Hungry Hungry Bones: Electrolyte Abnormalities in the Presence of Severe Malnutrition

Hungry Hungry Bones: Electrolyte Abnormalities in the Presence of Severe Malnutrition | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Hungry Hungry Bones: Electrolyte Abnormalities in the Presence of Severe Malnutrition Eva M. Goren, Stephanie Ferrin, Sowmya Krishnan, Amy B. Middleman This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8603877/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Severe malnutrition in the presence of child maltreatment and anorexia nervosa can lead to significant effects on bones. We present a case of severe malnutrition from child maltreatment that developed into AN, osteoporosis, and persistent electrolyte abnormalities due to hungry bone syndrome (HBS). We describe a 15-year-old female with a history of medical neglect and severe malnutrition presenting to the hospital after removal from mother’s home. The patient was admitted and monitored for refeeding syndrome. She had an elevated parathyroid hormone (PTH) level (761pg/ml), vitamin D deficiency, hypocalcemia (6.3mg/dl), and hypomagnesemia (1.5mg/dl), requiring daily management for weeks. The team delayed the initial Dual-energy X-ray Absorptiometry (DXA) scan because the patient could not lie flat. Once obtained, DXA demonstrated a total-body-less-head (TBLH) Z score of -5.9 standard deviations below the age-matched mean. HBS began with secondary hyperparathyroidism after severe malnutrition; PTH increased bone resorption to maintain normal calcium levels. With refeeding, a sudden fall in PTH led to net calcium movement into bones, resulting in hypocalcemia. In patients with HBS, hypomagnesemia and hypophosphatemia may also be observed due to bone formation. Hypomagnesemia and hypocalcemia occurred in our patient and required continuous electrolyte replacement and supplementation. Although rare, providers managing refeeding syndrome among severely malnourished patients should be aware of the risk of HBS and accelerated electrolyte consumption. Anorexia Nervosa Hungry Bone Syndrome DXA Scan Severe Malnutrition Adolescent Health Introduction Severe malnutrition in childhood can lead to many health problems including significant effects on growing bone. We present a case of severe malnutrition in the presence of child maltreatment that evolved to a diagnosis of anorexia nervosa-restricting sub-type, osteoporosis including multiple fractures, and persistent electrolyte abnormalities during the refeeding process due to hungry bone syndrome (HBS). Case Presentation A 15-year-old female patient with a history of medical neglect presented to the Emergency Department after removal from her mother’s home with weakness, inability to sit up or ambulate, bilateral leg pain, and severe malnutrition. The patient stated that her mother and sibling had followed a “vegan diet” since the patient was a little girl. The patient’s daily diet typically consisted of two to three bowls of a homemade vegetable soup, occasionally with cheese sprinkled on top, and two oranges. In the proximate year, her food was typically brought to the couch for her by her sibling due to the patient’s progressive immobility. The patient stated that she felt “kind of slim”. When asked further about weight, the patient questioned if the examiner was referring to “fat” or “blubber”. The patient denied vomiting, diarrhea, constipation, hyper-exercise, or any self-directed attempts to lose weight. She did, however, endorse the use of laxatives per her mother’s recommendations to “get rid of parasites” and “push them out of [her] system”. In addition, the patient described exercises that she would perform under the direction of her mother, including resistance band stretches and isometric exercises. As the patient became weaker, the patient’s mother increased the “exercises” for the patient to become “stronger”; mother would pull on the patient’s legs with the resistance bands until the patient “felt the burn”. The patient described that she had been unable to walk for about the last year. Instead, she would use a chair as support to scoot to the bathroom, and she was no longer able to sit down while urinating because it would “take too long” to sit and then subsequently stand. The patient’s estimated menarche was at 11-12 years of age, and although her menstrual cycles used to be regular, they had become infrequent over the past year. Her last menstrual period was 5 days prior to presentation. She had no history of endocrine abnormalities. The patient meets diagnostic criteria for Anorexia Nervosa; that in combination with severe abuse in the home caused severe malnutrition. At the initial physical exam, the patient’s height was 146 cm and she was 63% of the median estimated body mass index, qualifying her for severe malnutrition. The patient’s physical exam was remarkable for psychomotor slowing; cachexia; temporal wasting; tachycardia; delayed capillary refill and cool extremities; inability to stand, sit comfortably or ambulate due to pain; and limited movement of her foreshortened torso and lower extremities/hips due to pain. On X-ray examination, the patient was found to have multiple rib fractures, bilateral humeral fractures, bilateral scapular fractures, tibial fractures, and metatarsal