Calcium Replacement Research Articles

7193 Hypocalcemia: Pitfalls, Paradoxes, And Conundrums

Abstract Disclosure: K. Dash: None. P. Eswaran: None. K. Maharajan: None. S. Nangia: None. U. Ayyagari: None. 58 year old female with PV bleed was diagnosed as Carcinoma Cervix and recommended radical radiotherapy with 6 weeks of concurrent chemotherapy with Cisplatin and IV Magnesium premedication. Post 6th cycle of chemo, she presented with nausea, perioral and facial tingling, and lower limb cramps of one day duration. Investigations showed Serum Magnesium 0.4 mg/dl (range 1.6–2.5), Calcium 5.9 mg/dl (8.4-10.2), Potassium 3.3 mg/dl (3.5-5.5). She was treated with IV Calcium gluconate and discharged home post correction with serum Calcium 7.9, Magnesium 1.8, PTH 88.7. She was readmitted twice, 5 and 9 days later, with hypocalcemia, given IV Calcium Gluconate, and discharged post correction of serum calcium levels. She presented to Endocrine OP 2 days later, asymptomatic, serum Calcium 5.9, Magnesium 0.6, K 3.8. She was admitted and replacement commenced with IV Magnesium and Calcium. Over the next day her Calcium and Magnesium levels improved. She was stabilized on oral Calcium and Magnesium replacement and discharged. Calcium replacement was weaned over the next 2 weeks with stable serum Calcium levels on continuing oral Magnesium replacement to date. Cisplatin is a commonly used chemotherapeutic agent. It binds to the N7 reactive center on purine residues and causes DNA damage in cancer cells blocking cell division resulting in apoptotic cell death. This interaction with DNA and the formation of covalent adducts with purine DNA bases is the source of the cytotoxic effect of cisplatin. Therapy is associated with side effects including neuro-, nephro-, hepato-, and cardiotoxicity. Electrolyte disturbances including hypomagnesemia, hypocalcemia, hypokalemia, and hyponatremia are recognized in association with cisplatin therapy. The signs and symptoms of dyselectrolytemias may be nonspecific and a high index of suspicion is required to diagnose. Hypomagnesemia is described in up to 78% of patients on cisplatin due to magnesium wasting attributed to reduced magnesium reabsorption in the distal tubule and/or inadequate intestinal magnesium absorption. Magnesium is primarily an intracellular cation and stored in bone. Serum levels are a poor indicator of total body magnesium and serum concentrations <1.8 mg/dl indicate more severe underlying deficit. Hypocalcemia, possibly due to end organ unresponsiveness to PTH, frequently coexists with hypomagnesimia, and can be resistant to treatment unless hypomagnesimia is corrected. While hypomagnesimia stimulates PTH secretion, very low serum concentrations can induce a paradoxical block. Our case illustrates the importance of recognizing and correcting underlying hypomagnesimia to stabilize serum calcium levels. The normal PTH level, despite low serum Calcium, suggests hypomagnesimia impairing parathyroid gland function. Due to the acute presentation, and ongoing IV correction, we were unable to measure urinary magnesium excretion. Presentation: 6/1/2024

6408 Familial Hypoparathyroidism With Elevated Parathyroid Hormone Due To A PTH Mutation Responsive To Teriparatide

Abstract Disclosure: N. Mukhtar: None. B. Alghamdi: None. M. Alswailem: None. A.S. Alzahrani: None. Introduction: Apart from vitamin D disorders, causes of congenital hypocalcemia (HypoCa) include genetic defects causing familial hypoparathyroidism (FH), and defects in PTH receptor or its signalling pathway (PTH resistance). The former is typically characterized by low plasma PTH and the latter by elevated PTH levels. In this report, we describe a family with FH but with significant elevation of functionally inactive PTH due to a PTH mutation. We also show a positive therapeutic impact of recombinant human PTH (teriparatide) therapy on HypoCa in one of these siblings who was not well controlled on calcitriol and calcium replacement. Case description: The proband is a 34-year-old lady who has history of chronic HypoCa since birth with several admissions for severe HypoCa and recurrent seizures during childhood. She and her three brothers (a 32-year-old male twin and an 18-year-old male) were diagnosed to have Pseudohypoparathyroidism type 1b based on the presence of chronic HypoCa (serum Ca 1.6-1.85 mmol/l) since birth associated with significantly elevated plasma PTH levels in the range of 310-564 pg/dl (normal range 10-65) and absence of signs of Albright hereditary osteodystrophy. Laboratory workup of the proband recently showed: PTH 514 ng/L (NR 15-65) , calcium 1.81 mmol/l (NR 2.1-2.6), phosphate 1.67mmol/L (NR 0.8-1.4), magnesium 0.73 mmol/L (NR 0.7-1.0), albumin 38 g/L (NR 40-50), Alkaline phosphatase 56 U/L, eGFR >60 ml/min/1.73 m2, creatinine 78 umol/L and 25-hydroxyvitamin D 77 nmol/l (NR 50-120). Daily excretion of calcium was normal at 3.38 mmol and an ultrasound of the kidneys suggest nephrocalcinosis. Skeletal X-rays and bone mass densitometry were normal. Molecular studies: WES showed no potentially pathogenic variants in GNAS, PTHR, CASR, VDR, and CYP27B1 but a previously reported homozygous variant in the PTH, exon 3 (NM_000315.4: c.128G>A, p.Gly43Glu). This was confirmed by Sanger sequencing in the patient and two of her brothers. This variant was assessed to be likely pathogenic or likely damaging by several in silico analysis tools including Polyphen2, MutPred, PROVEAN, DEOGEN2 and VUS by ACMG, SIFT, Mutation Assessor and FATHMM. Management: Because the patient’s HypoCa was not controlled on large doses of calcitriol and calcium carbonate, a trial of teriparatide 20 mcg SC daily resulted in normalization of calcium and PTH levels. The patient reported significant improvement in her general wellbeing with loss of numbness, tingling, muscle spasms and tetany of the fingers. She has been on teriparatide for the last year with excellent improvement in her quality-of-life Conclusion: High PTH in the presence of congenital hypoCa is not always due to receptor or post-receptor defect and can be due to a mutated biologically inactive PTH. In such cases, treatment with Teriparatide may result in stabilization of biochemical profile and improve quality of life. Presentation: 6/2/2024

