Anaemia Flashcards
How long do RBCs live?
120 days
What hormone stimulates RBC production? Where is it released?
EPO: erythropoietin
Mostly the renal cortex, but 10% comes from the liver
What is a reticulocyte?
What is ferritin?
What is haemosiderin? Which is soluble and which isn’t?
Immature RBCs
Ferritin is protein + iron (soluble)
Haemosiderin is fragmented ferritin
(insoluble)
What is the structure of haemoglobin?
How many oxygen molecules can one Hb carry?
Two alpha chains
Two beta chains
4 Haem groups each containing iron atom
4 oxygen molecules, one on each haem group
Causes of microcytic and macrocytic anaemia?
Microcytic:
Iron deficiency
Chronic disease
Thalassaemia
Macrocytic: B12 deficiency Folate deficiency Alcohol excess Bone marrow failure
What causes iron deficiency anaemia?
Blood loss (GI, gynaecological)
Malabsorption: coeliac disease
High demand: pregnancy
Symptoms of iron deficiency anaemia?
Fatigue Dyspnoea Angina Palpitations Glossitis Pruritus Headache
What investigations would you do for iron deficiency anaemia?
Bloods:
- FBC, ferritin
- blood film
- LFTs
Investigate underlying causes:
- OGD
- Colonoscopy
- Gynae investigations
What would the FBC and blood film show in iron deficiency anaemia?
Microcytic
Hypochromic
Ferritin low
Transferrin high
Management of iron deficiency anaemia?
What are the side effects?
Ferrous sulphate 200mg BD or TDS
Black stools, nausea, reflux
What two types of macrocytic anaemia are there? Explain and give examples.
Megaloblastic: impaired DNA synthesis resulting in bigger cell
- B12 and folate deficiency
Non-megaloblastic: fatty deposits in cell
- alcohol excess
- hypothyroid
What is folate’s other name?
In what foods are B12 and folate found?
Vitamin B9
B12: animal sources, fortified foods
Folate: green veg, cereal
Where and how is B12 absorbed?
Combines with intrinsic factor in the stomach and is absorbed in the terminal ileum
How long does B12 deficiency take to manifest?
What about folate?
B12 takes years
Hepatic stores of B12 take years to empty.
Folate takes months as liver stores are smaller
What causes B12 deficiency?
Pernicious anaemia (80% cases)
IBD
GI surgery
H. pylori
Dietary
What is a serious complication of B12 deficiency?
Subacute spinal cord degeneration
Symmetrical dorsal column loss
- peripheral neuropathy initially
- UMN signs later
- lower limbs more affected
How and where is folate absorbed?
Absorbed in the duodenum / jejunum
What is the link between B12 and folate?
Folate depends on B12 for activation
What causes folate deficiency?
Alcohol excess
Dietary
Malabsorption
Drugs
Your patient has macrocytic anaemia. How can you differentiate between B12 and folate deficiency?
Check folate levels in serum and RBCs
B12 deficiency: LOW red cell folate, NORMAL serum folate
Folate: LOW red cell folate and LOW serum folate
What is pernicious anaemia? What vitamin deficiency does it cause any why?
Autoimmune disease that attacks the parietal cells in the stomach
Parietal cells produce intrinsic factor
So reduced intrinsic factor means reduced B12 absorption
Who gets pernicious anaemia?
Which conditions are associated with pernicious anaemia?
Commonly women over 60
Vitiligo
Hypothyroidism
Addison’s
Type I diabetes
Clinical features of pernicious anaemia?
Anaemia symptoms
- Fatigue
- Anorexia
- Weight loss
Diarrhoea
Dyspepsia
Jaundice
Investigations for pernicious anaemia?
Bloods:
- FBC
- Blood film
- Serum B12 and folate
- anti-IF
- anti-parietal cell
Bone marrow aspirate
Management of pernicious anaemia?
What should you not give and why?
B12 injections
Folate injections, because of the risk of severe neuropathy
What are the possible complications of pernicious anaemia?
Gastric carcinoma
Gastric polyps
Neurological damage if left untreated: fatigue, depression, memory loss
Iron deficiency
What is haemolytic anaemia?
Abnormal breakdown of RBCs
What are some causes of haemolytic anaemia?
Hereditary erythrocyte defects:
- Spherocytosis
- G6PD deficiency
- Pyruvate kinase deficiency
- Sickle cell
Autoimmune Transfusion Malaria DIC Myelofibrosis
What is spherocytosis?
Pathophysiology
Inheritance
Production of abnormal RBCs
They are sphere shaped rather than biconcave
They’re called spherocytes
Caused by a defect in the proteins of the RBC cytoskeleton
Autosomal dominant
They have normal oxygen carrying capacity but they are more fragile and mistaken for old RBCs by the spleen and thus destroyed
In which anaemias are spherocytes seen?
All haemolytic anaemias have some spherocytes
But in spherocytosis there are only spherocytes
What’s the treatment of spherocytosis?
Splenectomy or partial splenectomy
So the spleen can’t destroy all the spherocytes
Investigations of spherocytosis? What would the results be?
FBC: hyperchromia
Blood film: RBCs look small and don’t have pale middle as they’re not biconcave
Reticulocytosis
Osmotic fragility test: spherocytes rupture easily in solutions less concentrated than the inside of the RBC
What’s the osmotic fragility test? Which blood disorder does it detect? How does it work?
Detects spherocytosis
It relies on the fact that spherocytes will rupture easily in solutions less concentrated than themselves
What is G6PD deficiency?
Pathophysiology
Inheritance
G6PD is an X-linked recessive inborn error of metabolism
Glucose-6-phosphate dehydrogenase is an enzyme that protects RBCs from breakdown triggered by infections, drugs or foods (fava beans)
Only when there is a trigger does haemolysis and therefore symptoms occur
What are some triggers for a haemolytic crisis in G6PD deficiency?
Illness especially infections
Drugs
Fava beans (broad beans)
DKA
AKI
Investigations for G6PD deficiency? What would the results be?
FBC
Blood film:
- Macrocytic anaemia
- Reticulocytosis
G6PD enzyme assay
List the hereditary erythrocyte defects?
G6PD deficiency
Hereditary spherocytosis
Pyruvate Kinase deficiency
What is pyruvate kinase deficiency?
Pathophysiology
Inheritance
Autosomal recessive
But can also be acquired secondary to leukaemia
Deficiency of an enzyme which limits RBC ATP production
Investigations of pyruvate kinase deficiency? What will they show?
FBC and blood film: macrocytic anaemia, retculocytosis
LFTs: bilirubin high
Management of pyruvate kinase deficiency?
Transfusion
Splenectomy may help with symptoms
Bone marrow transplant
Management of G6PD deficiency?
Avoid triggers
Splenectomy can help
