Anaemia Flashcards
Calculation of haemoglobin normal range
Measure haemoglobin in normal individuals
Work out the mean and SD
Normal range is the Mean +/- 2SD
Different in men and women so different normal ranges are required
Definition of anaemia
Haemoglobing concentration below normal range
Males <12.5g/dl
Females <11.5g/dl
Symptoms of anaemia
Fatigue, reduced exercise tolerance, shortness of breath: on exertion, at rest
Postural hypotension, dizziness, palpitations
Angina
Heart failure: Shortness of Breath (SOB)
Postural hypotension
occurs when a person’s blood pressure falls when suddenly standing up from a lying or sitting position
Signs of anaemia
Palor Tachycardia Heart murmurs Koilonychia (iron deficiency) Angular stomatitis Glossitis (B12/folate deficiency)
Full blood count
Haemoglobin -mean cell volume: MCV -mean cell haemoglobin concentration: MCHC White cell count Platelet count
Mean cell volume: MCV
Normal MCV 82-96 fl
Low < 82 Microcytic anaemia
Normal: Normocytic
High >96 Macrocytic anaemia
Classification of anaemia: microcytic
Iron deficiency
Thalassaemia
Anaemia of chronic disease (rarely)
Classification of anaemia: Macrocytic
Vitamin B12 deficiency Folate deficiency Macrocytosis without anaemia: -liver disease -hypothyroidism -alcohol
Classification of Anaemia: Normocytic
Acute bleeding Haemolysis -congenital -acquired Aplastic anaemia Anaemia of chronic disease
Adaptation to Anaemia
Tachycardia Cardiomegaly Increased cardiac output Right shift oxygen dissociation curve - better delivery of oxygen to the tissues
Differential Diagnosis of Microcytic Anaemia
Iron Deficiency
Thalassaemia
Anaemia of chronic disease
Causes of Iron Deficiency
Reduced intake ( almost impossible in the UK) Increased requirements pregnancy/ childbirth, malabsorbtion, coeliac disease
Causes of iron deficiency: Causes blood loss
Menorrhagia
GI Blood loss: Upper GI/ Lower GI
Diagnosis of Iron Deficiency
FBC: Hb, MCV, MCHC
Serum Ferritin
(Fe and TIBC)
Bone marrow/ liver biopsy = tissue iron stores
Investigation of Iron Deficiency
History Examination Ferritin Gastroscopy Colonoscopy
Treatment of Iron Deficiency
Treat the cause
Ferrous sulphate 200mg oral tds, until haemoglobin normal and then further 3 months to rebuild stores
B12 and Folate Deficiency
Necessary for haematopoiesis Necessary for DNA synthesis all cells Deficiency causes megaloblastic anaemia -macrocytic anaemia (High MCV, >96fl) -also leukopenia and thrombocytopenia
B12 metabolism
Dietary sources- Bacteria, animal products
Adsorption-intrinsic factor from stomach absorbed in terminal ileum as complex
Body storage 4 years
B12 Deficiency
Lack of intrinsic factor Pernicious anaemia, gastrectomy Failure absorption in terminal ileum resection, Crohn’s, TB, lymphoma ?Dietary deficiency- vegans Macrocytic anaemia, megaloblasts in bone marrow Pancytopenia: low WBC and Platelets Affects all body cells Neuropathy
Pernicious Anaemia
Autoimmune disorder
Usually seen in elderly
Achlorhydria
Autoantibodies against intrinsic factor – block binding of IF to vitamin B12
Associated with other autoimmune disorders esp thyroid disease and vitiligo
B12 Deficiency Diagnosis
Serum B12 levels
In Pernicious anaemia
-intrinsic factor antibodies (50%)
-parietal cell antibodies ( 80%, but not specific!)
B12 Treatment
Parenteral Hydroxycobalamin 1 mg im every 2 days initially Give before folate if mixed / unknown deficiency Reticulocyte response, Hb increase 1-1.5g per week Risk of hypokalaemia 1 mg every 3 months for life maintenance
Folate Deficiency
Necessary for DNA synthesis Marcocytic anaemia Megaloblastic bone marrow Pancytopenia with low WBC and platelets Dietary sources fresh fruit and vegetables Absorbed in proximal intestine Low body stores, easy to deplete
Causes of Deficiency of Folate
Dietary Malabsorption- coeliac disease Increased requirements: -pregnancy -haemolysis -some drugs eg folate antagonists
Folate Deficiency Treatment
Oral folate 5mg tablet daily
Works for all causes including malabsorption
Haemolytic Anaemias: Hereditary
Red cell membrane defect -eg hereditary spherocytosis Abnormal red cell metabolism -eg G6PD deficiency, pyruvate kinase deficiency Haemoglobin abnormalities -eg sickle cell disease
Haemolytic Anaemias: Acquired
Immune -autoimmune -alloimmune eg Rhesus Disease of the newborn Red cellfragmentation syndromes Infections
Sickle cell disease
Autosomal recessive
Afro-Caribbean population
Single point mutation
Heterozygous patients protected from malaria
Develop painful vaso-occlusive sickle cell crises
Crises precipitated by infection, cold, hypoxia etc
Diagnose by requesting FBC, sickle cell test and haemoglobin electrophoresis
