Anaemia Flashcards
Anaemia
What are the two causes of raised Hb?
True polycythaemia
Pseudopolycythaemia
What is the normal pathway for erythrocytosis?
Tissue hypoxia
Raised EPO production from kidney
RBC production in bone marrow
What are the two types of true polycythaemia?
Primary (polycythaemia vera)
Secondary (high EPO)
What are some causes of secondary polycythaemia?
COPD
Renal cell carcinoma
High altitude
Smoker
What is polycythaemia vera?
Clonal haematopoietic disorder of bone marrow resulting in erythrocytosis
May be associated with thrombocytosis, leukocytosis, and splenomegaly
What is the genetic link with PCV?
85% are related to a JAK2 V617F mutation
What are the symptoms of PCV?
Asymptomatic Headache, dizziness, fatigue Aquagenic pruritus- itching after shower Blurred vision Tinnitus Thrombosis Gangrene
What are the signs of PCV?
Choreiform movements
Hepatosplenomegaly
Red face, fingers, palms, toes, heels
What are the investigations for PCV?
FBC- raised Hb, Hct, WCC, platelets
Gene mutation screen for JAK2 V617F
What is anaemia?
Reduction in Hb, red cell count, and packed cell volume below reference age and sex
What are some general features of anaemia?
Pale conjunctivae, mucous membranes + skin
Fatigue
Faintness
Dyspnoea, tachycardia (if severe)
Intermittent claudication/angina (severe)
What are the three types of anaemia and what are the MCV levels that distinguishes them?
Microcytic (<80)
Normocytic (80-96)
Macrocytic (>96)
What are the causes of microcytic anaemia?
Iron deficiency anaemia (IDA)
Thalassaemia
Anaemia of chronic disease
Sickle cell anaemia
What are the 3 broad causes of IDA? Give examples for each
Blood loss (GI malignancy, menstruation, peptic ulcer, IBD) Increased demand (pregnancy/growth/breast feeding) Decreased absorption (malnutrition, coeliac, IBD, post-gastrectomy)
What are the investigations for IDA?
FBC Iron studies Blood film Upper GI endoscopy + colonoscopy (if unexplained) Coeliac serology (IgA TTG antibodies)
What is the management for IDA?
Treat underlying cause
Animal iron>plant
Oral Fe
IV/IM Fe if poor tolerance/uptake
What can cause ACD?
Chronic inflammation (RhA)
Chronic infection (TB)
Chronic malignancy
No other obvious cause of anaemia
What are the investigations for ACD?
Raised ESR/CRP
FBC- low Hb, low/normal MCV
Iron studies:
- low serum iron
- high/normal ferritin (acute phase protein)
- low/normal transferrin
- normal transferrin sat
What is normal haemoglobin made of?
2 alpha globin chains
2 beta globin chains
What are the two main types of thalassaemia?
Alpha thalassaemia Beta thalassaemia (most common)
How many genes code the alpha Hb chain?
4 genes, 2 from each parent
Chr 16
How does alpha thalassemia present depending on number of defective genes?
- Alpha thalassaemia silent (1 absent gene)
- Alpha thalassaemia trait (2 absent genes)
= these cause very mild anaemias - Haemoglobin H (3 absent genes) = significant, requires transfusions
- Haemoglobin Barts (4 absent genes) = death in utero
What are the characteristics of alpha thalassaemia silent?
No clinical symptoms
What are the characteristics of alpha thalassaemia trait?
Low MCV + MCH
Can be confused with IDA
Hb electrophoresis shows low/normal HbA2
What are the characteristics of haemoglobin H?
Microcytic hypochromic anaemia Target cells and Heinz bodies Hepatosplenomegaly Presents in childhood/early adulthood Needs lifelong transfusions
What are the characteristics of haemoglobin Barts?
Often fatal in utero unless intrauterine transfusions
What are the types of beta thalassaemia?
Beta thalassaemia minor
Beta thalassaemia trait/intermedia
Beta thalassaemia major
What are the characteristics of beta thalassaemia minor?
Asymptomatic heterozygous carrier Mild/absent anaemia Low MCV Normal ferritin Electrophoresis shows increased HbA2
What are the characteristics of beta thalassaemia trait?
Combination of homozygous beta and alpha thalassaemias
Moderate anaemia that doesn’t require transfusions
Splenomegaly, gallstones, bone deformities, recurrent leg ulcers
What are the characteristics of beta thalassaemia major?
Presents first 2-3 months of life
Severe anaemia, failure to thrive, recurrent infections
Bony abnormalities due to bone marrow hypertrophy
Extramedullary haematopoiesis
Electrophoresis shows HbF and reduced/absent HbA
What are the investigations for thalassaemia trait? What would they show?
FBC- low Hb, low MCV
Iron studies would be NORMAL
Gel electrophoresis
What is the management for severe thalassaemia?
Blood transfusions Iron chelators Bone marrow transplant: -only curative treatment -causes infertility
What are the types of macrocytic anaemia?
Megaloblastic
Normoblastic
What is a megaloblast?
developing RBCs in the bone marrow with a delayed nuclear maturation relative to their cytoplasm
What are the causes of megaloblastic macrocytic anaemia?
Vit B12 deficiency
Folate deficiency
What are the causes of normoblastic macrocytic anaemia?
Pregnancy Alcohol excess Reticulocytosis Liver disease Hypothyroidism Haematological disorders (eg. aplastic anaemia) Drugs (eg. hydroxycarbamide)
What are the causes of Vit B12 deficiency?
Low intake (eg. vegans)
Impaired absorption:
Stomach: pernicious anaemia, gastrectomy
Small bowel: Crohn’s, coeliac, tropical sprue
What is pernicious anaemia?
Autoimmune condition of atrophic gastritis and the destruction of parietal cells
Lack of intrinsic factor, which is needed for B12 absorption
What are the symptoms of B12 deficiency?
Progressive anaemia Weight loss Change in bowel habits Muscle weakness Symmetrical paraesthesia Visual impairment Memory disturbance
What are the signs of B12 deficiency?
Progressive anaemia Jaundice (ineffective erythropoiesis- RBC precursor breakdown) Glossitis Angular stomatitis Polyneuropathy
What are the investigations for B12 deficiency?
FBC and film:
-low Hb, high MCV, low reticulocytes, hypersegmented neutrophils
Serum vit B12- low
Serum autoantibodies: 90% parietal cells, 50% IF
What is the management for B12 deficiency?
IM hydroxycobalamin or oral cyanocobalamin