ANAEMIA

✓ Medically ReviewedDISEASEID: MDBT0151🚨 TRIAGE: URGENTICD-10: D64.9

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Definition

CLINICAL DEFINITION

Anaemia is a haemoglobin (oxygen-carrying red pigment) deficit below age and sex thresholds. Red cells (oxygen carriers) fall in number, size or haem content. Tissues face reduced oxygen delivery (low supply to organs) with fatigue and pallor (pale skin). Causes split into blood loss (bleeding), poor production (marrow failure) and excess destruction (haemolysis with early cell breakdown). Diagnosis pairs full blood count (cell profile) with iron, B12 (cobalamin) and cause search.

IN PLAIN ENGLISH

Blood has red cells. They carry air round the body. Low blood makes you tired. Skin and eyes look pale. Pills and food can build blood back.

COMMON MISCONCEPTION / WHAT IT DOES NOT MEAN

Anaemia is not polycythaemia (excess red cells) with high haemoglobin. It is not haemodilution (thin blood from excess fluid) alone without true red cell loss. It is not thalassaemia trait (inherited small-cell trait) alone without low haemoglobin. It is not transient pallor (brief pale look) from cold or fear without low counts.

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Word Breakdown

an-

=without meaning lack or absence

haem-

=blood meaning red fluid that carries oxygen

-ia

=condition meaning disease state

Literal Meaning: condition of lacking blood

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Abbreviations

Hb=Haemoglobin - red pigment that carries oxygen in blood

MCV=Mean cell volume - average size of red cells

IDA=Iron deficiency anaemia - low iron with small pale cells

B12=Cobalamin - vitamin needed for red cell formation

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Synonyms & Variants

Anemia›Low haemoglobin›Iron deficiency anaemia›

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Category-Specific Context

Anaemia is a Disease because it is a sustained red-cell disorder with causes, grades and cure. It is not a single Symptom (patient complaint) such as fatigue alone. It spans microcytic (small cells), normocytic (normal size) and macrocytic (large cells) forms with acute and chronic courses. Management joins cause control with iron, vitamin or transfusion (donor blood) support. It needs count review with bleed and marrow watch.

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Clinical Context & Usage

CLINICAL SETTINGS

Primary Care for Fatigue and PallorEmergency Department for Symptomatic Anaemia with Chest PainAntenatal Clinic for Pregnancy AnaemiaGastroenterology Clinic for Suspected Blood LossHaematology Outpatient ServicePaediatric Clinic for Poor Growth with Pallor

USAGE & DOCUMENTATION NOTES

Use anaemia for haemoglobin below WHO thresholds with symptoms or cause, not pallor alone. Specify severity and red-cell size such as microcytic, normocytic or macrocytic and state acute or chronic. Note bleeding, diet, pregnancy, kidney disease (filter failure) and drugs each visit. Do not label mild dilution in pregnancy or after fluids as true anaemia without repeat count. Record haemoglobin, MCV (cell size), ferritin (iron store test), B12 and bleeding review.

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Primary Causes & Pathophysiology

PATHOPHYSIOLOGY

Blood loss (bleeding) depletes iron (core haem metal) and red mass faster than marrow (blood factory) can replace. Iron, B12 (cobalamin) or folate (cell vitamin) lack stalls haem (oxygen pigment) and DNA (cell code) building. Marrow then yields small pale or large fragile cells with short life. Chronic disease (long inflammation) locks iron away via hepcidin (iron gate hormone) and blunts response. Haemolysis (early red breakdown) outpaces production while bleeding lowers volume and oxygen carriage.

PRIMARY CAUSES

Iron deficiency from chronic blood loss

Menstrual (monthly period), gut or urinary bleeding drains iron stores causing small pale cells

Vitamin B12 and folate deficiency

Cobalamin or folate lack stalls DNA building causing large fragile cells with poor release

Anaemia of chronic disease and inflammation

Hepcidin (iron gate hormone) traps iron in stores during infection or inflammation limiting supply

Haemolysis from immune or inherited causes

Antibodies (attack proteins) or membrane defects (cell wall flaws) break cells early outpacing marrow

Marrow failure from kidney disease or aplasia

Low erythropoietin (kidney red-cell signal) or stem harm cuts production causing normocytic fall

Haemoglobinopathies such as thalassaemia and sickle disease

Globin gene (haem protein code) defects yield faulty haem causing chronic haemolysis and small cells

