Ch 22 - Haem disorders Flashcards Preview

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Flashcards in Ch 22 - Haem disorders Deck (31):
1

By which point should all the HbF be converted to HbA?

6 months

2

Define anaemia - give vaules for neonates/ children

Low Hb Neonate

3

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

4

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

5

Red cell aplasia: causes (3)

Diamond-blackfan anaemia transient erythroblastopenia of childhood parvovirus B19 - only if have haemolytic anemia

6

Red cell aplasia: Ix (5)

low reticulocytes normal Hb, Br Negative Coombs absent erythroblasts on BM examination

7

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

8

transient erythroblastopenia of childhood trigger (1), features (1)

Viral infection > same features as DBA - but no RPS mutations or anomalies & always recovers

9

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

10

hereditary spherocytosis: features (4)

FH jaundice anaemia splenomegaly aplastic crisis gallstones

11

hereditary spherocytosis: Ix (4)

Blood film > spherocytes Unconjugated hyperbilirubinaemia Osmotic fragility test Coombs -ve

12

Management of hereditary spherocytosis (3)

Oral folic acid splenectomy aplastic crisis - blood transfusions

13

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

14

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

 

15

SCD: Features (7)

  1. anaemia - lethargy, pallor, jaundice
  2. 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 
  3. 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
  4. 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
  5. Priapism 
    1. splenomegaly 

16

SCD: management  (prophylaxis (2), acute crises (3), chronic problems (2))

Prophylactic daily oral penicillin (protects against pneumococcal) + Folic acid for increased haemolysis 

Acute crises: analgesia + good hydration + O2 + exchange transfusion

chronic problems (recurrent crises): Hydroxyurea - increases HbF, BMT 

17

ß-Thalassaemias: Types (3), features (6), Ix (3), Rx (3)

T: Major - no HbA, Intermedia - Some HbA + lots of HbF, Trait - asymp - raised HbA2 & HbF

F - severe anaemia, FTT, pallor, jaundice, bossing of skull & maxiallry growth (rare in developed countries due to transfusions), hepatosplenomegaly. Compliactions of iron overload from transfusions - cariomyopathy, DM, cirrhosis

Ix - microcytic hypochromic anaemia (often misdiagnosed as IDA), to differentiate - will see high HbA2 & normal ferritin (low in IDA)

M - Lifelong monthly transfusions, Desferrioxamine (iron chelation), BMT 

18

a-Thalassaemia: 3 types & 2 features for each

Hb Barts/ major - all 4 alpha genes deleted - no HbA (or A2) > fetal hydrops - death inutero or few hours post natal

HbH - 3 alpha globin genes deleted - mild-moderate anaemia, sometimes transfusion dependent 

a-thalassemia trait - asymp, anaemia mild or absent, may have hypochromic microcytic RBCs 

19

Anaemia of the newborn: reduced RBC production; 2 causes, what would the Ix show (Hb, RBC, reticulocytes, Br)

  1. Parvovirus B19
  2. Diamond-Blackfan anaemia

Hb low, RBC low, reticulocytes low, Br normal

 

20

Anaemia of the newborn: haemolytic anaemia: causes (4), Ix (RBCs, reticulocytes, Br) 

Main causes of haemolytic anaemias in neonates:

  1. immune - haemolytic disease of new born
  2. Hbpathies - SCD, thalassemias
  3. RBC membrane defects - Hereditary spherocytosis
  4. RBC enzyme defects - G6PD def

Ix - RBC may be spherical if membrane defect, high reticulocytes, unconjugated hyperbilirubinaemia

  1. if suspect immune - postive Coombs test (DAT) 

21

Anaemia of the newborn: Blood loss causes (3), anaemia of prematurity causes (3)

Blood loss - feto-maternal haemorrhage, twin-to-twin transfusion, placental abruption. Ix - increased reticulocytes + normal Hb 

anaemia of prematurity - inadequate EPO production, Fe/folic acid def, reduced RBC lifespan 