fractures. The patient was admitted to the hospital and monitored closely from the start of her admission for refeeding syndrome. She was found to have a very elevated PTH, vitamin D deficiency, significant hypocalcemia, hypomagnesemia, and hypophosphatemia requiring replacement as discussed below (Table 1). The patient was initially given cholecalciferol and calcium supplementation. On day 3 of inpatient hospitalization the patient was diagnosed with Rickets and pediatric osteoporosis by pediatric endocrinology. To address her low magnesium levels, she started magnesium supplementation on day 13. From day 34 forward, the patient's calcium levels were within normal range. We could not get a DXA scan soon after admission due to the patient’s inability to lie flat on the table for the procedure. When obtained during her hospital admission, the patient’s DXA scan demonstrated a total-body-less-head (TBLH) Z-score of -5.9. The Z-score describes how many standard deviations from age and sex matched norms the patient's bone mineral density is. A genetic panel for osteogenesis imperfecta was negative. Diagnoses made during her hospital stay included rickets, pediatric osteoporosis, and HBS, all secondary to severe malnutrition. Follow up care over the next year included MgO discontinuation with CaCO₃ and cholecalciferol continued. Follow up DXA scan, TBLH, 2 years after initial admission, showed Z-score improvement from -5.4 to -1. Guardian consent and patient assent were obtained to write the case report. Follow up This case represents a very rare occurrence of HBS in a child that resulted from severe malnutrition. The prevalence of HBS has varied greatly in the literature [1] [2][3]. The majority of HBS is found in adults with very few reported pediatric cases, in part because the most common cause of HBS is a parathyroidectomy due to primary or secondary hyperparathyroidism which is not common in children [3]. PTH helps regulate calcium levels in the body; when calcium levels are low, PTH stimulates the release of calcium from the bones, increases reabsorption of calcium and decreases phosphate resorption from the kidneys, and plays a role in the synthesis of 1,25-dihydroxy vitamin D cholecalciferol from 25 OH vitamin D in the proximal tubules. 1,25 dihydroxy vitamin D increases absorption of calcium from the intestines. The sudden drop in PTH tilts the scales toward bone formation, and patients become hypocalcemic and hypomagnesemic as these electrolytes play pivotal roles in bone formation. Of reported pediatric cases, the majority of HBS presents post parathyroidectomy [4][5]. The patient described in this case report had intact parathyroid and thyroid glands; she is the only reported case we found in the literature that occurred as a result of malnutrition secondary to disordered eating. While isolated cases of HBS have been reported after prolonged vitamin D deficiency, the vitamin D deficiency was found to be secondary to and not due to malnutrition [6][7]. Our patient had vitamin D deficiency and total electrolyte deficiencies due to her prolonged malnutrition and neglect. HBS is usually a rare response to a sudden decrease in previously elevated PTH. Most patients with hyperparathyroidism have a rise in PTH that then induces high levels of calcium in the bloodstream. Our patient did not have high levels of calcium secondary to high levels of PTH, rather the calcium stores in her bones had already been depleted to maintain circulating levels of calcium for survival. As a result, her bone density was very low. Our patient’s high PTH level was an appropriate response to calcium deficiency due to severe malnutrition. When the patient started to refeed and calcium and vitamin D were introduced into her body, she became more anabolic; as her intake of calcium increased, calcium moved into the bones, resulting in persistent hypocalcemia requiring further supplementation. Her PTH secretion started to go down, but the decrease was slowed because the calcium was being absorbed by bone and was not available to maintain appropriate levels in the blood. Blood levels of magnesium, an important electrolyte that supports bone mineralization as a crucial component for the activation of vitamin D, are also known to drop with refeeding syndrome. Our patient’s levels were persistently low as it was needed for bone remineralization. This necessitated magnesium supplementation as well. Hypomagnesemia can also cause PTH resistance and could be another factor explaining her persistently elevated PTH levels. We have described an unusual case of malnutrition and bone demineralization so profound that the patient developed HBS while refeeding. There is no standard treatment for HBS[11] however the literature available providing recommendations is based primarily on HBS that occurs secondary to parathyroidectomy [2]. Treatment involves either intravenous or oral supplemental elemental calcium of about 6-12 g/day, the exact dose is dependent on severity and persistence of decreased serum calcium levels [2][8]. The supplementation of calcium is coupled with active metabolites of vitamin D, calcitriol or alfacalcidol [2][9][10]. Depending on the specific case, magnesium supplementation may be required if hypomagnesemia is observed [2]. Our patient required all of the