Ch 22 - Haem disorders Flashcards
By which point should all the HbF be converted to HbA?
6 months
Define anaemia - give vaules for neonates/ children
Low Hb Neonate
IDA: causes (3), iron sources (3)
inadequate intake (delay in introduction of mixed feeding beyond 6 months) malabsorption blood loss Iron sources - breast milk; low iron but high absorption, supplemented formula, cow’s milk; high iron but low absorption, solids at weaning
IDA: features (4), Ix (1), management (2)
lethargy, weight loss, FTT, poor feeding, pallor, Pica - inappropriate eating of non-food material e.g. chalk Ix - blood film - hypochromic microcytic RBCs; low serum ferritin Management - dietary advice, PO iron until Hb normal
Red cell aplasia: causes (3)
Diamond-blackfan anaemia transient erythroblastopenia of childhood parvovirus B19 - only if have haemolytic anemia
Red cell aplasia: Ix (5)
low reticulocytes normal Hb, Br Negative Coombs absent erythroblasts on BM examination
What is diamond blackfant anaemia & how to manage (2)
RPS gene mutations + FH > 2-3months of age > anaemic symptoms, abnormal thumbs > oral steroids +/- monthly blood transfusions
transient erythroblastopenia of childhood trigger (1), features (1)
Viral infection > same features as DBA - but no RPS mutations or anomalies & always recovers
hereditary spherocytosis: what is it?
autsomal dom mutations in genes relating to membrane proteins - spectrin/ankyrin > causes sphere shape Sphere shape & lack of these proteins > inflexible + more prone to rupture So taken to spleen for haemolysis > haemolytic anaemia
hereditary spherocytosis: features (4)
FH jaundice anaemia splenomegaly aplastic crisis gallstones
hereditary spherocytosis: Ix (4)
Blood film > spherocytes Unconjugated hyperbilirubinaemia Osmotic fragility test Coombs -ve
Management of hereditary spherocytosis (3)
Oral folic acid splenectomy aplastic crisis - blood transfusions
G6PD deficiency: definition, features (6), Ix (2), management (1)
D - X-linked def in G6PD enzyme. Mediterranean/middle east F - precipitated by flava beans, dugs e.g. nitrofurantoin, aspirin, quinines, fever malaise, increased free plasma Hb, decreased haptoglobins Ix - RBC G6PD acitivity M - avoid precipitants
Sickle cell disease: cause, types (4), pathogenesis
C - mutation in codon 6 of b-globin gene - AA changes from glutamine > valine - reduces charge on Hb (glutamine -ve and valine neutral)
T: HbSS - majority of Hb is HbS
HbSC - HbC is due to another mutation on B-globin gene (no normal B globin > so no HbA)
Sickle ß thalassemia - no HbA (HbS from 1 parent & ß-thalaessmia trait from another)
Sickle Trait - asymp carriers - 1 HbS & 1 normal ß-globin > 40% of Hb is S.
Pathogenesis: HbS polymerizes > Sickling of RBCs > microcirculation trapping > vaso-occlussion. Ischaemia worsens if cold, dehydrated, low pO2
SCD: Features (7)
- anaemia - lethargy, pallor, jaundice
- Infection - increased susceptiblity to encapsulated pathogens - due to hyposplenism 2ndary to microinfarction of spleen in infancy (due to sickling) (spleen produces opsonins) e.g. pneumococci, haemophillus influenza
- painful crises - vaso-occluive crises; commonly present with hand-foot syndrome: dactylitis + swelling + pain of fingers and/or feet from vaso-occlusion, acute chest syndrome - most serious vasoc-occlusive crises; may require ventilation
- acute anaemia - sudden drop in Hb due to: haemolytic crises (perhaps w. infectio) aplastic crises, sequestration crises - sudden splenomegaly + abdo pain + circulatory collapse from accumulation of sicled cells in spleen
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Priapism
- splenomegaly