Haemolytic anaemia Flashcards
2 categories of haemolytic anaemia
- Inherited conditions:
- cause RBCs to be more fragile and break down faster than normal
- Leads to chronic haemolytic anaemia - Acquired conditions:
- Lead to increased RBC breakdown and haemolytic anaemia
Inherited haemolytic anaemias:
- Hereditary Spherocytosis
- Hereditary Elliptocytosis
- Thalassaemia
- Sickle Cell Anaemia
- G6PD Deficiency
Acquired haemolytic anaemias:
- Autoimmune haemolytic anaemia
- Alloimmune haemolytic anaemia (transfusions reactions and haemolytic disease of newborn)
- Paroxysmal nocturnal haemoglobinuria
- Microangiopathic haemolytic anaemia
- Prosthetic valve related haemolysis
Features of haemolytic anaemia:
Anaemia
- due to reduction of circulating RBCs
Splenomegaly:
- spleen filled with destroyed RBCs
Jaundice:
- Bilirubin is released during the destruction of RBCs
Investigation for haemolytic anaemia:
FBC - Shows normocytic anaemia
Blood film - shows schistocytes (RBC fragments)
Direct Coombs Test - positive in AUTOimmune haemolytic anaemia
Most common inherited haemolytic anaemia in northern europeans:
Hereditary Spherocytosis
Hereditary spherocytosis characteristics and presentation:
Autosomal dominant
Spherical RBCs - fragile and easily broken in spleen
Presentation:
- Jaundice, gallstones, splenomegaly
- APLASTIC CRISIS in presence of parvovirus
Hereditary spherocytosis diagnosis:
Diagnosed by family history and clinical features
BLOOD FILM: spherocytes on the blood film
The mean corpuscular haemoglobin concentration (MCHC) is raised - on FBC
Raised reticulocytes (rapid turnover)
Management of hereditary spherocytosis
Folate supplementation
Splenectomy
Cholecystectomy - if gall stones become a problem
Hereditary Elliptocytosis:
Same as hereditary spherocytosis except RBCs are ellipse shaped
Autosomal dominant
Presentation and treatment are the same as well
G6PD Deficiency: general
Defect in RBC enzyme G6PD
More common in mediterranean and african patients
X linked recessive
G6PD Deficiency crisis triggers
Infections
Fava/broad beans
Medications -
- primaquine (an antimalarial),
- ciprofloxacin
- sulfonylureas
- sulfasalazine
- sulphonamide drugs.
Presentation of patient with G6PD haemolytic anaemia
Jaundice (usually during neonatal period)
Gallstones
Anaemia
Splenomegaly
Heinz bodies on blood film
Diagnosis can be made by doing a G6PD enzyme assay.
Diagnosis of G6PD deficiency
G6PD enzyme assay
Autoimmune Haemolytic Anaemia (AIHA)
occurs when antibodies are created against the patient’s red blood cells. - lead to destruction of RBCs
2 types based on temperature at which auto-antibodies function - to cause destruciton
Warm type
Cold type
Warm Type Autoimmune Haemolytic Anaemia
more common type.
Haemolysis occurs at normal or above normal temperatures.
It is usually idiopathic, meaning that it arises without a clear cause.
Cold Type Autoimmune Haemolytic Anaemia
This is also called cold agglutinin disease
At lower temperatures (e.g. less than 10ºC) the antibodies against RBCs attach themselves to the RBCs and cause them to clump together (agglutination)
Results in destruction - immune system activated against them and they get filtered and destroyed in spleen
Often secondary to other conditions such as:
- lymphoma, leukaemia, systemic lupus erythematosus
or infections such as:
- mycoplasma, EBV, CMV and HIV.
Cold type AIHA is often secondary to other conditions such as
lymphoma,
leukaemia,
systemic lupus erythematosus
infections such as: mycoplasma, EBV, CMV HIV.
Management of autoimmune haemolytic anaemia
Blood transfusions
Prednisolone (steroids)
Rituximab (a monoclonal antibody against B cells)
Splenectomy
Alloimmune Haemolytic Anaemia
Occurs either when:
- there is foreign RBC circulating (destroying foreign RBCs)
- there is foreign antibody circulating (acts against own RBCs causing hemolysis)
2 scenarious when this occurs:
- transfusion reactions
- Haemolytic disease of newborn
hemolytic transfusion reactions
Type of Alloimmune Haemolytic Anaemia
Immune system produces antibodies against antigens on those foreign RBCs
Creates immune response that leads to the destruction of those RBCs
haemolytic disease of the newborn
Type of Alloimmune Haemolytic Anaemia
There are antibodies that cross placenta from mother to foetus
Maternal antibodies target antigens on RBCs of the foetus
Causes destruction of RBCS in the foetus and neonate
Paroxysmal Nocturnal Haemoglobinuria
rare condition that occurs when a specific genetic mutation in the haematopoietic stem cells in the bone barrow occurs during the patients lifetime
Mutation results in loss of proteins on the surface of RBCs that inhibit the conplement cascade
- loss of protection against complement cascade results in activation on the surface of RBCs resulting in destruction
Paroxysmal Nocturnal Haemoglobinuria
Presentation
Characteristic presentation is red urine in the morning containing haemoglobin and haemosiderin
Patient anaemic due to haemolysis
Patient predisposed to:
- thrombosis - (DVT, PE, hepatic vein thromboses)
- Smooth muscle dystonia (oesophageal spasm and erectile dysfunction)
Management of Paroxysmal Nocturnal Haemoglobinuria
Eculizumab or bone marrow transplantation
Eculizumab - monoclonal antibody that targets C5 complement protein
- causing suppression of complement system
Bone marrow transplantation can be curative
Microangiopathic Haemolytic Anaemia (MAHA)
Small BVs have structural abnormalities that cause haemolysis of the blood cells travelling through them
Usually secondary to an underlying condition
Conditions that can lead to Microangiopathic Haemolytic Anaemia (MAHA) (x5)
Haemolytic Uraemic Syndrome (HUS)
Disseminated Intravascular Coagulation (DIC)
Thrombotic Thrombocytopenia Purpura (TTP)
Systemic Lupus Erythematosus (SLE)
Cancer
Prosthetic Valve Haemolysis
Haemolytic anaemia is key complication of prosthetic heart valves
Occurs in both bioprosthetic and metallic valve replacement
Caused by collision of RBCs with implanted valve
Management of Prosthetic Valve Haemolysis
Monitoring
Oral iron
Blood transfusion if severe
Revision surgery may be required in severe cases