above to manage the accelerated electrolyte consumption. After a lengthy period of electrolyte derangement, the patient was able to wean from supplementation. This patient has gone on to live in a safe home with close monitoring of her bone density. HBS can be life threatening, leading to dangerous arrhythmias and seizures. Although rare, providers managing refeeding syndrome among severely malnourished patients should be aware of the risk of HBS and accelerated electrolyte consumption. Declarations Acknowledgements: There are no other acknowledgements to be made at this time Conflict of Interest: Dr. Amy Middleman receives royalties in her role as section editor for the Adolescent Medicine section for UpToDate.com Funding Declaration: There is no funding to declare. Statement of Authorship Eva Goren: Involved in data interpretation, writing the primary version of the manuscript, and the revisions and approval of the final version of the manuscript. Stephanie Ferrin, MD: Involved in the data collection and interpretation and the review, edits and approval of the final version of the manuscript. Sowmya Krishnan, MD: Involved in direct clinical service, data collection and interpretation and the review, edits and approval of the final version of the manuscript Amy Middleman, MD: Involved in the data collection and interpretation and the review, edits and approval of the final version of the manuscript. References Brasier A.R., Nussbaum S.R. Hungry bone syndrome: clinical and biochemical predictors of its occurrence after parathyroid surgery. Am J Med. 1988;84(4):654-660. doi:10.1016/0002-9343(88)90100-3 Witteveen J.E., van Thiel S., Romijn J.A., Hamdy N.A. Hungry bone syndrome: still a challenge in the post-operative management of primary hyperparathyroidism: a systematic review of the literature. Eur J Endocrinol. 2013;168(3):R45-R53. doi:10.1530/EJE-12-0528 Carsote M, Nistor C. Forestalling Hungry Bone Syndrome after Parathyroidectomy in Patients with Primary and Renal Hyperparathyroidism. Diagnostics (Basel). 2023;13(11):1953. doi:10.3390/diagnostics13111953 Kale N, Basaklar AC, Sonmez K, Uluoglu O, Demirsoy S. Hungry bone syndrome in a child following parathyroid surgery. J Pediatr Surg. 1992;27(12):1502-1503. doi:10.1016/0022-3468(92)90484-o Boggs E, Szymusiak J. Common in Adults and Often Overlooked in Pediatrics: A Case Report of Primary Hyperparathyroidism in an Adolescent Patient. Cureus. 2023;15(4):e38112. doi:10.7759/cureus.38112 Lombard J, Biarent D, Michez D. Severe persistent hypocalcemia occurring despite vitamin D and calcium supplementation in children with symptomatic vitamin D deficiency. Belgian Journal of Paediatrics. 2023;25(3):180-183. https://www.belgjpaediatrics.com/index.php/bjp/article/view/55 Statha, E., Paltoglou, G., Doulgeraki, A., Vakali, E., Vlachopapadopoulou, E., Economou, S., Sakou, I., Soldatou, A.,Karavanaki, K., Fryssira E. A toddler with severe vitamin D-dependent rickets type 1 A (VDDR1A), hungry bone syndrome, and severe RSV infection: presentation and therapeutic challenges. Hormones. 2024;23: 835–839. https://doi.org/10.1007/s42000-024-00579-2 Anwar F, Abraham J, Nakshabandi A, Lee E. Treatment of hypocalcemia in hungry bone syndrome: a case report. Int J Surg Case Rep. 2018;51:335 339. 10.1016/j.ijscr.2018.08.011 Ho, L.-Y., Wong, P.-N., Sin, H.-K., Wong, Y.-Y., Lo, K.-C., Chan, S.-F., … Wong, A. K.-M.. Risk factors and clinical course of hungry bone syndrome after total parathyroidectomy in dialysis patients with secondary hyperparathyroidism. BMC Nephrology. 2017;18(1). doi:10.1186/s12882-016-0421-5 Jain N, Reilly RF. Hungry bone syndrome. Curr Opin Nephrol Hypertens. 2017;26(4):250-255. doi:10.1097/MNH.0000000000000327 Table Table 1: A calendar of the patient’s labs and related treatments while being treated inpatient. Days in which no labs were taken or there was no change in treatment are not noted. Day K+ (mEq/L) Mg (mg/dL) Phos (mg/dL) Ca (mg/dL) PTH (pg/mL) Vitamin D (ng/mL) Treatment Administered 1 3.6 X X 7.1 761.3 10.9 Cholecalciferol, 3000 units daily 2 3.4 1.5 2.8 6.3 X X Calcium carbonate (CaCO₃), 750 mg three times daily; continued cholecalciferol 10 X X X X X X Changed cholecalciferol to 50,000 IU weekly; stopped daily cholecalciferol; continued CaCO₃ 11 3.7 1.6 3.2 7.6 707 X Increased CaCO₃ to 1000 mg four times daily; continued cholecalciferol 13 X X X X X X Started Magnesium Oxide and MgSO₄ 400 mg each three times daily; continued cholecalciferol and CaCO₃ 14 4.6 1.7 4.2 8.7 664 X Stopped MgO and MgSO₄ due to intolerance; continued cholecalciferol and CaCO₃ 16 4.2 1.8 4.5 8.4 X X Continued cholecalciferol and CaCO₃ 17 X X X X X X Started calcitriol 0.25 𝜇g QD; continued cholecalciferol and CaCO₃ 21 3.9 1.5 4.4 8.7 273 14.1 Restarted MgO and MgSO₄ 400 mg each daily; continued cholecalciferol, calcitriol and CaCO₃ 22 4.7 1.6 4.4 8.8 273.1 14.1 Continued cholecalciferol, calcitriol, CaCO₃, MgO and MgSO₄ 23 X X X X X X Stopped MgSO₄; continued cholecalciferol, calcitriol, CaCO₃ and MgO 24 X X X X X X Increased MgO to 400 mg twice daily; continued cholecalciferol, calcitriol and CaCO₃ 27 4.2 1.7 X 8.9 141.8 X Continued cholecalciferol, calcitriol, CaCO₃ and MgO 34 3.8 1.5 5.1 9.1 X X Continued cholecalciferol, calcitriol, CaCO₃ and MgO 41 3.8 1.6 5.7 9.0 121.8 X Continued