Match each of the following patient vignettes, representing complex hemostatic disruptions, to the most accurate underlying pathophysiologic mechanism or diagnosis.
- A 32-year-old woman is evaluated for recurrent spontaneous abortions. Vitals are normal. Physical exam is unremarkable. Labs: Platelets 180,000/mm³, PT 12 sec, aPTT 58 sec. Immediate 1:1 mixing study with normal plasma yields an aPTT of 55 sec. The dilute Russell viper venom time (dRVVT) is prolonged but normalizes with the addition of excess phospholipid.Presence of an autoantibody against phospholipid-binding proteins, causing in vitro test interference without clinical bleeding (Lupus Anticoagulant)
- A 68-year-old man presents with a massive spontaneous thigh hematoma. Vitals: HR 110/min, BP 105/65 mmHg. Labs: Platelets 220,000/mm³, PT 13 sec, aPTT 66 sec. Immediate 1:1 mixing study yields an aPTT of 33 sec. However, after incubating the plasma mixture for 2 hours at 37°C, the aPTT significantly prolongs again to 61 sec.Presence of a time- and temperature-dependent autoantibody neutralizing a specific intrinsic pathway coagulation factor (Acquired Hemophilia A)
- A 12-day-old male newborn is brought in for continuous bleeding from the umbilical stump and poor tissue healing. Vitals are normal. Labs: Platelets 310,000/mm³, PT 11 sec, aPTT 30 sec, Thrombin time 14 sec (normal <15). A formed fibrin clot from his blood dissolves rapidly when placed in 5M urea.Deficiency of the transglutaminase responsible for cross-linking fibrin polymers to mechanically stabilize established clots (Factor XIII Deficiency)
- A 24-year-old woman is seen for heavy menstrual bleeding and frequent epistaxis. Exam shows scattered petechiae. Labs: Platelets 110,000/mm³, PT 12 sec, aPTT 45 sec. Specialized platelet aggregation testing demonstrates a paradoxical, hyper-responsive aggregation strictly to very low-dose ristocetin.Gain-of-function mutation leading to enhanced spontaneous binding of a large multimeric carrier glycoprotein to platelet glycoprotein Ib (Type 2B von Willebrand Disease)
- A 71-year-old man is admitted with generalized edema and new-onset periorbital purpura. Exam shows macroglossia and pitting pedal edema. Labs: Platelets 205,000/mm³, PT 22 sec, aPTT 54 sec. Specific factor assays reveal a Factor X activity level of 8%. Urinalysis shows 4+ protein.Extravascular tissue deposition of monoclonal light chains leading to targeted adsorption and rapid systemic clearance of a coagulation factor (AL Amyloidosis)
Answer
The correct pairings match lupus anticoagulant to phospholipid autoantibodies (L1-R1), acquired hemophilia A to time-dependent Factor VIII inhibitors (L2-R2), Factor XIII deficiency to transglutaminase deficiency diagnosed via urea solubility (L3-R3), Type 2B vWD to gain-of-function GpIb binding (L4-R4), and AL amyloidosis to tissue deposition of light chains adsorbing Factor X (L5-R5).
Each clinical and laboratory profile accurately corresponds to a distinct pathophysiological mechanism of disrupted hemostasis. Their accurate identification requires advanced interpretation of specialized coagulation testing (time-dependent mixing studies, urea clot solubility, and variable-dose ristocetin aggregation).
Step-by-Step Solution
Key Concept
Advanced Coagulation Diagnostics and Rare Hemostatic Disorders