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Gwen - Haematology > Thrombocytopenias and Thrombocytosis > Flashcards

Thrombocytopenias and Thrombocytosis Flashcards

1
Q

What is thrombocytopenia?

A

Low platelets

This is caused by reduced platelet production in the bone marrow, excessive peripheral destruction of platelets or sequestration in an enlarged spleen

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2
Q

What classes can the causes of thrombocytopenia be divided into?

A
  • Impaired production
    • Bone marrow depression - hereditary eg faconi anaemia
    • Bone marrow infiltration - leukaemia, storeage disease
    • Acquired ​- drugs, chemo, infections
  • Sequestrion
    • ​Splenomegaly
  • Excessive Destruction/increased consumption
    • ​Immune
      • ITP (antibodies taking the antibodies),
      • Secondary to infection, cytotoxic drugs, SLE
    • Non immune
      • DIC (normally severe underlying cause - severe trauma, sepsis etc - multorgan failure because little clots all the way through),
      • Hypersplenism -
      • Prosthetic heart valve
          • Sequestration
  • Dilutional
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3
Q

What are causes of impaired production which leads to thrombocytopenia?

A
  • Selective megakaryoctye depression
  • Bone marrow failure
  • Myelodysplastic syndromes
  • Myeloma
  • Myelofibrosis
  • Solid tumour infiltration
  • Aplastic anaemia
  • HIV infection
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4
Q

What are causes of excessive destruction or increased consumption which can lead to thrombocytopenia?

A
  • Autoimmune - ITP
  • Drug induced
  • Post-tranfusion purpura
  • DIC
  • Thrombotic thrombocytopenia purpura
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5
Q

What are causes of sequestration of platelets leading to thrombocytopenia?

A
  • Splenomegaly/Hypersplenism
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6
Q

What are causes of dilutional thrombocytopenia?

A

Massive transfusion

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7
Q

If thrombocytopenia was caused by a something which impaired production, how would you treat it?

A
  • Treat the cause
  • If platelets are critically low - platelet tranfusion
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8
Q

What is immune thrombocytopenic pupura?

A

Thrombocytopenia is due to immune destruction of platelets. The antibody-coated platelets are removed following binding to Fc receptors on macrophages.

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9
Q

What age range does ITP present in children?

A

2-6 years old

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10
Q

What can precipitate the development of ITP in children?

A

Infection - recent viral infection, including varicella zoster or measles

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11
Q

How soon after infection can ITP present in children?

A

Approx 2 weeks after infection

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12
Q

What are features of acute ITP?

A

Common

  • Easy bruising
  • Purpura
  • Epistaxis
  • Mucosal bleeding
  • Menorrhagia

Rare

  • Major haemorrhage
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13
Q

Does someone with ITP typically present with splenomegaly?

A

No - extremely rare

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14
Q

Which sex is ITP characteristically seen in adults?

A

Females

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15
Q

What is the overriding feature of chronic ITP?

A

Fluctuating course of bleeding, epistaxis etc.

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16
Q

What investigations would you perform if you suspected ITP?

A
  • Bloods - FBC, PT, APTT, Clotting Factors, Thrombin time, bleeding time
  • Bone marrow aspirate
17
Q

What might you find on investigation for ITP?

A
  • Thrombocytopenia (everything else is normal apart from platelet count)
  • Megakaryocytes on bone marrow
18
Q

How would you manage someone with ITP?

A

Aim to keep platelets >30x109/L

  • If mild - nothing
  • If platelets < 20x109/L - prednisolone 1mg/kg/d, then reduce after remission
  • If pred fails -
    • Immunosuppression (splenectomy - removing the antibody carriers that are ruining everything by stealing the plaelets)
    • IV IgG
    • Thrombopoietin analogues
19
Q

What is thrombotic thrombocytopenia?

A

TTP is a rare, but very serious condition, in which platelet consumption leads to profound thrombocytopenia. It appears to be due to platelet aggregation by very high molecular weight multimers of von Willebrand factor. Such multimers are normally secreted by endothelial cells but are rapidly degraded into smaller multimers.

In all forms of TTP there is deficiency of ADAMTS 13 - the protease that rapidly degrades these multimers.

20
Q

What are features of TTP?

A

Symptom complex

  • Florid purpura
  • Fever
  • Fluctuating cerebral dysfunction
  • Microangiopathic haemolytic anaemia
  • Renal problems
21
Q

What are secondary causes of TTP?

A
  • Pregnancy
  • Oral contraceptives
  • SLE
  • Infection
  • Drug treatment
22
Q

What might you find on investigation for TTP?

A
  • Normal coagulation screen
  • Increased LDH
23
Q

What investigations would you perform if you suspected TTP?

A
  • Bloods - FBC, PT, APTT, Clotting Factors, Thrombin time, bleeding time, LDH
  • Bone marrow aspirate
24
Q

How would you manage someone with TTP?

A
  • Plasma exchange - provides a source of ADAMTS-13 and removes associated autoantibody in acute TTP
  • Methylprednisolone - acutely
25
Q

What is thrombocytosis?

A

Where platelet count rises above 400 × 109/L

26
Q

What are causes of thrombocytosis?

A
  • Splenectomy
  • Malignant disease
  • Inflammatory disorders - RA, IBD
  • Major surgery
  • Post haemorrhage
  • Myeloproliferative disorders
  • Iron deficiency.
27
Q

Which part of the immune response does thrombocythaemia occur in conjunction with?

A

Acute-phase

28
Q

What deficiency is present in TTP?

A

ADAMTS 13

29
Q

Why does liver failure cause clotting problems?

A

Decreased synthesis of clotting factors, decreased vit K absorption and abnormalities of platelet function.

Prolonged PT, APTT, reduced fibrinogen.

30
Q

What bleeding happens in portal vein thrombosos?

A

Both a haemorrhagic and prothrombotic disorder (because clotting factors made in liver go down, but agents for normal fibrolysis are also made in the liver also go down).

31
Q

What’s haemorrhagic disease of the new born

A

Immature coagulation systems - need vit K (defficent in factors 2, 7, 9 and 10)

Completely preventable by administration of vit K at birth

Gwen - Haematology (33 decks)

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