Lithium treatment increases intact and midregion parathyroid hormone and parathyroid volume

FCH-PET/CT in primary hyperparathyroidism with discordant/negative MIBI scintigraphy and ultrasonography

CONTEXT

The contribution of [18F]F-fluorocholine (FCH)PET/CT in normocalcemic primary hyperparathyroidism (nPHPT) remains unknown.

OBJECTIVE

To evaluate the sensitivity and specificity of FCH-PET/CT in a cohort of osteoporotic nPHPT patients with discordant or negative MIBI scintigraphy and ultrasonography who all underwent parathyroidectomy (PTX).

DESIGN

Longitudinal retrospective cohort study in patients referred for osteoporosis with mild biological primary hyperparathyroidism.

SETTING

Tertiary referral center with expertise in bone metabolism and surgical management of hyperparathyroidism.

PATIENTS

Among 109 PHPT patients analyzed, three groups were individualized according to total serum calcium (tCa) and ionized calcium (iCa): 32 hypercalcemic patients (HtCa group), 39 patients with normal tCa and elevated iCa (NtCa group), and 38 patients with both normal tCa and iCa (NiCa). All patients had biochemical follow-up confirming or not the success of PTX.

MAIN OUTCOME MEASURES

To evaluate the performance of FCH-PET/CT in terms of sensitivity and specificity, and to compare with first-line imaging procedures in the setting of nPHPT.

RESULTS

The sensitivity of FCH-PET/CT was 67% in the hypercalcemic, 48% in the NtCa group (p = 0.05 vs HtCa), and 33% in the NiCa group (p = 0.004 vs HtCa). Specificity ranged from 97 to 99%. FCH-PET/CT was positive in 64.3% of patients with negative conventional imaging, with biochemical resolution after PTX in 77.8% of patients. Triple negative imaging was observed in 20 patients, with PHPT resolution in 85% of these patients.

CONCLUSION

This study highlights the contribution of [18F]F-fluorocholine PET/CT in a well phenotyped cohort of normocalcemic patients with discordant or negative findings in MIBI scintigraphy and ultrasonography. However, negative imaging in nPHTP does not rule out the possibility of surgical cure by an experienced surgeon.

Drug-Related Hypercalcemia

This review focuses on the commonly prescribed medicaments that can be responsible for hypercalcemia, considering the prevalence, the predominant pathophysiological mechanisms, and the optimal medical management of each drug-induced hypercalcemia. Vitamin D supplements and 1α-hydroxylated vitamin D analogues increase intestinal calcium absorption, renal calcium reabsorption as well as bone resorption. In patients with hypoparathyroidism receiving recombinant human PTH, transient hypercalcemia can occur because of overtreatment, usually during acute illness. Thiazide-induced hypercalcemia is mainly explained by enhanced renal proximal calcium reabsorption, changing preexistent asymptomatic normocalcemic or intermittently hypercalcemic hyperparathyroidism into the classic hypercalcemic hyperparathyroidism. Lithium causes hypercalcemia mainly by drug-induced hyperparathyroidism.

[The clinical practice guidelines for primary hyperparathyroidism, short version]

Primary hyperparathyroidism (PHPT) is an endocrine disorder of parathyroid glands characterized by excessive secretion of parathyroid hormone (PTH) with an upper normal or elevated blood calcium level. Classical PHPT refers to a symptomatic, multi-system disorder, wich can lead to a significant decrease in the quality of life, disability of patients, and even an increased risk of premature death. Hypercalcemia and the catabolic effect of PTH on various cells are considered as the main pathogenetic mechanisms of the PHPT associated complications. In the last two decades, there has been an increase in the incidence of PHPT, mainly due to the mild forms of the disease, primarily due to the routine calcium screening in North America, Western Europe and, Asia. High prevalence of the disease, as well as the variety of clinical manifestations, cause the attention of different specialists - physicians, rheumatologists, urologists, nephrologists, cardiologists and other doctors. This review cover the main issues of Russian guidelines for the management of PHPT, approved in 2020, including laboratory and instrumental methods, differential diagnosis, surgical and conservative approach, short-term and long-term follow-up. This guidelines also include the recommendations for special groups of patients with hereditary forms of PHPT, parathyroid carcinoma, PHPT during pregnancy.

Lithium-associated hyperparathyroidism

Lithium is a mood stabiliser widely used in the treatment and prophylaxis of mania, bipolar disorders and recurrent depression. Treatment with lithium can give rise to various endocrine and metabolic abnormalities, including thyroid dysfunction, nephrogenic diabetes insipidus and hypercalcaemia. Lithium may induce hypercalcaemia through both acute and chronic effects. The initial acute effects are potentially reversible and occur as a result of lithium's action on the calcium-sensing receptor pathway and glycogen synthase kinase 3, giving rise to a biochemical picture similar to that seen in familial hypocalciuric hypercalcaemia. In the long term, chronic lithium therapy leads to permanent changes within the parathyroid glands by either unmasking hyperparathyroidism in patients with a subclinical parathyroid adenoma or possibly by initiating multiglandular hyperparathyroidism. The latter biochemical picture is identical to that of primary hyperparathyroidism. Lithium-associated hyperparathyroidism, especially in patients on chronic lithium therapy, is associated with increased morbidity. Hence, regular monitoring of calcium levels in patients on lithium therapy is of paramount importance as early recognition of lithium-associated hyperparathyroidism can improve outcomes. This review focuses on the definition, pathophysiology, presentation, investigations and management of lithium-associated hyperparathyroidism.

