Tenofovir-induced osteopenia and hyperparathyroidism: A case report and literature review

Tenofovir disoproxil fumarate is the first-line antiviral therapy for chronic viral hepatitis B, but long-term use is associated with renal failure and hypophosphatemic osteomalacia. Tenofovir disoproxil fumarate-induced osteoporosis and secondary hyperparathyroidism are less commonly reported. Herein, we describe the case of a patient with bone and multijoint pain who was initially misdiagnosed as having normocalcemic primary hyperparathyroidism associated with prolonged exposure to tenofovir disoproxil fumarate. The patient's 24-h urinary calcium and phosphorus excretion levels and serum calcium levels were at the lower end of the normal range. After reviewing these findings, the diagnosis was amended to osteoporosis and secondary hyperparathyroidism caused by tenofovir disoproxil fumarate. In this report, we describe the differences in clinical and laboratory manifestations of hyperparathyroidism induced by tenofovir disoproxil fumarate and normocalcemic primary hyperparathyroidism. We also discuss relevant pathophysiological mechanisms and propose a feasible treatment strategy.

A Systematic Review and Meta-analysis of Efficacy and Safety of Calcimimetic Agents in the Treatment of Secondary Hyperparathyroidism in Patients with Chronic Kidney Disease

BACKGROUND

Some reports have pointed out that calcimimetics agents are effective in the treatment of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD) patients, but there is no detailed description of the advantages and disadvantages of calcimimetics agents of SHPT in CKD patients. We tried to pool the published data to verify the effectiveness of calcimimetics agents and to compare the advantages and disadvantages of cinacalcet compared with control in the treatment of SHPT in CKD patients.

METHODS

We included eligible studies of published papers from January 1st, 2000 to December 31st, 2020 in Medline, Pubmed and Web of science databases, and the data were extracted for this meta-analysis.

RESULTS

Twenty-seven studies were eligible, and all the included studies were randomized controlled trials (RCT) including patients treated with long-term dialysis. The results indicated that calcimimetic agents can reduce the parathyroid hormone (PTH, pg/ml) level (WMD = -178.22, 95% CI: -238.57, -117.86, P < 0.00001), calcium (Ca, mg/dl) level (WMD = -0.71, 95% CI: -0.86, -0.55, P < 0.00001), phosphorus (P, mg/dl) level (WMD = -0.32, 95% CI: -0.55, -0.08, P = 0.008), calcium-phosphorus product level (WMD = -7.73, 95% CI: -9.64, -5.82, P < 0.00001). Calcimimetic agents increased the bone alkaline phosphatase (BSAP, ng/ml) levels and rate of achieving target PTH, and reduced osteocalcin levels and the rate of parathyroidectomy. Calcimimetic agents increased the total adverse events' rate, the rate of hypocalcemia and gastrointestinal side effects (nausea, vomiting, abdominal pain and diarrhea), but there was no significant difference in serious adverse events between the calcimimetic agent group and control group.

CONCLUSION

Calcimimetic agents can reduce the PTH level, Ca level, P level, calcium-phosphorus product level and do not increase serious adverse events.

Nitrite-induced acute kidney injury with secondary hyperparathyroidism: Case report and literature review

RATIONALE

Acute kidney injury (AKI) with hyperparathyroidism caused by nitrite was rare, and renal function and parathyroid hormone (PTH) decreased to normal range after therapy.

PATIENT CONCERNS

Acute kidney injury was diagnosed in a 40-year-old male with hyperparathyroidism and cyanosis of his hands and both forearms.

DIAGNOSES

The patient ate some recently pickled vegetables, and he experienced nausea, vomiting and diarrhoea without oliguria or anuria; Additionally, his hands and both forearms had a typical blue ash appearance. After admission, the laboratory findings indicated theincreasing serum creatinine (Scr) and parathyroid hormone (PTH). He was diagnosed as acute kidney injury with hyperparathyroidism caused by nitrite.

INTERVENTIONS

The patient stopped eating the pickled vegetables and was given rehydration, added calories and other supportive therapy without any glucocorticoids.

OUTCOMES

According to his clinical manifestations, laboratory findings and imaging results, the patient was diagnosed with acute kidney injury with secondary hyperparathyroidism. He was given symptomatic supportive care therapy. After one week, the serum creatinine, parathyroid hormone (PTH), hypercalcemia, hyperphosphatemia, proteinuria, and urine red blood cell values decreased to normal range.

