Haemolytic Anaemia Flashcards
Definition of haemolytic anaemia?
Anaemia due to the destruction of RBCs
Investigations for haemolytic anaemia?
FBC (shows increased reticulocytes)
Blood film - essential
Bilirubin - shows unconjugated hyperbilirubinaemia
Lactic dehydrogenase (LDH) - increased in haemolysis
Specific investigations?
Coomb’s Test
EMA-binding - for hereditary spherocytosis
Glucose-6-phosphate dehydrogenase assay - for G6PD deficiency
Haemoglobin electrophoresis - can be used in diagnosis of thalassaemia
What is the Coomb’s test?
It looks for antibodies to RBCs
Indirect antiglobulin test - looks for antibodies in the patient’s serum. This test is used to cross match blood for suitability for transfusion. Positive test means donor RBCs are INCOMPATIBLE
DAT (direct antiglobulin test) - done to detect antibody to patient’s own serum causing AIHA (autoimmune haemolytic anaemia)
Features of haemolytic anaemia
Anaemia - due to reduction in circulating RBCs
Splenomegaly - as the spleen becomes filled with destroyed RBCs
Jaundice - as bilirubin is released during destruction of RBCs
Congenital/Inherited haemolytic anaemias
RBC membrane abnormalities - hereditary elliptocytosis, hereditary spherocytosis
RBC enzyme deficiencies - G6PD deficiency, pyruvate kinase
RBC haemoglobin disorders - thalassaemias, sickle cell disease
Acquired causes of haemolytic anaemia
AIHA (autoimmune haemolytic anaemia)
Microangiopathic haemolytic anaemia (HUS, TTP, DIC)
Drugs, infections, toxins
Copper deficiency (Wilson’s disease)
Who is Hereditary spherocytosis common in?
Northern Europeans
- Autosomal dominant
Presentation of Hereditary spherocytosis?
Jaundice
Gall stones
Splenomegaly
Diagnosis of hereditary spherocytosis?
Look for positive family history
FBC
Reticulocyte count - immature RBCs and is raised due to rapid turnover of RBCs
Blood film - look for spherocytes (sphere RBCs)
EMA-binding
Treatment of hereditary spherocytosis?
Give folic acid regularly
Often need splenectomy
Removal of gallbladder
In whom is G6PD deficiency seen?
Mainly males - X-linked
Common in people from the Mediterranean (e.g. Turkish)
What are the triggers of G6PD deficiency?
Fava/broad beans
Infections
Medications
- need to avoid: Antimalarial, Aspirin (large doses), Chloramphenicol, Dapsone, Phenylhydrazine, Nalidixic acid, Nitrofurantoin and Vitamin K
Symptoms of G6PD deficiency?
Feeling unwell and lack energy
Become pale and yellow in colour (intermittent jaundice)
Have a backache
Passing dark urine (cola)
How is GP6D deficiency diagnosed?
Done using a G6PD assay
On a blood film - ‘Heinz’ bodies are seen (denatured haemoglobin)
What genes are present in sickle cell anaemia and in what populations?
Autosomal recessive disorder
- Carriers: HbAS
- Affected: HbSS
Prevalent in Africa
What is vaso-occlusive crises sickle cell anaemia?
Vaso-occlusive crisis
- The cells can ‘sickle’ which blocks capillaries causing ischaemia
- Causes extreme pain (deep pain) and fever can result
- Can be triggered by dehydration and infections
- (Priapism - painful erection)
How to manage vaso-occlusive crisis?
Give fluid (via IV if needed)
Abx if necessary
Analgesia - consider opiates
Keep warm
Acute chest syndrome crisis and its management?
Syndrome that requires fever or respiratory symptoms with new infiltrates seen on x-rays - lungs can suddenly lose their ability to breathe in O2
Can be caused by infections or vast-occlusion
Emergency so needs - Abx/antivirals, blood transfusions and NIV or even intubation
What splenic issues may arise in sickle cell anaemia?
Auto-infarction of spleen - increased risk of infection
Splenic sequestration
- Cells can block blood flow to spleen causing an acute painful splenomegaly
- Due to blood build up in spleen, it can reduce circulating volume -> leading to shock
- Treated with: blood transfusions and fluid resus.
Stroke risk in sickle cell disease prevention?
Primary stroke prevention - done using a transcranial Doppler to assess Circle of Willis
- Give regular transfusions
Secondary stroke prevention - following a stroke start regular blood transfusions
Treatment of sickle cell anaemia?
Avoid dehydration and other triggers of crises
Ensure vaccines are up to date (e.g. give regular Pneumovax - stops pneumococcus)
Abx prophylaxis - penicillin V
Hydroxyurea - e.g. hydroxycarbamide
- enables production of HbF (fetal haemoglobin - 15% helps prevent crises)
Immediate morphine - for agonising bone pain
What is thalassaemia?
A complex group of autosomal recessive disorders that affect the haemoglobin chains
In thalassaemia, the red blood cells are more fragile and break down more easily
Microcytic anaemia
What are the signs and symptoms of thalassaemia?
Pallor Jaundice Gallstones Splenomegaly Poor growth and development Bone deformities - pronounced forehead and deformed cheek bones
What is management based upon for thalassaemia?
Long term blood transfusions and iron chelation (removal of excess iron)
Don’t start chelation too early – wait till Ferritin >1000ug/L to avoid neuro and skeletal toxicity
What medication is used in treatment of thalassaemia?
First line treatment up to age of 6 - Desferal
- SC injection up to 5x per week
- Painful
- Poor compliance
- Potential neuro and skeletal toxicity
First line treatment >6 years - Exjade (desferasirox)
- PO OD
- No neuro/skeletal toxicity
- Good compliance
What is autoimmune haemolytic anaemia (AIHA) and the types?
Autoimmune haemolytic anaemia occurs when antibodies are created against the patient’s RBCs
There two basic types: warm (more common) and cold depending on the thermal range across which the antibody is active
- Cold at occurs at less than 10C
- Warm has POSTIVE DAT test
What does the blood film show for warm AIHA?
IgG
Micro-spherocytes (red arrows) and polychromatic macrocytes (blue arrows)
Blood film is just like hereditary spherocytosis but Coomb’s test is positive in AIHA
Extravascular
Steroid responsive
What does blood film show for cold AIHA?
IgM
Clumps of red cells agglutinated by the presence of cold agglutinins
Intravascular haemolysis can lead to haemoglobinuria
Treat by avoiding cold
What are the underlying causes?
Warm AIHA - more common
- Idiopathic
- Secondary: Rheumatoid disease e.g. SLE(systemic lupus ertythematous), Lymphoma
- Chronic Lymphatic Leukaemia Drugs: e.g. cephalosporins Ovarian Teratoma
Cold AIHA
- Idiopathic
- Secondary: EBV (Epstein Barr Virus) infection, Mycoplasma pneumonia, Ulcerative Colitis
Management of AIHA?
Blood transfusions
Prednisolone (steroids) - 1mg/kg in acute scenario (OD)
- (BD will result in patient staying awake)
5mg OD Folic Acid
Rituximab (a monoclonal antibody against B cells)
Splenectomy