[Chronic metabolic and renal disorders related to lithium salts treatment]

Lithium salts are the main treatment of bipolar disorder, which is characterized by potentially life-threatening maniac and/or depressive episodes. They have proven efficient in the prevention and treatment of acute episodes as well as in the prevention of suicidal risk. However, this efficacy is counterbalanced by a narrow therapeutic range that can lead to potentially harmful overdose, and by adverse long-term events. Nevertheless, they remain first-line treatment, notwithstanding therapeutic alternatives. In this review, we will describe toxic effects of long-term treatment at therapeutic levels of lithium salts. Regarding renal effects, early-impaired urine concentrating ability might lead to polyuria and polydipsia, and even to hypernatremia if free access to water is compromised. Long-term lithium treatment might also lead to chronic kidney disease, characterized by tubulo-interstitial multicystic nephropathy. End-stage renal disease requiring renal replacement therapy is a rare complication. Major extra-renal toxic effects are hypercalcemia and hypothyroidism. Treatment cessation due to these adverse events should be a multidisciplinary and case-by-case decision based on the benefit/risk ratio. Since these toxic effects are mild and display slow progression, treatment cessation is uncommon. However, regular medical and biological check-up is needed in order to prevent these disorders, and patients might be referred to nephrologists and/or endocrinologists once the disorders are established.

Lithium use and risk of fracture: a systematic review and meta-analysis of observational studies

This systematic review and meta-analysis summarized the results from nine eligible observational studies. Lithium use was significantly associated with a decrease risk of fractures.

INTRODUCTION

The association between lithium use and risk of fracture is uncertain. To date, there have been no meta-analyses that have studied the association between the two. We conducted a systematic review and meta-analysis to examine the effect of lithium medication on the risk of fracture.

METHODS

A comprehensive literature search was performed in PubMed, Embase, and MEDLINE to include eligible observational studies. Three reviewers conducted the literature search, study selection, study appraisal, and data abstraction independently. Random effects models were used to obtain the overall estimate for meta-analysis. Cochran's Q and Higgins' I² were used to assess heterogeneity. A funnel plot and Egger's regression test were employed to assess publication bias.

RESULTS

Of the 3819 studies that were identified by our search strategy, eight were eligible for the systematic review, while seven of them qualified for the meta-analysis. In studies that reported risk ratio (RR) of fracture as an outcome (five studies [n = 1,134,722]), lithium use was associated with a 20% decrease in risk of fracture (RR = 0.80; 95% CI, 0.73-0.87; p < 0.01). A decreased risk of fracture associated with lithium was also observed in studies that adjusted for previous fractures (RR = 0.81; 95% CI, 0.73-0.89; p < 0.01). The decreased risk of fracture associated with lithium use remained consistent in all the analyses with different inclusion criteria. Neither significant heterogeneity nor significant publication bias was observed.

CONCLUSION

The present systematic review and meta-analysis demonstrated that lithium use was associated with a significant decreased risk of fracture.

Endocrinological Disorders Related to the Medical Use of Lithium. A Narrative Review

The prescribing of Lithium is common in psychiatric clinical practice. The aim of this study was to identify the most common endocrine side effects associated with this drug and to clarify the pathophysiological basis. A systematic review was conducted in Psycinfo, Embase, PubMed, and Scopus. A computerised search for information was performed using a PICO (patient, intervention, comparative, outcomes) strategy. The main neuroendocrine alterations were reported in kidneys, thyroid and parathyroid glands, pancreas, and the communication pathways between the pituitary and adrenal glands. The pathophysiological mechanisms are diverse, and include the inhibition of the thyroid adenylate cyclase sensitive to the thyroid stimulant hormone (TSH) sensitive adenylate cyclase, which causes hypothyroidism. It also reduces the expression of aquaporin type 2, which is associated with nephrogenic diabetes insipidus, and the loss of the ionic balance of calcium that induces hyperparathyroidism and hypercalcaemia. Other considerations are related to alterations in the hypothalamic-pituitary-adrenal axis and a decrease in the production of catecholamines. Finally, another side-effect is the glycaemic dysregulation caused by the insulin resistance. Periodical clinical and para-clinical evaluations are necessary. The author proposes an evaluation scheme.

Primary Hyperparathyroidism: Effects on Bone Health

Primary hyperparathyroidism (PHPT) is the most common cause of chronic hypercalcemia. With the advent of routine calcium screening, the classic presentation of renal and osseous symptoms has been largely replaced with mild, asymptomatic disease. In hypercalcemia caused by PHPT, serum parathyroid hormone levels are either high, or inappropriately normal. A single-gland adenoma is responsible for 80% of PHPT cases. Less frequent causes include 4-gland hyperplasia and parathyroid carcinoma. Diminished bone mineral density and nephrolithiasis are the major current clinical sequelae. Parathyroidectomy is the only definitive treatment for PHPT, and in experienced hands, cure rates approach 98%.

