Consequences of long-term hyperparathyroidism

Forestalling Hungry Bone Syndrome after Parathyroidectomy in Patients with Primary and Renal Hyperparathyroidism

Hungry bone syndrome (HBS), severe hypocalcemia following parathyroidectomy (PTX) due to rapid drop of PTH (parathormone) after a previous long term elevated concentration in primary (PHPT) or renal hyperparathyroidism (RHPT), impairs the outcome of underlying parathyroid disease.

OBJECTIVE

overview HBS following PTx according to a dual perspective: pre- and post-operative outcome in PHPT and RHPT. This is a case- and study-based narrative review.

INCLUSION CRITERIA

key research words "hungry bone syndrome" and "parathyroidectomy"; PubMed access; in extenso articles; publication timeline from Inception to April 2023.

EXCLUSION CRITERIA

non-PTx-related HBS; hypoparathyroidism following PTx. We identified 120 original studies covering different levels of statistical evidence. We are not aware of a larger analysis on published cases concerning HBS (N = 14,349). PHPT: 14 studies (N = 1545 patients, maximum 425 participants per study), and 36 case reports (N = 37), a total of 1582 adults, aged between 20 and 72. Pediatric PHPT: 3 studies (N = 232, maximum of 182 participants per study), and 15 case reports (N = 19), a total of 251 patients, aged between 6 and 18. RHPT: 27 studies (N = 12,468 individuals, the largest cohort of 7171) and 25 case reports/series (N = 48), a total of 12,516 persons, aged between 23 and 74. HBS involves an early post-operatory (emergency) phase (EP) followed by a recovery phase (RP). EP is due to severe hypocalcemia with various clinical elements (<8.4 mg/dL) with non-low PTH (to be differentiated from hypoparathyroidism), starting with day 3 (1 to 7) with a 3-day duration (up to 30) requiring prompt intravenous calcium (Ca) intervention and vitamin D (VD) (mostly calcitriol) replacement. Hypophosphatemia and hypomagnesiemia may be found. RP: mildly/asymptomatic hypocalcemia controlled under oral Ca+VD for maximum 12 months (protracted HBS is up to 42 months). RHPT associates a higher risk of developing HBS as compared to PHPT. HBS prevalence varied from 15% to 25% up to 75-92% in RHPT, while in PHPT, mostly one out of five adults, respectively, one out of three children and teenagers might be affected (if any, depending on study). In PHPT, there were four clusters of HBS indicators. The first (mostly important) is represented by pre-operatory biochemistry and hormonal panel, especially, increased PTH and alkaline phosphatase (additional indicators were elevated blood urea nitrogen, and a high serum calcium). The second category is the clinical presentation: an older age for adults (yet, not all authors agree); particular skeleton involvement (level of case reports) such as brown tumors and osteitis fibrosa cystica; insufficient evidence for the patients with osteoporosis or those admitted for a parathyroid crisis. The third category involves parathyroid tumor features (increased weight and diameter; giant, atypical, carcinomas, some ectopic adenomas). The fourth category relates to the intra-operatory and early post-surgery management, meaning an associated thyroid surgery and, maybe, a prolonged PTx time (but this is still an open issue) increases the risk, as opposite to prompt recognition of HBS based on calcium (and PTH) assays and rapid intervention (specific interventional protocols are rather used in RHPT than in PHPT). Two important aspects are not clarified yet: the use of pre-operatory bisphosphonates and the role of 25-hydroxyitamin D assay as pointer of HBS. In RHPT, we mentioned three types of evidence. Firstly, risk factors for HBS with a solid level of statistical evidence: younger age at PTx, pre-operatory elevated bone alkaline phosphatase, and PTH, respectively, normal/low serum calcium. The second group includes active interventional (hospital-based) protocols that either reduce the rate or improve the severity of HBS, in addition to an adequate use of dialysis following PTx. The third category involves data with inconsistent evidence that might be the objective of future studies to a better understanding; for instance, longer pre-surgery dialysis duration, obesity, an elevated pre-operatory calcitonin, prior use of cinalcet, the co-presence of brown tumors, and osteitis fibrosa cystica as seen in PHPT. HBS remains a rare complication following PTx, yet extremely severe and with a certain level of predictability; thus, the importance of being adequately identified and managed. The pre-operatory spectrum of assessments is based on biochemistry and hormonal panel in addition to a specific (mostly severe) clinical presentation while the parathyroid tumor itself might provide useful insights as potential risk factors. Particularly in RHPT, prompt interventional protocols of electrolytes surveillance and replacement, despite not being yet a matter of a unified, HBS-specific guideline, prevent symptomatic hypocalcemia, reduce the hospitalization stay, and the re-admission rates.

