Disorder of Plts

Question 1

Giant Plts are seen in

Answer 1

myoproliferative neoplasms to compensate for inc plts destruction

Question 2

3 resons for thrombocytopenia

Answer 2

1. decreased production: bc dec. # MK in BM = dec [plt] in PB
2. Altered distribution: splenomegaly => plt sequestration ≠ cirtculate in blood
3. increased destruction: Non-immune (e.g. DIC) or immune (drug induced)

Question 3

Describe Disseminated IV COagulation (DIC)

Answer 3

• non-immune
• plts & coag factors consumed faster > synthesised\
• fibrinolysis follows fibrin formation

Question 4

Describe Thrombotic Thrombocytopenic Purpura (TTP)

Answer 4

• non-immune
• microangiopathic destruction of plts (in sml BV)
• microangiopathic haemolytic anaemia = shistocytosis
• dec vWF cleaving protein (ADAMTS13 > dx factor)

Question 5

Describe immune-mediated thrombocytopenia

Answer 5

• destruction of plts in PB, normal/Inc MK in BM

- associated w/ drugs (Heparin)

Question 6

describe idoipathic thrombocytopenia Purpura (ITP)

Answer 6

• dec plt production & premature destruction of AUTO-Ab-coated plts
• thrombocytopenia persist for months - years

Question 7

Describe post viral thrombocytopenia

Answer 7

• inc. ‘reticulated plts

- normal to inc MK

Question 8

lab tests to investigate plts fucntions

Answer 8

• aggregometry
• adhesion test
• Flow cytometry

Question 9

pathophysiology of May-hegglin anomaly

Answer 9

• autosomal dominant inheritance
• point mutation in MYH9 gene
• giant plts & thrombocytopenia
• Neutrophil cytoplasmic inclusion (like dohle bodies)`

Question 10

pathophysiology bernard-soulier syndrome

Answer 10

• autosomal recessive disorder
• giant plts + dec plts
  => ineffective aggregation

Question 11

how can you distinguish bernard-soulier syndrome w/ May-hegglin anomaly

Answer 11

• B-S S: no neutrophil inclusions

* M-H A Abnormal ristocetin aggregation

Question 12

Describe Glanzmann’s thrombasthenia

Answer 12

• rare autosomal recessive disorder
• plt # & morphology are normal
• but Plts fail to aggregate normally w/ agonist bc
• deficiency in glycoprotein IIb/IIIa (for fibrin dependent plt-plt interactions)

Question 13

other functions of plts besides wound healing (2)

Answer 13

1. inflammation: bind to pathogens & stimulate inflamm. resp

2. Wound healing: release growth factors

Question 14

differentiate post viral thrombocytopenia w/ Glanzmann’s thrombasthenia

Answer 14

• P V T: immature plts

- G T: normal plts