Haematology AS Flashcards
What values define anaemia?
Males: Hb 140 (<14g/L)
Females: Hb <120 g/L (<12g/L)
Or 125 g/L (<12.5g/dL) in adults.
What are the symptoms of anaemia?
Fatigue Dyspnoea Faintness Palpitations Headache Tinnitus
What are the signs of anaemia?
Pallor Hyperdynamic circulation - Tachycardia - Flow murmur: apical ESM - Cardiac enlargement
Ankle swelling with heart failure.
What are the causes of a microcyctic anaemia?
Haem defect
- Iron deficiency anaemia
- anaemia of chronic disease (because of reduced iron, inadequate secretion of EPO for erythropoiesis, reduced red cell survival). Ferritin is acute phase reactant. Iron is not released from stores therefore despite having low circulating iron, total iron body stores are increased so transferrin is reduced, meaning TIBC is reduced.
- Sideroblastic/lead poisoning
Globin defect
- Thalassaemia
What are the causes of a macrocytic anaemia?
Megaloblastic
- Vit B12 or folate
- Anti-folate drugs (phenytoin, methotrexate)
- Cytotoxic: Hydroxycarbamide
Non-megaloblastic
- Reticulocytosis
- Alcohol or liver disease
- Hypothyroidism (stimulatory effect of thyroid hormones on erythropoiesis).
- Myelodysplasia
What are the causes of a normocytic anaemia ?
- Recent blood loss
- Bone marrow failure
- Renal failure
- Early ACD
- Pregnancy (increased plasma volume)
In Haemolytic Anaemia what are the signs of increased red cell breakdown?
- Anaemia with increased MCV + polychromasia = reticulocytosis
- Increased unconjugated bilirubin
- Increased urinary urobilinogen
- Increased LDH
- Bile pigment stones
What are the signs of intravascular haemolytic anaemia?
- Haemoglobinaemia
- Haemoglobinuria
- Decreased haptoglobins
- Increased urine haemosiderin
- Increased MCHC
- Methaemalbuminaemia
What sign indicated extravascular haemolytic anaemia?
Splenomegaly (phagocytosis of red blood cells).
What are the acquired haemolytic anaemias?
Immune-mediated DAT +ve
- AIHA: warm, cold,
- Drugs: penicillin, quinine, methyldopa
- Allo-immune: acute transfusion reaction, HDFN.
Non-Immune (DAT -ve) - PNH Mechanical - MAHA: DIC, HUS, TTP - Heart Valve
Infections: Malaria
Burns
Hereditary
- Enzyme: G6PD and pyruvate kinase deficiency
- Membrane: HS, HE
- Haemoglobinopathy: SCD, thalalassaemia
What are the signs of iron deficiency anaemia?
- Koilonychia
- Angular Stomatitis/cheiolsis
- Post-cricoid Web: Plummer-Vinson (IDA, Dysphagia, Oesophageal webs)
What are the causes of IDA?
Increased loss: Menorrhagia, GI bleeding, Hookworms
Decreased intake: Poor diet
Malabsorption: Coeliac, Crohn’s
What are the investigations of IDA?
- MCV
- Reticulocytes
Haematinics:
- decreased ferritin (correlates with iron stores), - increased TIBC (High as this reflects low iron stores),
- decreased transferrin saturation (not saturated as free)
- high transferrin (to bind and carry iron)
Film:
Anisocytosis (size) , poikilocytosis (Shape), pencil cells, hypochromic
Men of any age with a Hb below 110 should be referred for upper and lower GI endoscopy as a 2WW.
- Upper and Lower GI endoscopy
- Coeliac screen
- H.pylori
Management of IDA?
Ferrous Sulphate 200mg PO TDS
IV iron for those with Iron deficiency anaemia prior to surgery when oral iron can’t be tolerated or not enou
- SE: GI upset
What is sideroblastic anaemia
- Body has enough Iron, but unable to make haemoglobin.
- Ineffective erythropoiesis
- Increased iron absorption
- Iron loading in BM –> ringed sideroblasts. (Granules of iron in mitrochondria)
- Haemosiderosis: endo, liver, cardiac damage.
What are the causes of sideroblastic anaemia
Congenital
Acquired
- Myelodysplastic/myeloproliferative disease
- Drugs: Chemo, anti-TB, lead.
What are the investigations for Sideroblastic anaemia?
- Microcytic anaemia not responsive to oral iron
- Increased ferritin, increased serum iron, normal TIBC
Management of sideroblastic anaemia?
Remove cause
- Pyridoxine may help
What is the pathophysiology of Thalassaemia?
Point mutations/deletions –> Unbalanced production of globin chains
–> Precipitations of unmatched globin
Membrane damage –> haemolysis while still in BM and removal by the spleen.
What is the epidemiology of thalassaemia?
Common in Mediterranean and Far East (Egyptian girl/Greek man)
What is B-Thalassemia Trait?
- B normal/B + or B/B0 (no production).
- Mild anaemia usually harmless.
- Decreased MCV (too low for the anaemia) - <75
- Increased HbA2 (a2delta 2) and increased HbF (a2y2).
- HbA2 (>3.5%)
However, there is no history to suggest this and the microcytosis is disproportionately low for the haemoglobin level. This combined with a raised HbA2 points to a diagnosis of beta-thalassaemia trait
Normally seen when fetal haemoglobin transitions to adult haemoglobin.
What is B-Thalassaemia Major?
- Ineffective B-chain therefore severe deficiency in most red-blood cells.
- Features develop from 3-6 months:
Severe anaemia
Jaundice
Failure to Thrive
Extramedullary erythropoiesis - Frontal bossing
- Maxillary overgrowth
- Hepatosplenomegaly
Haemachromatosis after 10yr (transfusion)
What are the investigations for B-thalassaemia major
- Decreased Hb (microcytic) - haemoglobin problem.
- Decreased MCV
- Very high HbF
- V high HbA2
- High reticulocyte
Film: Target cells (Thalassaemia) and nucleated RBC
Electrophoresis
- Fast migrating are Hb H and Barts.
Management of B-Thall major?
- Life-long transfusion
- SC- desferrioxamine Fe Chelation
- Splenectomy
- BM transplant may be curative