Poncet’s Disease – A Commonly Missed Diagnosis

Tuberculosis (TB) is the leading cause of mortality among infectious diseases with estimated 1.5 million deaths from TB in 2018 -19 and presented as a public health concern. In 1897, the Frenchman Antonin Poncet first described Poncet's disease (PD) as a rare syndrome, where polyarthritis in an acute stage of TB, resolved without joint damage. Similar reports on patients of tuberculosis and joint pain led authors to improve the definition, and in 1978, PD was described as a para infective arthritis by Bloxham and Addy. Regardless of its doubtful existence, cases have been continued to be reported over the years. Poncet's disease is a form of reactive arthritis which is characterized by articular affection in patients diagnosed with TB where there is immune reaction to the tuberculous protein but there is no direct invasion by the micro-organism.1,2 PD is to be differentiated from tuberculous arthritis where there is monoarticular and direct tubercular involvement of the joint. Before more obvious features develop, the sole manifestation of the disease is joint involvement. Crippling pain is experienced during polyarthritis which limits the mobility and activities of patients. Polyarthritis can also occur in common causes such as rheumatological diseases as a symptom and thus can be easily misdiagnosed. Polyarthropathy, that is multiple large and small joints involvement in the body, is the one of the rarest presentations in both active pulmonary and extrapulmonary tuberculosis. This polyarticular impairment observed in patients with active TB, a form of reactive arthritis is known as Poncet’s disease. Since there is no direct bacillary invasion of the joints, it is an aseptic form of arthritis. It is not to be confused with tuberculous arthritis, which is usually monoarticular and where there is direct tuberculin infection. Poncet's disease remains a diagnosis of exclusion. Since case reports are very rare even in countries where tuberculosis is common thus no accepted diagnostic criteria is set for Poncet's disease. This diagnostic possibility becomes increasingly important as the use of corticosteroids, immune suppressants or biologicals can risk further dissemination of the disease. We describe the case of a 50-year-old woman, who presented with active tuberculosis where polyarthralgia was the first and only symptom for four months. Polyarthritis patients were being treated with both non-steroidal anti-inflammatory drugs and antitubercular therapy and to the surprise patients with antitubercular treatment had complete resolution of symptoms after 6-week therapy whereas non-steroidal anti-inflammatory drugs (NSAIDS) offer no benefit. The total duration of therapy was 6 months.