Anaemia - Presentation, Diagnosis and Treatment Flashcards
What factors may be considered when diagnosing anaemia?
- All biological measurements will have a range of normality
- Range will be age/gender related
- Expressed as reference range- often a “normal distribution”
What Hb range is used to diagnose anaemia?
For Hb typically in adult male 135-175, female 120-155 g/ (previously g/dl)
What are the symptoms of anaemia?
“Tired all the time”- need to unpack this
Symptoms relating to reduced O2 delivery
- short of breath
-muscle pain on exertion
-dizzy
-angina
Symptoms relating to the cause of the anaemia
What are the clinical signs of anaemia?
- Palor in skin and conjunctiva
- Tachycardia
- Rapid breathing
- Peripheral oedema if severe anaemia
- Signs relating to cause of anaemia
What are the symptoms of mild anaemia?
Mild anaemia likely to cause no symptoms unless extreme exertion
What is the effect of anaemia on cardiac output?
Cardiac output increases- rate and stroke volume
• Changes in distribution of blood flow
What factors are used to classify the type of anaemia?
- Under-production or increased loss of RBC
- Congenital or acquired
- Acute or chronic
- By mean cell volume (MCV) – microcytic/normocytic/macrocytic
How do you calculate the classification of anaemia by mean cell volume?
Haematocrit (Hct) (%) X10
RBC count (number as 1012/l)
• MCH- mean cell Hb - Hb RBC
• MCHC- mean cell Hb concentration- Hb Hct
•RDW red cell distribution width is a measure of spread of RBC size eg retics/transfusion
What is a mean cell volume of 60-80fl indicative of?
Microcytic anaemia- iron def, thalassaemia
What does microcytic anaemia refer to?
Abnormally small erythrocyte, linked to certain types of anaemia
What is a mean cell volume of 80-100fl indicative of?
Normocytic anaemia - blood loss, anaemia of chronic disease,
renal impairment
What does normocytic anaemia refer to?
An anaemia caused by chronic disease, v prevalent in over 85 y/o
What is a mean cell volume of 100 -120fl indicative of?
Macrocytic anaemia - megaloblastic anaemia- B12/folate deficiency, myelodysplasia
What does macrocytic anaemia refer to?
Abnormally large erythrocytes linked to certain types of anaemia
What is hypochromic anaemia?
Any type of anaemia where the erythrocyte is paler than normal, iron def, thalassaemia
What is the most common cause of anaemia worldwide?
Iron deficiency anaemia
What is the pathology of iron deficiency anaemia?
Typically reduction in MCV (microcytic) to 65-80, then in Hb, low ferritin, low transferrin saturation with iron. Rest of blood count normal- ?raised platelets if bleeding.
What may cause iron deficiency anaemia?
-Poor intake of iron
- Blood loss- menstrual
- —GI tract ?haematemesis or melaena eg peptic ulcer/cancer/angiodysplasia/hookworm
- Malabsorption- coeliac disease
- Increased need eg growth spurt/pregnancy
What are the clinical features of iron deficiency anaemia?
- Pale
- Tachycardia
- Koilonychia
- Hair loss
- Pica
- Glossitis/angular stomatitis
- Features relating to the cause eg wt loss/abdo pain/bowel change/heavy periods
How should one investigate iron deficiency anaemia?
- Be guided by history- recent and past and clinical findings
- Confirm iron def by low ferritin and typical FBC •Screen for coeliac disease (IgA tissue transglutaminase or tGA)
- Upper and lower endoscopy for all except pre-menopausal women
- Consider other imaging/capsule endoscopy
How should one orally treat iron deficiency anaemia?
- Oral- replacement with sufficient iron for long enough period eg ferrous sulfate 200mg 2 or 3 per day- 65mg elemental iron per dose
- Side effects- nausea/abdo pain/constipation- dose related- may improve if changed to ferrous gluconate or fumarate
- Typically patients need 3 months of iron AFTER correction of anaemia to build up iron stores
- Treat the underlying cause
- Rise in Hb generally 10g/l per week if not bleeding
How should one treat iron deficiency anaemia parenterally?
• Intramuscular- not used now- painful, multiple doses, stains skin
• Intravenous-
Ferric carboxymaltose- ferinject- over 15-30mins. Often needs 2 doses Iron dextran- cosmofer- over 4-6 hours after a test dose.
All IV iron preparations can cause ‘flu like symptoms and a small risk of hypersensitivity reaction or anaphylaxis
Describe B12 deficiency
Think KT
• Typically a macrocytic anaemia- MCV 100-120 and later a pancytopenia. Often bilirubin and LDH raised
• Can also cause peripheral neuropathy- demyelination and posterior column damage
• B12 result can be falsely low in pregnancy/oral contraceptive/on metformin
• Pernicious anaemia- gastric atrophy and auto antibodies to parietal cells and intrinsic factor preventing absorption
• Strict vegan or terminal ileal disease also possible
What treatments are available for B12 deficiency?
