Haematology Flashcards
sx of anaemia
fatigue dyspnoea lightheaded palpitations headache tinnitus anorexia (angina if pre-existing coronary disease)
signs of anaemia
pallor (+ of conjunc)
tachycardia
flow murmurs (ejection systolic over apex)
causes of microcytic anaemia
iron def
thalassaemia
sideroblastic
causes of normocytic anaemia
chronic disease acute blood loss bone marrow failure renal failure (erythropoetin) hypothyroid haemolysis pregnancy
in a patient with normocytic anaemia who also has low WCC an low platelets, what diagnosis would you suspect?
marrow failure
causes of high MCV (macrocytic) anaemia
B12/folate def alcohol excess/ liver disease reticulocytosis (e.g. with haemolysis) cytotoxics e.g. hydroxycarbamide myeloma marrow infiltration hypothyroid antifolate drugs e.g. phenytoin
causes of iron deficiency anaemia
blood loss - menorrhagia, GI
poor diet
malabsorption - coeliac
hookworm
signs of iron deficiency anaemia (now rare)
koilonychia (spoon nails)
atrophic glossitis
angular stomatitis
tests in iron deficiency
FBC haematinics blood film coeliac serology gastroscopy + colonoscopy
Tx for iron deficiency anaemia
treat the cause
ferrous sulphate
(then IV iron)
Side effects of ferrous sulphate
nausea
abdo discomfort
constipation/ diarrhoea
black stools
pathophysiology behind anaemia of chronic disease
- poor use of iron in erythropoesis
- cytokines shorten RBC survival
- reduced EPO production + response to it
examples of causes of anaemia of chronic disease
malignancy RA chronic infection vasculitis renal failure
Mx of anaemia of chronic disease
treat underlying cause
EPO
what is sideroblastic anaemia
ineffective erythropoesis and iron loading in marrow
what is haemosiderosis in sideroblastic anaemia
endocrine, liver and hear damage due to iron deposition
causes of sideroblastic anaemia
congenital idiopathic chemo anti-TB drugs irradiation alcohol excess
what test results would you see in sideroblastic anaemia
low Hb low MCV high ferritin hypochromic blood film sideroblasts in marrow biopsy
Tx of sideroblastic anaemia
remove cause
tranfusion
pyridoxine
tests in macrocytic anaemia
FBC, haematinics, LFT, TFT
blood film
bone marrow biopsy
in what foods is folate found?
liver
green veg
nuts
yeast
maternal folate deficiency causes what problem in fetus
neural tube defects
causes of folate deficiency
- poor diet e.g. elderly, poverty, alcoholics
- increased demand e.g. preg, increased cell turnover (CA, haemolysis, inflamm disease, renal dialysis)
- malabsorption [coeliac]
- alcohol
- drugs [antiep, methotrex, trimeth]
management of folate deficiency
Ix + Mx
assess for poor diet
coeliac serology
folic acid + B12
causes of glossitis
B12 deficiency iron def contact derm/ food allergy crohns, coeliac drugs alcoholism
causes of B12 deficiency
diet [vegan]
malabsorp [PA, crohns, resection]
food sources of B12
meat
fish
dairy products
describe how absorption of B12 occurs
intrinsic factor from the stomach binds B12, allowing it to be absorbed in the terminal ileum
clinical features of B12 deficiency
lemon tinged skin [pallor + jaundice]
glossitis
anaemia Sx
psych: irritable, dementia, depression, psychosis
parasthesia, peripheral neuropathy
subacute combined degeneration of the spinal cord
classical triad of subacute combined degeneration of the spinal cord - seen in B12 deficiency
extensor plantars
absentknee jerks
absent ankle jerks
describe briefly the patholgy behind pernicious anaemia
autoimmune
atophic gastritis
leading to reduced secretion of intrinsic factor from the parietal cells
unbound B12 therefore not absorbed
other diseases associated with pernicious anaemia
autoimmune: thyroid, addisons, vitiligo, hypoparathyroidsim
gastric carcinoma
Ix in pernicious anaemia
FBC [Hb, MCV, WCC, platelets] haematinics parietal cell autoantibodies intrinsic factor antibodies blood film [hypersegmented neutrophils] marrow
Mx of B12 deficiency
treat cause
B12 IM/ PO
why is there a marked continuing high MCV after initiating B12 treatment for deficiency
reticulocytosis
normal lifespan of a RBC
120 days
haemolysis can occur intravascularly or extravascularly. Explain extravascular haemolysis
macrophages in liver, spleen, bone marrow (reticuloendothelial system)
investigation findings that would support incerased red cell breakdown
- raised bilirubin
- low Hb, normal or high MCV
- high urinary urobilinogen
- high serum LDH (released from red cells)
what blood test finding would suggest increased red cell production?