cholecalciferol, calcitriol, CaCO₃ and MgO 48 X 1.9 X 9.3 X 31.4 Stopped calcitriol; continued cholecalciferol, CaCO₃ and MgO 55 3.9 1.7 X 8.9 138.9 X Continued cholecalciferol, CaCO₃ and MgO 57 X X X X X X Stopped MgO; continued cholecalciferol and CaCO₃ 62 4.3 1.5 5.6 10 41 X Continued cholecalciferol and CaCO₃ 63 X X X X X X Discharged with dose of cholecalciferol 3,000 IU, CaCO₃ 1000 mg four times daily, and MgO 400 mg twice daily Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 24 Feb, 2026 Reviewers invited by journal 24 Feb, 2026 Editor invited by journal 24 Feb, 2026 Editor assigned by journal 20 Jan, 2026 First submitted to journal 16 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8603877","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":596472351,"identity":"ec116a81-1fac-47cf-a687-97261ee235ba","order_by":0,"name":"Eva M. Goren","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYDADfiA+wNgAIonVItlAshYDkEqitPBLJD9+8XGPTZ7xjezEAz93MMjx3Ugg4J4ZaWaWM56lFZvdyN1wsPcMg7EkIS0GZw6YGfMcOJy4DajlMGMbQ+IGQlrszxz/BtTyP3HzDIiWeoJaDNh7jB/zHDiQuEECoiXBgJAWieM9ZYwzDiQnzjjzFuiXNgnDmWce4NfC38y++cOHA3aJ/e25mz/8bLOR5ztOwBYgYJNAtpWgchBg/kCUslEwCkbBKBi5AAAqEFB0xIWmzgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0009-0008-2040-9395","institution":"University of Michigan","correspondingAuthor":true,"prefix":"","firstName":"Eva","middleName":"M.","lastName":"Goren","suffix":""},{"id":596472352,"identity":"cc7368f4-7faf-406a-9fb6-cd8d792a7b46","order_by":1,"name":"Stephanie Ferrin","email":"","orcid":"","institution":"Oklahoma State University Health Services","correspondingAuthor":false,"prefix":"","firstName":"Stephanie","middleName":"","lastName":"Ferrin","suffix":""},{"id":596472353,"identity":"783e1e74-bf69-4292-8b34-d5f8f4134eab","order_by":2,"name":"Sowmya Krishnan","email":"","orcid":"","institution":"University of Oklahoma: The University of Oklahoma","correspondingAuthor":false,"prefix":"","firstName":"Sowmya","middleName":"","lastName":"Krishnan","suffix":""},{"id":596472354,"identity":"63c86776-9603-4492-bcc6-b8754f6cb647","order_by":3,"name":"Amy B. Middleman","email":"","orcid":"","institution":"University Hospitals","correspondingAuthor":false,"prefix":"","firstName":"Amy","middleName":"B.","lastName":"Middleman","suffix":""}],"badges":[],"createdAt":"2026-01-14 16:44:39","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8603877/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8603877/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104399374,"identity":"32fe2b0a-91c7-4173-a3cf-fa36ca2d306e","added_by":"auto","created_at":"2026-03-11 12:05:47","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":475489,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8603877/v1/934cc289-6a14-4e8e-a9b3-902c8f7a091b.pdf"}],"financialInterests":"","formattedTitle":"Hungry Hungry Bones: Electrolyte Abnormalities in the Presence of Severe Malnutrition","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSevere malnutrition in childhood can lead to many health problems including significant effects on growing bone. We present a case of severe malnutrition in the presence of child maltreatment that evolved to a diagnosis of anorexia nervosa-restricting sub-type, osteoporosis including multiple fractures, and persistent electrolyte abnormalities during the refeeding process due to hungry bone syndrome (HBS).\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 15-year-old female patient with a history of medical neglect presented to the Emergency Department after removal from her mother\u0026rsquo;s home with weakness, inability to sit up or ambulate, bilateral leg pain, and severe malnutrition.\u003c/p\u003e\n\u003cp\u003eThe patient stated that her mother and sibling had followed a \u0026ldquo;vegan diet\u0026rdquo; since the patient was a little girl. The patient\u0026rsquo;s daily diet typically consisted of two to three bowls of a homemade vegetable soup, occasionally with cheese sprinkled on top, and two oranges. In the proximate year, her food was typically brought to the couch for her by her sibling due to the patient\u0026rsquo;s progressive immobility.\u003c/p\u003e\n\u003cp\u003eThe patient stated that she felt \u0026ldquo;kind of slim\u0026rdquo;. When asked further about weight, the patient questioned if the examiner was referring to \u0026ldquo;fat\u0026rdquo; or \u0026ldquo;blubber\u0026rdquo;. The patient denied vomiting, diarrhea, constipation, hyper-exercise, or any self-directed attempts to lose weight. She did, however, endorse the use of laxatives per her mother\u0026rsquo;s recommendations to \u0026ldquo;get rid of parasites\u0026rdquo; and \u0026ldquo;push them out of [her] system\u0026rdquo;.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn addition, the patient described exercises that she would perform under the direction of her mother, including resistance band stretches and isometric exercises. As the patient became weaker, the patient\u0026rsquo;s mother increased the \u0026ldquo;exercises\u0026rdquo; for the patient to become \u0026ldquo;stronger\u0026rdquo;; mother would pull on the patient\u0026rsquo;s legs with the resistance bands until the patient \u0026ldquo;felt the burn\u0026rdquo;. The patient described that she had been unable to walk for about the last year. Instead, she would use a chair as support to scoot to the bathroom, and she was no longer able to sit down while urinating because it would \u0026ldquo;take too long\u0026rdquo; to sit and then subsequently stand. The patient\u0026rsquo;s estimated menarche was at 11-12 years of age, and although her menstrual cycles used to be regular, they had become infrequent over the past year. Her last menstrual period was 5 days prior to presentation. She had no history of endocrine abnormalities. The patient meets diagnostic criteria for Anorexia Nervosa; that in combination with severe abuse in the home caused severe malnutrition.