Long-term outcome after parathyroidectomy for lithium-induced hyperparathyroidism

BACKGROUND

The accepted management of lithium-associated hyperparathyroidism (LiHPT) is open four-gland parathyroid exploration (OPTX). This approach has recently been the subject of controversy. A recent study has shown very high long-term recurrence rates after OPTX, whereas some have promoted unilateral focused parathyroidectomy as appropriate management. The aim was to evaluate long-term outcomes after surgery for LiHPT and to assess the accuracy of preoperative imaging.

METHODS

This was a retrospective cohort study that comprised all patients undergoing initial surgery for LiHPT between 1990 and 2013. The cumulative recurrence rate was calculated by the Kaplan-Meier method. The sensitivity and specificity of sestamibi scintigraphy and ultrasound imaging for identification of single-gland versus multigland disease was investigated using intraoperative assessment as reference.

RESULTS

Of 48 patients, 45 had OPTX and three underwent focused parathyroidectomy. Multiglandular disease was documented in 27 patients and 21 had a single adenoma. The median follow-up was 5·9 (range 0·3-22) years and 16 patients died during follow-up. The 10-year cumulative recurrence rate was 16 (95 per cent confidence interval 2 to 29) per cent. No permanent complications occurred after primary surgery for LiHPT. Twenty-four patients had at least one preoperative ultrasound or sestamibi scan. For concordant sestamibi scintigraphy and ultrasound imaging, the sensitivity and specificity for identifying single-gland versus multigland disease was five of nine and five of eight respectively.

CONCLUSION

Surgery provided a safe and effective management option for patients with LiHPT in this series, with a long-term cure rate of well over 80 per cent.

The influence of lithium on calcium homeostasis in older patients in daily clinical practice

BACKGROUND

Lithium can influence calcium homeostasis resulting in changes in parathormone set point and renal calcium handling. The clinical significance of these changes in older patients is unknown. The objective of this study was to investigate the possible association between duration of lithium treatment and corrected calcium, parathormone and 24-h urinary calcium excretion in older psychiatric patients corrected for renal function and vitamin 25OH D and also to estimate the point prevalence of hypercalcemia and raised parathormone.

METHODS

A cross-sectional study of psychiatric outpatients visiting a specialized facility for older patients treated with lithium was performed. Patients underwent a comprehensive assessment and blood and urine testing. Potential confounders of calcium homeostasis were recorded. On the basis of the duration of lithium treatment, patients were divided into four groups.

RESULTS

One hundred eleven patients were included, mean age 75.2 years. There was no significant association between the duration of lithium treatment and corrected calcium, parathormone and 24-h urinary calcium excretion. The point prevalence of hypercalcemia was 2.7% and 47.8% for raised parathormone. There was an unexpected but significant negative association between the duration of lithium treatment and vitamin 25OH D, with 76.9% vitamin 25OH D deficiency (<50 nmol/L) in the group using lithium for more than 10 years.

CONCLUSIONS

No association was found between duration of lithium treatment and calcium parameters in older psychiatric outpatients, but there was a high prevalence of raised parathormone and an unexpected negative association between duration of lithium treatment and 25OH D.

Lithium-associated hypercalcemia and hyperparathyroidism in the elderly: what do we know?

BACKGROUND

Lithium has been reported to induce hypercalcemia and hyperparathyroidism, yet few studies have examined the impact on older patients. We therefore undertook this review and report our findings.

METHOD

We undertook a systematic review of articles on lithium-associated hypercalcemia and/or hyperparathyroidism that were identified via electronic English language database searches through PubMed.

RESULTS

Among reported cases and case series of lithium-associated hyperparathyroidism in which ages of specific subjects were provided, 40% of affected individuals were over age 60. Mean serum calcium levels are reported to be higher in lithium treated patients over age 60 compared with younger patients. While many patients who develop lithium-associated hypercalcemia and hyperparathyroidism are asymptomatic, symptomatic complications may be more of a concern in older patients, especially in those with co-morbid renal disease.

LIMITATIONS

To date, all cross-sectional studies of lithium-associated hypercalcemia and hyperparathyroidism are of mixed age group cohorts and more specific studies focused on older patients have yet to be performed.

CONCLUSIONS

Lithium-induced hypercalcemia and hyperparathyroidism are under-recognized potential complications of lithium therapy which may occur more frequently in older patients. Psychiatrists should be vigilant in screening for hypercalcemia and hyperparathyroidism in their older patients receiving lithium, both prior to starting treatment and at least annually thereafter.

Focused parathyroidectomy with intraoperative parathyroid hormone monitoring in patients with lithium-associated primary hyperparathyroidism

BACKGROUND

Lithium-associated hyperparathyroidism has been attributed to multigland hyperplasia requiring bilateral exploration and subtotal parathyroidectomy. Recent studies suggest that some patients may have single gland disease and be eligible for minimally invasive parathyroidectomy.

