Haematology Flashcards
Define microcytic anaemia
Low haemoglobin concentration and low MCV on blood test
List causes of microcytic anaemia
- Iron deficiency anaemia (blood loss, pregnancy, decreased absorption due to coeliac disease and h.pylori, nutritional deficiency)
- Thalassemia
- Sideroblastic anaemias (very rare - alcoholism)
- Anaemia of chronic disease
- Lead poisoning
List signs on examination of microcytic anaemia
Iron deficiency
- Koilonychia
- Angular cheilosis
- Pallor
- Atrophic glossitis
- Tachycardia, murmurs, cardiac enlargement
- Dry skin/hair
- Alopecia
Thalassemia
- Hepatosplenomegaly
- Bony deformities
- Jaundice
- Pallor
- Cardiac flow murmur
List symptoms of microcytic anaemia
- Dyspnoea
- Fatigue
- Cognitive dysfunction
- Restless leg syndrome
- Vertigo
- Dysphagia
- Syncope
- Dizziness
- Irritability
- Weakness
Describe epidemiology of iron deficiency anaemia
- Iron deficiency anaemia is the most common cause of anaemia, affecting 500 million people worldwide
- Especially prevalent in low income populations
- 2-5% adult men and post-menopausal women
- Higher incidence in childbearing years (38% pregnant, 29% non-pregnant women worldwide. 23% pregnant and 14% non pregnant UK)
Describe epidemiology of thalassemia
- 1.5% population are carriers of B thallasemia. Especially prevalent in mediterranean, middle east, southern china, central, south and southeast asia
- 5% carriers of a-thallaemia. Most prevalent in southease asia, africa, india
- Typically presents from 3rd - 6th month of life in B, in a present from birth
Describe epidemiology of sideroblastic anaemia
- More common in males
- Onset usually before 30
- Rare
List investigations to diagnose microcytic anaemia
- FBC
- Ferritin
- Transferrin, transferrin saturation, iron, ferritin, transferrin binding capacity
- B12 and folate
- Coeliac screen
- Top and tail
- Iron deficiency: Low MCV, low iron, low hb, high transferrin, low transferrin saturation, low ferritin, high transferrin binding capacity. Pencil cells on smear
- Thalassemia increased ferritin and saturation, electrophoresis for diagnosis, no normal blood test history. HbA2 raised
- Sideroblastic anaemia sideroblasts seen in mcicroscopy
- Anaemia of chronic disease – low iron, low iron binding capacity, high or normal ferritin
Describe management of microcytic anaemia
- Treat underlying cause
- If iron deficiency oral ferrous sulphate
- If sideroblastic, transfusion may be needed, withdraw causative agents
- Screen for coeliac
- If thalassemia blood transfusion, with chelating agents. Bone marrow transplants are curative
List complications of microcytic anaemia
- Heart failure
- Adverse immune status
- Cognitive and behavioural impairment in children
- Impaired muscular performance
- In pregnancy, iron deficiency associated with increased morbidity, preterm delivery, depressive symptoms, infant iron deficiency
- Thalasemia major carries 80% mortality in the first 5 years of life. Stem cell transplant associated with 85-90% survival
What is red cell distribution width? What makes it abnormal?
- Red cell distribution width (RDW) – a measure of the variation in RBC size.
- If high this suggests a large variation in sizes, seen in iron deficiency, myelodysplastic syndrome and haemoglobinopathies.
List causes of macrocytic anaemia
- Megaloblastic B12 and folate deficiency (methotrexate, trimethoprin, dietry deficiency, excessive requirements eg.in pregnancy, excessive urinary excretion, genetic disorders)
- Non-megaloblastic (liver disease, alcohol, hypothyroidism, myelodysplasic syndrome, acute leukaemia)
Alcoholics (alcohol raised GGT)
Myelodysplasia (pancytopaenia and bone marrow)
Have (hypothyroidism)
Liver (liver disease)
Failure (folate/B12 deficiency)
Define macrocytic anaemia
- Abnormally large red blood cells
- High MCV, low Hb
Describe epidemiology of macrocytic anaemia
- In the UK (and the US) the prevalence of vitamin B12 deficiency is around 6% in people aged less than 60 years.
- For people aged over 60 years, this rises to around 20%.
- For people with vegan diets, around 11% are deficient in vitamin B12.
- Adult pernicious anaemia (the most common cause of B12 deficiency and megaloblastic anaemia) occurs most commonly in people aged 40–70 years, with a mean age of onset of 60 years among white people.
- In black people the mean age is 50 years, with a biomodal distribution due to an increased occurence in young black females.
- The prevalence of folate deficiency (serum folate below the World Health Organization [WHO] clinical threshold for folate deficiency [7 nanomol/L]) amongst adults and children is no more than 5%.
- Medication 40%
- Alcoholism 25%
- Vit B12 and folate deficiency 6%
- Liver disease 6%
List symptoms of macrocytic anaemia
- Fatigue
- SOB
- Angina
- Headache
- Palpitations
- Reduced sensation, parasthesia, ataxia, reduced proprioception
List signs of macrocytic anaemia
- Pallor (nail beds, tongue, conjunctiva)
- Lemon tinge skin colour in pernicious anaemia
- Bounding pulse
- Systemic flow murmur
List investigations for macrocytic anaemia
- Blood test and film (absent reticulocytes suggests non-megaloblastic, target cells indicates non-megaloblastic)
- Vit B12, anti-intrinsic factor antibody (pernicious anaemia)
- Folate
- Thyroid function tests
- Liver funciton tests (for liver disease - B12 and folate deficiency may have raised bilirubin)
- Coeliac serology if indicated
Describe management of macrocytic anaemia
- Pernicious or B12 deficiency (B12 injections every 3 months)
- Folate deficiency (folic acid 5mg faily for 4 months. Must treat B12 first if both are low)
- Refer if neurologicalsymptoms, pregnancy, suspected haematological malignangy, no cause identified
- Gasto referal if malabsorption
List complications of macrocytic anaemia
- Heart failure
- B12 - neruological symptoms, optic atrophy and severe psychiatric symptoms
- Folate - Prematurity, cardiovascular disease and some cancers
- Neural tube defects
- Ineffective production of any blood cells from the bone marrow
- Sterility
Describe prognosis of macrocytic anaemia
- Generally good once cause is identified
- Vitamin deficiencies can be replaced
- Can cause permanent damage to the nervous system
Define normocytic anaemia
- Low Hb
- Normal MCV
Compare neutrophilia to lymphocytosis
- Neutrophilia acute inflammation
- Lymphocytosis chronic inflammation
Describe causes of microangiopathic haemolytic anaemia
- DIC (decreased platelets and fibrinogen, increased PT and APTT, increased D dimer and fibrin degradation products)
- Haemolytic uraemic syndrome (increased Hb decreased bilirubin, uraemia, decreased platelets)
- Thrombocytic thrombocytopenic purpura (HUS, fever and neurological manifestations)
List causes of haemolytic anaemia
Hereditary
- Red cell membrane (hereditary spherocytosis, elliptocytosis)
- Enzyme deficiency (G6PD deficiency)
- Haemoglobinopathy (Sickle cell disease, Thalassaemias)
Acquired
- Autoimmune
- Drugs
- Infection
- MAHA