1113651
Description
Flashcards by Luke Granger, updated more than 1 year ago
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Created by Luke Granger
almost 10 years ago
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| Question | Answer |
| Young RBCs larger than RBCs blue in colour (polychromasia) | Reticulocytes |
| Raised retic count seen in...(3) | bleeding haemolysis responding to haematinic replacement raised retics = >2% of RBCs or >100x10^9/l |
| low retic count seen in... (2) | Bone marrow failure underproduction of EPO |
| Origin of EPO | peritubular cells in the JGA of the kidney |
| What switches on EPO? | Major driver is hypoxia (via HIF) |
| Haematinics (3) and function | 1) B12 - nucleic acid production 2) Folate - works with B13 for nucleic acid production 3) Iron - for Hb synthesis |
| RBC lifespan | 120 days |
| Where are red blood cells broken down and what are the breakdown products? | Reticuloendothelial cells, mainly in the spleen. Fe -> recycled globin chains -> amino acids porphyrin ring -> bilirubin |
| Hb normal range | Men: 13-17g/dl Women: 12-15g/dl |
| Causes of a microcytic anaemia | MCV <80 Fe deficiency & Blood loss Thalassaemia - MCV too low for Hb, RBC incr. Ix - HPLC Sideroblastic anaemia Anaemia of chronic disease (usually normocytic) |
| Differential and definition of a normocytic anaemia | MCV 80-96 Acute blood loss anaemia of chronic disease chronic kidney disease CTD Marrow failure (also low WCC & plts) Pregnancy Hypothyroidism & haemolysis (but usually incr MCV) |
| Differential and definition of a macrocytic anaemia | MCV > 96 B12/folate def (also antifolate drugs e.g. phenytoin) Alcohol & Liver disease Haemolytic anaemia (reticulocytosis) Hypothyroidism Myelodysplastic syndromes Marrow infiltration Cytotoxics e.g. hydroxycarbamide |
| Sx of anaemia | fatigue, SOB, faintness, palpitations, headache, tinnitus, anorexia angina (if there is pre-existing heart disease) |
| Signs of anaemia | May be absent. Pallor. Hyperdynamic circulation (if <8g/dl) -> tachycardia, flow murmurs (ejection systolic, loudest over apex), cardiac enlargement Retinal haemorrhages (rare) Later, heart failure may occur (in which blood transfusion can be fatal). |
| What will Iron studies show when investigating a microcytic anaemia? | Fe deficiency - serum Fe low, ferritin low, total iron binding capacity (TIBC)/ transferrin high Thalassaemia & sideroblastic anaemia - accumulation of iron, therefore: serum Fe high, ferritin high, TIBC/transferrin low |
| Signs of haemolytic anaemia | normocytic/macrocytic anaemia retics >2% of RBCs or >100x 10^9/L haptoglobin low bilirubin & urobilinogen high, mild jaundice, no bilirubin in urine (as it's prehepatic) |
| When to give a blood transfusion? | 1) acute cause e.g. peptic ulcer with haemorrhage -> transfuse up to 8g/dl 2) chronic cause -> don't give e.g. Fe def - ascertain cause, Fe supplements 3) Severe anaemia c heart failure -> give packed RBCs slowly with 10-40mg furosemide IV/PO with alternate units. If CCF gets worse stop & Tx. If immediately needed - exchange transfuse 2-3 units (remove at same rate as replace) |
| Causes of Fe def anaemia | Blood loss (menorrhagia, GI bleed) Dietary insufficiency - babies & children, rare in adults Malabsorption (coeliac disease) - refractory Fe def anaemia Tropics -> hookworm (GI blood loss) most common |
| Signs of Fe def anaemia | koilonychia atrophic glossitis angular chelosis post-cricoid webs (Plummer-Vinson syndrome) |
| What is haptoglobin and when would you measure it? | A plasma protein that binds Hb released from RBCs with high affinity, preventing the oxidative effects of Hb. The haptoglobin-Hb complex is then removed by the spleen. Levels will therefore be low in intravascular haemolysis. Used to screen for and monitor intravascular haemolysis. |
| What is the significance of MCH (mean cell Hb) and MCHC (mean cell Hb conc)? | These values are typically low with Fe def anaemia or thalassaemia (microcytic anaemias) Translates as hypochromia on a blood film |
| Poikilocytosis = Abnormally shaped RBCs. Various causes incl Fe def anaemia, b12/folate def, membrane abnormalities (e.g. spherocytosis), or trauma (e.g. schistocytes) | |
| Anisocytosis = unequal size RBCs commonly seen in anaemia... but not specific to a particular type of anaemia. | |
| Investigations in Fe def anaemia | FBC - microcytic, hypochromic anaemia Blood film - anisocytosis, poikilocytosis Iron studies - low ferritin & serum Fe, incr TIBC Incr RBC protoporphyrin Ix for cause: Gastroscopy, sigmoidoscopy, colonoscopy, barium enema Stool microscopy for ova (if ?hookworm) |
| Tx of Fe def anaemia | Tx cause. Ferrous sulphate 200mg/8h PO s/e - nausea, abdo discomfort, diarrhoea, constipation, black stools Hb should rise by 1g/dl per week & should see reticulocytosis Cont. for 3mo after Hb normal If not working-> ?not taking pills, cont. blood loss, malabsorption... |
| Anaemia of chronic disease: Ix & Tx | Ix: mild normocytic anaemia, ferritin normal or raised Tx: the cause. In CRF & malignancy -> recombinant EPO can be given (s/e = flu-like Sx, HTN, mildly raised plts) |
| Sideroblastic anaemia....what would alert you to it, and how would you investigate it? |
Consider if microcytic anaemia not responding to Fe replacement.
Ix: 1) ferritin (raised, not low)
2) blood film (hypochromic)
3) marrow (look for ring sideroblasts - perinuclear ring of Fe granules)
Image:
ring_sideroblast (image/jpg)
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| Sideroblastic anaemia: pathogenesis and causes | path = ineffective erythropoiesis, leads to: - incr Fe absorption in the gut - Fe loading in the marrow - Haemosiderosis (endocrine, liver & heart damage from Fe deposition) Causes: Congenital (rare, X-linked) Acquired - idiopathic as an MDS disease; post-chemo, anti-Tb drugs, irradiation, alcohol, lead excess |
| Angular cheilosis differential (ulceration of the corners of the mouth) | Fe deficiency anaemia B12 or B2 (riboflavin) deficiency Glucagonoma |
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