Anaemia Flashcards
Define anaemia
Low Hb concentration due to either:
- low red cell mass
- increased plasma volume (e.g. in pregnancy)
Two general ways of decreased RBCs?
Increased loss of RBCs
Decreased production of RBCs
What are the Sx of anaemia?
May be asymptomatic if slow onset
Generalised:
- Fatigue, Dyspnoea, Headache and faintness, Palpitation, Tinnitus, Anorexia, Angina (if pre-existing CV disease)
What are the general signs of anaemia?
Pallor / pale conjunctiva
Hyperdynamic circulation - tachycardia, ejectin systolic murmur, cardiac enlargement
Retinal haemorrhages (rare)
Heart failure => peripheral oedema
What are the causes of microcytic anaemia?
Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia
Anaemia of chronic disease
What are the causes of normocytic anaemia?
Acute blood loss Anaemia of chronic disease Bone marrow failure (suspect if pancytopaenia) Renal failure Hypothyroidism Haemolysis Pregnancy
What are the causes of macrocytic anaemia?
Vit-B12/folate deficiency Alcohol excess/liver disease Hypothyroidism Antifolate drugs, e.g. phenytoin Reticulocytosis Cytotoxics Myelodysplastic syndrome Marrow inflitration
Describe haemolytic anaemia
May be normocytic or macrocytic
When should haemolytic anaemia be suspected?
Reticulocytosis Macrocytosis Haptoglobin decreased Raised bilirubin and urobilinogen Mild jaundice
What is haptoglobin?
Protein that binds to Hb to remove it
What are the causes of decreased red cell (marrow) production?
Stem cell defects/dysfunction
Hypoproliferation
Marrow infiltration
Nutrutional deficiencies
What are the causes of stem cell defects?
Intrinsic = stem cell aplasia/abnormalities e.g. leukaemia
Extrinsic = killed/impaired stem cell function
- drugs, viruses, chemicals, radiation
What can cause hypoproliferation of marrow?
Hypostimulation
- i.e. in renal insufficiency, endocrinopathies
Exrinsic inhibition of proliferation
- cytokines, viral infections, autoimmune disease
What can cause marrow infiltration?
Cancers (Metastases, lymphomas, myelomas, leukaemias)
Fibrosis
Nutritional deficiencies that can cause reduced marrow production?
Iron
Folate / Vit-B12
Protein malabsorption
What can cause excess peripheral loss of RBCs?
Bleeding
Haemolysis
List the causes of haemolysis
Intrinsic
- abnormal Haemoglobins (sickle, beta-thalassaemia)
- membrane protein defects
Extrinsic
- autoimmune reactions
- hypersplenism - increased RBC lysis
- microangiopathic disorders - e.g. TTP, DIC
- Infections - malaria, clostridia
What are the causes of iron deficiency anaemia?
Blood loss - Menorrhagia
Poor diet - poverty
Malabsorption - e.g. coeliac disease
GI blood loss due to parasites such as hookworm
Specific signs of chronic iron deficiency anaemia?
Koilonychia
Angular stomatitis/cheilosis
Atrophic glossitis
Post-cricoid webs
What will Ix show in iron-def anaemia?
Microcytic hypochromic anaemia
Ferritin decrease (increased in inflammation)
Decreased serum iron
Increased TIBC
How should iron deficiency anaemia be treated?
Treat the underlying cause
Oral Iron e.g. ferrous sulfate 200 mg/8H
What are the SEs of oral iron?
Nausea, abdo discomfort, diarrhoea, constipation, black stools
What will Ix show in anaemia of chronic disease?
Mild, normocytic anaemia
Normal increased ferritin