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Pathology > Haematology - Haemolytic anaemias > Flashcards

Haematology - Haemolytic anaemias Flashcards

1
Q

what are the different ways haemolytic anaemia can be classified?

A
  • intravascular
  • extravascular (removal in reticuloendothelial system)
  • inhertied
  • axquired
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2
Q

list some extravascular causes

A
  • AI
  • alloimmune
  • hereditary spherocytosis (AD inheritance)
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3
Q

list some intravascular causes

A
  • malaria
  • G6PD and PK deficiencies
  • mismatched ABO blood transfusion
  • cold anti-body haemolytic syndromes
  • drugs
  • microangiopathic HA’s (i.e. TTP)
  • paroxysmal nocturnal haemoglobinuria
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4
Q

what can hereditary haemolytic anaemias affect?

A
  • membrane (cytoskeltal proteins, cation permeability)
  • red cell metabolism
  • haemoglobin (thalassaemia, SSD, unstable Hb variants)
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5
Q

what are the consequences of haemolysis?

A
  • anaemia
  • erythroid hyperplasia (inc RBC production and reticulocyte circulation)
  • inc. folate demans
  • susceptibility to: parvovirus B12, gallstones, iron overload, osteoporosis, hepatic siderosis
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6
Q

why is parvovirus such a problem?

A

stops production of new RBCs

if got decreased survival of RBCs need new ones ASAP

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7
Q

how do patients with a hemolytic disorder present clinically?

A
  • pallor
  • jaundice
  • splenomegaly
  • pigmenturia
  • FHx
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8
Q

how do patients with a hemolytic disorder present in lab results?

A
  • anaemia
  • reticulocytosis
  • polychromasia
  • inc BR
  • inc LDH
  • dec haptoglobins
  • haemoglobinuria
  • haemosiderinuria
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9
Q

name 2 disorders where there is a defect in RBC membrane

A
  • hereditary spherocytosis

- hereditary elliptocytosis

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10
Q

what is the problem in hereditary spherocytosis? inheritance?

A
  • spectrin or ankyrin deficiency (problems in RBC cytoskeleton)
  • B19 susceptibility and propensity to develop gallstones
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11
Q

how do you test for hereditary spherocytosis?

A
  • inc. sensitivity to lysis in hypotonic saline (osmotic fragility test)
  • Di-binding test
  • pathology slide: lack of central pallor, extravascular haemolysis
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12
Q

where is the mutation in hereditary elliptocytosis?

A

spectrin mutation

autosomal dominant

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13
Q

what do you get if you are homo/heterozygous in spectrin mutation?

A

Homo state: hereditary pyropoikilocytosis (dangerous)

Hetero state: hereditary elliptocytosis (not very dangerous)

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14
Q

who does G6PD def affect? inheritance?

A

X-linked

clinical effects in males or homozygous females

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15
Q

what does G6P do?

A

catalyses 1st step in pentose phosphate pathway to generate NADPH
this protects the RBC from oxidative damage

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16
Q

clinical effects of G6PD

A
  • neonatal jaundice
  • acute haemolysis (triggered by oxidants/infection)
  • chronic haemolytic anaemia
17
Q

what can trigger acute haemolysis in G6PD?

A
  • anti-malarials
  • antibiotics (sulphonamides, ciprofloxacin, nitrofurantoin)
  • dapsone, Vit K
  • fava beans and mothballs
18
Q

how does G6PD present on a pathology slide?

A
  • bite cells
  • hemi-ghosts
  • nucleated RBCs
  • Heinz bodies (methyl violet stain)
19
Q

what are other metabolic RBC disorders and how do they appear on slide?

A
  • pyruvate kinase def (echinocytes and spherocytes. echinocytes = hedgehog-like)
  • pyrimidine 5’ nucleotide def
20
Q

what are the different investigations for HA?

A
  • Direct antiglobulin test (AI haemolysis)
  • urinary haemosiderin/Hb
  • osmotic fragility (spherocytosis)
  • G6P +/- PK activity
  • Hb separation A and F percentage (Thalassaemia)
  • Heniz body stains (G6PDD)
  • Ham’s test (Paroxysmal nocturnal haemoglobinuria)
  • thick and thin blood films
21
Q

what are the different management steps for HA?

A
  • give folic acid
  • advice precipitating factors in G6PD
  • red cell transfusion
  • immunisation (Hep A and B)
  • monitor for complications
  • cholecystectomy for symptomatic gallstones
  • splenectomy if indicated
22
Q

what are the criteria for splenectomy?

A
  • transfusion dependence
  • growth delay
  • physical limitation (Hb < 8g/dL)
  • hypersplenism
  • age (not <3, but before 10)
23
Q

what are the HAs that are DAT +ve/ Coombs +ve?

Coombs +ve = autoimmune HA

A
  • Warm AI HA = most common

- cold agglutin disease

24
Q

what are the features of warm AI HA?

A
  • 37 degrees
  • IgG
  • spherocytes
25
Q

causes and management of warm AI HA?

A
  • mainly primary idiopathic
  • lymphoma, CLL, SLE, methyldopa
    Tx: steroids, splenectomy, immunosuppression
26
Q

features of cold agglutin disease (cold AI HA)

A
  • <37 degrees
  • IgM
  • often with Raynaud’s
27
Q

what are the causes and management of cold agglutin disease?

A
  • primary idiopathic
  • lymphoma, infections (EBV, mycoplasma)
    Tx: treat underlying condition, avoid cold, chlorambucil (chemo)
28
Q

what is paroxysmal cold haemoglobinuria (PCH)?

A
  • Hb in urine caused by viral infection (measles, syphilis, VZV)
29
Q

how do you detect PCH?

A
  • Donath-Landsteiner antibodies
    they stick to RBCs in cold
    complement mediated haemolysis on rewarming
30
Q

what is Coombs -ve?

A

mostly non-immune

31
Q

what is paroxysmal nocturnal haemoglobinuria?

A
  • acquired loss of protective surface GPI markers on RBCs
  • complement mediated lysis
  • chronic intravascular haemolysis esp at night
32
Q

what are the features of PNH?

A
  • morning haemoglobinuria

- thrombosis (+ Budd-Chiari = hepatic V thrombosis)

33
Q

how do you diagnose PNH?

A

immunophenotype = altered GPI

Ham’s test = in vitro acid-induced lysis

34
Q

how do you tx PNH?

A
  • iron/folate
  • prophylactic vaccines/antibodies
  • monoclonal antibodies that prevent complement binding to RBCs
35
Q

what is microangiopathic haemolytic anaemia (MAHA)?

A

mechanical RBC destruction
forced through fibrin/platelet mesh in damaged vessels
get schistocytes

36
Q

what are the causes of MAHA?

A
  • HUS
  • TTP
  • DIC
  • pre-eclampsia
  • exclampsia
37
Q

tx of MAHA

A

plasma exchange

38
Q

features of TTP

A
  • AI
  • MAHA
  • fever
  • renal impairment
  • neuro abnormalities
  • thrombocytopaenia
39
Q

features of HUS

A
  • causes by E. coli
  • impaired renal function
  • MAHA
  • diarrhoea
  • children and elderly

Pathology (21 decks)

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