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Flashcards in Platelet disorders Deck (19):
1

Define immune thrombocytopenic purpura

Immune destruction of platelets

2

Describe brief pathophysiology of immune thrombocytopenic purpura

IgG antibodies bind to glycoproteins on the platelets and megakaryocytes -> opsonizes them -> phagocytosis

3

Primary causes of immune thrombocytopenic purpura

May follow viral infection/immunisation

4

Secondary causes of immune thrombocytopenic purpura

Occurs in association with some malignancies (CLL) and infections (HIV, Hep-C)

5

Clinical presentation of immune thrombocytopenic purpura

Easy bruising, purpura

6

Diagnosis of immune thrombocytopenic purpura

Thrombocytopenia (decreased platelets)
Increased/normal megakaryocytes in BM
Platelet auto antibodies (in 60-70%)

7

Treatment of immune thrombocytopenic purpura

FIRST LINE = Immunosuppression, e.g. Corticosteroids (such as Prednisolone)
Give platelets
Tranexamic Acid - inhibits fibrin breakdown - not for urinary tract

8

Define thrombotic thrombocytopenic purpura

Spontaneous platelet aggregation in microvasculature, e.g. brain, kidney, heart

9

Pathophsiology of thrombotic thrombocytopenic purpura

Due to a reduction in a protease enzyme (ADAMTS13) -> failure to breakdown high molecular weight VWF -> widespread aggregation and adhesion of platelets -> microvascular thrombosis -> consumption of platelets -> profound thrombocytopenia

10

Causes of thrombotic thrombocytopenic purpura

Autoimmunity (e.g. SLE), Cancer, Pregnancy, Drugs (e.g. Quinine), idiopathic

11

Clinical presentation of thrombotic thrombocytopenic purpura

PENTAD -->
Fever
Microangiopathic haemolytic anaemia
AKI
Neurological symptoms (headache, palsies, seizures, confusion, coma)
Reduced platelets

12

Diagnosis of thrombotic thrombocytopenic purpura

Haematuria/proteinuria
Blood film = fragmented red blood cells, low platelets, low Hb

13

Treatment of thrombotic thrombocytopenic purpura

URGENT PLASMA EXCHANGE = life saving! - Replaces ADAMTS13 and removes antibody
Immunosuppression
Do NOT give platelets --> increases thombosis

14

Define Disseminated Intravascular Coagulation

Cytokine release in response to systemic inflammatory response syndrome (SIRS)

15

Pathophysiology of DIC

Leads to widespread systemic generation of fibrin within blood vessels, caused by initiation of the coagulation pathway.
Either causes:
- Microvascular thrombosis -> organ failure
- Consumption of platelets and coagulation factors -> bleeding -> inhibiting fibrin polymerisation

16

Causes of DIC

Sepsis
Major trauma
Advanced cancer
Obsteric complications
Pancreatitis
Acute promyelocytic leukaemia

17

Clinical presentation of DIC

Bruising, bleeding, renal failure
Bleeding from venepuncture sites and nose/mouth

18

Diagnosis of DIC

Blood films - fragmented RBC's
Thrombocytopenia
Prolonged PT and APTT
Low fibrinogen
High D-dimers

19

Treatment of DIC

If non-bleeding --> Heparin

If bleeding -->
- Platelets
- Fresh Frozen Plasma (FFP)
- Cryoprecipitate
- Red cell transfusion