METHODS

We performed a retrospective review of a prospective, single institution parathyroid database of 1,010 patients who underwent parathyroidectomy between December 1999 and October 2010.

RESULTS

Nineteen patients with a history of lithium therapy and sporadic hyperparathyroidism were identified. Median age was 50 years (16-68); median duration of therapy was 19 years (1-37); 11 (58%) were on active therapy with lithium for multiple reasons. Preoperative median serum calcium was 10.9 mg/dL (10.0-12.3), median parathyroid hormone was 111 pg/mL (60-186). A total of 18 patients underwent preoperative imaging. Of 12 patients with single-site localization, 6 (50%) underwent a minimally invasive parathyroidectomy, 2 (17%) underwent unilateral explorations, 1 (8%) underwent bilateral exploration, and 3 (25%) had concomitant thyroidectomies. Six patients did not localize and underwent bilateral exploration for multigland disease. One patient without preoperative imaging had single-gland disease. In all operations surgeons used intraoperative parathyroid hormone (IOPTH) monitoring and met intraoperative criteria. Median IOPTH decrease was 74% (54-86) in single-gland disease and 85% (76-95) in multigland disease. Median abnormal gland weight was 590 mg (134-6,750) in single-gland disease and 296 mg (145-2,170) in multigland disease. All patients were normocalcemic at a median follow-up of 19 months (2-118).

CONCLUSION

Of 19 patients with lithium exposure, 6 (32%) had multigland disease. However, of the 13 (68%) patients with single gland disease, all 12 who had preoperative imaging had single-site localization. If localization suggests single gland disease, minimally invasive parathyroidectomy with IOPTH monitoring can be successfully performed.

Normocalcemic primary hyperparathyroidism

Primary hyperparathyroidism, a common endocrine disorder, is traditionally defined by hypercalcemia and elevated levels of parathyroid hormone (PTH). A newer presentation of primary hyperparathyroidism has been described over the past decade, in which PTH is elevated but serum calcium is consistently normal, in the absence of secondary causes of hyperparathyroidism, such as renal disease or vitamin D deficiency. Recognition of this phenotype of primary hyperparathyroidism, normocalcemic primary hyperparathyroidism, supports a biphasic chronological time course in some individuals in which PTH levels are first elevated but serum calcium is normal, followed by the development of frank hypercalcemia. This review focuses on the available literature regarding this newly described phenotype of primary hyperparathyroidism.

Surgical approach and outcomes in patients with lithium-associated hyperparathyroidism

BACKGROUND

Patients receiving lithium therapy are at elevated risk of developing hyperparathyroidism. In lithium-associated hyperparathyroidism (LAH), the incidence of multiglandular disease (MGD) is unclear, and the need for routine bilateral cervical exploration remains controversial. Therefore, in LAH patients, surgical approaches, pathologic findings, cure rates, and factors associated with persistent or recurrent disease were investigated.

METHODS

Retrospective analysis of 27 patients with LAH undergoing parathyroidectomy with the intraoperative parathyroid hormone (PTH) assay.

RESULTS

The median postoperative follow-up was 7 months; 17 patients had >6 months follow-up. Cervical exploration was unilateral in 9, bilateral in 18 (3 were converted from unilateral). Sixteen patients (62%) had MGD, 12 with four-gland hyperplasia and 4 with double adenomas. Ten patients (38%) had a single adenoma. Twenty-five (93%) of 27 patients had initially successful surgery. Of the 17 patients with >6 months follow-up, two had persistent disease and two experienced recurrent disease. All patients with a single adenoma remain free of disease. Three (75%) of four patients with persistent/recurrent disease had MGD and were receiving lithium at the time of surgery. Patients with persistent/recurrent disease were older (p = 0.01) and had experienced a longer duration of hypercalcemia (p = 0.04).

CONCLUSIONS

LAH patients have a high incidence of MGD, and bilateral exploration is frequently necessary. With access to the intraoperative PTH assay, it is reasonable to initiate a unilateral approach because many patients will harbor single adenomas and can be reliably rendered normocalcemic. Patients with MGD remain at higher risk of persistent/recurrent disease.

Emerging therapeutic opportunities for skeletal restoration

Osteoporosis, a syndrome characterized by thin bones and fractures, has become more prevalent in both women and men. Established therapies for treating this disorder consist primarily of drugs that prevent bone loss, such as the bisphosphonates and selective oestrogen receptor modulators. Although these drugs have been shown to reduce fractures in randomized trials, there is an urgent need for treatments that could lower fracture risk further without additional adverse effects. The introduction of parathyroid hormone (teriparatide), which significantly increases bone mineral density, albeit for a relatively short duration, raised expectations that drugs that stimulate bone formation might cure osteoporosis. After outlining current approaches for treating osteoporosis, this Review focuses on emerging therapeutic opportunities for osteoporosis that are based on recent insights into skeletal physiology. Such novel strategies offer promise not only for reducing age-related bone loss and the associated risk of fractures but also for restoring bone mineral density to healthy levels.