LESSONS

Nitrite-induced acute kidney injury with secondary hyperparathyroidism was relatively rare. After therapy, the function of the kidney and parathyroid returned to normal. This case suggests that detailed collection of medical history, physical examination and correct symptomatic treatment is very important.

Furosemide Increases the Risk of Hyperparathyroidism in Chronic Kidney Disease

BACKGROUND

Diuretics are widely used in patients with chronic kidney disease (CKD). While thiazide-like diuretics limit urinary calcium excretion, loop diuretics (LD) promote calcium wasting, which might facilitate the development of secondary hyperparathyroidism (HPT2). We sought to investigate, in CKD patients not on dialysis, the influence of either hydrochlorothiazide (Hydro) or furosemide (Furo) on circulating parathyroid hormone (PTH) and whether such actions are determined by the effects of these compounds on calcium excretion.

METHODS

Electronic charts of all nephrology outpatients (CKD stages 2-5) who were given Hydro or Furo were included. We assessed estimated glomerular filtration rate (eGFR), biochemical parameters and 24-hour calcium excretion. Hyperparathyroidism was defined as PTH >65 pg/ml.

RESULTS

Out of 275 patients, 108 (29%) were taking Hydro and 167 (61%) Furo. Patients on Hydro were younger, mostly female and had higher eGFR. The median 24-hour urinary calcium excretion in the overall cohort was 41 (22, 76), being lower in Furo than in Hydro patients (37 (16, 68) vs. 47 (26, 88) mg/24 h, respectively, p = 0.016). Logistic regression showed that, after adjustment for eGFR, calcium excretion rate was found not to increase the risk ratio for HPT2, whereas Furo was a strong predictor of HPT2.

CONCLUSION

Furo increased the risk of HPT2 among CKD patients compared to Hydro. This effect was independent of eGFR or calcium excretion. The use of LD in CKD, currently preferred in advanced stages, should be reappraised.

Osteomalacia in a patient with Paget's bone disease treated with long-term etidronate

A 93 year-old woman with Paget's disease of bone had been treated with etidronate without interruption during 20 years. The daily dose was usual (5mg/kg/day) but this prescription had never been stopped by her physicians. Two fractures had already occurred in pagetic (right tibia) and non pagetic bones (right fibula) within the last 2 years, and she presented rib fractures, another right tibia fracture and right femur fracture during hospitalization time. X-rays films showed major osteolysis of left ulna and right tibia. Blood samples and technetium bone scan brought no evidence for sarcoma or lytic evolution of the disease. A transiliac bone biopsy on non pagetic bone site confirmed the diagnosis of osteomalacia (increased osteoid parameters), with secondary hyperparathyroidism (hook resorption). In Paget's disease of bone, continuous treatment by etidronate may induce generalized osteomalacia, and increase the risk of fracture in both pagetic and non-pagetic bones. Whereas physicians and pharmaceutical industry try to improve the observance of those drugs, this striking observation also points out that a prescription always needs to be updated.

Secondary hyperparathyroidism but stable bone-mineral density in patients with chronic myeloid leukemia treated with imatinib

Imatinib is currently the standard treatment for chronic myeloid leukemia(CML). Previous studies have shown that imatinib affects bone metabolism in CML patients. However, these effects are not well-studied prospectively. The authors studied bone-mineral density (BMD) and bone metabolism in 17 CML patients and matched controls in 2007 and now repeated the analyses prospectively in 2011. All CML patients were in complete cytogenetic remission during this 4-year period and treated with 400 mg imatinib q.d. (n 5 15) or 600 mg imatinib q.d. (n 5 2). Mean treatment duration was 102 months (range 69–129) in 2011. The authors found that serum levels of parathyroid hormone increased significantly in the patients between 2007 and 2011, and seven out of 17 patients had secondary hyperparathyroidism in 2011. However, the mean areal and volumetric BMDs were stable in the CML patients over the 4-year-observation period. Moreover, the CML patients had significantly higher volumetric BMD in the cortical compartment when compared with controls in 2011 and 2007. Thus, despite a high incidence of secondary hyperparathyroidism,there were no signs of osteoporosis or osteomalacia in imatinib-treated CML patients as suggested earlier.

