26 May 2022

11/9/16 Resident Morning Report – Hemarthrosis, Acquired Factor VIII Inhibitor

CC: 2 days of L knee pain and swelling

ID: 58 yo homeless male with alcohol abuse and seizure disorder presents with 2 days of L knee pain and swelling.  He reports a history of frequent falls (while intoxicated) and increased joint swelling after these falls over the past 4-5 months.  Exam was notable for diffuse L knee swelling, full ROM, stable varus/valgus maneuvers, negative posterior drawer test with improvement in pain with passive motion.  Joint fluid analysis demonstrated markedly bloody red fluid with 1,333 nucleated cells, 25% neutrophils, 40% lymphocytes, 29% monocytes, and 6% eosinophils.  Labs were notable for Hgb of 8.8, Plts of 384, and PTT of 84 secs which did not correct on mixing study – subsequent workup with a Factor VIII inhibitor assay was remarkable at 760 Bethesda Units.  Patient was ultimately found to have a renal cell carcinoma (RCC) and diagnosed with hemarthrosis likely secondary to acquired Factor VIII inhibitor from his underlying RCC.


Joint Fluid Analysis (PDF)


Pearls from morning report:

  • Causes of bloody joint effusions include: hemophilia, trauma, malignancy, Charcot joint, and arteriovenous malformations.
  • Causes of acquired factor inhibitors include: pregnancy, malignancy, drugs,

Random trivia:

The lupus anticoagulant antibody was identified by our very own Dr. Donald Feinstein in 1972.  Dr. Feinstein continues to round with our hematology consult service here at LAC+USC!

Want to read more?

Acquired haemophilia: an overview for clinical practice (European Journal of Haematology)
How I manage patients with acquired haemophilia A (British Journal of Haematology)


Siva C, Velazquez C, Mody A, Brasington R. Diagnosing acute monoarthritis in adults: a practical approach for the family physician. Am Fam Physician. 2003;68(1):83-90.

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