Anaemia Flashcards
What is anaemia
Low Hb conc <135g/L for men and <115g/L women
Anaemia presentation
Fatigue
Dyspnoea
Pallor
Anaemia types
Microcytic
Normocytic (including haemolytic)
Macrocytic (can be haemolytic if immature RBCs)
Microcytic anaemia causes
Iron-deficient
Thalassaemia
Sideroblastic
Normocytic anaemia causes
Acute blood loss Anaemia of chronic disease Bone marrow failure Renal failure Hypothyroidism Haemolysis Pregnancy
Macrocytic anaemia causes
B12/folate deficiency
Liver disease
Reticulocytosis
Myelodysplastic syndromes
Hypothyroidism
Antifolate drugs
Cytotoxics
Indication for transfusion in anaemia
Hb <70g/L in acute, chronic better tolerated
Severe anaemia with heart failure, give slowly with furosemide 10-40mg IV/PO
Iron deficiency anaemia causes
Bleeding e.g. menorrhagia
Poor diet
Malabsorption (e.g. coeliac)
Iron deficiency anaemia signs
Koilonychia
Atrophic glossitis
Angular cheilosis
Iron deficiency anaemia tests
Blood film is hypochromic + microcytic
Confirmed by decreased ferritin, serum iron and increased TIBC
Iron deficiency anaemia treatment
Ferrous sulfate 200mg/8h PO, Hb up by 10g/L/week
Treat cause e.g. GI bleed
2ww referral for upper + lower GI endoscopy if Male with Hb<110
Anaemia of chronic disease causes
Poor use of erythropoesis
Dec production /response to EPO
Cytokine induced life-shortening of RBCs
Anaemia of chronic disease tests
Ferritin normal/inc in mild normo/microcytic anaemia
Sideroblastic anaemia definition
Ineffective erythropoiesis so inc iron absorption, iron loading in marrow ± haemosiderosis (organ damage due to iron deposition)
Sideroblastic anaemia causes
Congenital
Idiopathic
Can follow chemo/ anti-TB/ irradiation/ alcohol
Sideroblastic anaemia tests
Inc ferritin
Hypochromic blood film
Sideroblasts in marrow
Sideroblastic anaemia treatment
Remove cause
Pyridoxine ± transfusions for severe anaemia
Macrocytosis tests
Blood film shows hypersegmented neutrophils, target cells if liver disease
Red cell folate and serum B12
Bone marrow biopsy shows either (megaloblastic/ normoblastic (e.g. liver/ hypothyroid)/ abnormal erythropoiesis/ inc erythropoiesis (haemolysis))
Causes of folate deficiency
Poor diet (alcoholics, elderly, poverty)
Increased demand e.g. malignancy, pregnancy
Malabsorption
Drugs (phenytoin, valproate, methotrexate, trimethoprim)
Folate deficiency treatment
Assess underlying cause
Folic acid 5mg/day PO for 4 mths, always with B12 unless pt known to have normal B12
400mcg/day prophylactically in pregnancy until at least 12 wks
B12 deficiency causes
Dietary (vegans)
Malabsorption due to lack of IF (pernicious anaemia) or terminal ileum damage
Congenital metabolic errors
B12 deficiency presentation
Pallor and mild jaundice from haemolysis shows lemon tinge + anaemia signs
Peripheral neuropathy
Subacute combined degeneration of spinal cord (extensor plantars, absent knee jerk + absent ankle jerk triad); pain and temp intact
What is pernicious anaemia
Autoimmune atrophic gastritis so lack of IF secretion by gastric parietal cells
Pernicious anaemia tests
Tests for macrocytic anaemia and B12 deficiency
Parietal cell Abs and sometimes IF Abs may be found
B12 deficient anaemia treatment
Hydroxocobalamin (B12) 1mg IM every other day for 2wks
If pernicious 1mg IM every 3mths for life after that
If dietary intake oral B12 50-150mcg daily between meals
Watch for hypokalaemia and iron deficiency due to new RBCs
Identifying type of haemolytic anaemia
Increased RBC breakdown (normocytic with inc bilirubin, urinary urobilinogen, serum LDH)
Increased RBC production (reticulocytes so inc MCV + polychromosia)
Extravascular (splenomegaly) or intra (more Hb in plasma/bound to albumin; Hb or haemosiderin in urine)
Acquired causes of haemolytic anaemia
Direct Coombs +ve: drug induced, autoimmune (AIHA), paroxysmal cold Hburia seen in viruses, acute transfusion reaction
Direct Coombs -ve: hepatitis, post vaccination
Microangiopathic: mechanical damage to RBCs due to TTP, eclampsia, heart valves
Infection: all can exacerbate but malaria causes
Paroxysmal nocturnal Hburia: stem cell disorder with haemolysis, marrow failure + thrombophilia
Hereditary causes of haemolytic anaemia
