help with side e
fumarate and may be more acceptable. Safe storage should be emphasised as overdose can be fatal.
Full blood count monitoring is required to assess the response to supplementation. A haemoglobin rise of 2g/100 ml would
be expected by four weeks.
Intravenous iron supplementation
Intravenous iron is reserved for those with true intolerance of oral iron (e.g. in
to respond to oral iron supplementation. Intravenous iron produces a more rapid response and better repletion of stores
than oral iron but has side e
There is a risk of anaphylaxis associated with intravenous iron replacement, so it should only be administered where there
are adequate resuscitation facilities.
5
Ongoing iron supplementation
An ongoing prophylactic dose of iron (oral ferrous sulfate 200 mg daily) may be bene
Recurring anaemia and further investigations are not indicated/appropriate
A diet unlikely to meet daily iron intake recommendations (e.g. plant-based diet)
Malabsorption (e.g. coeliac disease)
Menorrhagia
Had a gastrectomy
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Complications

Complications of iron de
1
Cognitive and behavioural impairment in children
Reduced exercise capacity and endurance
High-output heart failure
Immunode
and perinatal mortality
In the context of pregnancy, it can lead to increased morbidity for mother and infant, increased risk of preterm delivery

References

NICE CKS. A n a e m i a – I r o n D e LINK]
Patient.info I r o n-d e LINK]

Related notes

Saboor, M., Zehra, A., Qamar, K., & Moinuddin. D i s o r d e r s a s s o c i a t e d w i t h m a l a b s o r p t i o n o f i r o n \: A c r i t i c a l r e v i e w . Published
2015. Pakistan journal of medical sciences, 31(6), 1549–1553. Available from\: [LINK]
Miller J. L. I r o n d e
Acute Myeloid Leukaemia
medicine, 3(7), a011866. Available from\: [LINK]
Anaemia Overview
BMJ Best Practice. I r o n d e LINK]
Chronic Myeloid Leukaemia
Patient.info. P l u m m e r-V i n s o n s y n d r o m e . Last edited 27 Jan 2017. Available from\: [LINK]
Disseminated Intravascular Coagulation (DIC)
C Heitz. License\: [CC BY]. Available from\: [LINK]
Haemolytic anaemia
Gotter, A. M i c r o c y t i c A n e m i a . Last reviewed 6 Nov 2018 by Deborah Weatherspoon. Available from\: [LINK]
Erhabor Osaro. I r o n d e CC BY-SA]. Available from\: [LINK]

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Reviewer

Contents

Dr BK Sinha
General Practitioner
Introduction
Aetiology
Risk factors
Clinical features
Di
Investigations
Management
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