Normocytic anaemia Flashcards
Causes of normocytic anaemia
- Acute blood loss
- Haemolytic anaemia
- Anaemia of chronic disease
- Chronic kidney disease
- Aplastic anaemia
What are the two mechanisms of normocytic anaemia and how do you differentiate the two?
Increased destruction (haemolysis) = Increased reticulocytes
or
Reduced production (bone marrow failure) = Reduced reticulocytes
Causes of normocytic anaemia with increased reticulocytes
- Hereditary
- Hereditary spherocytosis
- Sickle cell anaemia
- Glucose-6-phosphate dehydrogenase deficiency
- Pyruvate kinase deficiency
Acquired
- Autoimmune haemolytic anaemia
- Paroxysmal nocturnal haemoglobinuria
- Micro/macroangiopathic haemolytic anaemia
Causes of normocytic anaemia with reduced reticulocytes
- Chronic renal failure
- Aplastic anaemia
- Myelophthisic process
Symptoms of anaemia
- Fatigue
- SOB on exertion
- Chest pain
- Palpitations
Signs of anaemia
- Tachycardia
- Tachypnoea
- Hypotension
- Pallor
General investigations in anaemia
Bedside
- Full set of observations
Bloods
- FBC: reduced Hb. Assess MCV
- Blood film
- Iron studies
- B12 and folate levels
- Haemolysis screen: bilirubin, haptoglobin, Coombs test
- U&Es: CKD
- TFTs: hypothyroidism
- LFTs: chronic liver disease
Imaging
- Assess for site of blood loss
Special tests
- Bone marrow biops
Definition of hereditary spherocytosis
Inherited defect in RBC membrane proteins leading to a haemolytic anaemia
Epidemiology of hereditary spherocytosis
- Northern European and North American populations
- 1 in 2000 people
Clinical features of herediatary spherocytosis
- General features of anaemia
- Neonatal jaundice
- Splenomegaly
- Gallstones
Investigations in hereditary spherocytosis
FBC
Blood film
LFTs
LDH
- FBC: normocytic anaemia
- Raised reticulocyte count
- Blood film: spherocytes
- LFTs: raised bilirubin
- LDH: raised
Managment of hereditary spherocytosis
Define sickle cell anaemia.
What is meant by sickle cell disease, sickle cell trait and sickle cell crisis?
Epidemiology of sickle cell disease
- Sickle cell trait: highest incidence in Sub-Saharan Africa
- 8% of Afro-Caribbean people carry the sickle cell gene
- Protective against falciparum malaria
Clinical features of sickle cell anaemia
- General features of anaemia
- Jaundice
- Failure to thrive
- Frontal bossing
Types of sickle cell crisis
- Sequestration crisis
- Aplastic crisis
- Haemolytic crisis
- Vaso-occlusive crisis
Features of sequestration crisis
Features of aplastic anaemia
- Infection with parovirus B19
- Bone marrow suppression with reduced reticulocyte count
Features of haemolytic crisis
- Usually occurs in context of vaso-occlusive crisis
- Increased haemolysis
- Decreased Hb and increased reticulocytes
Features of vaso-occlusive crisis
Precipitants of vaso-occlusive crisis
- Infection
- Dehydration
- Hypoxia
- Acidosis
Investigations for sickle cell anaemia
- Newborn screening: Guthrie heel prick test
- FBC:
- Normocytic anaemia (MCV 80-95fL)
- Increased reticulocytes
- Blood film: sickle cells, Howell-Jolly bodies
- Hb electrophoresis
Genes affected, HbA, HbA2, HbF and HbS proportion in sickle cell trait and sickle cell disease
Trait: 1 gene; HbA 55%, HbA2 2%, HbF <2%, HbS 40%
Disease: 2 genes; HbA 0%, HbA2 2%, HbF 8%, HbS 90%
Investigations in sickle cell crisis
Management of sickle cell crisis
- Supportive
- Oxygen
- Analgesia: often requires opiates
- Rehydration: dehydration precipitates sickling
- Antibiotics: particularly in chest crisis
- Chest physiotherapy
- Blood transfusion: in a severe crisis a blood transfusion reduces the proportion of HbS
- Exchange transfusion: involves removal of HbS in exchange for normal Hb in a life threatening crisis eg organ damage
Long term management of sickle cell disease
- Avoid precipitants: eg infections, dehydration, hypoxia, cold
- Pain managment: regularly prescribed medications to manage chronic pain
- Hydroxycarbamide: increases HbF; indicated for patients with recurrent chest or pain crisis
- Folic acid supplementation: 5mg once weekly
- Lifelong phenoxymethylpenicillin: patients are at risk of infection from encapsulated bacteria due to hyposplenism from autosplenectomy
- Regular vaccinations: pneumococcal vaccine every 5 years and annual influenza
Definition of G6PD deficiency
Inherited X-linked recessive disorder resulting in a haemolytic anaemia.
(Results in reduced half life of RBCs)
Epidemiology of G6PD deficiency
- African, Mediterranean and Asian ethnicity
- Prevalence of 50-70% in Kurdish Jews
- Protetive role against malaria
What is the life span of a red blood cell?
120 days
What does G6PD do?
It protects the cells from oxidative damage.
Red cells are particularly prone to oxidative stress.
Investigations in G6PD deficiency
Managment of G6PD deficiency
- Neonatal jaundice
- Phototherapy or exchange transfusion
- Blood transfusion
- Hb <70g/L or
- Hb <80g/L and cardiac co-morbidity
- Folic acid
- Daily until splenectomy
- Splenectomy
- Spleen removal reduces haemolysis
- Delayed until patients are >6 years of age to reduce the risk of post splenectomy sepsis
Define autoimmune haemolytic anaemia
Antibody mediated destruction of RBCs.
Divided into cold and warm depending on what temperature the anatibodies most avidly bind RBCs.
Difference in pathophysiology between warm and cold autoimmune haemolytic anaemia.
- Warm: IgG binds RBCs; Extravascular haemolysis
- Cold: IgM binds RBCs; Extravascular and intravascular haemolysis
Causes of warm autoimmune haemolytic anaemia
- Idiopathic
- SLE
- CLL
- Drugs
- Penicillins
- Cephalosporins
Causes of cold autoimmune haemoglobin anaemia
- Idiopathic
- M. Pneumoniae
- EBV
Investigations in autoimmune haemolytic anaemia
- Bloods
- FBC:
- Normocytic anaemia (MCV 80-95fL)
- Increased reticulocytes
- Blood film: spherocytes
- LFTs: bilirubin raised
- LDH: raised
- Haptoglobin: reduced
- FBC:
- Special test
- Coombs test
- Direct
- Indirect
- Cold aggltinin titre
- Coombs test
Managment of haemolytic anaemia
- Treat underlying cause
- Avoid cold in cold agglutinin disease
- Blood transfusion
- Immunosupressants
- Plasmapheresis
- Splenectomy
Why does normocytic anaemia occur in chronic renal failure?
Decreased production of RBCs due to reduced EPO
Pathophysiology of aplastic anaemia
Myelophthisic process
Process which replaces bone marrow eg malignancy
