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Zorluk: ZorHemodynamic and Coagulation Processes

A hematology consultation service is evaluating four patients with undiagnosed bleeding diatheses and suspected hereditary coagulopathies. Pair each patient's clinical presentation and initial laboratory screening with the specific confirmatory diagnostic finding that best establishes the underlying defect.

  • A 24-year-old female with lifelong mucocutaneous bleeding and normal prothrombin time (PT) and activated partial thromboplastin time (aPTT); initial aggregometry shows no response to ADP or epinephrine.Normal platelet agglutination in response to ristocetin, with absent aggregation to all other standard physiologic agonists
  • A 4-year-old boy with a history of delayed umbilical stump separation presenting with spontaneous intramuscular hematomas; PT, aPTT, fibrinogen, and platelet counts are entirely normal.Rapid dissolution of a cross-linked fibrin clot when incubated in a 5M urea or 1% monochloroacetic acid solution
  • A 32-year-old female with recurrent first-trimester pregnancy losses and a family history of mixed bleeding and thrombotic events; PT and aPTT are normal, but thrombin time is markedly prolonged.Prolonged reptilase time with a significant discrepancy between functional and antigenic fibrinogen measurement assays
  • A 17-year-old male with a history of severe epistaxis, mild thrombocytopenia, and large platelets on peripheral smear; PT and aPTT are within reference ranges.Absent platelet agglutination to ristocetin that fails to correct upon the addition of normal donor plasma

Cevap

The presentations map to classic laboratory findings for Glanzmann thrombasthenia, Factor XIII deficiency, Dysfibrinogenemia, and Bernard-Soulier syndrome.
Each clinical presentation describes a classic hereditary bleeding or coagulation disorder that requires specialized laboratory testing beyond standard PT/aPTT panels. By correlating the cellular or molecular defect with its distinct in vitro behavior, the correct pathophysiology is matched precisely to the diagnostic assay.

Adım Adım Çözüm

1
Analyze the 24-year-old female with absent response to ADP/epinephrine.
Identified as Glanzmann thrombasthenia, which uniquely shows normal ristocetin agglutination.
Deficiency of GPIIb/IIIa impairs aggregation to standard agonists but preserves ristocetin-induced agglutination via the intact GPIb receptor.
2
Evaluate the 4-year-old boy with delayed umbilical stump bleeding and normal standard coagulation times.
Identified as Factor XIII deficiency, confirmed by clot dissolution in 5M urea.
Factor XIII stabilizes fibrin but its activity is not captured by PT/aPTT assays; the clot solubility test is the definitive diagnostic step.
3
Assess the 32-year-old female with prolonged thrombin time, pregnancy loss, and normal PT/aPTT.
Identified as dysfibrinogenemia, characterized by discordant functional/antigenic levels and prolonged reptilase time.
Structurally abnormal fibrinogen prolongs TT and reptilase time while demonstrating a mismatch between quantity (antigenic) and quality (functional).
4
Analyze the 17-year-old male with macrothrombocytopenia and epistaxis.
Identified as Bernard-Soulier syndrome, defined by absent ristocetin response that does not correct with plasma.
The absence of the GPIb receptor prevents ristocetin-induced agglutination, and because the defect is cellular rather than humoral, donor plasma cannot correct it.

Anahtar Kavram

Diagnostic laboratory evaluation of specialized coagulation factor defects and hereditary platelet function disorders
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Konular

Hemodynamic and Coagulation Processes

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