Lithium therapy and hyperparathyroidism: an evidence-based assessment

BACKGROUND

Prolonged therapeutic exposure to lithium compounds can have adverse consequences on calcium homeostasis. A unique form of hyperparathyroidism appears to be causally linked to chronic lithium exposure. We provide a comprehensive review of relevant literature using a structured, evidence-based approach.

METHODS

Published data were identified from systematic electronic literature searches. References are assigned a level of evidence according to a validated classification schema.

RESULTS

Level III and V evidence supports an etiologic link between sustained lithium therapy and both hypercalcemia and hyperparathormonemia (grade C recommendation). Level V evidence supports the use of preoperative parathyroid imaging if a focused exploration is planned (grade C recommendation). Level V evidence supports the use of intraoperative parathyroid hormone monitoring to guide appropriate surgical therapy (grade C recommendation). There is conflicting and equally weighted level V evidence supporting a routine preoperative plan of bilateral neck exploration versus selective unilateral exploration (no recommendation). There may be a role for calcimimetic drug therapy as an alternate, nonsurgical means of controlling lithium-associated hyperparathyroidism (grade C recommendation).

CONCLUSIONS

Evidence-based recommendations support screening of patients on chronic lithium therapy for hypercalcemia. Appropriate surgical therapy may consist of either a bilateral or a unilateral approach when performed by an experienced endocrine surgeon. Focused approaches should be guided by preoperative imaging and intraoperative hormone monitoring. Calcimimetic therapy is a potential alternative to parathyroidectomy.

Long-term results of surgery for lithium-associated hyperparathyroidism

BACKGROUND

Lithium therapy for affective bipolar disease is frequently associated with hyperparathyroidism (HPT), but the results of surgical treatment are virtually unknown. The aim of this retrospective review was to analyse the long-term outcome after surgery for lithium-induced HPT in a large series of patients.

METHODS

Seventy-one patients on chronic lithium therapy who underwent surgery in three university and three district hospitals in Sweden were followed for a median of 6.3 years. Histopathology, complications of surgery and normocalcaemia at 6 months after surgery and last follow-up were analysed.

RESULTS

The primary histopathological diagnoses were adenoma (45 per cent), double adenomas (3 per cent) and hyperplasia (52 per cent). No permanent paresis of the recurrent laryngeal nerve was recorded but 13 per cent of the patients suffered from permanent hypoparathyroidism. At follow-up, the rate of persistent and recurrent HPT was 42 per cent regardless of the histopathological diagnosis.

CONCLUSION

The results of conventional surgery for lithium-associated HPT are poor. The surgical approach should be adjusted for the multiglandular disease that is usually the cause of HPT in patients on chronic lithium therapy.

Lithium's effect on bone mineral density

Lithium salts are widely used in treating psychiatric patients. Lithium may be associated with hyperparathyroidism, a risk factor for osteoporosis. However, the data on the effect of lithium on bone mass are conflicting. We assessed bone mineral density with dual-energy X-ray absorptiometry at the hip and lumbar spine in 75 lithium treated outpatients and 75 normal subjects matched for age, sex and body mass index. Serum total calcium, intact parathyroid hormone (PTH), estradiol, osteocalcin, total alkaline phosphatase (ALP) and C-telopeptide (CTX) in addition to fasting urinary calcium excretion were also determined in both groups. The mean (+/-SD) bone density in lithium treated patients was 4.5% higher at the spine (P<0.05), 5.3% higher at the femoral neck (P<0.05) and 7.5% higher at the trochanter (P<0.05). In addition, lithium treated patients had lower serum total ALP (P<0.005), lower serum osteocalcin (P<0.005) and lower serum CTX (P<0.05) but the total calcium, PTH and urinary calcium excretion did not differ significantly between patients and controls. In conclusion, our results suggest that maintenance therapy with lithium carbonate may preserve or enhance bone mass. These data also suggest a lower bone turnover state in those receiving lithium.

Long-term lithium therapy leading to hyperparathyroidism: a case report

PURPOSE

This paper reviews the effect of chronic lithium therapy on serum calcium level and parathyroid glands, its pathogenesis, and treatment options. We examined the case of a lithium-treated patient who had recurrent hypercalcemia to better understand the disease process.

CONCLUSION

Primary hyperparathyroidism is a rare but potentially life-threatening side effect of long-term lithium therapy. Careful patient selection and long-term follow-up can reduce morbidity.

PRACTICAL IMPLICATIONS

As much as 15% of lithium-treated patients become hypercalcemic. By routinely monitoring serum calcium levels, healthcare providers can improve the quality of life of this patient group.