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Drug-Induced Causes

💊 Nonsteroidal anti-inflammatory drugs (ibuprofen, diclofenac) ↗

Mechanism: Erode stomach lining (gut wall) causing chronic oozing with iron loss

→ Stop or switch with gastroprotection (stomach shield) and test stool with iron replacement

💊 Anticoagulants and antiplatelets (warfarin, apixaban, aspirin, clopidogrel) ↗

Mechanism: Impair clotting (blood sealing) prolonging any bleed and depleting red mass

→ Review indication with dose, check gut source, hold only per bleeding protocol

💊 Cytotoxic chemotherapy (alkylators, antimetabolites) ↗

Mechanism: Suppress marrow (blood factory) cutting all lines including red cells

→ Dose review with transfusion (donor blood) and growth-factor (marrow boost) per oncology plan

💊 Proton pump inhibitors with prolonged use (omeprazole) ↗

Mechanism: Lower acid (stomach juice) reducing iron uptake (absorption) over months

→ Check iron with diet review and supplement while reviewing need

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Epidemiology

Prevalence:Anaemia affects about one quarter of people worldwide. Women of reproductive age and young children carry highest burden. Iron deficiency (low iron stores) causes about half of cases. Pregnancy with chronic kidney disease (filter failure) raises risk further.

Age Group:All ages can develop anaemia after loss or poor intake. Young children face high risk from diet gaps and worms (gut parasites). Women of reproductive age carry higher burden from menstrual (period) loss and pregnancy demand. Older adults face higher burden from gut bleeding, kidney disease and marrow disorders.

Sex Predilection:Female

Geographic Distribution:Anaemia occurs worldwide in all regions and climates. Iron deficiency patterns follow diet and bleeding risk everywhere. Malaria (mosquito fever) and hookworm (gut worm) add burden where those infections circulate. No climate restriction applies because causes are blood loss and poor build.

Red Flags & Triage ★

TRIAGE LEVEL

🚨 URGENT

DO NOT MISS — LIFE-THREATENING PRESENTATIONS

Gastrointestinal cancer with silent iron loss in older adults
Severe anaemia with chest pain or breathlessness needing transfusion
B12 deficiency with numbness or cord signs needing urgent replacement
Haemolysis with jaundice and dark urine signalling rapid breakdown
Pregnancy anaemia with high demand and bleed risk
Marrow failure with low white cells and platelets

URGENT EVALUATION TRIGGERS

Chest pain or breathlessness at rest with pallor
Fainting with fast pulse and low pressure
Black stools or vomited blood with fatigue
Numbness with unsteady gait suggesting B12 cord harm
Fever with pallor and low white cells or platelets
Pregnancy with severe fatigue and breathlessness

Contraindications & Precautions

CONTRAINDICATIONS

Do not give iron with transfusion need delayed when severe symptomatic anaemia needs urgent blood
Do not start B12 (cobalamin) as folate alone when combined deficiency exists because cord harm can progress
Do not use erythropoiesis agents (marrow boost drugs) without iron repletion (store refill) and clot review
Do not attribute rectal bleeding to piles (swollen veins) without gut workup in older adults

SPECIAL PRECAUTIONS

Check reticulocytes (new red cells) with ferritin (iron store test), B12 and folate before treatment
Ask about menstrual, gut, urinary and nose bleeding with diet and drug review
Screen pregnancy with kidney function and inflammation markers (infection signals)
Recheck haemoglobin within 2 to 4 weeks and ferritin after 3 months of iron
Counsel iron dosing away from tea, coffee and antacids (stomach neutralisers) with vitamin C (citrus aid)

Complications

DOWNSTREAM CLINICAL COMPLICATIONS

Severe fatigue (heavy tiredness) with reduced exercise tolerance
Heart failure (weak pump) with fast rate from chronic strain
Restless legs (urge to move legs) with poor sleep in iron deficiency
Preterm birth (early labour) with low birth weight from pregnancy anaemia
Cognitive delay (slow learning) in young children with lasting deficit
Pica (craving non-foods) with pagophagia (ice craving) signalling iron lack

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Reference Ranges

NORMAL RANGEHaemoglobin 130 to 180 g per L in adult men and 120 to 160 g per L in adult nonpregnant women

CRITICAL (PANIC) VALUEBelow 70 g per L or below 80 g per L with chest pain, breathlessness or low pressure

