Haemolytic anaemia Flashcards
What are the causes of intravascular vs haemolytic anaemia
Intravascular
Malaria
G6PD and PK deficiencies
Mismatched ABO blood transfusion
Cold anti-body haemolytic syndromes
Drugs
Microangiopathic HA’s (i.e. TTP)
Paroxysmal nocturnal haemoglobinuria
Extravascular
Autoimmune
Alloimmune
Hereditary spherocytosis [AD inheritance]
What are the causes of acquired haemolytic anaemia
Immune:
- Warm: CLL, SLE
- Cold: mycoplasma, EBV
Non-immune:
- Mechanical: metal valves, trauma
- PNH, MAHA
- Infections e.g. malaria
- Drugs
What are the causes of inherited haemolytic anaemia
Membrane defect: hereditary spherocytosis/eliptocytosis
Enzyme defect: G6PD deficiency, pyruvate kinase deficiency
Haemoglobinopathies: SCD, thalassaemia
What are the features of hereditary spherocytosis (inheritance, pathology, presentation)
Autosomal dominant (25% recessive or de novo)
Norther Europe more common
Spectrin or ankyrin deficiency
S/S: susceptibility to parvovirus B19, gallstone development, splenomegaly (extravascular haemolysis)
What investigations should be done to diagnose hereditary spherocytosis
Blood film: Spherocytes seen
Osmotic fragility test: raised (lysis in hypotonic solution)
Di-binding test
Flow cytometry (EMA binding test)
Cryohaemolysis test
DAT coombs NEGATIVE
What is the management for hereditary spherocytosis
Folic acid
± splenectomy
What are the consequences of haemolysis
Anaemia
Erythroid hyperplasia
Increased folate demand
Susceptibility to parvovirus B19. gallstones, iron overload, osteoporosis, and hepatic siderosis
What is haemolysis in G6PDD triggered by
Anti-malarials e.g. primaquine
Sulphonamides, ciprofloxacin, nitrofurantoin
Vitamin K
Fava beans
Henna
Naphthalene (moth balls)
Infections
What is G6PDD
deficiency in G6PD which catalyses the first step in the pentose phosphate pathway to generate NADPH
Common in Mediterranean populations
X-linked
Untreated → neonatal jaundice → kernicterus
What is the testing and management for G6PDD
Testing:
- Fluorescent spot test (G6PD and NADP)
- Methaemoglobin (Methylene blue)
- Guthrie spot
- G6PD activity
- film: bite cells, heinz bodies
management: folate supplements, phototherapy in neonates
Avoid precipitants
Transfuse if severe
Genetic screening
What are the features of pyruvate kinase deficiency on blood film
Echinocytes (“hedgehog-like”)
Spherocytes
What are the features of warm autoimmune haemolytic anaemias and what are the causes
37oc
IgG
Positive coombs test
Spherocytes seen on blood film
Causes: idiopathic, lymphoma, CLL, SLE, methyldopa
What are the features and causes of cold agglutinin disease (autoimmune haemolytic anaemia)
<37oC
IgM
Positive Coombs test
Often with Raynaud’s
Causes: idiopathic, lymphoma, infections (EBV, mycoplasma)
What are the causes of MAHA
HUS
TTP
DIC
Pre-eclampsia
What is TTP
Antibodies against ADAMTS13 → long strands of vWF which shear RBCs (haem emergency)
Pentad:
1. MAHA
2. Fever
3. Renal impairment
4. Neuro abnormalities
4. Thrombocytopenia
