Metastatic renal cell carcinoma to the pituitary presenting with hyperprolactinemia.

UNLABELLED: Reactive arthritis is a form of seronegative spondylarthritis that presents following an infection, with clear associations to specific microorganisms. It is a rare entity and typically affects young adults. An 88-year-old woman, admitted in our ward with pseudomembranous enterocolitis and acute renal lesion, presented with axial oligoarthritis on the 11th day after onset of symptoms. It was accompanied by elevation of inflammatory parameters - positive HLA-B27 and seronegative to rheumatoid factor, and anti-cyclic citrullinated peptide. The patient improved following treatment with non-steroidal anti-inflammatory drugs and inflammatory parameters normalised, with no recurrence after one year on follow-up. This case illustrates a rare entity in the elderly, with an established association in more recent years with Clostridioides difficile.

LEARNING POINTS: Post-infectious disease syndromes are poorly understood, and their management relies on their distinct pathophysiologies.Reactive arthritis can occur days or weeks after a gastrointestinal or urogenital bacterial infection and can present as Reiter's syndrome. The diagnosis is clinical, and its treatment should consider prevention, effective treatment of the causative agent and should target inflammation.We present a case of reactive arthritis that was diagnosed in an elderly patient (less common) with a trigger bacterium that has been implicated more and more consistently in recent years.