6539 Hungry Bone Syndrome & Osteoblastic Metastasis In The Setting Of Prostate Cancer : A Rare Cause Of Hypocalcemia

Abstract Disclosure: B. Sharma: None. M. Khan: None. A. Rao: None. P. Guido: None. Background: Hungry bone syndrome (HBS) is due to excessive calcium and phosphorus sequestration in the bone, manifesting as hypocalcemia and hypophosphatemia.It is most commonly seen as a postoperative complication of parathyroidectomy.Advanced prostate cancer with osseous metastasis has been previously described as is a rare cause of HBS. Clinical Case: A 65 year old male was admitted to the hospital with acute congestive heart failure and severe hypocalcemia.He exhibited symptoms of muscle spasms and perioral paraesthesias. Physical exam was positive for Trousseau's sign.Initial tests were consistent with severe hypocalcemia (corrected non-ionized calcium 6.8 [8.8-10.2] mg/dL), low ionized calcium (0.58 [1.10-1.30] mmol/L). Three weeks prior to admission, corrected non-ionized calcium was 9.8 mg/mL. Other labs showed normal magnesium, normal phosphorus, elevated alkaline phosphatase (1044 [45-117] U/L), low Vitamin D (12 [>30] ng/mL ), elevated iPTH (567 [19-88] pg/mL) and low PTH-rp (9 [11-20] pg/mL]. His electrocardiogram showed regular rate and rhythm with Qtc prolongation (497 ms).He had a significant oncological history of prostate cancer and multiple myeloma in remission.He was previously treated with zoledronic acid, discontinued 1 year prior to admission, for reducing skeletal complications while being treated for multiple myeloma. He had a recent workup with medical oncology for recurrence of prostate cancer due to elevated Prostate-specific antigen (380 [<4.00] ng/mL).Computed tomography imaging showed diffuse osteoblastic metastatic disease in the axial skeleton, pelvis and proximal femur. During hospital admission hypocalcemia was persistent, likely also due to concurrent furosemide use, necessitating the administration of intravenous calcium infusion and use of cholecalciferol and calcitriol.He was discharged on calcium carbonate 4500 mg twice a day, cholecalciferol 50 000 units weekly for 12 weeks and calcitriol 2 mcg twice a day. Conclusion: Hypocalcemia in the setting of prostate cancer is most commonly due to the use of bisphosphonates or Receptor activator of nuclear factor kappa-B ligand (RANK-L) inhibitors. Hypocalcemia in this case was due to sequestration of calcium in the bone by osteoblastic metastasis. This case illustrates the importance of recognising osteoblastic metastasis as a differential in protracted and severe hypocalcemia in malignancy.High doses of calcium, vitamin D, and calcitriol replacement are often needed as the hypocalcemia is usually severe and refractory with some cases requiring prolonged IV calcium infusion.Treatment of the underlying cancer and bone metastases with chemotherapy has been shown to improve hypocalcemia and reduce the requirement of calcium and vitamin D supplementation.There is limited data to suggest if bisphosphonates can be safely used in these cases for prevention of skeletal related events. Presentation: 6/1/2024

Effect of vitamin D on risk of falls and fractures – The contribution of recent mega-trials

Three recently-completed, large clinical trials in the U.S, New Zealand, and Australia, referred to herein as the ‘mega-trials’, were conducted to determine the impact of supplemental vitamin D on a variety of outcomes including falls and fractures. The trials were similar in design and collectively included over 50,000 generally vitamin D replete, older men and women. The mega-trials established that vitamin D supplementation with the equivalent of 2000 to 3300 IU/d of vitamin D3 had no favorable effect on risk of falls or fractures. This review focuses on specific design elements of the trials and how they likely influenced these trial findings. While these trials were in progress, evidence emerged that circulating 25-hydroxyvitamin D levels have a U-shaped association with risk of falling, raising concern about a potential untoward effect of high dose supplementation. There is compelling evidence that in older, vitamin D- and calcium-insufficient nursing home residents, the combination of vitamin D and calcium in modest replacement doses dramatically reduces the risk of hip and other fractures. Community-dwelling older adults in many populous countries around the globe have widespread vitamin D and calcium insufficiency. It is time to follow the evidence trail and determine the effect of vitamin D and calcium replacement on their risk of falls and fractures.

