Anaemia Flashcards
causes microcytic anaemia
iron deficiency, thalassaemia
causes normocytic anaemia
blood loss, haemolysis, chronic disease, marrow infiltration
causes macrocytic anaemia
megaloblastic anaemia
causes of iron deficient anaemia
bleeding from GI tract- benign, malignant; menorrhagia; pregnancy; malabsorption; malnutrition; bleeding urinary tract; hookworm, pulmonary haemosiderosis
symptoms/ signs iron deficient
koilonychia, glossitis, angular stomatitis, gastritis
investigations iron defi
endoscopy/colonoscopy, if GIT normal- test urine for haematuria; CXR
what can you give to correct iron deficiency
ferrous sulphate 200mg. give for 6 months
side effects ferrous sulphate
nausea, epigastric pain, diarrhoea constipation
what is the MCV for macrocytic
> 98
MCV for normocytic
78-98
MCV for microcytic
what is megaloblastic anaemia caused by
B12 or folate deficiency
what are folate and B12 needed for
synthesis DNA
what is the name for B12
cobalamin
what do you get B12 from
animal sources- meat, fish, eggs, butter, milk
what does B12 combine with and where is it absorbed
combines with intrinsic factor (secreted by parietal cells), absorbed in the terminal ileum
causes of B12 deficiency
inadequate diet, intestinal malabsorption- ileal resection, crohns, congenital malabsorption, deficient gastric intrinsic factor- pernicious anaemia, gastrectomy
what is pernicious anaemia
autoimmune gastritis- reduced gastric secretion IF
presentation pernicious anaemia
patient is often early greying of the hair, blue eyes, fhx, associated autoimmune disorders- myxoedema, vitiligo, Addisons, thyrotoxicosis
features B12 deficiency
gradual onset symptoms. jaundice. glossitis and angular cheilosis. neuropathy- tingling in the feet, gait, visual.
treatment B12 deficiency
1mg hydroxycobalamin. then vit B12
where is folate in diet
in most foods. especially liver and green veg
where is folate absorbed
upper small intestine
causes of folate deficiency
malabsorption- coeliac, small bowel disease/resection, tropical sprue; dietary; liver disease; increased demand- pregnancy, haemolytic anaemia, malignancy, inflammatory diseases
features folate deficiency
same as B12 def but with no neuropathy
tests for causes B12 def
history, tests for IF antibody and parietal cell antibodies, upper GI endoscopy
tests for causes folate def
history, TTG and endomysial antibodies, duodenal biopsy. serum folate low, red cell folate low
treatment folate deficiency
5mg folic acid for 4 months
other causes raised MCV
alcohol, liver disease, myxoedema, reticulocytosis, cytotoxic drugs, aplastic anaemia, pregnancy, myeloma
normal red cell lifespan
120 days
what is haemolytic anaemia
abnormal destruction red blood cells, decreased lifespan RBCs. may be caused by fault in red cell or abnormality in its environment
inherited haemolytic anaemias
red cell membrane- hereditary spherocytosis, elliptocytosis; Hb- thalassaemia, sickling; G6PD
acquired haemolytic anaemias
immune- warm and cold autoimmune haemolytic anaemias; rhesus or ABO incompatability; trauma; infection; hypersplenism
features haemolytic
anaemia, jaundice, incr gallstones, splenomegaly, megaloblastic caused by decr folate
lab features haemolytic
extravascular- hb may be normal or reduced, raised reticulocyte, blood film, bone marrow shows incr erythropoiesis, bilirubin raised, haptogloibin absent. intravascular- raised Hb, positive Schumm test, haemosiderin in urine
causes of haemolytic anaemia- red cell fragmentation syndromes
cardiac valve, TTP, DIC, haemolytic uraemic syndrome
why is there jaundice in haemolytic
incr catabolism Hb releasing increased amounts bilirubin
what type of jaundice in haemolytic
uconjugated bilirubin so not present in urine
what is the most common inherited HA
hereditary spherocytosis
hereditary spherocytosis what is the defect in
red cell membrane protein- ankyrin
hereditary spherocytosis signs
splenomegaly, severe anaemia. fhx.
tests for hereditary spherocytosis
direct antiglobulin test- negative. EMA
treatment hereditary spherocytosis
splenectomy. folic acid. cholecystectomy- if gallstones
what happens in G6PD deficiency
red cells susceptible to oxidant stress- by drugs, infections, fava beans, neonatal period. X linked.
