Anemia Flashcards
Definition of anemia
WHO:
Anemia is a condition in which the no. of RBCs/ their O2 carrying capacity is insufficient to meet physiologic needs which vary by age, sex, altitude, smoking and pregnancy status
Clinical practice
Hemoglobin below normal reference range for age and sex
Traits of RBC
Pink - hemoglobin
No nucleus - fill up w/ more Hb
Biconcave - for gas exchange
How long do RBCs circulate in the blood?
120 days
How are old RBCs broken down?
Macrophages
What are signs of anemia related to?
Lack of O2 in tissues
Symptoms of anemia
Fatigue
Weakness
Dyspnea
Palpitations
Dizziness
(only some listed)
Signs of anemia
Pallor
Tachycardia
Bounding pulse
Hemic murmur
Cardiac failure
When does conjunctival pallor happen?
When Hb < 9
When does skin crease pallor happen?
When Hb < 7
What are the parameters you look at to check for anemia?
MCV (size)
MCH (colour)
RDW (size distribution - how size of cells vary)
Red cell count
What are the 3 main cell lines use in investigations?
Hb
White cell
Platelet
How does folate deficiency affect cells?
Big cells
How does Fe deficiency affect cells?
Small pale cells
What is an easy way to classify anemia?
MCV
What does microcytic RBCs indicate?
Issue with ferritin
Low ferritin
- Fe deficiency
Normal/high ferritin
- thalassaemia
- inflammation anemia
- sideroblastic anemia
What do normocytic RBCs indicate?
Increased production
- acute bleeding
- haemolysis
Decreased production
- renal anemia
- inflammatory anemia
- marrow disease
What do macrocytic RBCs indicate?
Issue with folate/B12
Megaloblastic anemia
- B12/folate deficiency
Non-megaloblastic anemia
- reticulocytosis
- alcohol
- liver disease
How is anemia classified if MCV is normal?
By mechanism of anemia (reduced production/ increased destruction or loss)
What is observed when there is reduced production of RBCs?
Reduced reticulocytes
Eg of anemia due to reduced production?
Haematinic deficiencies
- Fe, B12/folate deficiency
Reduced globin chain
- thalassaemia
Bone marrow failure
- suppression -> inflammation
- infiltration -> malignancy
- defective production -> AA, myelodysplasia
Insufficient EPO
Inability to utilise Fe
What is observed when there is increased destruction/loss of RBCs?
Increased reticulocytes
Eg of anemia due to increased destruction (hemolysis)
Immune
- AIHA
- CHAD
- PCH
Non-immune
- haemoglobinopathy
- membrane
- enzyme
- mechanical
- infections
Eg of anemia due to increased loss (bleeding)
Menorrhagia
Surgery/trauma
GIT
Genitourinary
Impt initial work up for anemia after hist/examination
Full blood count (FBC)
MCV
Reticulocyte count
Peripheral blood film
What is special about ferritin?
It’s an acute phase reactant, increases w/ infection/ inflammation -> high ferritin does not always exclude Fe deficiency
Eg of causes of increased Fe requirement
Pregnancy
Eg of causes of increased Fe loss
GI bleed
Menstruation
Eg of causes of decreased Fe intake
Vegetarianism/ veganism
Drugs that reduce stomach acidity
Lack of balanced diet
Possible side effects of Fe supplements
Upset stomach
Nausea
Diarrhea
Faintness
Vomiting
Dark stools
Constipation
Why will platelet count increase during Fe deficiency?
No Fe -> hematopoiesis divert to make more platelet as they come from same lineage
What causes megaloblastic anemia?
B12/ folate deficiency
Clinical presentation of megaloblastic anemia
Gastrointestinal
- glossitis
Neurology
- subacute combined degeneration of spinal cord (B12 deficiency) -> numbness, weakness
Psychiatric
- personality changes
- psychosis
- memory loss
Causes of B12 deficiency
Mainly due to malabsorption
Causes of folate deficiency
Low diet/ increased demands
Treatment of B12 deficiency
IM B12 injections
- if neurological involvement -> every other day till no further improvement
- otherwise -> 6 injections over 2 weeks then monthly
Oral B12 tablets
- if Hb normalised
Treatment of folate deficiency
Oral folate replacement
What does spherocytes in PBF suggest?
Anemia is due to immune cause
What do bite / blister cells in PBF suggest?
Anemia is due to oxidative hemolysis
What do cell fragments in PBF suggest?
Anemia is due to MAHA / mechanical
How to know if the anemia is immune-mediated?
Use Direct Coombs test