Parathyroid carcinoma presenting with ventricular bigeminy in pregnancy

Parathyroid carcinoma is very rare in pregnancy. Clinical features are similar to primary hyperparathyroidism. A 38-year-old pregnant woman had repeated hospital admissions for palpitations, headaches, dizziness and polydipsia. Blood investigations showed severe hypercalcaemia with raised parathyroid hormone and 24-hour ECG showed ventricular bigeminy and premature ventricular contractions. Neck ultrasound showed a lesion in the right thyroid lobe. Consequently, she underwent an en bloc resection of the right parathyroid and thyroid lobe at 23 weeks gestation. Histology results confirmed parathyroid cancer. This case highlights the complexities of identifying hypercalcaemia in pregnancy due to the overlapping features with common disorders of pregnancy. Early recognition and timely surgical management can prevent maternal and fetal complications. Also, the case demonstrates the value of interprofessional collaboration between different specialities in providing quality care and improving outcomes. An abridged version of this case was presented at European Congress of Endocrinology 2021.

Symptomatic primary hyperparathyroidism in a young woman presenting with multiple skeletal destructions: a case report and review of literature

BACKGROUND

Multiple pathological manifestations are rarely present in patients with primary hyperparathyroidism (PHPT). Here we described a case of a young woman who presented with multiple skeletal destructions and received an unclear diagnosis at several hospitals.

CASE PRESENTATION

A 30-year-old woman was admitted to our hospital due to pain in both knees and walking difficulty that lasted for 6 and 2 years, respectively. Her laboratory test results revealed a high parathyroid hormone level (822 pg/ml) and hypercalcemia (2.52 mmol/L) in the blood. Parathyroid imaging revealed a lumpy concentration of radioactive uptake detected at the lower pole in the right lobe of the thyroid, and was nearly 2.2 cm * 2.4 cm in size. Next, the patient was treated with parathyroidectomy that resulted in a significant improvement in physiological and clinical symptoms. Moreover, the skeletal destruction and bone mineral density were significantly improved after a 5-years follow-up period.

CONCLUSIONS

Multiple skeletal destructions can be caused by PHPT that should be taken into consideration in young patients with complex bone lesions.

Risk factors and evolution of calcium and parathyroid hormone levels in hungry bone syndrome after parthyroidectomy for primary hyperparathyroidism

INTRODUCTION

Hungry bone syndrome (HBS) is a complication occurring after parathyroid surgery that can cause severe and prolonged hypocalcemia. The study objective was to know the risk factors for HBS after surgery for primary hyperparathyroidism and its relationship with serum calcium and parathyroid hormone levels.

MATERIAL AND METHODS

A case-control, observational, analytical study was conducted in patients who had undergone surgery for primary hyperparathyroidism in the past 10 years (2007-2016). Changes over time in serum calcium and PTH levels and the general characteristics of patients were analyzed.

RESULTS

The incidence rate of HBS in our series was 12.2%. HBS was found to be significantly associated to thyroid surgery during the surgical procedure itself (adjusted odds ratio [aOR]=17.241), to age older than 68 years (aOR=6.666), and to lesions greater than 1.7cm (aOR=7.165). A statistically significant relationship was seen between presence of HBS and corrected serum calcium levels higher than the mean the day after surgery and one week and 3 months later, and also with PTH levels higher than the mean before, during, and one day after surgery.

CONCLUSION

In our series, independent risk factors for development of HBS included patient age, lesion size, and whether or not the procedure was accompanied by thyroid surgery, which requires closer monitoring of mineral metabolism during the perioperative period.

Risk factors of developing the hungry bone syndrome after parathyroidectomy for primary hyperparathyroidism

Background.

Around 13% of patients undergoing parathyroidectomy for primary hyperparathyroidism (PHPT) postoperatively develop a condition known as the hungry bone syndrome (HBS). Although the condition is quite prevalent, the research in this field is very limited. The aim of our study was to determine possible risk factors of developing HBS after parathyroidectomy for PHPT.

Materials and methods.

