BER via simultaneous strand cleavage by AP endonuclease (Ape1) or glycosylase (Ogg1)
may lead to build up of repair intermediates, threatening genomic stability and inducing DSB.
A RARE BIOCHEMICAL VARIANT OF PRIMARY HYPERPARATHYROIDISM: NORMOHORMONAL PRIMARY HYPERPARATHYROIDISM AS A CAUSE OF HYPERCALCEMIA Andrew Koepnick, Laxman Yashwant Byreddi, Pramod Ponna; LSU Health - Shreveport School of Medicine, Shreveport, LA.
Introduction: NHPHP poses a surgical dilemma as these patients have normal PTH levels and negative preoperative localization imaging. Clinicians should keep this variant in their differential when evaluating parathyroid abnormalities to ensure timely diagnosis, treatment and avoid surgery delays. Case: A 50-year-old female with a past medical history significant for rheumatoid arthritis, Sjogren's syndrome, hypothyroidism, gastroesophageal reflux disease, chronic kidney disease, left ureteral calculus, and morbid obesity was admitted from a nursing home for low blood pressure. She was not taking Vitamin D supplements or antacids. The physical exam was unremarkable. Vitals significant for blood pressure at 90/70 mmHg. Initial investigations showed corrected calcium 14.4 mg/dL [8.7-10.5 mg/dL], creatinine 3.20 mg/dL [0.50-1.40 mg/dL]. A workup for hypercalcemia revealed PTH 21.0 pg/mL [9.0-77.0 pg/ mL]. PTH-related protein, 1,25-dihydroxy vitamin D, 25-hydroxyvitamin D, and thyroid function tests were normal. The urine calcium-to-creatinine clearance ratio was 0.52, ruling out familial hypocalciuric hypercalcemia. A diagnosis of NHPHP was established, and endocrinology was consulted. ENT
recommended outpatient follow-up for localization imaging and parathyroidectomy. Cinacalcet was initiated and serum calcium normalized. Discussion: NHPHP remains an obscure disease, and the lack of consensus on optimal management poses a significant diagnostic challenge for clinicians. Potential pathophysiological mechanisms include the secretion of abnormal PTH molecules with increased biological activity or increased peripheral tissue sensitivity to normal PTH. Parathyroidectomy is definitive and appears to have clinically significant benefits for patients. Single and smaller adenomas which do not show on imaging are typically observed in this variant, which mandates 4-gland surgical exploration. Current literature suggests that intraoperative PTH reduction of 50% or below 30 pg/mL indicates a successful procedure. Patients who are not surgical candidates might benefit from medical management. Initial therapy should include cinacalcet, a calcimimetic that increases the sensitivity of calcium-sensing receptors on parathyroid glands, thereby decreasing PTH secretion and serum calcium levels. It is an appropriate choice for these patients until parathyroidectomy is performed.
DISCERNING FEVER OF INFECTIOUS AND AUTOIMMUNE ORIGINS IN THE SETTING OF VEXAS SYNDROME Yichi Zhang, Elizabeth Holland; Tulane University School of Medicine, New Orleans, LA
Introduction: VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is an autoimmune disease caused by mutations in UBA1, which encodes for a ubiquitin enzyme in hematopoietic cells. VEXAS is extremely rare, and the first known cases were described in 2020. Case: 80-year-old gentleman with a past medical history of known VEXAS on low-dose prednisone taper, recurrent Clostridium Difficile colitis status post fecal transplant, gram-negative bacteremia with UTI, community-acquired pneumonia, and splenectomy after motor vehicle trauma presents
with fever and generalized malaise and fatigue of 2-day duration. He also reports associated mild neck stiffness, and headache but denies significant shortness of breath, cough, chest or abdominal pain, dysuria, or new skin rashes or lesions. He has chronically loose stool but has not had a worsening in the past weeks. He does report missing a 12mg dose of prednisone the day prior to this presentation. He denies recent travel history or exposure to sick contacts. He was febrile to 104, and tachycardic to 110, but otherwise has stable vitals and not requiring oxygen. Admission labs show neutrophil- predominant leukocytosis to 13.8, chronic macrocytic 49
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