Prognostic role of serum parathyroid hormone levels in advanced prostate cancer patients undergoing zoledronic acid administration

BACKGROUND

Secondary hyperparathyroidism is frequent in prostate cancer patients with bone metastases, and this condition is worsened by the administration of potent bisphosphonates. Serum parathyroid hormone (PTH) elevation can impair the efficacy of these drugs in terms of survival.

METHODS

The prognostic role of elevated serum PTH levels at baseline and after 3 months of zoledronic acid administration was assessed prospectively in 643 bone metastatic prostate cancer patients enrolled in a prospective randomized, placebo-controlled study.

RESULTS

On multivariate analysis, after adjusting for major prognostic factors and bone turnover markers, elevated baseline serum PTH level was negatively associated with overall survival (hazard ratio [HR], 1.448; 95% confidence interval [CI], 1.045-2.006; p < .03) in zoledronic acid-treated patients but not in placebo-treated patients. In patients with normal baseline PTH levels, there was a trend but insignificant association between zoledronic acid administration and a better survival outcome than with placebo (HR, 0.81; 95% CI, 0.65-1.01; p = .065), whereas a trend in the opposite direction was observed in patients with elevated PTH levels (HR, 1.45; 95% CI, 0.87-2.39; p = .151); interaction test, p = .040. Elevated serum PTH level after 3 months of zoledronic acid treatment was not significantly associated with survival outcome.

CONCLUSIONS

Secondary hyperparathyroidism has a negative prognostic impact in metastatic prostate cancer patients undergoing zoledronic acid administration. Counteracting elevated PTH levels by adequate doses of vitamin D may improve the efficacy of this drug.

Profound hypocalcemia following effective response to zoledronic acid treatment in a patient with juvenile Paget's disease

Juvenile Paget's disease (JPD) is a rare, autosomal recessive osteopathy. Although it has phenotypic overlap with Paget's disease of bone (PDB), it is probably a distinct entity. Because of its rarity, optimal disease management has not yet been established by randomized controlled trials. However, clinical, biochemical, and radiographic improvement has been reported after treatment with antiresorptive agents, including calcitonin and bisphosphonates (BPs). Compared with other BPs, zoledronic acid (ZOL) has a higher affinity to bone mineral and is a stronger inhibitor of the enzyme farnesyl pyrophosphate synthase (the main target of nitrogen-containing BPs), properties that explain the prolonged effect of ZOL on bone turnover and render it a therapeutic option for JPD, similar to PDB. We describe hereby, for the first time in the literature, the case of a patient with JPD who developed severe hypocalcemia and secondary hyperparathyroidism following effective treatment with ZOL.

Insufficient bilateral femoral subtrochanteric fractures in a patient receiving imatinib mesylate

We present a case of insufficient bilateral femoral subtrochanteric fractures in a patient who was treated with imatinib mesylate, an anticancer drug, for 1 year after a diagnosis of chronic myelogenous leukemia (CML). A 60-year-old woman presented with bilateral thigh pain for 6 months. A plain radiograph revealed bilateral progressive insufficient fractures on the subtrochanteric areas of the femurs. MRI of the femurs revealed incomplete stress fractures and no evidence of bone metastasis on either femur. Bone densitometry showed normal T-scores around the hip joint and spine. The patient had normal serum levels of calcium, vitamin D derivatives, and thyroid hormones. Serum phosphate levels were decreased, and parathyroid hormone levels were increased. Serum osteocalcin and urinary N-telopeptide of collagen cross-links (NTx) were both decreased. A bone biopsy demonstrated normocellular marrow without leukemic cells. A histomorphometric evaluation of her bones revealed reduced bone turnover despite secondary hyperparathyroidism. The serum markers for bone metabolism and histomorphometric evaluations in this patient suggest that the drug may have an effect on bone metabolism. These effects could be seen for both bone formation and resorption: this could result in impaired bone mineralization, a severely suppressed bone turnover rate, insufficient fractures, and bone necrosis, which are sometimes seen with long-term use of bisphosphonates. To our knowledge, this is the first case of an insufficient bilateral femoral shaft fracture that is potentially related to the use of imatinib mesylate in a patient with CML. Careful examination of bone metabolism should be performed in patients with CML because imatinib mesylate treatment is a lifelong process.