In this study we enrolled patients who underwent parathyroidectomy for PHPT from January 2005 to December 2016 and performed a retrospective analysis. We used the definition of HBS as hypocalcaemia with normal or elevated PTH values. Patients were divided into two groups by the postoperative HBS prevalence: patients with postoperative HBS and those without postoperative HBS.

Results.

In all, 94 patients were included into the final analysis. We found that patients who developed HBS more often underwent parathyroidectomies simultaneously with a thyroid surgery, underwent longer operations (73.9 ± 41.7 vs. 102.4 ± 44.8 minutes; p = 0.001), and had heavier parathyroid glands removed (0.6 (0.3–8.0) vs. 0.8 (0.15–14.0) g; p = 0.041). Also, these patients had higher preoperative PTH values (15.3 (6.1–63.7) vs. 22.4 (9.2–47.8) pmol/l; p = 0.003). From the ROC curve of the preoperative PTH values and the development of the hungry bone syndrome (AUC = 0.721 (95% CI 0.59–0.85); p = 0.003) we found a 45 pmol/l PTH cut-off value that shows a 90% tendency to develop postoperative HBS.

Conclusions.

Patients undergoing longer parathyroidectomies and those with heavier removed parathyroid glands tend to develop HBS. A preoperative PTH value higher than 45 pmol/l determines an over 90% risk of developing HBS.

The impact of vitamin D status on hungry bone syndrome after surgery for primary hyperparathyroidism

OBJECTIVE

Prolonged hypocalcemia but normal intact parathyroid hormone (iPTH) levels after surgery for primary hyperparathyroidism (PHPT) are referred to as 'hungry bone syndrome' (HBS). The aim was to evaluate preoperative risk factors for HBS with a focus on the impact of 25-hydroxyvitamin D (25(OH)D) deficiency.

DESIGN

Patients having undergone initial successful surgery for sporadic PHPT within 6 years were considered for retrospective analysis.

METHODS

A total of 385 patients were evaluated, of whom 33 (8.6%) developed HBS influencing negatively the postoperative bone metabolism. All patients underwent biochemical evaluations two days before parathyroid surgery and were followed biochemically on a daily basis in the first postoperative week and thereafter at 8 weeks and 6 months.

CONCLUSIONS

No relationship was established between preoperative 25(OH)D deficiency and HBS. The only significant risk factor for HBS in multivariable analysis was high levels of preoperative iPTH. As HBS therefore cannot be predicted preoperatively, we recommend a consistent postoperative calcium and vitamin D supplementation to improve the bone metabolism.

Bone disease in primary hyperparathyroidism

Bone disease in severe primary hyperparathyroidism (PHPT) is described classically as osteitis fibrosa cystica (OFC). Bone pain, skeletal deformities and pathological fractures are features of OFC. Bone mineral density is usually extremely low in OFC, but it is reversible after surgical cure. The signs and symptoms of severe bone disease include bone pain, pathologic fractures, proximal muscle weakness with hyperreflexia. Bone involvement is typically characterized as salt-and-pepper appearance in the skull, bone erosions and bone resorption of the phalanges, brown tumors and cysts. In the radiography, diffuse demineralization is observed, along with pathological fractures, particularly in the long bones of the extremities. In severe, symptomatic PHPT, marked elevation of the serum calcium and PTH concentrations are seen and renal involvement is manifested by nephrolithiasis and nephrocalcinosis. A new technology, recently approved for clinical use in the United States and Europe, is likely to become more widely available because it is an adaptation of the lumbar spine DXA image. Trabecular bone score (TBS) is a gray-level textural analysis that provides an indirect index of trabecular microarchitecture. Newer technologies, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), have provided further understanding of the microstructural skeletal features in PHPT.

Characteristics, management and outcome of primary hyperparathyroidism in South Africa: a single-centre experience

INTRODUCTION

Primary hyperparathyroidism (PHPT) is a common endocrine disorder characterised by hypercalcaemia and elevated parathyroid hormone (PTH) levels. However, it remains a relatively underdiagnosed disease in the developing world primarily due to a lack of routine blood chemistry screening. The aim of this analysis was to evaluate the characteristics, management and outcome of patients with PHPT at a tertiary referral clinic in South Africa.

