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Anaemia

Anaemia. Oliver R ácz, 2015. Repetition of physiology and biochemistry. Red cell properties and function Number, synthesis, life span, degradation Haemoglobin structure and function Structure, oxygen affinity and its regulation, variants, degradation Iron metabolism

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Anaemia

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  1. Anaemia Oliver Rácz, 2015

  2. Repetition of physiology and biochemistry • Red cell properties and function • Number, synthesis, life span, degradation • Haemoglobin structure and function • Structure, oxygen affinity and its regulation, variants, degradation • Iron metabolism • See trace element lecture • Vitamin B12 and folic acid

  3. Definition of anaemia • Deficiency in the oxygen-carrying capacity of the blood due to diminished erythrocyte mass (THEORY) • Low red cell count, Hb, HT(PRACTICAL MEDICINE) • May be due to: • Erythrocyte loss (bleeding, haemolysis) • Decreased erythrocyte production • Bone marrow dysfunction • Low erythropoietin/high hepcidin • Iron deficiency • Vitamin B12, folic acid deficiency

  4. Indicators of anaemia • MEASURED ON AUTOMATIC ANALYZERS • Haemoglobin, grams of Hb/liter of whole blood (or g/dL in USA) • Hematocrit, ratio between cell and plasma volume • RBC = millions/microliter (= mm3) of whole blood (or 1012/liter) • MCV = Mean corpuscular volume (of 1 RBC) • > 100 femtoliterMacrocytes (1 fl = 10-15 liter) • 80 – 100 femtoliter Normocytes • < 80 femtoliter Microcytes • MCH = Mean corpuscular Hb (norm is 20 pg/cell; pico = 10-12) • RDW = Red blood cell distribution width • (Standard deviation of red cell volume/mean cell volume) × 100 • Normal value is 11-15% • If elevated, suggests large variability in sizes of RBCs

  5. Normal and decreased values • Hb (160) • Women: <120 severe <100 • Men: < 135 • Ht (0,45) • Women: < 0,36 severe < 0,30 • Men: < 0,41

  6. Symptoms of Anaemia ? • Decreased oxygenation • Pallor • Exertional dyspnea • Dyspnea at rest • Fatigue • Decreased mental function • Decreased circulating volume • Fatigue • Muscle cramps • Postural dizziness • Syncope • Disease/condition specific, e.g. • Jaundice • Other FOR LONG TIME MOSTLY NOTHING, HIDDEN BEHIND THE BASIC DISEASE OR COMPENSATED NO CYANOSIS

  7. Special considerations • Acute Bleeding • Drop in Hb & Ht may not be shown until some time after acute blood loss (even though patient may be hypotensive) • WHY??? • Later reticulocytosis • Pregnancy • In third trimester, RBC and plasma volume are expanded but there is a bigger expansion of plasma volume than of red cell mass. • Lab values show reductions in Hb, Ht, and RBC count, often to pathological levels, but according to RBC mass this is a haemodilution and not anaemia. • BUT! Real anaemia is also frequent in gravidity • Volume Depletion • Patient’s who are severely volume depleted may have physiological Ht results and do not show anaemic values until rehydrated !!!

  8. RBC Life Cycle • In the bone marrow, erythropoietin enhances the growth of differentiation of burst forming units-erythroid (BFU-E) and colony forming units-erythroid (CFU-E) into reticulocytes. • Reticulocytes spend ≈ 3 days maturing in the marrow, and ≈ 1 day maturing in the peripheral blood (reticulocyte count ≈ 0,5% of RBCs). • After blood loss or haemolysis increased % of reticulocytes if bone marrow is OK • Mature RBCs circulate in the peripheral blood for 120 days. Under steady state conditions, the rate of RBC production equals the rate of RBC loss. (Around 1/120 ≈ 0,8 % of cells/day. Iron recycling!)

  9. Erythrocyte loss - bleeding • Acute/Haemodynamically significant (not a haematological problem in general practice) • Injury (shock!) • Gastrointestinal (ulcus, oesophagus, polyps…) • Retroperitoneal • Hemophilia and other coagulation disorders • Chronic • kidney, abnormal menstrual cycle, ulcer disease in the past • If not treated it can transform to iron deficiency anaemia

  10. Haemolysis • Osmotic – only in test tube (distilled water) • Mechanical – artificial heart valves (past) • Streptococcus haemolyticus ? • ABO or Rh incompatibility • Malaria, Babesiosis, and many others • Autoimmune, toxic • Inherited – Hb S and other Hbpathies, thalassemia, membranopathies, enzymopathies