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAt the initial physical exam, the patient\u0026rsquo;s height was 146 cm and she was 63% of the median estimated body mass index, qualifying her for severe malnutrition. The patient\u0026rsquo;s physical exam was remarkable for psychomotor slowing; cachexia; temporal wasting; tachycardia; delayed capillary refill and cool extremities; inability to stand, sit comfortably or ambulate due to pain; and limited movement of her foreshortened torso and lower extremities/hips due to pain.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eOn X-ray examination, the patient was found to have multiple rib fractures, bilateral humeral fractures, bilateral scapular fractures, tibial fractures, and metatarsal fractures. The patient was admitted to the hospital and monitored closely from the start of her admission for refeeding syndrome. She was found to have a very elevated PTH, vitamin D deficiency, significant hypocalcemia, hypomagnesemia, and hypophosphatemia requiring replacement as discussed below (Table 1).\u003c/p\u003e\n\u003cp\u003eThe patient was initially given cholecalciferol and calcium supplementation. On day 3 of inpatient hospitalization the patient was diagnosed with Rickets and pediatric osteoporosis by pediatric endocrinology. To address her low magnesium levels, she started magnesium supplementation on day 13. From day 34 forward, the patient\u0026apos;s calcium levels were within normal range.\u003c/p\u003e\n\u003cp\u003eWe could not get a DXA scan soon after admission due to the patient\u0026rsquo;s inability to lie flat on the table for the procedure. When obtained during her hospital admission, the patient\u0026rsquo;s DXA scan demonstrated a total-body-less-head (TBLH) Z-score of -5.9. The Z-score describes how many standard deviations from age and sex matched norms the patient\u0026apos;s bone mineral density is. A genetic panel for osteogenesis imperfecta was negative.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDiagnoses made during her hospital stay included rickets, pediatric osteoporosis, and HBS, all secondary to severe malnutrition.\u003c/p\u003e\n\u003cp\u003eFollow up care over the next year included MgO discontinuation with \u0026nbsp;CaCO₃ and cholecalciferol continued. Follow up DXA scan, TBLH, 2 years after initial admission, showed Z-score improvement from -5.4 to -1. Guardian consent and patient assent were obtained to write the case report.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFollow up\u003c/p\u003e\n\u003cp\u003eThis case represents a very rare occurrence of HBS in a child that resulted from severe malnutrition. The prevalence of HBS has varied greatly in the literature [1] [2][3]. The majority of HBS is found in adults with very few reported pediatric cases, in part because the most common cause of HBS is a parathyroidectomy due to primary or secondary hyperparathyroidism which is not common in children [3]. PTH helps regulate calcium levels in the body; when calcium levels are low, PTH stimulates the release of calcium from the bones, increases reabsorption of calcium and decreases phosphate resorption from the kidneys, and plays a role in the synthesis of 1,25-dihydroxy vitamin D cholecalciferol from 25 OH vitamin D in the proximal tubules. 1,25 dihydroxy vitamin D increases absorption of calcium from the intestines. The sudden drop in PTH tilts the scales toward bone formation, and patients become hypocalcemic and hypomagnesemic as these electrolytes play pivotal roles in bone formation. Of reported pediatric cases, the majority of HBS presents post parathyroidectomy [4][5]. The patient described in this case report had intact parathyroid and thyroid glands; she is the only reported case we found in the literature that occurred as a result of malnutrition secondary to disordered eating. While isolated cases of HBS have been reported after prolonged vitamin D deficiency, the vitamin D deficiency was found to be secondary to and not due to malnutrition [6][7]. Our patient had vitamin D deficiency \u0026nbsp;and total electrolyte deficiencies due to her prolonged malnutrition and neglect.