Anaemia Flashcards
What factors influence the normal range of haemoglobin?
○ Age ○ Sex ○ Ethnic origin ○ Time of day sample taken ○ Time to analysis
What are the refernce ranges of haemaglobin?
- Male 12-70 (140-180)
- Male >70 (116-156)
- Female 12-70 (120-160)
- Female >70 (108-143)
What are the clinical features of anaemia?
○ General features due to reduced oxygen delivery to tissues: - Tiredness/pallor - Breathlessness - Swelling of ankles - Dizziness - Chest pain ○ Depend on age and Hb level ○ Related to underlying cause: - Evidence of bleeding □ Menorrhagia □ Dyspepsia, PR bleeding - Symptoms of malabsorption □ Diarrhoea □ Weight loss - Jaundice - Splenomegaly/ Lymphadenopathy
What is the pathophysiology of anaemia?
- Bone marrow □ Cellularity □ Stroma □ Nutrient - Red cell □ Membrane □ Haemoglobin □ Enzyme - Destruction loss □ Blood loss □ haemolysis □ Hypersplenism
What are the red cell indices?
○ Automated measurement of red cell size and haemoglobin content
- MCV = Mean cell volume (cell size)
- MCH = Mean cell haemoglobin
○ Can give a morphological description of anaemia
What are the different morphological desriptions for anaemia?
- Hypochromic microcytic (small and pale)
- Normochromic normocytic (normal)
- Macrocytic (big and dark)
What investigations are done in anaemia?
○ Investigation involves use of a discriminating test to guide further investigations
○ If laboratory is given adequate clinical information it will advise on further appropriate investigations
○ Hypochromic microcytic
- serum ferritin (iron)
○ Normochromic normocytic
- reticulocyte count
□ Shows whether the bone marrow is working
○ Macrocytic
- B12/ folate
- bone marrow
What reason could someone have hypochromatic microcytic anaemia?
○ Serum ferratin - Low □ Iron deficiency - Norma/ increased □ Thalassaemia □ Secondary anaemia □ Sideroblastic anaemia (rare)
What is iron deficiency anaemia?
- Commonest cause of anaemia worldwide
- Description not a diagnosis – establish cause!
what should be looked out for in a history from someone with iron deficiency anaemia?
□ Dyspepsia GI bleeding
□ Other bleeding, e.g. menorrhagia
□ Diet (NB children and elderly)
□ Increased requirement - pregnancy
What should be done on examination of someone with iron deficient anaemia?
□ Signs of iron deficiency ® Atrophic tongue ® Angular cheilitis ® Koilonychia
□ Abdominal and rectal
What are the causes of iron deficient anaemia?
□ GI blood loss
□ Menorrhagia
□ Malabsorption
® gastrectomy ® coeliac disease
What is the management of iron deficient anaemia?
□ Correct the deficiency ® Oral iron usually sufficient ® IV iron if intolerant of oral ® Blood transfusion rarely indicated
□ Correct the cause ® Diet ® Ulcer therapy ® Gynae interventions ® Surgery
What do the different results in reticulocyte count in normocytic anaemia mean?
- Increased □ Acute blood loss □ Haemolysis
- Normal/ low □ Secondary anaemia ® Hypoplasia ® Bone marrow infiltration
What is haemolytic anaemia?
- Accelerated red cell destruction (decreased Hb)
- Compensation by bone marrow (Increased Retics)
- Level of Hb – balance between red cell production and destruction
What are the causes of haemolytic anaemia?
□ Congenital e.g. ® Hereditary spherocytosis (HS) ® Enzyme deficiency (G6PD deficiency) ® Haemoglobinopathy (HbSS) □ Acquired ® Auto-immune haemolytic anaemia (Extravascular) ® Mechanical e.g. artificial valve (Intravascular) ® Severe infection/DIC (Intravascular) ® PET/HUS/TTP (Intravascular)
What is the direct antiglobulin test (Coom’s test)?
□ Detects antibody or complement on red cell membrane
□ Reagent contains either ® anti-human IgG ® anti-complement
□ Reagent binds to Ab (or complement) on red cell surface and causes agglutination in vitro
□ Implies immune basis for haemolysis
How can you tell if a patient is haemolysing?
□ FBC, reticulocyte count, blood film
□ Serum bilirubin (direct/indirect), LDH
□ Serum haptoglobin (mops up haemoglobin)
What is the management of haemolytic anaemia?
□ Support marrow function
® Folic acid
□ Correct cause
® Immunosuppression if autoimmune ◊ Steroids ◊ Treat trigger e.g. CLL, Lymphoma ® Remove site of red cell destruction ◊ Splenectomy ® Treat sepsis, leaky prosthetic valve, malignancy etc. if intravascular
What is secondary anaemia?
- “Anaemia of chronic disease” □ 70% normochromic normocytic □ 30% hypochromic microcytic - Defective iron utilisation □ Increased hepcidin in inflammation □ Ferritin often elevated - Identifiable underlying disease □ infection, inflammation, malignancy
What do the different results in the B12/ folate assay mean in macrocytic anaemia?
- Megaloblastic □ B12 deficiency □ Folate deficiency - Non-megaloblastic □ Myelodysplasia □ Marrow infiltration □ Drugs
What happens in B12/ folate deficiency?
□ Anaemia
□ Neurological symptoms (subacute combined degeneration of the cord in B12 deficiency)
What are the causes of B12 deficiency?
□ Pernicious anaemia □ Gastric/ileal disease
What are the causes of folate deficiency?
□ Dietary
□ Increased requirements (haemolysis)
□ GI pathology (e.g. coeliac disease)
What are the signs of megoblastic anaemia?
□ “Lemon yellow” tinge ® Bilirubin, LDH ® Red cells friable
What is pernacious anaemia?
□ Commonest cause of B12 deficiency in western populations
□ Autoimmune disease
□ Antibodies against
® intrinsic factor (diagnostic) ® gastric parietal cells (less specific) □ Malabsorption of dietary B12 □ Symptoms/signs take 1-2 years to develop
What is the treatment of megoblastic anaemia?
□ Replace vitamin ® B12 deficiency ◊ B12 intramuscular injection ◊ Loading dose then 3 monthly maintenance ® Folate deficiency ◊ Oral folate replacement ◊ Ensure B12 normal if neuropathic symptoms
Other than B12/ folate deficiency what are the other causes of macrocytic anaemia?
- Alcohol
- Drugs
□ Methotrexate, Antiretrovirals, hydroxycarbamide - Disordered liver function
- Hypothyroidism
- Myelodysplasia
