Acquired Anaemias Flashcards
Firstly define Anaemia
A haemoglobin below the normal range for Age/Sex/Ethnicity
What are the clinical features of anaemia
Think poor perfusion: - Fatigue - SOB - Ankle Swelling - Dizziness - Chest Pain Symptoms of the cause
What is your first test when suspecting anaemia?
A FBC
Tells you the haemoglobin and the MCV/MCH
How do we describe anaemias?
Morphologically based on MCH & MCV
1) Hypochromic, Microcytic
2) Normochromic, Normocytic
3) Macrocytic
FBC shows hypochromic, microcytic anaemia, what are the likely causes?
Most likely Fe-deficiency Anaemia, if you’re in any doubt do a serum Ferritin to check (should be low)
If Ferritin is fine then it may be a secondary anaemia or Thalassaemia
Fe-deficiency anaemia is not a diagnosis but must have a cause, what could cause it?
Malabsorption e.g. gastritis or coeliac
Blood loss e.g. GI or menorrhagia
What elements of a history/exam could suggest iron deficiency anaemia?
Evidence of bleeds e.g. dyspepsia, PR bleeding or menorrhagia
Diet (in kids/elderly)
Pregnancy (increases Fe need)
Koilonychia, atrophic tongue & angular stomatitis
Also do Abdo & rectal exam looking for the cause
What tests can we do if we get a case of Fe-deficiency anaemia?
Endoscopy & barium study can be done if there’s evidence of GI blood loss
How do you treat Fe-deficiency anaemia?
Oral Iron +/- transfusion
Treat the cause
Patient presents with a Normochromic, normocytic anaemia, how would you proceed?
Test their Reticulocyte count.
If it’s increased it means you’re losing RBCs and the marrow is compensating –> Blood loss of haemolysis
If its normal or low –> Secondary anaemia, marrow infiltration etc
So lets say this patient’s reticulocyte count is high and you suspect a haemolytic anaemia. What could cause that?
Autoimmune HA (Extravascular haemolysis)
Or an intravascular cause:
- Mechanical e.g. art valve leaking
- Severe inf
- Pre-eclampsia, HUS or DIC
- Drugs
Congenital causes e.g.:
- G6PD deficiency
- Hereditary Spherocytosis
- Haemoglobinopathies e.g. Sickle cell
So we’ve done a FBC (normocytic/chromic) & a reticulocyte count (high).
How would we test a patient to see if they’re haemolysing?
Blood film = can see haemolysed cells
Serum Bilirubin = High
LDH = High
Serum Haptoglobin = low (eats up free haemoglobin)
How would we identify the cause of a haemolytic anaemia?
Coomb’s Test:
Detects Ab/complement on the red cell membrane so if +Ve suggests an immune source
Can also test urine for Haemosiderin & Urobilinogen
- Haemosiderinuria in intravascular haemolysis
- Extravascular haemolysis increases serum bilirubin –> high Urobilinogen
What can trigger an auto-immune haemolytic anaemia and how does coomb’s test help us with that?
Auto-antibodies from different triggers will agglutinate at different temperatures in coomb’s test so:
- Warm temps = idiopathic, drugs or CLL
- Cold Temps = CHAD, infection or lymphoma
How would we manage a haemolytic anaemia?
Support the marrow with Folic Acid
~Transfusion
Correct cause:
- IV Abx if septic
- Prosthetic valve replacement if leaky
- Immunosuppression & treat trigger if immune
Can also remove the site of haemolysis i.e. spleen
Most secondary anaemias are Normochromic Normocytic, some are Hypochromic, microcytic. What causes them?
Something causes inflammation –> Increased hepcidin –> Decreased Fe absorption
Look for infection, inflammatory disorders and malignancy
Ok so a FBC identifies a Macrocytic Anaemia, what would you do from there?
A blood film to test for Megaloblastic vs non-megaloblastic
Megaloblastic anaemia? how would you proceed?
It’s probably a B12 or Folate Deficiency so do a B12/folate assay to identify which one
Also look out for neuro symptoms from Subacute Combined Degeneration of the cord in B12 deficiency
What causes a B12 deficiency?
Gastric/ileal disease stopping absorption
More likely pernicious anaemia, an autoimmune attack on your gastric parietal cells/intrinsic factor
What causes a folate deficiency?
Diet
Haemolysis
GI pathology e.g. Coeliac
How do we treat a megaloblastic anaemia?
Oral Folate
B12 IM inj
What could cause a non-megaloblastic Macrocytic anaemia?
Some problem with the marrow e.g. Myelodysplasia, Marrow infiltration or drugs:
- Alcohol
- MTX
- Anti-retrovirals
- Hydroxycarbamide
What is haptoglobulin?
Protein which binds to hemoglobulin in blood plasma
What is hepcidin
Hepcidin is a regulator of iron metabolism. Hepcidin inhibits iron transport by binding to the iron export channel ferroportin which is located on the basolateral surface of gut enterocytes and the plasma membrane of reticuloendothelial cells (macrophages).