Multicenter analysis of massive transfusion practices demonstrates variabilities across trauma centers in the Southwestern Surgical Congress

BackgroundThis study's purpose is to investigate emergent blood (EB) usage, massive transfusion protocols (MTP), and the use of pharmacologic adjuncts to resuscitation across trauma centers in the Southwestern Surgical Congress (SWSC). MethodsAnonymous, voluntary 26-question survey conducted by the SWSC multicenter trials group. Descriptive statistical analysis was performed. Results36 institutions across 14 states responded. EB is immediately available at 27 institutions. 53 ​% have LTOWB available. LTOWB is incorporated into MTP at 39 ​% of institutions and is the primary MTP product used at 4 centers. 65 ​% of institutions use thromboelastography to guide resuscitation. 70 ​% of institutions reported using TXA and 11 ​% used fibrinogen concentrate. 36 ​% of responding institutions routinely draw ionized calcium values. Four institutions have a calcium replacement protocol. Only 6 centers report redosing antibiotics during MTP. ConclusionEB availability and MTP practices are evolving with variability across the SWSC. Pharmacologic therapies remain poorly incorporated into the MTP.

Severe hypocalcemia in the emergency department: a retrospective cohort study of prevalence, etiology, treatment and outcome.

The aim of this study was to evaluate the prevalence of severe hypocalcemia in patients attending the emergency department. Symptoms, causes, treatment, and outcome of severe hypocalcemia as well as course of calcium concentrations were assessed. This retrospective case series included all adult patients with measurements of serum calcium concentrations presenting to the emergency department of the Bürgerspital Solothurn between January 01 in 2017 and December 31 in 2020. Medical record reviews were performed of all patients with severe hypocalcemia, defined by a serum calcium concentration < 1.9mmol/L, to assess clinical presentation and management. 1265 (3.95%) patients had a serum calcium concentration of < 2.1mmol/L of which 139 (11%) had severe hypocalcemia of < 1.9mmol/L. 113 patients had at least one measurement of albumin. Of these, 43 (3.4%) had an albumin-corrected serum calcium < 1.9mmol/L defining true, severe hypocalcemia. Hypocalcemia was identified and documented in 35% of all cases. The mean serum calcium concentration was 1.74 ± 0.14mmol/L. Calcium concentrations in malignancy-related hypocalcemia were similar to non-malignancy-related hypocalcemia. The main symptoms attributed to hypocalcemia were cardiac and neurologic. 12% of patients with severe hypocalcemia received intravenous and 23% oral calcium replacement. Active malignancy was the main cause of severe hypocalcemia in 28%, while in most cases, the main cause remained unclear. 41.9% of severely hypocalcemic patients reattended the emergency department for another episode of hypocalcemia within 1 year. Hypocalcemia is common in patients attending the emergency department, however, appears to be neglected frequently. The disorder is often a manifestation of severe disease, triggered by multiple causes. Calcium replacement was administered in less than half of the patients with severe hypocalcemia in this study. Due to frequent readmissions to the emergency department and a high mortality, increased awareness of the disorder and careful follow-up are desirable.

#191 An unusual cause of hypocalcemia in a young patient

Abstract Background and Aims A 33-year-old man visited the Nephrology Department outpatient clinic with abnormal laboratory findings: his serum calcium level was 5.9 mg/dL in a recent health examination. He denied any underlying disease and was on no medications. He complained of a tingling sensation in his hands and of eyelid twitching. On physical examination, he showed Chvostek's sign. His laboratory findings including serum calcium level are shown in Table 1. He did not have any morphological abnormalities, such as a round face, brachydactyly, or dental anomalies. Method Since he showed hypocalcemia, normal 25-hydroxyvitamin D, and elevated parathyroid hormone (PTH) levels, the presence of PTH resistance was presumed. Under strong suspicion of pseudohypoparathyroidism (PHP) in this patient, DNA sequence analysis and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) of GNAS and STX16, genetic regions that are often affected by mutations or imprinting changes in PHP, was performed. No pathogenic mutations in GNAS and STX16 were detected by sequencing. Results Results of MS-MLPA of the GNAS locus demonstrated abnormal methylation patterns in the patient after HhaI restriction enzyme treatment. The methylation ratio showed a gain of methylation in the NESP55 region and loss of methylation in the AS, XL, and A/B differentially methylated regions (DMRs) in the patient as compared to a healthy control (Fig. 1). The patient was diagnosed with PHP type 1B (PHP1B) due to the methylation abnormalities in multiple DMRs. His parents both showed normal serum calcium levels; thus, no further genetic testing was conducted. He is on outpatient follow-up with adequate calcium replacement and no specific symptoms. Conclusion PHP is a rare disorder of unknown prevalence. It is characterized by hypocalcemia, hyperphosphatemia, and increased PTH levels. PHP1B is a subtype of PHP characterized by isolated renal PTH resistance, usually without physical abnormalities such as Albright hereditary osteodystrophy or other endocrine abnormalities. PHP1B can be sporadic or familial. The genetic characteristics of most sporadic PHP1B remains unclear, but GNAS imprinting abnormalities and hypomethylation at the A/B DMRs have been reported. Symptoms of PHP1B usually begin in childhood due to low calcium levels and may include numbness, seizures, tetany, cataracts, and dental problems. However, as in our case, specific symptoms may not occur until adulthood. Therefore, when evaluating the cause of hypocalcemia, it is necessary to differentiate PHP1B, even in adults, and particularly in cases with hyperphosphatemia and high PTH levels.