  11. Some forms of haemolytic anaemia • Hereditary spherocytosis • Glucose-6-phosphate dehydrogenase (G6PD) Deficiency • Most common enzyme defect in erythrocytes • X-linked • Brisk haemolysis when patients exposed to oxidative stress from drugs, infections or toxins. • Thrombotic Thrombocytopenic Purpura (TTP) • Thrombocytopenia and microangiopathic haemolytic Anaemia, fever, renal insufficiency, neurologic symptoms • Schistocytes on smear • Haemolytic Uremic Syndrome • Thrombocytopenia, Microangiopathic haemolytic Anaemia, renal insufficiency • Autoimmune Haemolytic Anaemia • Warm-antibody mediated • IgG antibody binds to erythrocyte surface • most common • Diagnosed by POSITIVE Coomb’s Test (detectgs IgG or complement on the cell surgace) • Can be caused drugs • Treated with corticosteroids or splenectomy if refractory • Cold agglutinin Disease • IgM antibodies bind to erythrocyte surface • Does not respond to corticosteroids, but usually mild. • Infections • Malaria • Babesiosis • Sepsis • Trauma • Includes some snake, insect bites

  12. BABESIOSIS

  13. Anaemia due to Low erythropoietin • Kidney Disease(including diabetic nephropathy) • Normocytic • Low reticulocyte count • Target Hb for patients on dialysis: 110 -120 g/L • Administer erythropoietin • Good iron stores should be maintained • Peripheral smear in uraemic patients frequently show echinocytes

  14. Aplastic anaemia(bone marrow dysfunction) • Radiation • Toxic substances • Drug side effects • Leukaemias

  15. Iron deficiency • Iron Deficiency • Can result from: • Pregnancy/lactation • Normal growth • Blood loss • Intravascular haemolysis • Gastric bypass • Malabsorption • Iron is absorbed in proximal small bowel; decreased abosrption in celiac disease, inflammatory bowel disease • May manifest as „pica“ • Tendency to eat ice, clay, starch, crunchy materials • May have pallor, koilonychia of the nails, beeturia • Peripheral smear shows microcytic, hypochromic red cells with marked anisopoikilocytosis.

  16. Koilonychia

  17. Laboratory findings • Serum Iron • LOW • Total Iron Binding Capacity (TIBC) • HIGH • Soluble transferrin receptors • HIGH • Serum Ferritin • LOW • Can be “falsely”normal in inflammatory states

  18. Cobalamin deficiency • Macrocytic Anaemia (megaloblastic, in the past “pernicious” • Lab Values • Cobalamin level < 200 pg/mL • Elevated serum methylmalonic acid • Elevated serum homocysteine • Vit B12 binds to intrinsic factor in the small bowel in order to be absorbed – the pernicious form was an autoimmune condition blocking intrinsic factor • Vit. B12 is needed for DNA synthesis • The anaemia is only the tip of an “iceberg” • Deficiency can result in cardiac and neuropsychiatric symptoms • Spastic ataxia, psychosis, loss of vibratory sense, dementia • Dilated cardiomyiopathy • Smear shows macrocytosis and hypersegmentation of polymorphonuclear cells, with possible basophilic stippling.

  19. Folate deficiency • Macrocytic Anaemia and a lot of other consequences (spina bifida) • Lab Values • Low folate • Increased serum homocystine • NORMAL methylmalonic acid • Often occurs with decreased oral intake, increased utilization, or impaired absorption of folate • Folate is normally absorbed in duodenum and proximal jejunum – deficiency found in celiac disease, regional enteritis, amyloidosis • Deficiency frequently in alcoholics, because enzyme required for deglutamation of folate is inhibited by alcohol. • Deficiency often found in pregnant women, persons with desquamating skin disorders, patients with sickle cell Anaemia (and other conditions associated with rapid cell division and turnover) • Smear shows macrocytosis with hypersegmented neutrophils • BE CAREFUL WITH FOLATE OVERDOSE

  20. Anaemia of „chronic disease“ • Usually normocytic, normochromic (but can become hypochromic, microcytic over time) • Occurs in people with inflammatory conditions such as collage vascular disease, malignancy or chronic infections • Iron replacement is not necessary • May benefit from erythropoietin supplementation. • HEPCIDIN BLOCKS RESORBTION – IRON IS A GROWTH FACTOR OF BACTERIA

  21. The anaemia of chronic disease the hepcidin story • Hepcidin – a 25 aminoacid peptide from liver discovered in 2001 • Ferroportin – a very specific transmembrane iron export system • Hepcidin injection: Serum Fe decrease by blocking the Fe export from cells storing iron • Hepcidin deficiency: High serum Fe – iron overload. • Inflammation – hepcidin elevated to block iron for microbes

  22. Normal peripheral „smear“

  23. Echinocytes (“burr cells”)

  24. Iron deficiency anaemia MICROCYTIC

  25. Megaloblasts and hypersegmented neutrophil

  26. Spherocytosis

  27. TTP / HUS – microangiopathic haemolysis with schistocytes

  28. Malaria

  29. Babesiosis

  30. Sickle Cell Anaemia

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