Anaemias Flashcards
HAEMOLYTIC ANAEMIA OVERVIEW
i) what happens?
ii) name three inherited conditions that cause it? name three acquired causes?
iii) why do you get anaemia/splenomegaly/jaundice?
iv) what is seen on FBC? what is seen on blood film?
v) which cause of HA worsens after eating fava beans, taking anti malarials or triggered by infections? what is seen on blood film?
i) destruction of RBC leading to anaemia
ii) inherited - hereditary spherocytosis, hereditary elliptocytosis, thalassemia, SCA, G6PD deficienct
acquired - AI haem anaemia, allo immune (transfusion reaction of HDNB), paroxymal nocturnal haemoglobunria, prostethic valve related haemolysis
iii) anaemia due to less RBC in circulation
splenomegaly as spleen becomes filled with destroyed RBC
jaundice as bilirubin is released during destruction of RBC
iv) FBC = normocytic anaemia
blood film = schistocytes (fragments of RBC)
direct coombs test is positive in AI HA
v) G6PD deficiency
AUTOIMMUNE HAEMOLYTIC ANAEMIA
i) what happens?
ii) what is the most common type? what happens here? which antibodies are usually implicated?
iii) what is cold agglutin disease? what happens to cause anaemia? which antibodies are usually implicated? what is it usually secondary to (3)
iv) name three ways AI haem anaemia can be managed?
v) how is rituximab used?
i) antibodies are created to patients RBC > destruction
ii) two types based on the temperature at which auto antibodies function
most common = warm AI HA where haemolysis occurs at normal or above normal body temps
implicates IgG
iii) CAD - antibodies against red blood cells attach themselves causing them to clump togther at low temperatures > filtered and destroyed by the spleen
implicates IgM
usually secondary to other conditions eg lymphoma, SLE, leukarmia, EBV, CMV
iv) blood transfusions, prednisolone, splenectomy
v) rituximab is a MAB against CD20 - targets B cells and prevents them releasing the antibodies that target the RBC
ALLOIMMUNE HAEMOLYTIC ANAEMIA
i) what causes it? (2)
ii) name two situations it is seen and what happens
i) there is either foreign RBC circ in the patient causing immune reaction (transfusion reac) or a foreign antibody circ in the blood that acts against own blood cells (HDNB)
ii) transfusion reaction - imm sys produces antibodies against antigens on foreign RBC > imm response and destruction
HDNB - antibodies cross the placenta from mother to fetus > maternal antibodies target antigens on foetal RBC > destruction
IRON DEFICIENT ANAEMIA
i) why is iron needed? name four ways that a patient can become iron deficient?
ii) which two main areas is iron absorbed? why may PPIs interfere with iron absorption? why may crohns or coeliac disease cause iron deficiency?
iii) name four causes? which cancer is may be suspected in IDA?
i) the BM requires iron to produce Hb
insufficient dietary iron, increased requirements (pregnancy), iron loss (bleeding), inadequate absorption
ii) abs in duodenum and jejunum
iron requires stomach acid to keep it in the soluble ferros form (when acid drops it changes to insol fom) therefore PPIs can cause insol > deficiency
iii) blood loss - most common cause in adults, dietary insufficiency, poor ans, increased req eg pregnancy
may suspect a GI tract cancer
TESTS FOR IRON DEFICIENCY
i) what is transferrin? what is total iron binding capacity? what is transferrin saturation?
ii) what is ferritin? when may there be extra ferritin released?
iii) what TIBC and transferrin levels are seen in iron deficiency?
iv) what ferritin levels will be seen? what will transferrin saturation be?
i) transferrin = carrier protein that binds to ferric ions (transports iron)
TIBC = how much space there is on the transferrin molecule for iron to bind
ii) ferritin is the storage form of iron
extra ferritin is released in inflammation eg infection or cancer
iii) high levels of TIBC and transferrin in IDA
iv) low ferritin levels (hallmark of IDA)
transferrin saturation will be low as there are low amounts of iron to shuttle
MANAGEMENT OF IDA
i) which investigation may be done if there is unexplained new IDA?
ii) name three ways iron deficiency can be managed
i) OGD or coloscopy to look for cancer of the GI tract
ii) mx with blood transfusions, iron infusion (avoid in sepsis) or oral iron (ferrous sulphate)
PERNICIOUS ANAEMIA
i) what type of condition is it? what happens? which vitamin will therefore be low?
ii) name three neurological symptoms that may be seen
iii) which investigation is most likely to reveal the cause?
iv) how can dietary deficiency of B12 be treated? is this enough in PA? what is first line tx for PA?
v) is it important to treat B12 or folate deficiency first? why?
i) autoimmune condition where antibodies form against gastric parietal cells or intrinsic factor
GP cells release IF which is needed for B12 absoroption therefore become B12 deficient
ii) peripheral neuropathy (w pins and needles), loss of vibration sense/proprioception, visual change, mood or cognitive change
iii) intrinsic factor antibody test
iv) dietary defic can be tx with cyancobalamin but this is not enough in PA
PA - intramuscular hydroxycobalamin 3x weekly for 2 weeks
v) treat B12 defic first > if not can cause sub acute combined degeneration of the cord
SICKLE CELL ANAEMIA
i) what is it? what type of anaemia does it lead to?
ii) what abnormal variant of Hb do patients with SCA have? what does this cause?
iii) what is the inheritance pattern? which gene is implicated? which chromosome?
iv) when are people tested for it?
i) genetic condition > sickled RBC > haemolytic anaemia
ii) HbS > causes RBC to be sickled
iii) auto recessive - abnormal betaa globin gene on chromosome 11
iv) newborn screening heel prick test at day 5
pregnant women are also screened
SCA MANAGEMENT
i) what should be avoided? which abx may be given prophylactically?
ii) what can be given to stimulate fetal Hb? what does it have a protective effect against? (2)
iii) name three things that can trigger a sickle crisis? name three ways it can be managed?
iv) what causes a painful crisis? what caan this leaad to? what will haematocrit be? what may happen in men?
i) avoid dehydration
given pen V prophylactically
ii) hydroxycarbamide to stim HbF > protective against sickle crises and acute chest syndrome
iii) triggered by infection, dehy, cold
mx by tx infection, keep warm, keep hydrated, simple analgesia
iv) sickled blood cells clog caps > distal ischaemia
assoc with dehydration and raised haematocrit
priapism (trap blood in penis > painful and persistent erection) - urol emergency need to aspirate blood
SCA COMPLICATIONS
i) what is splenic sequestration caused by? what can it lead to? (2) how is it managed? what may be done if it is persistent?
ii) what is an aplastic crisis? what is it most commonly caused by? what does it lead to? what is mx?
iii) which two things are required for a dx of acute chest syndrome? what can caue it? name four txs?
i) caused by RBC blocking blood flow within the spleen > can lead to enlarged and painful spleen > severe anaaemia and circ collapse (hypovol shock)
mx - supportive with fluid and blood resus
splenectomy if persiss
ii) aplastic - temp loss of creaation of new red cells, triggered by infection parvovirus B19
leads to signif anaemiaa and may need transfusion
usually self resolves within a week
iii) ACS - fever/resp symptoms + new infiltrates on CXR
can be caused by infective or non infective causes
antibiotics, blood trans, spirometry to encourage effective and deep breathing, invasive vent may be required