Restrictive calcium replacement in septic shock: a multicenter before-after intervention study.

To study the impact of a restrictive calcium replacement protocol in comparison with a liberal one in patients with septic shock. Multicenter retrospective before-after study that estimated the impact of implementing a restrictive calcium replacement protocol in patients with septic shock. Patients admitted to an intensive care unit between May 2019 and April 2021 were assigned to liberal calcium replacement, and those admitted between May 2021 and April 2022 were assigned to a restrictive protocol. The primary outcome measure was 28-day mortality. Patients were matched with propensity scores. A total of 644 patients were included; liberal replacement was used in 453 patients and the restrictive replacement in 191. We paired 553 patients according to propensity scores, 386 in the liberal group and 167 in the restrictive group. Mortality did not differ significantly between the groups at 28 days (35.3% vs 32.3%, respectively; hazard ratio, 0.97; 95% CI, 0.72-1.29) or after resolution of septic shock (81.5% vs 83.8%; hazard ratio, 0.89; 95% CI, 0.73-1.09). Nor did scores on the Sepsis-related Organ Failure Assessment scale differ (2.1 vs 2.6; P = 0.20). The implementation of a restrictive calcium replacement protocol in patients with septic shock was not associated with a decrease in 28-day mortality in comparison with use of a liberal protocol. However, we were able to reduce calcium replacement without adverse effects.

Impact of a calcium replacement protocol during massive transfusion in trauma patients at a level 2 trauma center.

Hypocalcemia is associated with increased mortality in trauma patients with hemorrhagic shock who require massive transfusion protocols (MTPs). Despite known risks of potentiating hypocalcemia with blood product administration, there is little research discussing appropriate calcium replacement. The purpose of this study was to evaluate the ability of a standardized calcium replacement protocol to reduce the incidence of hypocalcemia in trauma patients undergoing MTP. This retrospective, single-center, pre-post study evaluated the use of a calcium replacement protocol during MTP. Adult trauma patients with MTP orders who received at least one "round" of product transfusion were included. Patients were excluded if their ionized calcium (iCa) levels were unavailable or they were transferred to a higher level of care within 4 hours of presentation. The primary outcome was incidence of hypocalcemia (iCa of <1.1 mg/dL) within 24 hours of MTP initiation. Secondary endpoints included the incidence of severe hypocalcemia (iCa of <0.9 mg/dL), time to first calcium dose, total calcium dose administered (mEq), resolution of hypocalcemia within 24 hours, hypercalcemia, adherence to the calcium replacement protocol, and mortality. The incidence of hypocalcemia within 24 hours was significantly lower in the postprotocol group (63% vs 95.2%; P = 0.006). There was not a significant difference in the incidence of severe hypocalcemia between the groups (39.1% vs 69.1%; P = 0.083). Time to first calcium dose was significantly shorter in postprotocol patients compared to preprotocol patients (median [interquartile range], 5.5 [0-21] minutes vs 43 [22.8-73] minutes; P < 0.0001), and postprotocol patients were administered more calcium during MTP (40.8 [27.2-54.4] mEq vs 27.2 [14-32.2] mEq; P = 0.005). Adherence to the protocol was seen in only 37% of patients in the postprotocol group. There was no difference in the rate of adverse events or overall mortality. Trauma patients who received massive transfusion of blood products had a significantly lower incidence of hypocalcemia after a calcium replacement protocol was implemented.

Mandibular Fracture following Dental Implant Protocol: Clinical Report and One-Year Follow-Up

Bone fractures following mandibular dental implant protocols associated with diagnosed osteoporosis are rare in the literature. We present a case in which a 55-year-old male patient with no previous medical history presented to the emergency department with pain in the left mandibular parasymphysis and gingival bleeding. Clinical examination revealed crepitus, mandibular mobility, and clinical signs of localized fracture and infection. Further radiographs confirmed a mandibular fracture in the region of the alveolus of tooth 34 and four implants placed in the mandible as part of the patient’s immediate implant protocol. The infection developed into osteomyelitis, which was treated with a combination of antibiotics. After the infectious process had been eradicated, new complementary tests were carried out, which revealed that the patient had osteoporosis. Oral rehabilitation treatment and calcium replacement were carried out under specialist medical supervision. The importance of proper planning and clinical assessment of the patient is discussed, and the proposed long-term management of the case has been carried out.