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHBS is usually a rare response to a sudden decrease in previously elevated PTH. Most patients with hyperparathyroidism have a rise in PTH that then induces high levels of calcium in the bloodstream. Our patient did not have high levels of calcium secondary to high levels of PTH, rather the calcium stores in her bones had already been depleted to maintain circulating levels of calcium for survival. As a result, her bone density was very low. Our patient\u0026rsquo;s high PTH level was an appropriate response to calcium deficiency due to severe malnutrition. When the patient started to refeed and calcium and vitamin D were introduced into her body, she became more anabolic; as her intake of calcium increased, calcium moved into the bones, resulting in persistent hypocalcemia requiring further supplementation. Her PTH secretion started to go down, but the decrease was slowed because the calcium was being absorbed by bone and was not available to maintain appropriate levels in the blood. Blood levels of magnesium, an important electrolyte that supports bone mineralization as a crucial component for the activation of vitamin D, are also known to drop with refeeding syndrome. Our patient\u0026rsquo;s levels were persistently low as it was needed for bone remineralization. This necessitated magnesium supplementation as well. Hypomagnesemia can also cause PTH resistance and could be another factor explaining her persistently elevated PTH levels.\u003c/p\u003e\n\u003cp\u003eWe have described an unusual case of malnutrition and bone demineralization so profound that the patient developed HBS while refeeding.\u003c/p\u003e\n\u003cp\u003eThere is no standard treatment for HBS[11] however the literature available providing recommendations is based primarily on HBS that occurs secondary to parathyroidectomy [2]. Treatment involves either intravenous or oral supplemental elemental calcium of about 6-12 g/day, the exact dose is dependent on severity and persistence of decreased serum calcium levels [2][8]. The supplementation of calcium is coupled with active metabolites of vitamin D, calcitriol or alfacalcidol [2][9][10]. Depending on the specific case, magnesium supplementation may be required if hypomagnesemia is observed [2]. Our patient required all of the above to manage the accelerated electrolyte consumption. After a lengthy period of electrolyte derangement, the patient was able to wean from supplementation. This patient has gone on to live in a safe home with close monitoring of her bone density.\u003c/p\u003e\n\u003cp\u003eHBS can be life threatening, leading to dangerous arrhythmias and seizures. Although rare, providers managing refeeding syndrome among severely malnourished patients should be aware of the risk of HBS and accelerated electrolyte consumption.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere are no other acknowledgements to be made at this time\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e Dr. Amy Middleman receives royalties in her role as section editor for the Adolescent Medicine section for UpToDate.com\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Declaration:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is no funding to declare.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cstrong\u003eStatement of Authorship\u003c/strong\u003e\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eEva Goren: Involved in data interpretation, writing the primary version of the manuscript, and the revisions and approval of the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003eStephanie Ferrin, MD: Involved in the data collection and interpretation and the review, edits and approval of the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003eSowmya Krishnan, MD: Involved in direct clinical service, data collection and interpretation and the review, edits and approval of the final version of the manuscript\u003c/p\u003e\n\u003cp\u003eAmy Middleman, MD: \u0026nbsp; Involved in the data collection and interpretation and the review, edits and approval of the final version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBrasier A.R., Nussbaum S.R. Hungry bone syndrome: clinical and biochemical predictors of its occurrence after parathyroid surgery. Am J Med. 1988;84(4):654-660. doi:10.1016/0002-9343(88)90100-3\u003c/li\u003e\n\u003cli\u003eWitteveen J.E., van Thiel S., Romijn J.A., Hamdy N.A. Hungry bone syndrome: still a challenge in the post-operative management of primary hyperparathyroidism: a systematic review of the literature. Eur J Endocrinol. 2013;168(3):R45-R53. doi:10.1530/EJE-12-0528\u003c/li\u003e\n\u003cli\u003eCarsote M, Nistor C. Forestalling Hungry Bone Syndrome after Parathyroidectomy in Patients with Primary and Renal Hyperparathyroidism. Diagnostics (Basel). 2023;13(11):1953. doi:10.3390/diagnostics13111953\u003c/li\u003e\n\u003cli\u003eKale N, Basaklar AC, Sonmez K, Uluoglu O, Demirsoy S. Hungry bone syndrome in a child following parathyroid surgery. J Pediatr Surg. 1992;27(12):1502-1503. doi:10.1016/0022-3468(92)90484-o\u003c/li\u003e\n\u003cli\u003eBoggs E, Szymusiak J. Common in Adults and Often Overlooked in Pediatrics: A Case Report of Primary Hyperparathyroidism in an Adolescent Patient. Cureus. 2023;15(4):e38112. doi:10.7759/cureus.38112\u003c/li\u003e\n\u003cli\u003eLombard J, Biarent D, Michez D. Severe persistent hypocalcemia occurring despite vitamin D and calcium supplementation in children with symptomatic vitamin D deficiency. Belgian Journal of Paediatrics. 2023;25(3):180-183. https://www.belgjpaediatrics.com/index.php/bjp/article/view/55\u003c/li\u003e\n\u003cli\u003eStatha, E., Paltoglou, G., Doulgeraki, A., Vakali, E., Vlachopapadopoulou, E., Economou, S., Sakou, I., Soldatou, A.,Karavanaki, K., Fryssira E. A toddler with severe vitamin D-dependent rickets type 1 A (VDDR1A), hungry bone syndrome, and severe RSV infection: presentation and therapeutic challenges. Hormones. 