high MCV [reticulocytosis]
an examinatin finding that may suggest extravascular haemolysis
splenomegaly
important aspects of the history in suspected haemolytic anaemia
FH previous anaemia ethnicity dark urine drugs travel
important aspects of the examination in suspected haemolytic anaemia
jaundice
hepatosplenomegaly
gallstones [^bili]
leg ulcers
Ix in haemolytic anaemia
FBC LFT [bili] LDH urinary urobilinogen haptoglobin blood film
if travel Hx - malaria thick + thin films
extras:
osmotic fragility testing
direct coombs test
Hb electrophoresis
what does coombs test identify
immune causes of haemolytic anaemia
identifies RBCs coated with antibody
acquired causes of haemolytic anaemia
infection autoimmune malignancy CLL, lymphoma TTP, HUS drugs DIC transfusion hep B+C vaccinations pre-eclampsia
hereditary causes of haemolytic anaemia
enzyme defect: G6PD deficiency, PKD
membrane defect: hereditary spherocytosis
haemoglobinopathy: sickle cell, thalasaemia
how is sickle cell inherited
autosomal recessive
pathophysiology of sickle cell
abnormal haemoglobin results in deformed RBCs (sickle cells). these haemolyse -> vaso-occlusive crises
investigation findings in sickle cell
FBC - low Hb, ^reticulocytes/MCV
blood film - sickle cells + target cells
LFT - high bili
triggers for a vaso-occlusive ‘painful’ crisis in sickle cell
cold
hypoxia
dehydration
infection
presentation of vaso-occlusive ‘painful’ crisis
severe pain dactylitis in <3 yr olds acute abdomen [mesenteric ischaemia] stroke, seizure, cognitive defects avascular necrosis (e.g. femoral head) leg ulcers priapism
what is a sequestration crisis in sickle cell
and Mx?
pooling of blood in spleen and liver > organomegaly, shock, severe anaemia
transfusion
what is a aplastic crisis in sickle cell
parvovirus B19 infection leads to sudden reduction in marrow production of RBCs
complications of sickle cell
splenic infarction poor growth CKD gallstones retinal disease iron overload lung hypoxia -> fibrosis -> pULM HTN
Mx of chronic sickle cell
analgesia for crises hydroxycarbamide Abx prophylaxis + immunisations [splenic infarct] transfusions bone marrow transplant
Mx of sickle cell crisis
analgesia septic screen fluids O2 Abx if pyrexial transfusion/ exchange transfusion
Sx of acute chest syndrome in sickle cell
wheeze dyspnoea pain fever cough
what causes the infiltrates in acute chest syndrome in sickle cell
infection
fat embolism from bone marrow
Mx of acute chest syndrome in sickle cell
O2 analgesia Abx [cephalosporin + macrolide] bronchodilators in wheeze] transfusion/ exchange
examples of macrolide Abx
azithromycin
clarithromycin
erythromycin
examples of cephalosporin Abx
cefuroxime
ceftriaxone
what is thalasaemia
reduced production of one globin chain
leads to haemolysis
where in the world is thalassaemia common?
med to far east
Ix in beta thalasaaemia
FBC haematinics film Hb electrophoresis MRI [for myocardial siderosis]
clinical features of patient with beta thalassaemia
presents in 1st yr of life severe anaemia failure to thrive hepatosplenomeg skull deformity osteopenia
mx of beta thalassaemia
life long regular transfusions
folate
iron chelators [deferipone + desferrioxamine]
ascorbic acid -> iron excretion
splenectomy
Mx of endrocrine complications [DM, thyroid]
marrow transplant
side effect / risk of regular transfusions in beta thalassaemia, and the consequences of this
iron overload
endocrine: pituitary, thyroid, pancreatic failure [DM]. liver disease
cardiac toxicity
what are the 3 processes that halt bleeding after injury? (and therefore the 3 types of bleeding disorder)
vasoconstriuction
platelet plugging
coag cascade
bleeding disorders - platelet/vascular vs coagulation disorder. What is the pattern of bleeding in platelet/vascular disorders?
- prolonged bleeding from cuts
- bleeding into skin (bruising, purpura)
- Mucous membranes (epistaxis, gums, menorrhagia)
bleeding disorders - platelet/vascular vs coagulation disorder. What is the pattern of bleeding in coagulation disorders?
into joionts and muscles
bleeding disorders: give 4 examples of platelet disorders
decreased production: leukaemia, myeloma aplastic anaemia (marrow failure) cytotoxic drugs radiotherapy
destruction:
ITP (anti-platelet antibodies)
SLE
drugs e.g. heparin
non-immune:
DIC
TTP
HUS
bleeding disorders: congenital coagulation disorders
haemophilia
VWd