Effect of early intravenous calcium replacement after total thyroidectomy

Aim: This study was to evaluate the need for postoperative calcium replacement in patients undergoing total thyroidectomy, to evaluate the effect of intravenous calcium therapy given in the early postoperative period regardless of serum calcium level and physical examination on the length of stay of the patients, parathormone levels, and the need for oral calcium after discharge. Materials and Methods: The files of 73 patients who underwent bilateral total thyroidectomy between January 2018 and July 2023 were retrospectively reviewed, and the demographic characteristics, anti-TG, anti-TPO, postoperative calcium, parathormone, thyroid gland weight of the patients were recorded. The effect of intravenous calcium replacement on calcium requirement, parathormone levels, and length of hospitalization was evaluated independently of calcium levels. Results: It has been observed that replacement is associated with long-term calcium requirement in patients who underwent bilateral total thyroidectomy and received intravenous calcium in the early period. The length of stay was found to be longer in patients who underwent calcium replacement. Conclusion: Various treatment methods are used to prevent hypocalcemia. One of these treatment methods is early intravenous calcium replacement. In clinical practice, treatments given to prevent the development of complications and to discharge patients early may sometimes lead to the occurrence of complications that are tried to be prevented. The purpose of calcium replacement is to prevent the development of hypocalcemia, to reduce the complication rate and to provide early discharge. It was evaluated that intravenous calcium replacement therapy, which was applied in the early period to prevent postoperative hypocalcemia, caused patients to need longer-term calcium replacement and prolonged hospitalization. It is important to avoid calcium replacement in the early period and to evaluate the physical examination findings along with the serum calcium level of the patients for replacement.

The Challenge of Preoperative Panel Reactive Antibody Positivity in Parathyroid Transplantation.

Identifying suitable recipient criteria and matching recipients with appropriate donors are required to increase survival for parathyroid transplant. This study was undertaken to evaluate transplant survival rates while comparing preoperative panel reactive antibody positivity. The study included 14 hypoparathyroidism patients who presented to our clinic for parathyroid transplant. Preoperative ABO compatibility and negative cross-match tests were prioritized for recipient-donor matching, and panel reactive antibody screening tests were performed. During the 24-month follow-up, we evaluated medication use and serum calcium, phosphorus, and parathormone levels of patients. Preoperative panel reactive antibody positivity was assessed in 3 groups. The HLA class I-positive group (mean fluorescence intensity range, 179-1770) showed decreased medication use and stability in serum calcium levels. The HLA class IIpositive (mean fluorescence intensity range, 85-3959) showed decreased medication use by 25% to 50% and returned to their former prescription doses after 12 months. An opposite pattern was observed in 2 patients with panel reactive antibody positivity for both HLA classes (mean fluorescence intensity range, 462-2289), with 1 patient requiring medication for continuing symptoms and the other patient occasionally taking additional magnesium supplementation, despite decreased medication doses after 12 months. Serum calcium levels remained normal, and parathormone and phosphorus levels were elevated. Improving patient symptoms and having no requirement for intravenous calcium replacement are priorities, and monitoring serum levels is the next important step. Varied panel reactive antibody positivities and survival rates indicate a requirement, and each HLA class could require a proper limitation for the mean fluorescence intensity. Preoperative mean fluorescence intensity cut-off value should be <900. Higher mean fluorescence intensity values in panel reactive antibody screenings could increase risk of short-term graft survival after parathyroid transplant. Further studies should include immunological risk assessments by individualizing the outcome with donor-specific antibodies.

Hypocalcemia Diagnosis in the Surgical Environment.

Hypocalcemia, characterized by a total serum calcium level below 8.5 mg/dL (corrected for albumin) or an ionized serum calcium level below 4.65 mg/dL, presents a spectrum of clinical manifestations ranging from asymptomatic to life-threatening. Common after neck procedures, early detection and appropriate management are essential. Diagnostic tools include assessing calcium levels, correcting for albumin, and determining the underlying cause through tests like intact parathyroid hormone, serum phosphorus, magnesium, and creatinine. Treatment involves calcium replacement and addressing the root cause, with potential complications such as neuromuscular excitability and cardiac arrhythmias. Prognosis varies based on severity and underlying factors, emphasizing the importance of avoiding diagnostic pitfalls and overtreatment in chronic cases. ECG and genetic testing contribute to accurate diagnosis, aiding in differentiating causes like autosomal dominant hypocalcemia. Recognizing factitious hypocalcemia related to hypoalbuminemia or binding protein alterations is crucial. Understanding the pH-calcium relationship guides clinical evaluation. Holistic management requires a collaborative approach, emphasizing patient engagement and follow-up care.

