M103 T2 Symposia Flashcards
What are the two main causes of microcytic anaemia?
Fe deficiency – acquired
Thalassaemia – inherited
What causes acquired microcytic anaemia?
Chronic bleeding (GI tract, Menstrual)
Low ferritin
Low Fe, high transferrin, low transferrin saturation
What causes inherited microcytic anaemia?
alpha, beta (quantitative 𝛼/𝛽 imbalance)
normal ferritin, abnormal Hb electrophoresis/HPLC
What are the three main causes of macrocytic anaemia?
Lack of B12 (dairy) or folate (fruit/veg)
B12 deficiency – autoimmune pernicious anaemia
Folate deficiency – many causes
What can cause autoimmune pernicious anaemia?
B12 deficiency due to lack of intrinsic factor – inadequate absorption Other causes (vegan, gastric surgery, Crohn’s)
What are some of the causes of a folate deficiency?
dietary lack (tea and toast diet); alcohol malabsorption (coeliac); excess utilisation; pregnancy
What are the two main causes of normocytic anaemia?
Anaemia of chronic disease
Renal failure
What feature of a blood sample indicates normocytic anaemia as opposed to any other anaemia?
the presence of normal-sized red blood cells
What are some of the causes of anaemia of chronic disease?
Iron trapped inside macrophages
Cancer, inflammation, rheumatoid arthritis
Normal/raised ferritin, normal/low transferrin
Raised hepcidin (and inflammatory proteins)
What are some of the causes of renal failure leading to normocytic anaemia?
Lack of erythropoietin (low serum Epo level)
Red cell hormone produced by kidney
How is renal failure that has lead to normocytic anaemia treated?
with recombinant erythropoietin (weekly sc injection)
What are the two types of bone marrow failure?
congenital
acquired
What causes acquired bone marrow failure?
Marrow is empty (aplastic anaemia)
Marrow is full (infiltration e.g. leukaemia)
Marrow is not working (e.g. dysplasia)
What are the main features of bone marrow failure?
Not making enough red cells
Reticulocyte count is low
Haematinics are normal
What is excess consumption mainly caused by?
haemolysis - inherited or aquired
What is the function of a bone marrow biopsy?
shows all precursor cells
will diagnose patients with bone marrow failure conditions
What causes acquired haemolysis?
Immune (antibodies)
Non-immune (direct damage)
What causes inherited haemolysis?
Membrane problems
Haemoglobin problems
Metabolic problems
What are the three main causes of inherited RBC problems?
Membrane problems
Haemoglobinopathy
Metabolic
What causes the membrane problems that lead to inherited RBC problems?
Red cells are spherical, not biconcave
Splenectomy can help (may need cholecystectomy for gallstones also)
What are two examples of haemoglobinopathy that lead to inherited RBC problems?
sickle cell disease (wrong type of Hb)
thalassaemia (not enough Hb)
What causes the metabolic problems that lead to inherited RBC problems?
X-linked recessive, males, Afro-Caribbean
What is an example of a metabolic problem that leads to inherited RBC problems?
G6PD deficiency
How must patients change their lifestyles to prevent / reduce the effect of metabolic problems that lead to inherited RBC problems?
must avoid fava beans, legumes, certain antimalarials and antibiotics
What is an example of a membrane problem that leads to inherited RBC problems?
hereditary spherocytosis
What are the two types of genes you can get for β thalassaemia?
Thalassaemia trait (single defective gene - carrier) Thalassaemia major (both genes defective - severe) thalassemia intermedia (both genes defective - milder)
How does Thalassaemia major appear in peoples’ lives?
Babies born with two defective beta hemoglobin genes
usually are healthy at birth
but develop signs and symptoms within the first two years of life
What are the effects of Thalassaemia major?
problems of iron-overload
organ failure
How is Thalassaemia major treated?
will need to have regular blood transfusions to treat anaemia
takes a few hours each time
What are the two main types of acquired red cell problems?
Immune mediated (spherocytes) Non-immune (red cell fragments)
What are the two types of immune haemolysis?
autoimmune haemolysis
alloimmune haemolysis
What events can lead to non immune haemolysis?
the installation of mechanical heart valves
patients with DIC (very sick patients - sepsis, metastatic cancer)
MAHA (microangiopathic haemolytic anaemia)
What are the two forms of autoimmune haemolysis?
warm - regulated by IgG antibodies
cold - regulated by IgM antibodies
What can alloimmune haemolysis be caused by?
a reaction by the immune system against rbc transfusions
babies with haemolytic disease of the newborn due to resis disease
What does non immune haemolysis caused by?
fragmentation of the rbcs
What other names is rhesus disease known by?
haemolytic disease
disease of the foetus and newborn (HDFN)
What are the effects of rhesus disease on the mother and the baby?
it doesn’t harm the mother
can cause the baby to become anaemic and develop jaundice
How is haemolysis diagnosed?
take a history to find out if it is inherited
haemolysis screen
excessive bleeding (menstrual, internal from trauma etc)
sequestered bleeding (e.g splenic sequestration)
What are the stages of a haemolysis screening?
start with a Direct anti-globulin test (DAT or Coomb’s test)
check the bilirubin level to check for jaundice
check the blood film for spherocytes or rbc fragments
check the LDH level as it increases in haemolysis
check the reticulocyte count as it increases in haemolysis
check the haptoglobin level – levels go down in serum
check for haemoglobinuria
How does Coomb’s test screen for haemolysis?
it detects antibodies that are stuck to the surface of the red blood cells
How do you check for haemoglobinuria?
involves free Hb in urine
urine will be a dark colour
a urine dipstick will show urobilinogen (colourless)
What does urobilinogen in the urine mean?
normal urine will contain some urobilinogen
however if there is little or no urobilinogen in urine, it can mean the liver isn’t working correctly
a higher than normal level can indicate haemoglobinuria
What is a resultant condition from anaemia?
can result in tissue hypoxia
What are the symptoms of anaemia?
Tiredness
Breathlessness
Pallor
What is the equation for ejection fraction?
EF (%) = (SV / EDV) x100
What are the main three types of Acute Coronary Syndrome?
STEMI (most serious)
NSTEMI
unstable angina (least serious)
What are the symptoms of coronary artery spasm?
chest tightness or pain caused by tightening of a heart artery
arm or jaw pain
Under what circumstances might the symptoms of coronary artery spasm present?
cold weather, exercise or stress
What happens if an NSTEMI isn’t treated?
it can progress to serious heart damage or STEMI
What happens if an NSTEMI or unstable angina isn’t treated?
it can progress to serious heart damage or STEMI
What are the two ways in which cardioversion can be achieved?
by sending electric shocks to the heart through electrodes placed on the chest (most common)
medications
What diseases are associated with the SCN5A protein coding gene?
Long Qt Syndrome 3
Sudden Infant Death Syndrome
Where is a transvenous ICD routed?
inserted into the subclavian vein into the tricuspid valve, into the right ventricle
