Immune thrombocytopenic purpura (ITP)

Question 1

Define Immune thrombocytopenic purpura (ITP)

Answer 1

Haematological disorder characterised by isolate thrombocytopenia (platelet count < 100x10^9/L) in the absence of an identifiable cause

Question 2

Aetiology of Immune thrombocytopenic purpura (ITP)

Answer 2

Secondary to autoimmune phenomenon and involves antibody destruction of peripheral platelets, mainly due to Abs against GpIIb-IIIa and megakaryocytes

Primary ITP: idiopathic

Secondary ITP:
HIV
Hep C
H. Pylori 
Immunodeficiency 
Immunological/auto-immune disorders e.g. SLE, antiphospholipid
Lymphoproliferative disease
Drug-induced

Question 3

Symptoms of Immune thrombocytopenic purpura (ITP)

Answer 3

Large spontaneous bruising may appear on the arms and legs, severe -> torso
Minor mucocutaneous bleeding e.g. bleeding gums

NO systemic symptoms

Question 4

Signs of Immune thrombocytopenic purpura (ITP) on examination

Answer 4

Bruising
Petechiae (small red/purple spots 1-5mm mainly on the lower limbs)
Haemorrhagic bullae (3-5mm on mucosal surface of the oral cavity and tongue)

Absence of:
Hepatosplenomegaly
Lymphadenopathy

Question 5

Investigations for Immune thrombocytopenic purpura (ITP)

Answer 5

FBC: Platelet count < 100 x 109/L, all other cell lines should be normal
Peripheral blood smear: NO evidence of myelodysplasia or other disorders

H. Pylori: negative
Pregnancy test : Assess for treatment

HIV serology: negative
Hepatitis serology: negative
TFTs: Hyper/hypothyroid
Immunoglobulins: may reveal an immunodeficiency

Bone marrow biopsy/aspiration: increased megakaryoctes, no malignancy