- Hydroxocobalamin 1mg IM alternate days for 5 doses then 3 monthly if confirmed ongoing need eg pernicnious anaemia
- Cyanocobalamin available orally but not available on prescription
Describe Folate deficiency
- Blood count and film appearance same as B12 def.
- Limited stores of folate so deficiency can develop in weeks
- Poor intake, increased use eg pregnancy/haemolysis, malabsorption, drugs eg anti-epileptics or trimethoprim
- Replacement with oral folic acid 5mg per day
- Pre-conception folic acid reduces neural tube defects. Likely plan to add folic acid to flour
Describe anaemia due to blood loss
• Hb immediately after blood loss will be normal
• Drop after fluid replacement
• Each 500ml loss gives approx
drop of Hb by 10-15 g/l
• Retic response within hours/days
• May need blood transfusion to replace loss eg trauma/GI bleed/around delivery
Describe anaemia of chronic disease
- Typically a normocytic anaemia associated with chronic inflammatory disease
- Plentiful iron stores but poor transfer to RBC due to hepcidin and cytokines
- History of chronic disease, inflammatory markers increased eg CRP/ESR/plasma viscosity, exclusion of other causes
- Will respond to treatment of underlying disease
Describe anaemia of renal failure
- Drop in Hb once creatinine clearance drops below 20-30 ml/min chronically
- Mainly due to lack of erythropoietin
- Contribution from blood loss at dialysis, inflammatory disease
- Responds well to erythropoietin eg weekly or alternate weeks s/c
Describe effects and causes of haemolysis
• Increased RBC destruction, marrow can increase production 5 -10 fold
• Can be acute or chronic, congenital or acquired
• Issues to do with- RBC membrane
- RBC enzymes -Globin chains in Hb
What are the causes of haemolysis of the RBC membrane due to disease?
- Congenital spherocytosis- autosomal dominant defect in spectrin causing spherical cells – less able to deform so shortened survival
- Auto-immune haemolysis- auto antibodies against RBC surface antigens- Fc portion recognised by macrophages in spleen. Treated with steroids/splenectomy/rituximab
What are the mechanical and enzyme based causes of haemolysis of the RBC membrane?
Prosthetic heart valve- mechanical
Disseminated intravascular coagulation (DIC)- eg in sepsis, prostate cancer causing RBC fragmentation by fibrin
RBC enzyme def eg G6PD or pyruvate kinase can cause shortened RBC survival
What is the cause of anaemia due to abnormal haemoglobin?
Haemoglobinopathy eg Sickle cell disease- single point mutation causing Hb polymerisation in hypoxic cells in homozygotes
Describe anaemia due to abnormal haemoglobin
• Haemoglobinopathy eg Sickle cell disease- single point mutation causing Hb polymerisation in hypoxic cells in homozygotes
• Shortened RBC survival, reduced production
• Chronic anaemia and bone/liver/lung/brain
“crisis” ie acute infarction
• Treated by supportive care, hydroxycarbamide to increase HbF production, ??stem cell transplant
Describe anaemia due to thlassaemia
- Inbalance of globin chain production
- Beta thalassaemia- as Hb F (2 alpha, 2 gamma chains) declines after birth- progressive anaemia. Supportive care, transfusion, ?stem cell transplant
- Progressive iron overload
- Antenatal screen for Hb-opathy and thalassaemia
What is the physiological cause and treatment of anaemia due to marrow infiltration?
• Myeloma-
B cell malignancy of mature plasma cells- produce monoclonal immunoglobulin or light chains
Presents as chance finding, anaemia, renal failure, hypercalcaemia, bone pain or fracture
Treatment- supportive care, chemotherapy, radiotherapy
How does one discover anaemia due to marrow infiltration?
Presents as chance finding, look in anaemia, renal failure, hypercalcaemia, bone pain or fracture
Give a brief overview of anaemia due o marrow infiltration
- Haematological malignancy eg lymphoma, acute leukaemia
- Diagnosed by sampling marrow- pelvis or sternum
- Treated by chemotherapy/immunotherapy
- Other “solid” tumours can spread to marrow eg prostate, breast, small cell lung
What anaemias are caused by marrow failures?
- Myelodysplastic disorders- progressive decline in Hb, neutrophils, platelets, macrocytosis. Tendency to progress to acute leukaemia. Treated by supportive care, chemotherapy or stem cell transplant in some.
- Aplastic anaemia- pancytopenia. Expected result post chemotherapy but can be drug induced eg NSAIDs, chloramphenicol or idiopathic. Treated by supportive care, anti- thymocyte globulin, stem cell transplant
In summary, what be anaemia?
- Anaemia is a blood count finding with associated symptoms and signs
- Multiple causes relating to underproduction or increased loss
- Use other blood count indices to identify a likely cause
- Treatment relates to cause and underlying disease