who is G6PD common in
Mediterranean, middle eastern, oriental
what does the blood film show in G6PD
in a crisis can be absent Hb- bite and blister cells. Heinz bodies (denatured Hb)
what is autoimmune haemolytic anaemia
autoantibodies against red cell membrane
what temp does warm AIHA work
37 degrees
what temp does cold AIHA work
0-5 degrees (4)
features warm AIHA
splenomegaly. DAT scan positive (differentiating from hereditary spherocytosis where is it negative). IgG
treatment warm AIHA
prednisolone 1mg/kg PO. transfusion if necessary, immunosuppressive drugs, splenectomy if fails, remove cause, treat underlying disease
warm AIHA antibody
IgG
cold AIHA antibody
IgM
DAT scan in cold AIHA
positive with C3d
features cold AIHA
acrocyanosis (purplish skin), Raynaud phenomenon. may be intravascular haemolysis and if severe- rigors, haemoglobinuria, renal failure
why is Hb high in intravascular haemolysis
as RBCs are broken down and released into the blood stream
causes of intravascular haemolysis
mismatched blood transfusion, G6PD, red cell fragmentation, autoimmune haemolytic, drug and infection
what are present in cold AIHA
cold agglutinins directed against red cells.
treatment cold AIHA
keep the patient warm, immunosuppression, plasma exchange to lower antibody titre
what is red cell fragmentation syndrome
when red cells are exposed to an abnormal surface eg artificial heart valve, DIC, damaged small vessels eg TTP. haemolysis is intra and extra vascular
what is thalassaemia
autosomal recessive. disorders of alpha or beta globin chain synthesis
alpha thalassaemia severity depends on
number of a genes deleted or dysfunctional there are 4 genes 2 on each chromosome 16
what happens if all 4 alpha genes are inactive
hydrops foetalis. fetus cant make fetal or adult Hb. death in utero or neonatally
what is the lab of thalassaemia
hypochromic microcytic
what is it called when 3/4 a genes are inactive
haemoglobin H disease
what do you get if one or 2 a genes are inactive
a thalassaemia trait
what is thalassaemia major
complete or almost complete failure B globin chain synthesis. severe imbalance a:b chains and a chains are deposited in erythroblasts. innefective eryhthropoiesis, severe anaemia, extra medullary haemopoiesis
features thalassaemia major
anaemia (3-6m), failure to thrive, infection, pallor, jaundice, hepato and splenomegaly, frontal bossing and hair on end appearance on x ray. iron overload
management thalassaemia major
regular tranfusions- packed red cells, iron chelation- desferrioxamine (SC) 5-7 nights weekly. oral vit C incr iron excretion; deferiprone (oral)
why does anaemia present at 3-6m in thal major
switch from y to b chain synthesis
what is the presentation of thalassaemia intermedia
less severe. present later (2-5 years), normal bones changes and growth
b thalassaemia trait
asymptomatic hypochromic microcytic anaemia
if both parents have b thal trait, what is the chance of having thal major
25%
what is sickle cell disease
point mutation in B gene- substitution valine for glutamic acid. insolubility of HB S- crystallise causing sickling and vascular occlusion
what are the B like in sickle cell anaemia and trait
2 x BS in anaemia, BS with BA in trait
what are the crises in sickle cell
vaso-occlusive, sequestration, aplastic
what happens in vaso occlusive crises
incr sickling with blockage small vessels. infection, dehydration, acidosis, deoxygenation. abdominal pain, bone pain, CNS
what happens in sequestration crises
sickling with pooling red cells in liver, spleen, lungs. acute chest syndrome
what happens in aplastic crisis
follows infection by B19 parvovirus. temp arrest erythropoiesis. severe anaemia need transfusion
clinical features sickle cell
increased susceptibility to infection, gallstones, legulcers, avascular necrosis fem and hum heads, cardiomyopathy, pulm hypertension
diagnosis sickle cell
Hb 70-90, blood film- sickle cells, screening for sickling. can do cranial Doppler to assess for stroke, retinal exam
treatment sickle cell
avoid precipitants of crisis, vaccination, folic acid. red cell transfusion in severe anaemia.
how is vaso occlusive crisis treated
hydration, saline, analgesia
how is sequestration crisis treated
exchange transfusion to reduce HbS
what medication can be given in sickle cell to reduce freq sickle cell crises
hydroxycarbamide
how does sickle trait present
benign condition without anaemia, asymptomatic. can be haematuria in oxygen deprivation
conditions causing anaemia of chronic disease
chronic infections eg tb,osteomyelitis, HIV; ronic inflam- RA, SLE; malignant- carcinoma, lymphoma; CCF; endo- hypo and hyper thyroid
what is released by the liver in anaemia of chronic disease
hepicidin
what cells are seen on blood film in sickle cell
target cells, pencil cells