Polishing One Edge of the Lethal Diamond - a Study on Incidents of Hypocalcemia in Massive Transfusion Protocol and Its Role in Trauma Patient Outcomes

Introduction: In the United States, Hemorrhage is the most common cause of mortality in trauma patients. The key lifesaving intervention for these patients is to promptly initiate the Massive Transfusion Protocol (MTP). Originally, the factors included in the lethal triad associated with trauma were coagulopathy (INR&amp;gt;1.5), acidosis (PH &amp;lt;7.21), and hypothermia (&amp;lt;35°C). However, hypocalcemia as an additional parameter is recently being studied, making the triad into a lethal diamond. There are approximately 3g of citrate anticoagulant in every unit of Fresh Frozen Plasma (FFPs)/Packed Red Blood Cells(PRBCs). Hepatic clearance is impaired in a shock state, leading to increased citrate in the blood stream, leading to calcium chelation and hypocalcemia. Severe Hypocalcemia is defined as calcium of &amp;lt;0.9 mmol/L, associated with adverse cardiac effects and increased mortality in critically ill patients. MTP has been shown to cause hypocalcemia and worsen prognosis in this patient population. This study aims to determine the incidence of hypocalcemia in MTP and to assess it as an independent risk factor increasing mortality in this population. Methods: This is a single center, retrospective, and observational study that investigated 74 patients with severe trauma treated with MTP in an American College of Surgeons verified Level II Trauma Center between 2018-2022. Patient data in our study was collected from documentation in trauma flow sheets from electronic medical records. Adequate calcium replacement was defined as 1gm of calcium chloride/gluconate for every 4 units of blood transfused. Primary outcome was to determine the percentage of patients who developed hypocalcemia with ionized Ca &amp;lt;0.9 mmol/L following initiation of MTP and receiving at least 4 units of blood products, and to assess hypocalcemia as an independent risk factor for mortality. Secondary outcome was to determine if hypocalcemia increases the risk of mortality in patients with one or more factors of the lethal triad. Result: The interim data consists of 74 patients. Upon review, severe hypocalcemia was seen in 25% of patients at baseline and 21% of patients after receiving at least 4 units of blood after initiation of MTP. Thirteen patients who presented with normal ionized calcium at baseline developed hypocalcemia after 4 units of transfusion. Mortality among this subgroup was 30.76%, compared to 28.38% across the overall study population. For subgroup analysis among 24 patients with one or more parameters of lethal triad present, hypocalcemia was present in 9 patients. Mortality among this subgroup was 44%. Calcium replacement was done in 60.8% of patients in this study, and among these patients, 13.5% received adequate calcium replacement. We observed a lower mortality than expected due to hypocalcemia as an independent risk factor in this population. Conclusion: Hypocalcemia did not appear to independently increase mortality as claimed in previous literatures, which may be limited by a small sample size and lack of classification by injury severity scores. However, when combined with the lethal triad, it was shown to increase mortality in patients receiving MTP. Implementing calcium supplementation as a part of the massive transfusion protocol might improve overall patient outcomes.

THU433 Spontaneous Vertebral Fractures In The Setting Of Prolonged CRRT

Abstract Disclosure: F. Akanbi: None. M. Kutahyalioglu: None. P. Gogineni: None. S. Raja: None. Introduction: Bone resorption and hypercalcemia due to prolonged immobilization are known complications in critically ill patients. This is more pronounced in patients with high bone turnover rates such as in secondary hyperparathyroidism. In this case report, the chelation of calcium by citrate masked the immobilization hypercalcemia, resulting in marked bone loss and spontaneous vertebral fractures in the context of normal calcium levels. Case report: 23 year old man with no past medical history was seen on account of concerns for calcium loss from his bones as he was on CRRT, for 4 months and the amount of calcium in the extracorporeal circuit was more than expected. He had presented with new onset systolic heart failure (EF 10%) secondary to fulminant post-COVID-19 myocarditis, and renal failure due to acute tubular necrosis. CRRT with citrate dextrose anticoagulation was initiated at presentation. He had received pulse dose prednisone for presumed post-viral myocarditis. He was awaiting heart and kidney transplantation. Greater than average calcium clearance during CRRT prompted workup for hypercalcemia. He denied personal or family history of hypercalcemia, renal stones, fractures, dental issues or hyperparathyroidism. He reported eating adequate amounts of dairy products. Labs showed corrected calcium 9.3 (8.6-10.3 mg/dl), elevated PTH 189 (10-65 pg/ml), low serum protein and albumin, and low 25OHVD that was 14 (25-100 ng/mL) on presentation and actively being replaced with ergocalciferol. Phosphorus, magnesium, liver and thyroid function were normal. The patient had complained of back pain after being immobile for 3 months. MRI showed subacute vertebral fractures of T12 and L1. Thereafter, spine X-ray showed multiple vertebral fractures of L2-L5. Beta CTX was 4153 (120-946 pg/ml) and DXA scan revealed low bone density for age with Z score -3.7 in the femoral neck, invalid in the spine due to the fractures, felt to be the source of high extracorporeal calcium concentration. A dose of Denosumab was given for treatment with improvement of calcium clearance during CRRT. Discussion: Acute fractures and infrequently, prolonged immobilization cause hypercalcemia with suppression of PTH. In our patient who was critically ill and immobilized for 4 months, the use of CRRT maintained normocalcemic blood levels, and renal failure with vitamin D deficiency caused secondary hyperparathyroidism. Only the declining requirements for calcium replacement during CRRT prompted workup for hypercalcemia that lead to identification of significant vertebral fractures and treatment. Declining need for calcium replacement during CRRT should prompt investigation and treatment of disorders of hypercalcemia and metabolic bone disorders in this patient population. Presentation: Thursday, June 15, 2023