Cinacalcet in hyperparathyroidism secondary to X-linked hypophosphatemic rickets: case report and brief literature review

X-linked dominant hypophosphatemic rickets (XLH) is the most prevalent genetic form of hypophosphatemic rickets. Standard treatment of XLH patients includes long-term administration of phosphate and calcitriol. Treated patients usually respond well to the conventional therapy and demonstrate amelioration of rachitic symptoms and improved growth. However, long-term administration of phosphate and vitamin D preparations is sometimes complicated with nephrocalcinosis, secondary or tertiary hyperparathyroidism and arterial hypertension. We describe a patient with XLH, caused by a rare missense mutation of the PHEX gene. The patient, while under treatment with alphacalcidol and oral phosphate, developed hypercalciuria, nephrocalcinosis, secondary hyperparathyroidism and arterial hypertension. Cinacalcet was added to the therapeutic regimen and the long-term effects on calciotropic parameters and FGF23 levels are herein reported.

Differences in corrective mode for divalent ions and parathyroid hormone between standard- and low-calcium dialysate in patients on continuous ambulatory peritoneal dialysis--result of a nationwide survey in Japan

BACKGROUND

In patients on continuous ambulatory peritoneal dialysis (CAPD), dialysate calcium concentration has a strong influence on correction of serum calcium, phosphorus, and parathyroid hormone (PTH); however, the optimal concentration of Ca in PD solution is still uncertain. The aim of the survey reported here was to evaluate the prevalence of patients treated with standard- [SCD (approximately 3.25 - 4.0 mEq/L)] or low-calcium [LCD (approximately 1.8 - 2.5 mEq/L)] dialysate and differences in the clinical effects for correction of abnormalities in divalent ions and PTH.

MATERIALS AND METHODS

We used a questionnaire to survey 333 peritoneal dialysis facilities nationwide in Japan. Then, we analyzed serum Ca, P, and PTH levels and the prescription rates for CaCO(3) as a P binder and for vitamin D (VitD) analogs.

RESULTS

The 2384 CAPD patients enrolled in this analysis had a mean age of 60.5 +/- 14.2 years and a mean duration of CAPD of 44.1 +/- 39.2 months. The prevalences of SCD, LCD, and combination of SCD and LCD were, respectively, 49%, 50%, and 1% at initiation, and 40%, 38%, and 22% at the time of the survey. In 735 and 876 patients respectively, LCD and SCD had been prescribed from initiation to the time of the survey. In these two groups, we observed no difference in initiation and current serum levels of Ca and P. But prescription rates for CaCO(3) and VitD analogs were higher in the LCD group than in the SCD group, and PTH levels were higher in the LCD group than in the SCD group.

CONCLUSIONS

A beneficial effect of LCD was revealed in the increased doses of CaCO(3) and VitD analogs seen in that group without the occurrence of hypercalcemia; however, PTH levels in that group were not maintained within an acceptable range. The survey suggests that more serious attention should be paid to the Ca concentration in peritoneal dialysate so as to lessen mineral and PTH disorders in CAPD.

An observational study on the effects of nadroparin-based and citrate-based continuous venovenous hemofiltration on calcium metabolism

BACKGROUND

To study calcium homeostasis during citrate-based compared to nadroparin-based CVVH in critically-ill patients with acute renal failure.

METHODS

11 patients were observed during citrate anticoagulation, 9 with nadroparin and 10 controls. Citrate was chosen for patients with active or at risk for bleeding.

RESULTS

The controls had, at 24 h, a median serum iCa of 1.1 mmol/l, the citrate group 0.87 mmol/l and the nadroparin group 1.1 mmol/l (citrate vs. control p = 0.001, citrate vs. nadroparin p = 0.002). At 48 h, iCa was not significantly different anymore. Ca balance was negative for the citrate group in contrast to the nadroparin group (p = 0.012). Median serum PTH was higher (30.0 pmol/l vs. 6.5 pmol/l, p = 0.003) in the citrate group.

CONCLUSION

With a relative low target-serum-iCa (0.8-0.9 mmol/l) citrate CVVH-treated patients had a negative daily calcium balance and a temporarily lower iCa level resulting in an enhanced PTH response in comparison to nadroparin.

Lithium: a review of its metabolic adverse effects

Treatment with lithium has long been recognized to be associated with metabolic adverse effects notably hypothyroidism, hyperparathyroidism, weight gain and nephrogenic diabetes insipidus. It is important that clinicians prescribing lithium are aware of these adverse effects and have a strategy for their detection and management. We review aspects of these actions of lithium including their prevalence, risk factors, biochemical changes involved and management, and discuss some advances that have been made in their understanding in recent years.