METHODS

A retrospective analysis was undertaken on all patients with a diagnosis of PHPT attending the endocrinology clinic at a tertiary referral hospital in Durban, South Africa, between January 2003 and June 2009. Information on clinical presentation, past medical history, biochemistry, radiology, histology and surgical notes were recorded. Patients with multiple endocrine neoplasia were excluded.

RESULTS

A total of 28 case records of PHPT were reviewed. The mean age at presentation was 60±14.5 years with a female preponderance (78.6%). The mode of presentation included referral for investigation of an abnormal serum calcium (n: 23), referral from urologist with nephrolithiasis (n: 3) and for investigation of bone disease (n: 2). Symptomatic disease was found in 26 patients (92.9%), including bone pain (75%), fatigue (46.4%) and abdominal pain (32.1%). Mean serum calcium was 3.0+0.39 (normal 2.08-2.65) mmol/L, serum intact PTH 34.7±41.5 (normal 1.2-8.5) pmol/L and serum alkaline phosphatase 206.3±340.2 (normal 53-141) mIU/L. Sestamibi scan was performed on 24 patients and an adenoma was identified in 83.3%. Of the 19 (68%) patients who had parathyroidectomy, an adenoma was identified as the cause in all cases where histology was available (n:18). Surgery was successful in 18 patients with only one patient requiring repeat parathyroidectomy for persistent hypercalcaemia. Postoperative hypocalcaemia developed in eight patients (42.1%) including four patients who required intravenous calcium infusion for symptomatic hypocalcaemia.

CONCLUSIONS

PHPT is a treatable disorder with good surgical success. Asymptomatic disease was uncommon in this group of patients. This is compatible with the symptomatic pattern of presentation reported in other developing countries.

Hungry bone syndrome: still a challenge in the post-operative management of primary hyperparathyroidism: a systematic review of the literature

Hungry bone syndrome (HBS) refers to the rapid, profound, and prolonged hypocalcaemia associated with hypophosphataemia and hypomagnesaemia, and is exacerbated by suppressed parathyroid hormone (PTH) levels, which follows parathyroidectomy in patients with severe primary hyperparathyroidism (PHPT) and preoperative high bone turnover. It is a relatively uncommon, but serious adverse effect of parathyroidectomy. We conducted a literature search of all available studies reporting a 'hungry bone syndrome' in patients who had a parathyroidectomy for PHPT, to identify patients at risk and address the pitfalls in their management. The severe hypocalcaemia is believed to be due to increased influx of calcium into bone, due to the sudden removal of the effect of high circulating levels of PTH on osteoclastic resorption, leading to a decrease in the activation frequency of new remodelling sites and to a decrease in remodelling space, although there is no good documentation for this. Various risk factors have been suggested for the development of HBS, including older age, weight/volume of the resected parathyroid glands, radiological evidence of bone disease and vitamin D deficiency. The syndrome is reported in 25-90% of patients with radiological evidence of hyperparathyroid bone disease vs only 0-6% of patients without skeletal involvement. There is insufficient data-based evidence on the best means to treat, minimise or prevent this severe complication of parathyroidectomy. Treatment is aimed at replenishing the severe calcium deficit by using high doses of calcium supplemented by high doses of active metabolites of vitamin D. Adequate correction of magnesium deficiency and normalisation of bone turnover are required for resolution of the hypocalcaemia which may last for a number of months after successful surgery. Preoperative treatment with bisphosphonates has been suggested to reduce post-operative hypocalcaemia, but there are to date no prospective studies addressing this issue.

[Severe primary hyperparathyroidism and vitamin D deficiency]

Primary hyperparathyrodism is a common disease, often asymptomatic. A young post-partum woman was hospitalized for functional impotence of the upper right limb and poor health status. Laboratory tests revealed severe primary hyperparathyroidism (osteitis fibrosa cystica and nephrolithiasis) associated with vitamin D deficiency. Technetium 99m and thallium parathyroid scintigraphy showed increased uptake under the left thyroid lobe. After surgical resection of a parathyroid adenoma, serum calcium fell markedly and parathyroid levels declined but remained above normal. Calcium and 25(OH)-vitamin D supplementation led to normal calcium and vitamin D levels in three Months, with marked improvement in the bone lesions visualized on the six-Month x-rays. Based on this observation, we describe the many radiological aspects of bone involvement in long-standing hyperparathyroidism aggravated by vitamin D deficiency. Early diagnosis of hyperparathyroidism is crucial.