A Rare Cause of AKI in an Even Rarer Syndrome

Introduction: TEMPI syndrome is a rare condition characterized by Telangiectasias, Erythrocytosis, Monoclonal gammopathy, Perinephric fluid collections, and Intrapulmonary shunting. This case presents an unexpected - but unsurprising - cause of AKI in the setting of newly-diagnosed TEMPI syndrome. Case Description: A 58-year-old man with a history of hypertension and type 2 diabetes mellitus presented with 4 days of fatigue, weakness, and myalgias. On exam, he was noted to have widespread telangiectasias on his face, mucosal membranes, and abdomen. Labs were notable for a hemoglobin of 18, creatinine of 2.7 (baseline of 1.0), paraprotein gap of 4.8, and microscopic hematuria. Kidney ultrasound noted bilateral echogenic kidneys, as well as trace perinephric fluid adjacent to the right kidney. 24-hour urine protein electrophoresis was significant for monoclonal IgG Lambda and Lambda Bence-Jones proteins. Taken together, these findings were consistent with TEMPI syndrome. A kidney biopsy was performed, which revealed acute tubular injury, interstitial edema with scattered extravasated RBCs, marked congestion of peritubular capillaries, and a probable small venous thrombus. He was therefore started on plasma cell targeted therapy as well as serial sessions of therapeutic phlebotomy, and discharged in stable condition with planned follow-up. Unfortunately, the patient returned 2 weeks later with severe sepsis secondary to pneumonia, and subsequently died. Discussion: This case describes an AKI in a patient with newly-diagnosed TEMPI syndrome, which is broadly characterized as a plasma cell neoplasm with associated paraneoplastic syndrome. Beyond the simple educational value of exposure to such a rare disorder, an additional lesson can be gleaned from the kidney biopsy findings. Given the profile of TEMPI syndrome, and the UPEP findings of monoclonal and Bence-Jones proteins, the patient's AKI was presumed to be yet another manifestation of his plasma cell disorder, perhaps in the form of a monoclonal gammopathy of renal significance. The biopsy, however, implicated the erythrocytosis and consequent venous congestion and thrombosis as the likely primary cause of AKI. This case serves as an ever-important reminder to overcome one's anchoring bias, as well as to consider not just the apparent manifestations of a disease, but the sequalae and downstream effects of the underlying disease process.