2024;23: 835\u0026ndash;839. https://doi.org/10.1007/s42000-024-00579-2\u003c/li\u003e\n\u003cli\u003eAnwar F, Abraham J, Nakshabandi A, Lee E. Treatment of hypocalcemia in hungry bone syndrome: a case report. Int J Surg Case Rep. 2018;51:335 339. 10.1016/j.ijscr.2018.08.011\u003c/li\u003e\n\u003cli\u003eHo, L.-Y., Wong, P.-N., Sin, H.-K., Wong, Y.-Y., Lo, K.-C., Chan, S.-F., \u0026hellip; Wong, A. K.-M.. Risk factors and clinical course of hungry bone syndrome after total parathyroidectomy in dialysis patients with secondary hyperparathyroidism. BMC Nephrology. 2017;18(1). doi:10.1186/s12882-016-0421-5\u003c/li\u003e\n\u003cli\u003eJain N, Reilly RF. Hungry bone syndrome. Curr Opin Nephrol Hypertens. 2017;26(4):250-255. doi:10.1097/MNH.0000000000000327\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003e\u003cstrong\u003eTable 1: A calendar of the patient\u0026rsquo;s labs and related treatments while being treated inpatient.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDays in which no labs were taken or there was no change in treatment are not noted.\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"612\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDay\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eK+ (mEq/L)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMg\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(mg/dL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePhos\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(mg/dL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCa\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(mg/dL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePTH\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(pg/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVitamin D\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(ng/mL)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTreatment Administered\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e7.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e761.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eCholecalciferol, 3000 units daily\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e2.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e6.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eCalcium carbonate (CaCO₃), 750 mg three times daily; continued cholecalciferol\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eChanged cholecalciferol to 50,000 IU weekly; stopped daily cholecalciferol; continued CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e11\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e707\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eIncreased CaCO₃ to 1000 mg four times daily; continued cholecalciferol\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e13\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eStarted Magnesium Oxide and MgSO₄ 400 mg each three times daily; continued cholecalciferol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e14\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e4.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e8.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e664\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eStopped MgO and MgSO₄ due to intolerance; continued cholecalciferol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e16\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e8.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e17\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eStarted calcitriol 0.25 𝜇g QD; continued cholecalciferol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e21\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e8.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e273\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e14.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eRestarted MgO and MgSO₄ 400 mg each daily; continued cholecalciferol, calcitriol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e22\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e8.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e273.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e14.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol, calcitriol, CaCO₃, MgO and MgSO₄\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e23\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eStopped MgSO₄; continued cholecalciferol, calcitriol, CaCO₃ and MgO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e24\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eIncreased MgO to 400 mg twice daily; continued cholecalciferol, calcitriol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e27\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e8.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e141.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol, calcitriol, CaCO₃ and MgO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e34\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e5.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e9.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol, calcitriol, CaCO₃ and MgO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e41\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e5.