Haematology Flashcards
Definition of anaemia
Low Hb concentration
Low red cell mass or increased plasma volume
<135g/L for men
<115g/L for women
Symptoms of anaemia
Triad: Pallor, SOB, fatigue/lethargy
Hb<80: Tachycardia/flow murmurs (ESM) Splenomegaly Jaundice Cardiac enlargement Retinal haemorrhage
Iron deficiency anaemia: Abdominal discomfort Epigastric/central pain Angular stomatitis Atrophic glossitis Koilonychia
Where does red cell production occur?
Marrow of skull, ribs, sternum, vertebral column, pelvis and proximal ends of femurs
Maturation occurs in BM
What is required for red blood cell production?
Vitamin B12 and folic acid for DNA synthesis
Iron for haemoglobin synthesis
Where does absorption of iron occur?
Where is iron stored?
Duodenum via ferroportin receptors on enterocytes
Absorption controls iron metabolism
Storage:
2/3 incorporated into haemoglobin
1/3 in hepatocytes
How is iron regulated?
Hepcidin is the iron regulatory hormone
Its receptor ferroportin controls absorption/storage/diet
Diagnosis of anaemia
FBC:
Number and size of cells in blood
Hb, Hct, MCV, MCH, MCHC, RDW, reticulocyte count
Blood film:
Microscopy
Size, shape, colour, inclusions, Howell-jolly bodies
Additional tests:
WBC, platelet count, iron studies (ferritin, serum Fe, TIBC), haematinic levels (B12/folate)
What is included in iron studies?
Ferritin Transferrin saturation Serum Fe Transferrin/ferrin receptors Total iron binding capacity
Classification of anaemias
Size of RBCs:
Microcytic
Normocytic
Macrocytic
Cause:
Decreased production
Increased production
Blood loss
Examples of microcytic anaemia
Thalassaemia
Anaemia of chronic disease/iron deficiency anaemia
Lead poisoning/sideroblastic anaemia
What does high/low ferritin mean in microcytic anaemia?
High: acute/chronic illness
Low: iron deficiency, GI or gynae blood loss
Examples of normocytic anaemia
Acute blood loss
Anaemia of chronic disease
Chronic renal failure/low EPO
Bone marrow hypo/aplasia
Examples of macrocytic anaemia
Reticulocytosis Megaloblastic Others/multifactorial: Liver disease/alcoholism Drugs (HIV treatment, anticonvulsants) Folate antagonists Chemotherapeutics Antibiotics NO Hypothyroidism Myelodysplastic syndrome
Anaemia and B12
High B12 - myeloproliferative disorders
Normal B12 - alcohol/liver
Low B12 - Pernicious anaemia
Low B12 and low folate - dietary deficiency, malabsorption
Do patients with anaemia require blood transfusion?
No:
Treat cause and manage e.g. iron supplementation
Yes:
If severe acute anaemia with Hb <70g/L
Severe chronic anaemia with HF
Define anaemia of chronic disease
Low levels of red blood cells as a result of autoimmune disease
Pathophysiology of anaemia of chronic disease
Poor use of iron in erythropoiesis (decreased absorption in gut, decreased feroportin, stops iron released from Kupffer cells)
Cytokine induced shortening of RBC survival
Decreased production of and response to EPO
Causes of anaemia of chronic disease
Chronic infection Vasculitis Rheumatoid Malignancy Renal failure
Investigations for anaemia of chronic disease
Mild, normocytic anaemia
Blood film, ferritin, B12, folate, TSH, test for haemolysis
Management of anaemia of chronic disease
Treat underlying cause
EPO
Parenteral iron can overcome functional iron deficiency
Causes of iron deficiency (microcytic)
Too much out:
Blood loss, menstruation, GI tract loss, parasites
Not enough in:
Poor diet, malabsorption, increased physiological need
Dilution:
Pregnancy
Signs of iron deficiency
Koilonychia
Atrophic glossitis
Angular cheilitis
Post-cricoid webs
Investigations for iron deficiency
FBC History Ix GI loss - OGD, sigmoidoscopy/colonoscopy, stool microscopy for hookworm ova Coeliac disease screening H. pylori testing
Management of iron deficiency
Treat cause
Oral iron
IV iron if oral is impossible or ineffective
Eradicate H. pylori - omeprazole, amoxicillin, clarithromycin or metronidazole
