0401 - Platelet Disorders

Question 1

What are the similarities between petechiae, purpura, and ecchymosis. Sizes?

Answer 1

All skin rashes caused by sub-epidermal bleeding - do not blanch when pressed. Involve either primary or secondary platelet disorders.

Petechiae - 1-5mm

Purpura 5-10mm

Ecchymosis - >10mm

Question 2

What is the pathophysiology of Immune/Idiopathic thrombocytopenia purpura?

Answer 2

Anti-platelet IgG in plasma lead to platelet surface destruction and low platelet count

Question 3

What is the treatment for chronic idiopathic thrombocytopenia purpura?

Answer 3

Steroids

IVIg

Treatable via splenectomy (where destruction takes place and relevant Ig’s are formed).

Question 4

What is the typical presentation of chronic immune thrombocytopenia purpura?

Answer 4

Most common in women of childbearing age.

History of easy bruising and nosebleeds.

Petechiae/Purpura evident on skin, or possible melena/haematuria.

Increased MPV

Need to do a blood film.

Increased megakaryocytes in marrow.

Question 5

What is the typical presentation of acute immune thrombocytopenia purpura?

Answer 5

Age 2-8 yrs, post-infection

Very low platelet count

Common lymphocytosis

80% spontaneously resolve in 2-6 weeks.

Question 6

What is the pathophysiology of Thrombotic Thrombocytopenia Purpura/Haemolytic Uremic Syndrome?

Answer 6

Thrombotic micropangiopathies, characterised by:

Systemic or intrarenal aggregations of platelets

Thrombocytopenia; and

Mechanical injury to erythrocytes.

Question 7

What is the classical pentad of signs/symptoms in Thrombotic Thrombocytopenia Purpura/Haemolytic Uremic Syndrome?

Answer 7

Anaemia

Severe Thrombocytopenia

Neurological Symptoms

Renal Failure

Fever

Question 8

How do you diagnose Thrombotic Thrombocytopenia Purpura/Haemolytic Uremic Syndrome?

Answer 8

Confirm thrombocytopenia and haemolytic anaemia without underlying aetiology.

Initiate plasma exchange for treatment.