Lithium use and the risk of fractures

A recent study reported a decreased risk of fractures among lithium users. We conducted a case-control study within the UK General Practice Research Database, comparing never, ever, current, recent and past lithium use in 231,778 fracture cases to matched controls. In addition, the risk of fractures was assessed in relation to cumulative duration of use and time since discontinuation. Current use of lithium was associated with a decreased risk of fractures (adjusted odds ratio [OR]=0.75, 95% confidence interval [CI]=0.64-0.88), which did not vary with cumulative duration of use. Among past users an increased risk of fractures was observed (adjusted OR=1.35, 95% CI=1.01-1.79), increasing with time since discontinuation. Our results support the role of the underlying mental disorders in the aetiology of fractures and do not support a pharmacological effect of lithium based on lack of an association with cumulative duration of use.

Reversible Hypercalcemia and Hyperparathyroidism Associated With Lithium Therapy: Case Report and Review of Literature

OBJECTIVE

To present a case of reversible hypercalcemia and hyperparathyroidism associated with lithium therapy and to discuss the pathophysiology and management of this condition.

METHODS

The clinical and laboratory findings in a patient with lithium-induced hypercalcemia are presented. A PubMed search for associated English language articles (with use of the key words lithium, hypercalcemia, and hyperparathyroidism) was conducted, and the relevant literature to date was reviewed. An approach to the management of patients with lithium-induced hypercalcemia is suggested.

RESULTS

A 56-year-old man was referred for management of incidentally discovered hypercalcemia. The serum parathyroid hormone (PTH) level was increased; serum phosphorus and 24-hour urine calcium excretion were both normal. For 5 years, he had been treated with lithium carbonate for bipolar affective disorder. The laboratory features were consistent with lithium-induced primary hyperparathyroidism. Discontinuation of lithium treatment resulted in normalization of serum calcium and PTH levels. Review of the literature suggests that hypercalcemia and hyperparathyroidism are common consequences of lithium therapy.

CONCLUSION

Hypercalcemia associated with lithium-induced hyperparathyroidism is a common, but underrecognized, complication of lithium therapy. Most patients have mild asymptomatic hypercalcemia. The long-term consequences of mild lithium-induced hypercalcemia are unknown. After discontinuation of lithium, the hypercalcemia may not always resolve; thus, parathyroidectomy may be necessary in some cases. Measurement of the serum calcium and PTH levels before and periodically after the initiation of lithium treatment is advisable. The appropriate monitoring of patients with lithium-induced hypercalcemia and decisions regarding parathyroidectomy are unclear. The decision to continue lithium therapy in the presence of hypercalcemia should be individualized.

Revisiting lithium-associated hyperparathyroidism in the era of intraoperative parathyroid hormone monitoring

BACKGROUND

Chronic lithium therapy may cause hyperparathyroidism (HPT). The utility of intraoperative parathyroid hormone monitoring (IOPTH) in these patients is unknown. The authors' hypothesis was that multiglandular disease is more common in these patients, and the ability of IOPTH to predict cure may be limited.

METHODS

Twelve patients had HPT during chronic lithium therapy and underwent parathyroidectomy with IOPTH. Criteria for curative resection were a decrease > or =50% from baseline and into the normal range. Calcium and PTH levels were measured during follow-up.

RESULTS

Preoperatively, mean calcium was 11.0 +/- 0.1 mg/dL, and PTH was 116 +/- 14 pg/mL. Fifty percent of patients had multiglandular disease confirmed by IOPTH levels. Mean IOPTH decrease from baseline was 74 +/- 4%. Although 10 of 12 patients met criteria for curative resection, only 8 remain normocalcemic. The 2 patients who did not meet criteria remain normocalcemic. Mean postoperative calcium for all patients was 9.5 +/- 0.2 mg/dL. Of the 10 normocalcemic patients, 4 also have hyperparathormonemia (mean PTH, 119 +/- 19 pg/mL).

CONCLUSIONS

The incidence of multiglandular disease in HPT after chronic lithium exposure is higher than standard HPT. The ability of IOPTH to predict durable normocalcemia is limited. Bilateral neck exploration should be considered for these patients regardless of whether IOPTH monitoring is used.

Hypercalcémie grave secondaire à une hyperparathyroïdie induite par le lithium

Lithium treatment, which is still extensively used in bipolar affective disorders, may give rise to hypercalcaemia induced by hyperparathyroidism. We present a patient of 50-year-old treated with lithium for 19 years for bipolar illness and who developed an important hypercalcaemia. After symptomatic treatment of the hypercalcaemia and extrarenal dialysis the clinical evolution was favorable but measurements of serum calcium and parathormon showed that he had developed hyperparathyroidism. Neck exploration was performed and parathyroid adenomas, which had been detected by scintigraphy was removed. The lithium treatment expose to many side effects. Among other biologically and clinically important effects of lithium the possible induction of hyperparathyroidism was first suggested in 1973. Since, 1973, since about forty case reports have been described. Few cross-sectional studies show a relationship of lithium to hyperparathyroidism. Unusual metabolic features are associated with hyperparathyroidism and long-term lithium treatment: low urinary calcium excretion, normal urinary cyclic AMP excretion. The mechanism probably results from lithium linking with the calcium receptor on the parathyroid and then stimulating PTH secretion. The cessation of lithium therapy does not lead to normocalocaemia and a parathyroidectomy is usually indicated.

