Haematology Flashcards
Causes of microcytic anaemia
iron deficiency anaemia (most common cause of anaemia)
thalassemia
Sideroblastic anaemia
Causes of normocytic anaemia
Anaemia of chronic disease Acute blood loss Haemolytic anaemia Chronic renal failure combined haematinic deficiency
Causes of macrocytic anaemia
Vitamin B12 or folate deficiency (megaloblastic anaemia)
excess alcohol
Liver disease
Hypothyroidism
haemolytic anaemia (if presence of high RC)
Haematological diseases beginning with ‘M’: myeloproliferative, myelodysplastic, multiple myeloma
Causes of neutrophilia
Bacterial infection
Tissue damage (inflammation, infarct, malignancy)
steroids
Causes of neutropaenia
Viral infection
Chemo or radiotherapy
Carbimazole
Clozapine
Causes of lymphocytosis
viral infection
Lymphoma
Chronic lymphocytic leukaemia
Causes of thrombocytopaenia?
reduced production:
- infection (usually viral)
- drugs (esp. penicillamine (e.g. in rheumatoid arthritis treatment))
- myelodysplasia, myelofibrosis, myeloma
Increased destruction:
- heparin
- disseminated intravascular coagulation (DIC)
- idiopathic thrombocytopenic purpura (ITP)
- haemolytic uraemic syndrome/thrombotic thrombocytopenic purpura
Causes of thrombocytosis?
reactive:
- bleeding
- tissue damage (inflammation, infection, malignancy)
- postsplenectomy
primary:
myeloploriferative disorders
What differentiates Hodgkin’s lymphoma from Non-Hodgkin’s lymphoma?
Hodgkin lymphoma is marked by the presence of Reed-Sternberg cells. In non-Hodgkin lymphoma, these cells are absent.
What are the 4 globin chains found in adult Hb
2 alpha globin and 2 beta globin chains
What are the 4 globin chains found in fetal Hb
2 alpha globin and 2 gamma globin chains
What are thalassemias?
The thalassaemias are genetic diseases of unbalanced Hb synthesis, with underproduction (or no production) of one globin chain. Unmatched globins precipitate, damaging rbc membranes, causing their haemolysis while still in the marrow. They are inherited in an autosomal recessive pattern.
what is the relationship bw MCV and Hb lvls in thalassemias?
significant thalassemia causes microcytic anaemia. Usually in thalassemias, the MCV is ‘too low’ for their given Hb level and the red cell count is raised.
What are the clinical phenotypes of B Thalassemia?
The genes defect can either consist of abnormal copies that retain some function or deletion genes where there is no function in the beta-globin protein at all. Based on this, beta-thalassaemia can be split into three types:-
1. Beta thalassemia minor or trait
2. B thalassemia intermedia
3. B thalassemia major
the severity is not always associated with the genotype
B thalassemia minor/trait
heterozygous state. carrier state. usually asymptomatic. sometimes mild well tolerated anaemia which may worsen in pregnancy. MCV <75. Hb >90.usually patients only require monitoring and no active treatment.
B thalassemia intermedia
Thalassaemia intermedica causes a more significant microcytic anaemia and patients require monitoring and occasional blood transfusions. If they need more transfusions they may require iron chelation to prevent iron overload.
B thalassemia major
Patients with beta thalassaemia major are homozygous for the deletion genes. They have no functioning beta-globin genes at all. This is the most severe form and usually presents with severe anaemia and failure to thrive in early childhood (important to note doesn’t present immediately after birth though (then alpha thalassemia is more likely)).
it causes -
Severe microcytic anaemia
extramedullary heamatopoiesis (eg skull bossing, malar eminences
hepatosplenomegaly(this also occurs due to haemolysis)).
osteopaenia
Hb F (fetal haemoglobin) will be very high and ferritin will be normal.
What is a big SE of lifelong blood transfusions? What is the treatment for this SE?
