AnaemiaWhat is Anamia | A reduction the Hb concentration below normal ranges (M: <13g/dL / F: <12g/dL) | Aetiology | 1. Decreased RCB production 2. Loss of RBCs 3. Increased RBC destruction |
Anaemia Main CategoriesMicrocyctic / hypochomic | Low MCV / Low MCH | Normocyctic / normochomic | Normal MCV / Normal MCH | Macrocyctic / hyperchomic | High MCV / High MCH |
Clinical Presentationfatigue | dyspnoea | chest pain | dizziness | palpitations | headaches | worsening of other conditions - intermittent claudication |
Normocytic AnaemiaNormal MCV, indicating normal sized RBCs | DDx: Anaemia of chronic disease/inflammation | Haemolysis | | | Bone marrow infiltration | | | Acute blood loss |
Normocytic AnaemiaInvestigations | FBC | Low Hb, normal MCV | Blood Film | Normocytic, normochromic RBCs | Iron Studies | normal/low serum iron, low TIBC, normal/high serum ferritin | +/- other Ix | Serum erythropoietin (EPO) level is decreased in CKD | Management | Manage underlying cause | consult haem/medical team | EPO replacement | RCC transfusion if severe or symptomatic | Iron supplementation may or may not be needed |
Normocytic Anaemia CausesAnaemia of Chronic Diseases | Chronic renal disease, rheumatic disease, congestive heart failure | Mechanism | depends on underlying pathology | | | decrease in release of stored iron | | | shortened red cell survival | | | impaired marrow response in red cell relacement |
Macrocytic AnaemiaMacrocytic Anaemia | Large RBCs and increased MCV | Aetiology | Megaloblastic | B12 or folate deficiency | Normoblastic | alcohol excess, reticulocytosis, liver disease | Mechanism | Megaloblastic | Impaired DNA synthesis | Normoblastic | Unkown | Signs and symptoms | General symptoms of anaemia | | | Pallor +/- glossitis, angular stomatitis | | | B12 deficiency can lead to neurologic syndrome |
Megaloblastic AnaemiaVit B12 | Found in animal sources | Causes of deficiency | Pernicious anaemia (autoimmune disorder) | | | Veganism | | | Gastrectomy/gastric absorptive disease | | | Chron's disease/coeliac | Folate | green veg,, organ meat, fortified cereals | Causes of deficiency | Poor dietary intake | | | Alcohol | | | Anti-epileptic drugs (phenytoin) | | | Methotrexate | | | Coeliac disease |
Management Macrocytic AnaemiaTreat underlying cause | consult haem/medical team | B12 deficiency | IM hydroxocobalamin (B12): replenish levels with frequent administration then gradually reduce frequency | Folat deficiency | Oral folate replacement: folic acid 5mg OD |
| | Signs - on CEJaundice | can occur in haemolysis | Koilonychia | spoon shaped nails in IDA | conjunctive pallor | ensure looking at palpebral conjunctiva | sclera icterus | jaundice (haemolysis) | angular stomatitis | B12/folate/iron deficiency | systolic flow murmur | mid-systolic ejection murmur due to increased semi-lunar blood flow |
Anaemia Differential DiagnosisMicrocytic Anaemia | Normocytic Anaemia | Macrocytic Anaemia | Iron deficiency anaemia (50% of cases) | Anaemia of chronic disease | Vitamin B12 | Thallasaemia | Inflammation: | Chronic diseases | Chronic infection |
Iron Deficiency Anaemia4 main causes | Decreased intake (infant/vegan) | | | Decreased absorption (gastrectomy, IBD, coeliac disease) | | | Increased demand (childhood, pregnancy) | | | Increased loss (chronic slow bleed) | Potential Symptoms | GI blood loss, heavy menstrual bleeding, Pica |
IDA Investigations and ManagementInvestigations | FBC | decreased Hb and MCV. Check WCC & platelets (expect normal in IDA) | Iron Studies | decreased serum iron, serum ferritin, transferrin sat., increased TIBC | Blood Film | microcytic and hypochromic RBCs, Poikilocytosis / Anisocytosis | +/- other Ix | Faecal occult blood (FOB), OGD, colonoscopy | Management | Manage underlying cause | consult haem/medical team | Start supplemental iron | Aim 1-2g raise in Hb every week | 1st line: oral iron replacement eg. Ferrous fumerate | 2nd line: IV iron replacement (Ferrinject) | 3rd line: RCC transfusion (if severe) |
Don't forget to type and screen if giving a blood transfusion Microcytic AnaemiaLow Hb & MCV, indication RBCs | Causes of microcytic anaemia; mnemonic TAILS | Mechanism: | Defect in synthesis of haem | | | Thalassaemia - defect in synthesis of globin chain |
DDX:
T - Thalassemia
A - Anaemia of chronic disease
I - Iron deficiency anaemia
L - lead poisoning
S - sideroblastic anaemia Macrocytic AnaemiaInvestigations | FBC | Low Hb, MCV is elevated | B12/Folate Deficiency | check levels | Anti-parietal cell anti-body & intrinsic factor antibody | screening for pernicious anaemia | Anti-tTG & IgA | screening for coeliac disease | LFTs | GGT may be elevated in alcohol excess | Peripheral blood smear | anisocytosis, poikiloctyosis, hypersegmented neutrophils |
Don't forget to ask about diet (vegan), alcohol intake, medications IDA Iron StudiesSerum iron levels | LOW | measures amount of iron in transit in blood | Serrum ferritin | LOW | total iron stored in the body | Total iron binding capacity | HIGH | TIBC increases in order to try and maximise use of the little iron available | Transferrin saturation | LOW | level of saturation of transferring with iron: normal is 30%. Reduced in iron deficiency states |
Autoimmune Haemolytic Anaemia (Haemolysis)Warm AIHA | Antibody active at body temp | | | Aetiologies include: rheumatic disease and lymphoproliferative disorders | | | IgG antibodies +/- complement | Cold AIHA | Antibody active only at lower temps | | | Aetiologies include: infections (eg. mono) and lymphoma | | | IgM antibodies |
Haemolytic AnaemiaInvestigations | FBC | Low Hb, normal MCV | Reticulocytes | elevated | LDH | elevated | Haptoglonbin | low | LFT's | unconjugated Bilirubin - elevated | Direct Antioglobin (Coombs) Test | if + then autoimmune haemolysis likely | Blood Film | look for specific abnormalities | Management | Treat underlying cause | consult haem/medical team | Stabilize pt | consult haem re. need for transfusion | Warm AIHA | 1st line: corticosteroids, 2nd line: Rituximab, Azathioprine, Cyclosporin, 3rd line: splectomy | Cold AIHA | Avoid cold temps & treat underlying cause +/- immunosuppressant (rituximab) |
Haemolytic AnaemiaHaenolytic Anaemia | Haemolysis: destruction of red blood cells | Aetiologies | Autoimmune | Warm, cold, transfusion reaction, drug induces | Haemoglobinopathies | sickle cell, hereditary spherocytosis, thalassaemia | Infections | malaria | Enzyme defects | G6PD | Microangiopathic haemolytic anaemia (MAHA) | haemolytic uremic syndrome, TTP, DIC, eclampsia/HELLP | Mechanical haemolysis | heart valve prosthesis | Rare | Paroxysmal noctural, haemoglobinuria (PNH) |
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