Poncet Disease: A Case-based Review of an Uncommon Extrapulmonary Manifestation of Tuberculosis

Abstract

Background: Tuberculosis (TB), an ancient infectious disease caused by the bacteria Mycobacterium tuberculosis, still remains a leading cause of morbidity and mortality in our modern world, causing ∼1.3 million deaths worldwide in 2017 alone. Because it disproportionately impacts the developing world, the unique manifestations of TB may be less encountered and therefore less known to many physicians in developed countries. Case: A 63-year-old woman, with a past medical history of ulcerative colitis, who was on tumor necrosis factor-α inhibitor therapy, presented with fevers, lymphadenopathy, erythema nodosum, and diffuse joint pains. The differential diagnosis included sarcoidosis manifesting as Lofgren syndrome and TB. A tissue biopsy of her right supraclavicular lymph node confirmed the diagnosis of tuberculous lymphadenitis, reactivated in the setting of her adalimumab therapy. Given the patient’s arthritic symptoms, we were also suspicious for Poncet disease (PD), a lesser-known entity defined by reactive arthritis in the setting of TB. Discussion: This case of an immunocompromised woman with fevers, lymphadenopathy, polyarthritis, and erythema nodosum demonstrates a unique presentation of TB. PD is defined as reactive arthritis due to infection with TB elsewhere in the body. Although PD was first described in 1897, it stills remains a disputed and lesser-known entity. This case highlights the importance of recognizing this unique manifestation of TB to prevent misdiagnosis and delay. It also demonstrates the diagnostic challenge in distinguishing the overlapping features of sarcoidosis manifesting as Lofgren syndrome and PD.