Utilidad de la gammagrafía ósea en el diagnóstico de osteomalacia secundaria en un paciente en tratamiento con tenofovir

It is reported a HIV infected patient under antiretroviral therapy including tenofovir therapy who was referred to the Nuclear Medicine Department to complete bone pain study. A bone scan was performed at 3 hours after the injection of 740 MBq of 99mTc-MDP, revealing an abnormal distribution with characteristic changes compatible with osteomalacia. In further analysis, a secondary hyperparathyroidism and osteomalacia were diagnosed in the context of Fanconi syndrome, an infrequent complication described in patients under treatment with tenofovir.

Vitamin D Levels and Bone Turnover in Epilepsy Patients Taking Carbamazepine or Oxcarbazepine

PURPOSE

Evidence suggests that enzyme-inducing antiepileptic drugs (AEDs) may decrease serum 25-hydroxyvitamin D (25-OHD) levels and increase bone turnover. We sought to determine whether these are affected by treatment with carbamazepine (CBZ) or oxcarbazepine (OXC).

METHODS

We measured serum levels of 25-OHD, parathyroid hormone (PTH), osteocalcin (OCLN), bone alkaline phosphatase (BAP), and urinary N-telopeptides of type I collagen cross-links (NTX) in normal controls (n=24) and in epilepsy patients taking CBZ (n=21) or OXC (n=24) in monotherapy. CBZ patients were subsequently switched overnight to OXC monotherapy, and after 6 weeks, the tests were repeated.

RESULTS

25-OHD levels were lower in each drug-treated group (OXC, 19.4+/-2.3 pg/ml; CBZ, 20.4+/-2.4) than in the controls (27.5+/-2.8) (ANOVA, p=0.052). This difference was significant for the OXC group (p<0.05). PTH, BAP, and NTX did not differ significantly among groups. OCLN levels were somewhat elevated in the OXC group (2.79+/-0.47 ng/ml) and more clearly and significantly elevated in the CBZ group (3.63+/-0.36) compared with controls (2.38+/- 0.41) (p=0.053). Because the data were very similar between OXC and CBZ groups, they were combined to increase statistical power. The combined drug-treatment group had significantly higher BAP (p=0.02) and lower 25-OHD (p=0.015) than did controls. The latter remained significant even after accounting for the confounding effects of age on 25-OHD levels (p<0.05). No significant differences were found after CBZ patients were switched to OXC.

CONCLUSIONS

Epilepsy patients taking OXC or CBZ have significantly lower 25-OHD than do normal controls, with a pattern of changes in other bone biomarkers suggestive of secondary hyperparathyroidism. It may be prudent for patients taking CBZ or OXC to be prescribed 25-OHD replacement.

Zoledronic acid prevents bone loss after liver transplantation: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Clinically important rapid bone loss occurs within 3 to 6 months after liver transplantation and may be associated with osteoporotic fractures.

OBJECTIVE

To determine whether bisphosphonate treatment with zoledronic acid reduces transplant-related bone loss more than placebo in adults having liver transplantation for chronic liver disease.

DESIGN

12-month randomized, double-blind, placebo-controlled trial.

SETTING

2 large liver transplantation centers in Australia.

PATIENTS

62 adults having liver transplantation for chronic liver disease.

INTERVENTIONS

Infusions of zoledronic acid, 4 mg (n = 32), or saline (n = 30) were given within 7 days of transplantation and again at months 1, 3, 6, and 9 after transplantation. All patients received supplementation with calcium carbonate, 600 mg/d, and ergocalciferol, 1000 U/d.

MEASUREMENTS

The primary outcome was bone mineral density (BMD) measured by dual x-ray absorptiometry before transplantation and 3, 6, and 12 months later. Secondary outcomes included bone turnover markers that were measured before transplantation and 1, 3, 6, 9, and 12 months later.

