Haemolytic Anaemias Flashcards
congenital causes of haemolytic anaemia
- hereditary spherocytosis
- hereditary ellipocytosis
- G6PD deficiency
- PK deficiency
- thalassemia
- sickle anaemia
acquired causes of haemolytic anaemia
- autoimmune haemolytic anaemia
- microangiopathic haemolytic anaemia
- malaria
- wilson’s disease
- zieve’s syndrome
- mechanical haemolysis
clinical features of haemolytic anaemia
- pallor
- fluctuating jaundice
- dark urine
- splenomegaly
- gallstones
- folate deficiency
lab results of haemolytic anaemia
- increased unconjugated bilirubin
- increased urine bilinogen
- low haptoblobins
- reticulocytosis
- marrow erythroid hyperplasia
what happens when there is intravascular haemolysis?
- erythrocytes destroyed directly in circulation
- Free Hb released rapidly and saturates plasma haptoglobins
- Free excess Hb filtered by glomeruli
- Appears as haemoglobinuria
- Acute renal failure
- Laboratory features: haemoglobinuria, haemosidinuria
what is hereditary spherocytosis?
- autosomal dominant
- defect in spectrin
differential diagnosis for hereditary spherocytosis
autoimmune haemlysis (warm) - distinguish by Coombs test
investigations of hereditary spherocytosis
- blood film
- radiolabelled studies
- spectrin assays
- osmotic fragibility tests
- autohaemolysis test
treatment of hereditary spherocytosis
- splenectomy
- folate supplements
what does Coombs test do?
detects the antibody that causes autoimmune haemolysis
expected results from HS
- high bilirubin
- reticulocyte count
- splenomegaly
what are the different grades of severity?
- mild: compensates well
- severe: neonatal jaundice
what is G6PD deficiency?
- glucose-6-phosphase dehydrogenase deficiency
- X-linked
- rapid intravascular haemolysis precipitated by oxidative stress
- precipitants include infection, drugs, fava beans
- Hb is normal between crisis
how do you diagnose G6PD?
- blood film with bite cells and Heinz bodies
- G6PD assay
what is paraoxysmal noctural haemoglobinuria?
- rare acquired clonal effect
- red cell membrane unduely sensitive to complement mediated lysis
- chronic intravascular haemolysis
- recurrent thrombosis
how do you diagnose paraoxysmal noctural haemoglobinuria?
- flow cytometry (CD55 and CD59)
- Ham’s test
management of PNH?
- leucodepleted blood products
- long term anticoagulation
- eculuzumab
- BMT
what are the types of autoimmune HA?
- warm autoantibodies (IgG)
- cold autoantibodies (IgM)
causes of autoimmune HA
- idiopathic
- viral infections
- mycoplasma
- lymphoma
- systemic autoimmune diseaes
- exposure to certain drugs
lab features of autoimmune HA
- spherocytic cells
- bits of the red cell removed
investigations for autoimmune HA
- blood film
- DCT positive
management of autoimmune HA
- avoid transfusion
- immunesuppression
- splenectomy
- folate supplements
what is thalassemia?
failure to produce a globin chain
- autosomal recessive
which types of haemoglobin molecules are affected by alpha thalassemia?
HbA, HbF, HbA2
what happens if there is a globin chain imbalance?
the protein gets denatured
what type of anaemia does thalassemia give you?
microcytic hypochromic
expected lab results for b-thalassemia
- normal Hb
- MCV, MCH reduced
- RBC normal or raised
- raised HbA2
features that a thalassemia major patient has
- severe anaemia (transfusion-dependent)
- hyperplasia of bone marrow
- hepatosplenomegaly
- iron overload
- endocrine deficiencies
- osteoporosis
management of thalassemia major
- transfusion every month
- iron chelation (to prevent iron overload - done orally)
- splenectomy
- hormone replacement
- bisphosphonates
- folate supplementation
- bone marrow transplant
what is thalassemia intermedia?
condition which is intermediate in severity between the major and the minor
another name for thalassemia intermedia in alpha-globin deficiency
HbH disease
which amino acid substitution is in sickle cell anaemia
valine for glutamic acid
heretability of sickle cell anaemia
autosomal recessive
trigger for a sickle crisis
- infection
- dehydration
- cold
- hypoxia
presentation of sickle cell anaemia
- jaundice
- gallstones
- anaemia
- asplenic (multiple infarctions)
- organ failure (multiple infarctions)
- leg ulcers
- recurrent infections
- aseptic necrosis of bone
- chronic renal disease
- retinopathy
when does sickle cell anaemia present?
6 months of age
management of a sickle cell crisis
- oxygen (for hypoxia)
- IV fluids
- antibiotics
- analgesia
- exchange transfusion
management of a sickle cell patient
- hydroxyurea to increase HbF
- folate supplements
- penicillin, vaccines
- bone marrow transplant