UNIT OF MEASUREMENTg/L

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Confused With (LASA & DDx) ★

LEXICAL (LASA) — SIMILAR NAMES

Anuria

Differs by two letters but means absent urine (no pee) from kidney failure, not low haemoglobin

Anorexia

Shares an- prefix but means appetite loss (food refusal), not red-cell deficit

Anoxia

Shares low-oxygen theme but means absent tissue oxygen (no supply), not low haemoglobin itself

CLINICAL DIFFERENTIAL DIAGNOSES (DDx)

Thalassaemia trait

Key Distinguishing Feature: Very small red cells with normal iron stores and raised HbA2 (haem variant) without response to iron

Haemodilution in pregnancy or fluids

Key Distinguishing Feature: Mild low haemoglobin with normal stores that normalises after delivery or fluid balance

Acute blood loss without anaemia yet

Key Distinguishing Feature: Normal haemoglobin early after bleed with fast pulse and low pressure before dilution

Myelodysplasia

Key Distinguishing Feature: Persistent cytopenias (low blood lines) with dysplastic marrow (faulty factory) in older adults

Hypothyroidism

Key Distinguishing Feature: Fatigue with weight gain, cold intolerance and high TSH (thyroid signal) alongside mild anaemia

Chronic kidney disease effect

Key Distinguishing Feature: Normocytic anaemia with low erythropoietin (kidney signal) and raised creatinine (kidney waste)

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Clinical Pearls

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Check full count with reticulocytes plus ferritin, B12 and folate before pills and do not treat blindly.

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Replace iron daily for 3 months after haemoglobin normalises and recheck ferritin to refill stores fully.

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Treat B12 deficiency promptly by injection when neuro signs appear and never give folate alone in that setting.

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Transfuse below 70 g per L or below 80 g per L with heart disease or symptoms and fix the bleed at once.

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Take iron away from tea, coffee and antacids with vitamin C and review gut source when older or bleeding.

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Example Usage & SOAP

CLINICAL SENTENCE

""34-year-old with fatigue, pallor and low ferritin has iron deficiency anaemia.""

IN A SOAP NOTE

S: 34-year-old woman with 2-month fatigue, breathlessness on stairs and heavy periods, no chest pain, diet low in meat. O: Temp 37.1C, BP 112/70, HR 98, RR 16, SpO2 99 percent on air, pale conjunctiva (pale eye lining) with smooth tongue, no jaundice (yellow skin). A: Moderate iron deficiency anaemia from menstrual loss. P: Full count with ferritin, B12 and pregnancy test, start oral iron with vitamin C advice, refer gynaecology for bleeding review in 2 to 4 weeks.

DIFFERENTIAL DIAGNOSIS CONTEXT

Fatigue with pallor and low ferritin favours iron deficiency anaemia over thalassaemia trait. Very small cells with normal iron favour trait. Normal stores with mild fall in pregnancy favours dilution. Low white cells with dysplasia favours marrow disorder. Test full count with ferritin, B12 and bleed review.

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Classifications & Scoring

GRADING SYSTEM

WHO anaemia severity grades

Grades as mild, moderate or severe by haemoglobin bands to set urgency and transfusion review

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Prognosis

SHORT-TERM OUTCOME

Mild iron deficiency often lifts within weeks of iron with cause control. Fatigue eases as haemoglobin climbs with reticulocytes (new red cells) first. Ongoing bleeding or haemolysis (cell breakdown) stalls recovery despite pills. Severe anaemia with chest pain or breathlessness needs urgent transfusion (donor blood) review.

LONG-TERM PROGNOSIS

Most nutritional anaemia resolves fully with stores rebuilt over months. Chronic disease or inherited disorders need long term monitoring with specialist care. Pregnancy anaemia treated early usually ends well for mother and child. Repeated bleeding without source control predicts relapse and transfusion need.

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References & Coding

ICD-10 DIAGNOSTIC CODE

D64.9

LITERATURE CITATIONS & GUIDELINES

[1]WHO ICD-10 D64 Anaemia

[2]WHO Guideline on haemoglobin thresholds for anaemia

[3]British Society for Haematology anaemia guidance

[4]Harrisons Principles of Internal Medicine disorders of red cells

MEDICAL DISCLAIMER — This content is intended for educational purposes and qualified healthcare professionals only. Always refer to current clinical diagnostic criteria, institutional protocols, and official guidelines. Medobo is not responsible for clinical decisions made based on this content.