Haematology Flashcards
(173 cards)
Anaemia definition
Defined as blood with an insufficient concentration of haemoglobin
Pregnant women over 15 years: Hb <11g/dL
Non-pregnant women over 15 years: Hb <12g/dL
Men over 15 years: Hb <13g/dL
Anaemia general presentation
Symptoms: fatigue. Lethargy, dyspnea, palpitations, headache
Signs: pale skin, pale mucous membranes, tachycardia (compensatory to meet demand)
Microcytic/normoytic/macocytic anaemia definition
Microcytic anaemia: several types of anaemia characterised by small RBCs (known as microcytes). It is defined as when the mean corpuscular volume (MCV) is less than 80fL. Mean corpuscular volume describes the average size of RBCs.
Normocytic Anaemia: Anaemia with a MCV 80-100fL (normal range). Can be further divided:
- hyperproliferative (reticulocyte count >2%): the proportion of circulating reticulates increases as a compensatory response to increased destruction or loss of RBCs. The cause is usually acute blood loss or haemolysis
- hypoproliferative (reticulocyte <2%): primarily disorders of decreased RBC production, and the proportion of circulating reticulocytes remains unchanged
Microcytic Anaemia: where RBCs are larger than their normal volume (MCV > 100fL). Can be further divided as:
- megaloblastic: deficiency of DNA production or maturation resulting in the appearance of large immature RBCs (megaloblasts) and hyperhsegmented neutrophils in the circulation
- non-megaloblastic: encompasses all other causes of microcytic anaemia in which DNA synthesis is normal. Megaloblasts and hyperhsegmented neutrophils are absent.
Microcytic/normoytic/macocytic anaemia aetiology
Micro:
- chronic disease (cancer, HF, CKD)
- thalassaemia
- Fe deficiency (blood loss, poor diet, malabsorption, hookworm)
Normo:
- acute blood loss
- anaemia of chronic disease
- pregnancy
- renal failure
- combined haematinic deficiency (Fe & B12/folate deficiency > needed for haematopeiesis > consider malabsorption as a cause
Macro:
- B12/folate deficiency
- excess alcohol/liver disease
- hypothyroidism
- bone marrow failure
Iron deficiency anaemia definition
Occurs when the body has insufficient Fe to support RBC production.
Most common cause of anaemia worldwide and in pregnancy.
Premenopausal women have a higher presence of IDA because of menstrual blood loss and pregnancy. Is considered a microcytic anaemia and is by far the most common cause of it.
Iron deficiency anaemia aetiology
Causes of iron deficiency may be classfied as those due to:
Excessive blood loss:
- blood loss from GI tract is the most common cause of IDA in adult men and postmenopausal women
- blood loss due to menorrhagia is the most common cause in pre-menopausal women
Dietary inadequacy:
- growing children and elderly people with iron-poor diets may become deficient
Failure of iron absorption:
- some drugs: tetracyclines and quinolones
- anatacids and PPIs may impair absorption
- Vitamin C deficiency
- malabsorption conditions such as coeliacs
- from gastrectomy
- H. pylori infection
- Hookworm
Excessive requirements for iron:
- times of rapid growth in children
- pregnancy, especially with twins
- exfoliative skin disease
Iron deficiency anaemia presentation
General signs and symptoms of anaemia
Specific:
- brittle hair and nails
- atrophic glossitis (tongue inflammation with smooth tongue)
- Koilonychia (spoon shaped nails)
- Angular Stomatitis (inflammation fo corners of mouth)
Iron deficiency anaemia diagnosis
Drug history - NSAIDs, SSRIs, clopidogrel, corticosteroids
FBC: shows hypochroic microcytic anaemia
- hypochromia means there is a low mean corpuscular haemoglobin (MCH)
Serum ferritin: measured to confirm iron deficiency (except during pregnancy)
- low
Reticulocyte count - reduces
Endoscopy - possible GI bleed related cause
Urinalysis - evaluate blood loss from renal tract
Iron deficiency anaemia management
Iron salts should be given by mouth:
- side effects include black stools, constipation, diarrhoea, nausea, GI upset, epigastric pain
Folate deficiency anaemia definition
Deficiency of Folate, a B vitamin (B9). CLassically presents as megaloblastic anaemia, without any neurological signs. Unlike B12, reserves of B9 are low and only sufficient for around 4 months.
Iron deficiency anaemia aetiology
Main cause is poor intake Dietary deficiency - malabsorption (coeliacs etc) - anorexia Excessive requirements - pregnancy, lactation, infancy - malignancy - blood disorders (haemolytic and sick anaemia) Antifolate drugs
Iron deficiency anaemia presentation
May be completely asymptomatic
Normal anaemia signs and symptoms:
Loss of appetite and weight loss is a symptom of megaloblastic anaemia and the hallmark of folate deficiency
Glossitis (inflammation of the tongue) may be present
Angular stomatitis (ulcers in corners of mouth)
Lemon-yellow skin
Neurological features: mild compared to B12 deficiency
Iron deficiency anaemia diagnosis
FBC:
- low haemoglobin with elevated MCV and MCH
Peripheral blood smear:
- macrocytic naemia and hypersegmented neutrophils seen with both folate and B12 deficiency
Erythrocyte folate level
Iron deficiency anaemia differential diagnosis
Vitamin B12 deficiency, alcoholic liver disease, hypothyroidism, myelodysplasia and aplastic anaemia
Iron deficiency anaemia management
Daily folic acid tablets (build up folate levels)
Dietary advice - good sources of folate include: broccoli, nuts
Iron deficiency anaemia complications
Infertility, cardiovascular disease, cancer, problems in childbirth, neural tube defects and folic acid
Haemolytic anaemia defintiion
Disorder in which RBCs are destroyed faster than they can be made
Haemolytic anaemia risk factors
Sickle cell disorders
Haemolytic anaemia aetiology
Genetic: sick cell, thalaseeaemia, G6PD deficiency, pyruvate kinase deficiency
Acquired: autoimmune, infections, secondary to systemic disease
Haemolytic anaemia presentations
Symptoms:
- gallstones (excess bilirubin)
Signs:
- jaundice (increase bilirubin from RBC destructions) - bilirubin stones may cause abdo pain (gallstone pain)
- leg ulcers
- splenomegaly
- signs of underlying disease (SLE malar rash)
Haemolytic anaemia diagnosis
FBC - low Hb
Reticulocyte count - increase
Blood film - presence of Schistocytes
Haemolytic anaemia management
Folate and iron supplementation
Immunosuppressives
Splenectomy
B12 deficiency anaemia definition
Deficiency of Cobalamin, a B vitamin (B12). Classically presents as megaloblastic anaemia, with neurological signs
B12 deficiency anaemia aetiology
Pernicious anaemia
- autoimmune destruction of instrinsic factor due to intrinsic factor targeting antibodies
- often associated with autoimmune destruction of parietal cells (which produce intrinsic factor)
Dietary insufficiency
- veganism
Gastric causes
- atrophic gastritis
- gastrectomy
- H. pylori infection
Intestinal causes
- Crohn’s disease
- malabsorption
Drugs
- PPIs
- neomycin
- metformin