Pathology and outcome of surgical treatment for lithium-associated hyperparathyroidism

BACKGROUND

Hyperparathyroidism associated with long-term lithium therapy is well described. However, few studies have clearly defined the pathological findings or looked at the outcome of surgical treatment.

METHODS

The study was a retrospective review of 11 patients with bipolar affective disorder who had surgery for lithium-associated hyperparathyroidism.

RESULTS

Twelve patients were identified who had received lithium therapy, of whom 11 (nine women and two men, aged 46-84 (mean 65) years) had prolonged treatment from 2 to 30 (mean 15.3) years. At operation a single adenoma was identified in six patients, whereas multigland disease was seen in five patients. All patients resumed lithium treatment after operation. One patient had recurrent hyperparathyroidism at 3 years, while another had an increased serum level of parathyroid hormone in the presence of a normal serum calcium level after 1 year.

CONCLUSION

Hyperparathyroidism associated with lithium may be due to either parathyroid hyperplasia or adenoma. Observations in the present study supported a true cause and effect relationship. Routine bilateral neck exploration should be performed because of a relatively high frequency of multigland involvement. However, parathyroid resection should be limited to evident disease.

Hyperthyroidism During Lithium Therapy for Depression

OBJECTIVE

To report three cases of hyperthyroidism encountered within a period of 32 months in patients receiving lithium therapy for depression.

METHODS

Three detailed case reports are presented, and the related literature is discussed.

RESULTS

Although hypothyroidism during lithium therapy is well recognized and documented, appearance of cases of hyperthyroidism during lithium therapy is considered uncommon. The antithyroid effect of lithium through inhibition of generation of cyclic adenosine monophosphate tends to mask the underlying hyperthyroidism. Nevertheless, during a 32-month period, three cases of hyperthyroidism were encountered in patients who had received lithium treatment (900 to 1,200 mg/day) for 7 months to 17 years. These patients had symptoms of heat intolerance, palpitations, and tremor, and they were subsequently treated successfully with radioactive iodine.

CONCLUSION

Most likely, cases of hyperthyroidism that occur during lithium therapy may be under-diagnosed, underreported, or both.

Lithium Therapy and Disorders of the Parathyroid Glands

OBJECTIVE

To review the effects of lithium (Li+) on the parathyroid glands.

METHODS

We describe the incidence and clinical features of Li(+)-associated hyperparathyroidism and summarize the current state of knowledge of the in vitro and in vivo effects of Li+ on the parathyroid cell.

RESULTS

Li+ treatment is known to increase the calcium set-point in the parathyroid glands for inhibition of parathyroid hormone secretion. Evidence suggests that this change in calcium set-point occurs as a result of Li+ interference with transmembrane signal transduction in the parathyroid cell. Li+ therapy may accentuate the set-point error in patients with primary hyperparathyroidism and unmask preexisting hyperplastic or adenomatous changes in the parathyroid glands. Li+ may also cause de novo hypercalcemia and hyperparathyroidism that are usually mild, clinically insignificant, and reversible with discontinuation of Li+ therapy. In some patients receiving long-term Li+ therapy, however, persistent hyperparathyroidism develops despite discontinuation of Li+ therapy, and it may be symptomatic and associated with serious organ system sequelae. Li(+)-associated hypercalcemia can be a challenging clinical dilemma in patients with bipolar affective disorder because of the lack of effective therapeutic alternatives, as well as the potential for Li(+)-induced hypercalcemia to exacerbate psychopathologic symptoms.

CONCLUSION

Because severe hypercalcemia may occur as a result of toxic Li+ levels, Li+ and calcium levels should be monitored in patients on long-term Li+ therapy.

Effects of long-term lithium infusion on normal parathyroid tissue

BACKGROUND

Approximately 10% of patients taking lithium for manic-depressive disorders become hypercalcemic. It remains unclear whether lithium initiates disease or promotes underlying hyperparathyroidism. We have previously demonstrated that at therapeutic concentrations lithium stimulates in vitro incorporation of both tritiated thymidine and bromodeoxyuridine into abnormal human parathyroid tissue, reflecting growth-promoting properties. Whether lithium has similar growth-promoting properties in normal parathyroid tissue remains unresolved.

METHODS

We infused lithium (0 mmol/L, 3 mmol/L, or 10 mmol/L) through implantable subcutaneous pumps into normal rats for 3 months and measured levels of serum lithium, serum calcium, and serum parathyroid hormone (PTH) (with a radioimmunoassay specific for rat PTH 1-34.) On completion of the infusion, bromodeoxyuridine (30 mg/kg) was administered intraperitoneally. The parathyroid glands were removed and measured in two dimensions to calculate gland volume [V = (pi/6) x (d1) x (d2)2.] Parathyroid incorporation of bromodeoxyuridine was assessed by using immunocytochemistry.

RESULTS

Serum lithium level was significantly (p < 0.05) different between groups and constant within groups. Levels of serum calcium and PTH were inversely related to each other; however, no significant differences were noted between groups with respect to level of serum calcium or serum PTH at any measurement. Similarly, no significant differences were noted between groups with respect to gland size or number of bromodeoxyuridine-positive cells.