Measurement of Intact Serum Parathormone and Corrected Serum Calcium after Thyroid Surgery

Postoperative hypocalcemia is an important complication of thyroid surgery. The present study was undertaken to measure the serum levels of intact parathormone (iPTH) and corrected serum calcium (CSC) in the immediate postoperative period and then sequentially till 1 month after thyroid surgery. A total of 36 patients undergoing total thyroidectomy and 44 undergoing hemithyroidectomy had measurement of the level of iPTH and CSC at 1 hour, 1 day, 1 week, and 1 month after surgery. A mean drop of 9.3% in CSC, 40% in iPTH, and 10% in ionic calcium levels was noted 1 hour after total thyroidectomy. All the patients recovered to near preoperative levels at the 1-month follow-up. Among hemithyroidectomy patients, significant postsurgery drop in levels was not observed. The importance of the study is early recognition of a hypoparathyroid state at 1 hour after surgery and institution of calcium replacement, thereby sparing the patient from unpleasant symptoms of hypocalcemia. Furthermore, patients with a drop in the iPTH levels below the defined hypoparathyroidism levels should have careful evaluation of their thyroidectomy specimen for identification and possible autotransplantation of the parathyroid gland intraoperatively or in the immediate postoperative time frame.

Standardized Calcium Replacement in Massive Transfusion: A Quality Improvement Project.

Hypocalcemia is common in trauma patients receiving massive transfusion protocol and often leads to worsening coagulopathies. Despite the identified problem and recommendations for replacement, few institutions have implemented a standardized calcium replacement protocol. This study aims to assess whether a revised massive transfusion protocol, including standardized calcium replacement, increases the incidence of calcium administration in trauma patients receiving massive transfusion protocol. This quality improvement project used a retrospective pre-/postdesign to study the revision of the current facility's massive transfusion protocol to include calcium replacement and ionized calcium monitoring at an urban Level I academic trauma center. Pre- and postintervention data were collected from January 2022 through October 2022 to determine the number of times massive transfusion protocol was ordered, ionized calcium monitoring, and calcium administration rates. Feedback regarding the protocol was collected throughout the monitoring period and was utilized in the final analysis. A total of 40 patients received massive transfusion protocol, preintervention, 18 of 23 (78%) received calcium supplementation, postintervention, 15 of 16 (98%) were treated. The majority of protocol activations occurred in the trauma bay (79%) and postintervention; ionized calcium monitoring dropped by 14%. This study found that the addition of standardized calcium replacement improved administration rates of calcium in this patient population. Ongoing research will ensure the recommended changes improve the identified shortcomings and that patients maintain adequate ionized calcium levels with the current dosing parameters.

Revisiting Loré's retrograde thyroidectomy from the perspective of preserving the external branch of the superior laryngeal nerve.

Injury to the external branches of the superior laryngeal nerve (EBSLN) is the main reported cause of inexplicable post-thyroidectomy dysphonia (PTD) without recurrent laryngeal nerve (RLN) injury. Loré proposed a retrograde thyroidectomy (RT) technique in which the superior pole is dissected as a final step after the Berry ligament division, making this approach advantageous for protecting the EBSLN. However, evidence of this protective effect remains insufficient. We aimed to evaluate EBSLN function following RT and conventional thyroidectomy (CT) using postoperative electromyography (EMG). This is a retrospective cohort study conducted at a single tertiary center. Consecutive patients who had undergone CT or RT were included. Bilateral EMG of the cricothyroid muscle was performed 2-3 months postoperatively in all patients. Patient characteristics, postoperative findings of bleeding events, drain amount, hypocalcemia, calcium replacement, RLN function, and EBSLN function were thoroughly reviewed and compared between the two surgical approaches. Abnormalities in the EMG findings were reported based on the wave configuration, and the results were graded into four categories. Seven hundred and thirty-one consecutive patients who underwent CT (n=341), or RT (n=390) were included, and a total of 1,179 RLNs and EBSLNs were at risk in CT (n=601) and RT (n=578). The CT and RT groups had similar clinical characteristics and surgical data. Two groups presented similar postoperative results for bleeding incidence, drain amount, and hypocalcemia. All RLNs were identified in both groups and their permanent function was preserved. EBSLN was significantly less frequently identified in the surgical field during RT than it was during CT (0.3% vs. 4.2%, respectively; P<0.001). Abnormal rates of postoperative EMG on the EBSLN were significantly lower in the RT group than in the CT group (1.7% vs. 7.8%, respectively; P<0.001), while the CT group presented with a higher grade of abnormal EMG (P<0.001). The RT technique may be beneficial for preserving EBSLN function. Meticulous capsular dissection and appropriate traction of the upper pole facilitated by RT are crucial for decreasing the risk of EBSLN injury, which can be achieved without directly identifying the nerve.