Iron overload. it can affect endocrine organs, liver and the heart. it can be mitigated by using iron chelators (eg desferrioxamine or deferiprone). large amounts of vit C can also help by increasing urinary excretion of Fe.
hormone replacements or other treatment for endocrine complications may be required.
Treatment for B thalassemia major
lifelong blood transfusions required.
splenectomy (ideally after 5 yrs of age) if hypersplenism persists with increasing transfusion requirements.
histocompatible marrow transplant can offer the chance of a cure.
anaemia?
reduced red cell mass. dehydration can mask anaemia
red cell life span
apprx 120 days
red cell production site
bone marrow
red cell removal site
spleen
liver
bone marrow
RC count relevance in telling whether anaemia is production or removal problem?
if RC goes up then removal problem and if RC low then production problem (like bone marrow problem).
types of anaemia?
microcytic, normocytic, macrocytic and haemolytic (may be normocytic or, if there are many young (hence larger) rbcs and reticulocytes, macrocytic)
general symptoms of anaemia?
fatigue, dyspnoea, faintness, palpitations, headache, anorexia—and angina if there is pre-existing coronary artery disease.
If heart failure arises in severe anaemia, what do u need to be careful about?
here, rapid blood transfusion can be fatal.In severe anaemia with heart failure, transfusion is vital to restore Hb to a safe level. Give it slowly with diuretic. Check for signs of worsening overload: rising jvp and basal crackles: in this eventuality, stop and treat.
ix for anaemia?
Hx and examination FBC + film RC count U/Es, LFTs, TSH B12, folate and ferritin
causes of iron deficiency anaemia?
• Blood loss, eg menorrhagia or gi bleeding.
• Poor diet or poverty may cause ida in babies or children.
• Malabsorption (eg coeliac disease) is a cause of refractory ida.
• In the tropics, hookworm (gi blood loss) is the most common cause.
Increased requirement — physiological iron requirements are three times higher in pregnancy
S&S of iron def anaemia?
in addition to s&s of anaemia,
Pallor Intermittent claudication Nail changes, e.g. koilonychia Angular cheilitis Atrophic glossitis
what investigations can confirm fe deficiency
Confirmed by ↓ferritin (also ↓serum iron with ↑tibc, but these are less reliable). Ferritin is an acute phase protein and ↑ with inflammation, eg infection, malignancy.
Blood film: microcytic, hypochromic anaemia with anisocytosis and poikilocytosis.
A serum ferritin level of less than 15 micrograms/L confirms iron deficiency
management of iron def anaemia?
New iron deficiency in an adult without a clear underlying cause should be investigated with suspicion. This involves doing a oesophago-gastroduodenoscopy (OGD) and a colonoscopy to look for cancer of the gastrointestinal tract.
Treat the cause.
3 ways to correct anaemia -
1. blood transfusion (will immediately correct the anaemia but not the underlying iron deficiency and also carries risks)
2. parenteral iron (very small risk of anaphylaxis but it quickly corrects the iron deficiency. It should be avoided during sepsis as iron “feeds” bacteria)
3. Oral iron, eg ferrous sulfate se: nausea, abdominal discomfort, constipation, black stools.
When correcting iron deficiency anaemia with iron you can expect the haemoglobin to rise by around 10 grams/litre per week.
complications of IDA
Heart failure
Adverse effects on immune status and morbidity from infection
Cognitive and behavioural impairment in children
Impaired muscular performance
sign of megaloblastic anaemia on blood films
hypersegmented neutrophils in macrocytic RBCs
ix for macrocytic anaemia?
lft, tft, serum b12 (cobalamin), and serum folate (or red cell folate—a more reliable indicator of folate status, as serum folate only reflects recent intake).
co-existing B12 and folate deficiency. what shd u do?
treat B12 before folate
folate sources
broccoli brussels sprouts leafy green vegetables, such as cabbage, kale, spring greens and spinach peas chickpeas and kidney beans fortified breakfast cereal