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e9.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e121.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol, calcitriol, CaCO₃ and MgO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e48\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e9.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e31.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eStopped calcitriol; continued cholecalciferol, CaCO₃ and MgO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e55\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e8.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e138.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol, CaCO₃ and MgO\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e57\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eStopped MgO; continued cholecalciferol and CaCO₃\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e62\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e4.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003e1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e5.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eContinued cholecalciferol and CaCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 43px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e63\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 48px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 49px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eX\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 248px;\"\u003e\n \u003cp\u003eDischarged with dose of cholecalciferol 3,000 IU, CaCO₃ 1000 mg four times daily, and MgO 400 mg twice daily\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"hormones","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"HORM","sideBox":"Learn more about [Hormones](https://www.springer.com/journal/42000)","snPcode":"42000","submissionUrl":"https://www.editorialmanager.com/horm/default2.aspx","title":"Hormones","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anorexia Nervosa, Hungry Bone Syndrome, DXA Scan, Severe Malnutrition, Adolescent Health","lastPublishedDoi":"10.21203/rs.3.rs-8603877/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8603877/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSevere malnutrition in the presence of child maltreatment and anorexia nervosa can lead to significant effects on bones. We present a case of severe malnutrition from child maltreatment that developed into AN, osteoporosis, and persistent electrolyte abnormalities due to hungry bone syndrome (HBS).\u003c/p\u003e \u003cp\u003eWe describe a 15-year-old female with a history of medical neglect and severe malnutrition presenting to the hospital after removal from mother\u0026rsquo;s home. The patient was admitted and monitored for refeeding syndrome. She had an elevated parathyroid hormone (PTH) level (761pg/ml), vitamin D deficiency, hypocalcemia (6.3mg/dl), and hypomagnesemia (1.5mg/dl), requiring daily management for weeks. The team delayed the initial Dual-energy X-ray Absorptiometry (DXA) scan because the patient could not lie flat. Once obtained, DXA demonstrated a total-body-less-head (TBLH) Z score of -5.9 standard deviations below the age-matched mean.\u003c/p\u003e \u003cp\u003eHBS began with secondary hyperparathyroidism after severe malnutrition; PTH increased bone resorption to maintain normal calcium levels. With refeeding, a sudden fall in PTH led to net calcium movement into bones, resulting in hypocalcemia. In patients with HBS, hypomagnesemia and hypophosphatemia may also be observed due to bone formation. Hypomagnesemia and hypocalcemia occurred in our patient and required continuous electrolyte replacement and supplementation. Although rare, providers managing refeeding syndrome among severely malnourished patients should be aware of the risk of HBS and accelerated electrolyte consumption.\u003c/p\u003e","manuscriptTitle":"Hungry Hungry Bones: Electrolyte Abnormalities in the Presence of Severe Malnutrition","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-27 12:58:25","doi":"10.21203/rs.3.rs-8603877/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2026-02-24T18:30:59+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-24T17:43:01+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Hormones","date":"2026-02-24T11:35:52+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-20T05:05:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Hormones","date":"2026-01-16T16:12:44+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"hormones","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"HORM","sideBox":"Learn more about [Hormones](https://www.springer.com/journal/42000)","snPcode":"42000","submissionUrl":"https://www.editorialmanager.com/horm/default2.aspx","title":"Hormones","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7c22cf56-f57c-4d35-8179-67152162457c","owner":[],"postedDate":"February 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-28T07:51:13+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-27 12:58:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8603877","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8603877","identity":"rs-8603877","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}