IntroductionThe presence of distal extremity pain in children and adolescents usually triggers the search for rheumatologic diseases without thought to non-rheumatologic causes of joint pain. Even when classic signs of articular inflammation (swelling, reddening, local temperature increase, pain, etc.) are absent, laboratory evaluations, including non-specific serological markers of inflammation (C-reactive protein, erythrocyte sedimentation, etc.), and autoantibodies are ordered. In the absence of serological evidence of a disease, several rheumatic diseases cannot be completely excluded. As such, in many cases, it is necessary to perform tissue biopsy (e.g., nerve biopsy in peripheral nervous system primary vasculitis) to definitively confirm or exclude a diagnosis. This diagnostic journey, which was paved with numerous studies and analyses, takes up significant time and resources and at times leads nowhere. Approaching distal extremity pain with a complete differential diagnosis, including non-rheumatologic entities, may hasten diagnosis, thus decreasing cost and aiding in earlier initiation of an appropriate therapy. This study aimed to illustrate the requirement to include non-rheumatologic diseases as a differential diagnosis of distal extremity pain by presenting a case of a patient who after years of work up of arthralgia, which was actually attributed to rheumatologic causes, had an inherited metabolic disease.
Case PresentationA 32-year-old male presented to the clinic with complaints of distal pain in his four limbs, predominantly in the hands, since he was 8 years. Pain was consistent with neuropathic pain because of typical features (burning, tingling, lightning, and stabbing). It increased in intensity when exercising, with febril or subfebril fever, and with an environmental temperature increase. After 6 years of consultation in various pediatric centers, he was diagnosed with growing pains and was treated with non-steroidal anti-inflammatory drugs (NSAIDs), with no response. When he was 12 years, he began to experience gastrointestinal symptoms. In particular, the patient had postprandial pain, early satiety, and intermittent diarrhea. Because of all these symptoms, he had to stop playing sports.At the age of 15 years, laboratory investigations began targeting rheumatologic causes of his symptomatology. This was because of the persistence of his pain and the appearance of punctiform reddish lesions in the periumbilical and genital regions, which were considered to be petechiae. Varied and repeated studies revealed no autoantibodies, and at 24-h urine examination, the presence of microalbuminuria was only remarkable. When he was 20 years, he had slightly increased creatinine and proteinuria (500 mg/day) levels. His pain persisted, and there was gastrointestinal involvement. After 6 years, a diagnosis of chronic kidney disease of unknown etiology was made despite the absence of a kidney biopsy. He was followed up in our