Glanzmann Thrombasthenia

Snapshot

• A 1-month-old infant is brought to his pediatrician. He has been having multiple mini nosebleeds. His parents have also noticed some bleeding along his gums. On physical exam, his extremities are spotted with petechiae and purpura. Suspicious of a congenital bleeding disorder, the pediatrician orders labs. A complete blood count comes back with normal platelet count but increased bleeding time.

Introduction

• Impaired platelet aggregation from genetic deficiency of GpIIb/IIIa
• Genetics
  • autosomal recessive
• Pathogenesis
  • ↓ GpIIb/IIIa (a platelet integrin) 
    • recall that GpIIb/IIIa is a receptor on platelets
    • fibrinogen interacts with GpIIb/IIIa between two platelets, helping platelet aggregation 
    • recall abciximab inhibits this receptor  
  • defect in platelet plug formation
• Key lab finding
  • normal platelet count
• ↑ bleeding time

Presentation

• Symptoms from platelet abnormalities
  • mucocutaneous microhemorrhages
    • bleeding from mucous membranes
    • epistaxis
• petechiae/purpura

Evaluation

• ↑ Bleeding time 
• normal PT/PTT
• Complete blood count
  • normal platelet count
• normal platelet morphology

Differential Diagnosis

• Bernard-Soulier (↓ platelet count, ↑ bleeding time, and ↓ GpIb) 
• ITP (↓ platelet count, ↑ bleeding time, and anti-GpIIb/IIIa antibodies) 
• TTP (↓ platelet count, ↑ bleeding time, and defet/deficient ADAMTS 13) 

Treatment

• Platelet transfusions
  • with HLA-matched and leukocyte depleted blood products
• Supportive care
• iron and folate supplementation

 Prognosis, Prevention, and Complications

• Prognosis
  • good with supportive care
• Complications
  • uncontrolled bleeding