DISCUSSION
In the setting of positive serologic Lyme Disease testing, hemarthrosis was thought to be secondary to Lyme arthritis causing joint inflammation and bleeding symptoms exacerbated by concurrent ITP. Spontaneous hemarthrosis in ITP is an atypical presentation with the most common bleeding symptoms being mucocutaneous. It is of utmost importance to expedite therapy for hemarthrosis to prevent further joint damage. Initial differential was broad and included ITP, thrombotic thrombocytopenic purpura, disseminated intravascular coagulation, hemolytic uremic syndrome, hemophilia, septic or inflammatory arthritis, bursitis, intra-articular venous malformations, or trauma7,9,13. Upon reflection, a unifying explanation for the presentation is Lyme Disease with resultant inflammatory arthritis and severe thrombocytopenia as causative of the hemarthrosis. The initial symptom improvement was thought to be due to the anti-inflammatory effects of the steroid regimen without treatment of additional underlying disease. Realizing an additional contributing etiology, oligoarticular or monoarticular joint inflammation must be considered as an unrecognized cause for spontaneous hemarthrosis in a child with severe ITP.
This provides an example for clinicians to consider when evaluating abnormal bleeding presentations of ITP. It is important to keep a high index of suspicion for other treatable conditions. Limitations of this report include the inability to establish a causal relationship between the various disease processes occurring in this patient. A single case report limits generalizability, especially given the geographic distribution of Lyme Disease in the northeastern and north central United States11. Also, further diagnostic testing via magnetic resonance imaging or arthroscopy was not pursued to rule out additional pathology8,9. In conclusion, this report depicts a rare complication of ITP and suggests that additional underlying pathology may contribute to abnormal presentations with severe bleeding symptoms. Providers should be mindful of additional precipitating causes and consider appropriate testing to reduce overall morbidity and improve long-term outcomes.