#5586 EFFICACY OF ABLATION OF PARATHYROID AUTOGRAFTS FOR RECURRENT HYPERPARATHYROIDISM AFTER TOTAL PARATHYROIDECTOMY AND DELTOID AUTO TRANSPLANTATION

Abstract Background and Aims TPDI is the treatment of choice for patients with severe hyperparathyroidism who have failed medical therapy in our centre. The auto-transplantation of parathyroid tissue in the deltoid reduces the risk of permanent hypoparathyroidism. However, there is a risk of recurrent hyperparathyroidism from the implanted parathyroid tissue. Traditionally, these autografts are removed surgically in the event of recurrent hyperparathyroidism exposing the patients to the risk of permanent hypoparathyroidism. We attempted radiologically guided ablation of the implanted tissue to allow near but not complete ablation of the tissue. We aim to report our experience in using this technique to treat patients with recurrent hyperparathyroidism following TPDI. Method This is a single centre retrospective study of 9 patients who are on regular dialysis and underwent ablation of their deltoid parathyroid implants at Singapore General Hospital between May 2020 to July 2022. Baseline demographic data, as well as biochemistry results including intact parathyroid hormone (iPTH), serum calcium, phosphorus and alkaline phosphatase (ALP) levels were retrieved from electronic medical records and analysed. We define successful procedure as achieving 2 out of the following 3 criteria: i. &amp;gt;50% drop in iPTH level at 3 months, ii. correction of hypercalcemia at 3 months, iii. off calcimimetic at 3 months Results A total of 9 patients underwent ablation of their parathyroid deltoid implants, of which 8 (89%) had thermal ablation and 1 (11%) had cryoablation. 1 patient required a repeat procedure within 3 month as only 50% of the implanted tissue were targeted instead of the intended 80% and another patient had a repeat procedure &amp;gt;3 month after initial unsuccessful procedure. The median age of patients undergoing this procedure was 60 years (IQR 60, 66) and majority were female (5/9, 55.5%). 8 out of 9 patients were on haemodialysis. 7 out of 9 patients (78%) had a successful procedure based on our definition. 6 patients (67%) had a &amp;gt;50% reduction of iPTH at 3 month, 6 patients (67%) were off calcimimetic at 3 months and out of the 5 patients who were hypercalcemic pre procedure, 4(80%) patients had normalisation of hypercalcemia at 3 months. 3 patients (33%) had iPTH &amp;lt; 2x upper limit of normal with only 1 out of the 3 patient requiring high dose oral calcium replacement at 3 months. Pre ablation levels of PTH decreased from 191.87 ± 93.52 pmol/L to 99.77 ± 111.007 pmol/L (P = 0.773) 1 day after ablation and 92.450 ± 70.235 pmol/L (P = .0450) at 1 month and 91.25 ± 81.25 (P = .024) pmol/L at 3 months. Serum calcium levels decreased from 2.48 mmol/L ± 0.286 pre ablation to 2.11 mmol/L ± 0.322 1 day post ablation (P = 0.007) and remained 2.28 mmol/L ± 0.403 (P = .122) at 3 months post ablation. Serum ALP levels decreased from 478 ± 292.00 pre ablation to 238 ± 157 at 3 months post ablation. There were no re-admissions and no immediate post procedure complications in all patients. 4 out of 9 patients (44%) required intravenous calcium replacement post- procedure during the same admission. Limitations of this study are the relatively short follow-up duration and the small number of patients. 2 out of the 9 patients were lost to follow up at 3 months. Conclusion Ablation of deltoid parathyroid autografts may be a safe and effective minimally invasive procedure to manage recurrent hyperparathyroidism and minimising the risk of permanent hypoparathyroidism. However, further studies with larger sample sizes and longer follow up duration would be prudent to confirm our findings

Hypocalcemia in Trauma is Determined by the Number of Units Transfused, Not Whole Blood Versus Component Therapy

IntroductionBlood component resuscitation is associated with hypocalcemia (HC) (iCal <0.9 mmol/L) that contributes to coagulopathy and death in trauma patients. It is unknown whether or not whole blood (WB) resuscitation helps mitigate the risk of HC in trauma patients. We hypothesized that calcium homeostasis is maintained and mortality improved in patients who only receive WB. Materials and methodsThis is a retrospective review of all adult trauma patients who received WB from July 2018 to December 2020. Variables included transfusions, ionized calcium levels, and calcium replacement. Patients were characterized as follows based on blood products received: WB or WB with other blood components. Groups were compared with respect to HC, correction of HC, 24 h, and inpatient mortality. ResultsTwo hundred twenty-three patients received WB and met the inclusion criteria. 107 (48%) received WB only. HC occurred in 13% of patients who received more than one WB unit compared to 29% of WB and other blood component patients (P = 0.02). WB patients received less calcium replacement (median 250 mg versus 2000 mg, P < 0.01). HC and total units transfused within 4 h were associated with mortality in the adjusted model. HC significantly increased after 5 units of blood products were transfused, regardless of product type. WB was not protective against HC. ConclusionsHC and failure to correct HC are significant risk factors for mortality in trauma. Resuscitations with WB only and WB in combination with other blood components are associated with HC especially when more than 5 units of any blood product are transfused. Calcium supplementation should be prioritized in any large volume transfusion, regardless of blood product type.