Table 1

Clinical and laboratory features of three patients

CharacteristicsPatient 1Patient 2Patient 3
Age (years)615355
Comorbid conditionsAsthma, hypertension, high body mass indexFibromyalgiaNil
Time from vaccination to admission (days)161410
Medication on admissionHormone replacement therapy, indapamideNoneNone
Presenting symptomsShortness of breath, pain and swelling in the right legHeadaches, facial weakness, hemiparesisHeadaches, dysphasia, right arm weakness
Site of thrombosisRight main pulmonary artery extending into upper, middle and lower pulmonary arteries and left segmental pulmonary arteriesSuperior sagittal sinus, right sigmoid, right transverse sinusCortical veins, superior sagittal sinus, left transverse, left sigmoid sinus and left internal jugular vein
Platelet count nadir (×10⁹/L (reference range 150–450))252421
D-dimer peak (ng/mL (reference range 0–350))9376562047 881
PT INR peak (normal range 0.80–1.20)
aPTTR peak
(normal range 0.80–1.17)
Fibrinogen (Clauss) nadir (g/L (reference range 1.9–4.8))1.261.901.33
SARS-CoV-2 PCR test resultNot detectedNot detectedNot detected
Rapid particle gel immunoassayWeak positiveNegativeNegative
PF4-ELISA (optical density (cut-off for positive reaction >0.400))2.8712.6312.423
Platelet functional assayPositiveNegativeNegative
Anticoagulation therapyInitial split dose of LMWH then fondaparinuxNilAlteplase
Platelet transfusion1 unitMultipleMultiple
Other treatmentIVIG (1 g/kg)
Dexamethasone (20 mg once daily for 4 days)
NoneDexamethasone 20 mg
OutcomeFull recoveryDeathDeath
  • aPTT, activated partial thromboplastin time; IVIG, intravenous immunoglobulin; LMWH, low molecular-weight heparin; PF4, platelet factor 4; PT INR, prothrombin time international normalised ratio.