Introduction
Severe hypercalcemia from chronic gout is a rare phenomenon seen after the advent of newer drugs for its treatment. The hypercalcemia is secondary to either granuloma formation around the tophi or chronic immobilization from severe gouty arthritis. We present a patient with chronic tophaceous gout presenting with severe hypercalcemia and acute kidney injury.
Case presentation
A 63-year-old male patient with a past medical history of hypertension and chronic gout presented to the office with chronic, severe left knee pain. Initial evaluation of the knee with X-rays revealed destruction of the knee joint with cystic changes, and subsequent MRI with contrast showed soft tissue mass in the suprapatellar pouch with intraosseous extension and involvement of medial and lateral collateral ligament involvement. After interdisciplinary evaluation between radiology, orthopedic surgery, and oncology, this was concerning for highly aggressive pigmented villonodular synovitis of the knee, and a decision was made for the patient to undergo complete knee replacement. Perioperative workup was significant for severe hypercalcemia with a total calcium level of 13.2 mg/dl with ionized calcium of 7.2 mg/dl. Further evaluation into the cause of hypercalcemia revealed a low normal intact parathyroid hormone (PTH) level with normal phosphorus, calcidiol, and calcitriol levels. Other etiologies of hypercalcemia such as multiple myeloma, malignancies, metastatic disease, autoimmune, granulomatous, and infectious processes are excluded with extensive workup. The hypercalcemia is treated with fluids, diuretics, and bisphosphonates, eventually normalizing the calcium levels. The patient underwent total left knee replacement, and the mass identified was sent for biopsy. Biopsy revealed a prominent granulomatous reaction to amorphous crystals containing birefringent crystals under polarised light. Uniquely during our evaluation, vitamin D metabolites, uric acid, and PTH levels were normal despite the biopsy findings. The patient's calcium continued to be normal (8.4 to 10.4 mg/dl) over six months after the surgery. Thus, the scenario is supportive of hypercalcemia secondary to granulomatous inflammation around the large tophi.
Conclusion
Although rare, the knee joint is a site of severe tophaceous gout, and deposition of uric acid crystals can invoke a granulomatous reaction presenting with severe hypercalcemia as in our patient. Unique to our case, the patient can have benign lab findings on evaluation of hypercalcemia. Only a few case reports are illustrated in the literature, making our case and patient presentation unique.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:asrf-1854 |
| Date | 07 April 2022 |
| Creators | Namburu, Lalith, Bandarupalli, Tharun, Sanku, Koushik, Kommineni, Sai Karthik, Joseph, David |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | Appalachian Student Research Forum & Jay S. Boland Undergraduate Research Symposium |
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