Enzyme defects: G6PD deficiency (avoid precipitants and transfuse if severe) and pyruvate kinase deficiency Membrane defects (Coombs -ve, all need folate): sphero/ ellipto/ ovalo/ stomatocytosis Hbopathy: Sickle-cell, thalassaemia
Sickle-cell pathogenesis
HbS polymerises when deoxygenated, RBC deforms to sickle and haemolyse/block small vessels
Sickle-cell investigations
Hb 60-90g/L, inc reticulocytes and bilirubin
Blood film shows sickle + target cells
Sickle solubility test +ve but no distinction between HbSS and HbAS, Hb electrophoresis can do this
Sickle-cell presentations: Vaso-occlusive (microvascular) crisis
Pain/ cold/ dehydration/ infection/ hypoxia causes very painful, CNS infarct 10% of children, marrow affected
Sickle-cell complications
Splenic infarct before 2yrs increases susceptibility to infections
Poor growth
Chronic renal failure
Retinal disease
Lung damage (hypoxia -> fibrosis -> pulmonary hypertension)
Iron overload
Gallstones
Sickle cell chronic management
Hydroxycarbamide 20mg/kg/d increases fetal Hb production if frequent crises
Bone marrow transplant can be curative
Infection prophylaxis, especially with febrile children
Prenatal testing and parental education prevents deaths
Sickle cell crisis management
Analgesia early e.g. IV opiates
Septic screen and Abs if temp >38/ chest signs, watch for acute chest syndrome from fat embolus/ infection
Rehydrate with fluids, keep warm and O2 if needed
Measure PCV, reticulocytes, liver + spleen size bidaily
Crossmatch blood, check FBCs + reticulocytes
Blood transfusion if Hb/reticulocytes fall sharply
Exchange transfusion in those rapidly deteriorating
Thalassaemia types
Minor/trait - carrier which may have mild microcytic anaemia
Intermedia - moderate anaemia due to mild homozygous mutations or trait with anther Hbopathy, no transfusions needed
Major - Serious abnormalities in both beta-globin chains
beta-thalassaemia major features
Severe anaemia + failure to thrive from 1st year
RBCs made outside marrow causes skull bossing and skull XR shows hair on end sign
Hepatosplenomegaly from haemolysis
Blood film shows hypochromic, microcytic; target cells + nucleated RBCs
beta-thalassaemia major treatment
Life-long blood transfusions
Iron overload causes endo issues, control with deferiprone PO + desferroxamine SC 2 per wk; ascorbic acid can help inc urinary Fe excretion
Folate supplements + healthy lifestyle
Splenectomy >5yrs old if hypersplenism persists
Endo complication treatment
Marrow transplant can offer chance of cure
Alpha thalassaemia
4 alpha genes deleted then death in utero (Bart’s hydrops)
HbH disease if 3 deleted: moderate anaemia + haemolysis with beta-4 tetramers in blood film
2 genes deleted is asymptomatic carrier with dec MCV
1 gene deleted is normal clinical state
G6PD features
Heinz bodies, bite cells, blister cells on blood film Neonatal jaundice history Intravascular haemolysis Fava beans + henna can trigger African-Mediterranean descent
G6PD induced haemolysis causes
Sulph- antibiotics
Ciprofloxacin
Primaquine anti-malarial
Henna
Fava beans
What is hereditary spherocytosis
Most common hereditary haemolytic anaemia in Northern European descent
Sphere shaped RBCs shorter life-span as removed by spleen
Hereditary spherocytosis presentation
Jaundice Splenomegaly Gallstones Erythema infectiosum if with Parvovirus B19 and aplastic crisis Family Hx
Hereditary spherocytosis treatment
Folate replacement
Splenectomy
Hereditary spherocytosis diagnosis
Family Hx Normocytic anaemia Gallstones Raised MCHC is diagnostic EMA binding test if diagnosis ambiguous
Aplastic anaemia causes
Drugs (phenytoin, chloramphenicol, sulphonamides, gold)
Benzene
Parvovirus, hepatitis
Radiation
Sickle-cell presentations: Aplastic crisis
Parvovirus B19 suddenly reduces bone marrow production
Self-limiting <2wks usually but may need transfusion (reduced reticulocytes)
Sickle-cell presentations: Sequestration crisis
(inc reticulocytes) Mainly children, pooling of blood in spleen ± liver -> organomegaly, severe anaemia, shock (urgent transfusion needed)
Sickle-cell presentations: Acute sickle chest
SOB
Chest pain
Reduced pO2
Pulmonary infiltrates on CXR