22

Bone marrow failure syndromes: Facnconi anaemia: Defintion, features (4), Ix (2), Rx (1)

D - autosomall recessive inherited aplastic anaemia

F - short statur, renal malformations, abnormal radii/thumbs, pigmented skin lesions e.g. cafe au lait

Ix - Pancytopenia, increase chromosomal breakage of peripheral blood lymphocytes

M - SCT 

NB - high risk of acute leukaemia

23

Shwachman-Diamond syndrome: cause, features (4)

C - autsomal recessive SBDS gene mutation (very rare), also high risk of transformation to AML

F - BM failure, pancreatic exocrine failure, skeletal abnormalities, isolated neutropenia

 

24

Haemophilia: types, features (4), Ix (2), Rx (3)

Autosomal recessive disorder: A - Factor VIII def, B- Factor IX def

Features: increased bleeding into muscles/joints, prolonged bleeding post circumcision/venepuncture, IC haemorrhage

Ix: APTT prolonged (NB APTT measures Intrinsic pathway), VIII:C or IX:C ratio low 

Rx: recomb VIII or IX, avoid IM injections/ NSAIDS, DDAVP 

25

Von Willebrand disease: vWF roles (2), features (3), Ix (1), Rx (2)

2 main roles of vWF:

  1. facilitates platelet adhesion to damaged endothelium
  2. carries factor VIII (like joey of kangaroo), protecting it from inactivation/clearance

so a vWF def results in defective plt plug formation and FVIII def. 

F - bruising, prolonged post surgical bleeds, epistaxis/menorrhagia

Ix - low FVIII

Rx - type 1- DDAVP, more severe give VIII & avoid IM injections/NSAIDs

 

26

Acquired disorders of coagulation: causes (4), Vit K def - causes (3) & features (3)

C - haemorrhagic disease of newborn due to vit K def, ITP, DIC, hepatic disease

Vit K def: malabsorption - Coeliacs/CF, antagonists - warfarin, maternal anticonvulsant

F - low vit II, VII, IX, X so prolonged PT, also low Protein C/S/Z

27

Thrombocytopenia: causes (6)

Increased plt destruction/consumption

  • Immune: ITP, SLE
  • Non-immune: HUS, DIC, congenital heart disease

Impaired plt production

  • congenital: Fanconi anaemia, Bernard- Soulier syndrome
  • Acquired: aplastic anaemia, leukaemia

 

 

28

Thrombocytopenia: Platelet ranges for severe, moderate & mild thrombocytopenia. 4 features of Thrombocytopenia

Severe: <20 - spontaneous bleeding

Moderate: 20-50 - bleeding only after trauma

Mild: 50-150 - bleeding only after major trauma/operation

F - petechiae, purpura, mucosal bleeds, bruising

29

ITP: Features (4), Ix (1), Rx (3), Chronic ITP 

Most common cause of thrombocytopenia in childhood - auto IgG against plts

F - usually post-viral onset > petechiae, purpura, bruising, epistaxis

Ix - diagnosis of exclusion; isolated thrombocytopenia

Rx - usually acute self limiting within 6-8 weeks, if need to treat - oral pred, plt transfusion if severe

Chronic ITP - > 6 months; supportive treatment; Rituximab, splenectomy 

30

DIC: defintion, causes (4), features (3), Ix (3), Rx (4)

D - coagulation pathway activation leading to diffuse fibrin deposition in the microvasculature & consumption of of coag factors + plts 

C - sepsis, burns, trauma, shock

F - bruising, purpura, haemorrhage 

Ix - prolonged PT & APTT, thrombocytopenia, low fibrinogen, low anti coags e.g. Protein C/S & AT

Rx - treat underlying cause, FFP, plts, antithrombin & protein C concentrates 

31

Thrombophilas in children: give 4 inherited abnormalities

  1. Factor V Leiden - fV resistant to Protein C
  2. Def in Protein C - autosomal dominant; thrombosis predisposition when 20-30, if homozygous life-threatening
  3. Antithrombin def 
  4. Portein S def