CONCLUSIONS

Long-term lithium infusion in rats for a period representing approximately 15% of their life span failed to evoke changes in parathyroid gland size or function. These data are consistent with (1) lithium as a promoter of hyperparathyroidism and (2) resection of abnormal parathyroid tissue and resumption of lithium for patients requiring long-term therapy.

Biochemical hyperparathyroidism and bone mineral status in patients treated long-term with lithium

Lithium is known to interfere with normal calcium homeostasis, but the long-term effects and possible clinical significance are uncertain. Thus, we measured indices of parathyroid function including intact parathyroid hormone (PTH) and ionized and total calcium levels in 26 patients treated for manic-depressive psychosis with lithium for 10 years or longer (mean +/- SD duration, 15 +/- 6 years). Increased ionized calcium levels were found in 11 patients and increased PTH concentrations in five patients. Altogether, 54% of the patients (14 of 26) had ionized calcium and/or PTH levels above the laboratory reference range. The PTH/ionized calcium relationship of the lithium-treated patients was compared with that of a group of normal subjects (n = 23) and with those of three different groups of patients with abnormal parathyroid function (chronic hypoparathyroidism, n = 21; primary hyperparathyroidism [HPT], n = 50; and tertiary HPT, n = 21). Lithium-treated patients had significantly higher ionized calcium levels (P < .0001) but not significantly higher PTH concentrations (P = .08) than the normal subjects. In comparison to the normal controls, lithium-treated patients had a right-sided shift in their PTH/ionized calcium relationship that was in the same direction but less prominent than in primary or tertiary HPT. Dual-energy x-ray absorptiometry disclosed similar bone mineral densities (BMDs) of lithium-treated patients and age-, sex-, and body mass-matched normal controls in the whole body, lumbar spine, and femoral neck (Z scores: +1.20, +1.22, and +1.02, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of lithium on bone resorption in cultured foetal rat long-bones

Increased serum calcium has been observed in manic depressive patients treated with lithium (Li), and one of the mechanisms increasing serum calcium could be a sensitizing effect of Li on bone resorption. In a previous study, however, Li has been found slightly to inhibit PTH-stimulated resorption in cultured foetal rat long-bones. In this work, we extended the study of the effects of Li on bone resorption in culture when resorption of foetal rat long-bones was stimulated by factors other than PTH. Li 3 mM had no effect on basal resorption, a slight and inconsistent inhibitory effect on PTH stimulated bone resorption, a moderate and inconstant inhibitory effect on prostaglandin E2 (PGE2) stimulated resorption, and did not significantly affect the enhancement of resorption by interleukin 1 (IL1). The more constant effect of Li was a nearly complete inhibition of the resorption response to 1,25-dihydroxycholecalciferol (1,25(OH)2D3). This study confirms that Li has no stimulatory effect on bone resorption by itself, nor a sensitizing action on the stimulation of resorption by several activators. Conversely, Li has a striking inhibitory effect on bone resorption stimulated by 1,25(OH)2D3.

Advances in techniques for measurement of parathyroid hormone Current applications in clinical medicine and directions for future research

Immunometric assays that measure intact parathyroid hormone are replacing traditional radio immunoassays because they provide better discrimination of parathyroid gland function in classic disorders of calcium homeostasis, although radio immunoassays and bioassays continue to have roles in some clinical and research situations. The sensitivity and high precision of Immunometric assays will enable definition of parathyroid hormone's role in chronic and subtle disturbances of calcium and bone homeostasis, such as bone loss and calcium stone disease, in addition to assisting the clinician in the differential diagnosis of hypercalcemic and hypocalcemic disorders.

The role of parathyroid ultrasonography in the management of primary hyperparathyroidism

High-resolution, real-time sonography can be used to assess the size and location of the parathyroid glands. The authors review the types of information provided by sonography and outline the ways in which it contributes to the management of primary hyperparathyroidism. Sonography usually can differentiate parathyroid adenoma from hyperplasia. In milder cases, with less parathyroid enlargement, this differentiation is difficult but can be facilitated by determining three dimensions for each gland. Preoperative knowledge of the presumptive location of an adenoma is most useful when the strategy of unilateral neck exploration is to be used because it will allow the exploration always to begin on the correct side. Sonographic evidence of hyperplasia should trigger a preoperative search for multiple endocrine neoplasia and will alert the surgeon that a bilateral neck exploration and thymectomy will be needed. A more universal benefit is the ability to predict or exclude intrathyroidal and subcapsular parathyroid tumors, thus guiding the decision for thyroid versus thymic exploration in the event of a missing abnormal gland. Sonography often fails to visualize parathyroid tumors in an ectopic position away from the thyroid bed. Such tumors, however, may be anticipated when the sonogram shows only three enlarged glands in cases of hyperplasia, or only three glands of normal size in a patient with strong biochemical evidence of hyperparathyroidism. Because it is noninvasive and inexpensive and can provide a wealth of information, the authors have adopted sonography as a routine preoperative procedure for primary hyperparathyroidism.