RESULTS

There were statistically significant interactions between treatment effects and time for BMD measurements at the lumbar spine (P = 0.002), femoral neck (P = 0.001), and total hip (P < 0.001). Differences in acute bone loss 3 months after transplantation favored zoledronic acid over placebo. Differences between groups in percentage change from baseline adjusted for baseline weight and serum parathyroid hormone (PTH) level were 4.0% (95% CI, 1.1% to 7.0%) for the lumbar spine, 4.7% (CI, 1.9% to 7.6%) for the femoral neck, and 3.8% (CI, 1.7% to 6.0%) for the total hip. At 12 months after transplantation, the difference in percentage change from baseline between the 2 groups adjusted for baseline weight and serum PTH level was 1.1% (CI, -2.1% to 4.4%) for the lumbar spine, 2.7% (CI, 0.0% to 5.4%) for the femoral neck, and 2.4% (CI, 0.1% to 4.7%) for the total hip. Treatment with zoledronic acid induced temporary secondary hyperparathyroidism and postinfusion hypocalcemia statistically significantly more often than did placebo.

LIMITATIONS

The trial was not powered to assess fractures, and 10 of 62 (16%) patients were not included in adjusted analyses because of missing weight or serum PTH measurements.

CONCLUSION

Treatment with zoledronic acid can prevent bone loss within the first year after liver transplantation.

[Clinical features and outcomes of hyperthyroidism patients positive in propylthiouracil-induced antineutrophil cytoplasmic antibody]

OBJECTIVE

To analyze the clinical features and outcomes of hyperthyroidism patients positive in propylthiouracil (PTU)-induced antineutrophil cytoplasmic antibody (ANCA).

METHODS

The clinical data, including the clinical manifestations, treatment, and outcomes of 45 PTU-induced ANCA positive patients with hyperthyroidism were prospectively studied.

RESULTS

Seventeen of the 45 patients had clinically evident vasculitis and 28 of the 45 patients were not complicated by vasculitis. In the vasculitis group, 13 patients (76.5%) had renal involvement manifested by hematuria, proteinuria, and renal insufficiency. 7 of them (41.2%) had lung involvement and 6 of them had hemoptysis. Perinuclear ANCA (p-ANCA) was detected in all 17 patients and 16 of them (94.1%) were anti-myeloperoxidase antibodies (MPO-ANCA) positive. PTU was discontinued in all 17 patients and the treatment was switched over to methimazole (MMI) in 6 patients. Four patients with severe organ involvement received prednisone and immunosuppressant for 6 to 12 months. No relapse or death occurred during the follow-up period (8 to 60 months with a median of 30 months). All the 17 patients achieved clinical remission except for two that developed end stage renal disease due to late diagnosis. 27 of the 28 patients without vasculitis (96.4%) were p-ANCA positive and 14 of them (50.0%) were MPO-ANCA positive. PTU treatment was discontinued in 24 patients and switched over to MMI treatment in 15 patients, and 4 patients continued to take low dose PTU. No vasculitis manifestation occurred during the follow-up period (3 to 36 months with a median of 20 months). However, the ANCA titer declined slowly in most patients in both groups.

CONCLUSION

PTU treatment should be discontinued without delay in the PTU-induced ANCA positive patients with hyperthyroidism. Treatment can be switched over to MMI when necessary. Patients with severe organ involvement should receive prednisone and immunosuppressant. No vasculitis relapse is found during the follow-up after withdrawal of PTU. However, ANCA may keep positive for a long time.

[Defining the role of sevelamer chloride as a therapeutic agent for management of phosphate in patient with hemodialysis]

It has been about 18 months after the commercial release of sevelamer hydrochloride. I examined the phosphorus management in patient with hemodialysis with the use sevelamer hydrochloride. The phosphorus reduction of sevelamer hydrochloride was weaker than the precipitated calcium carbonate. Patients on artificial dialysis must undergo dietary therapy for the sevelamer hydrochloride to be effective. However, by switching from precipitated calcium carbonate to sevelamer hydrochloride, the calcium level dropped, and as a result the intact PTH rose. It was possible to subdue the rise of intact PTH with vitamin D. The usefulness of vitamin D dramatically increased with the decrease and the eventual cancellation of precipitated calcium carbonate. Furthermore, the calcium load lightened and the product of calcium and phosphorus decreased. At this point, I do not expect substantial phosphorus reduction from sevelamer hydrochloride. It must be recognized that the basis of phosphorus management is proper diet. Only with that can sevelamer hydrochloride be used to its fullest potential.

[Treatment of adynamic bone disease with the complete replacement from calcium carbonate to sevelamer hydrochloride]

The aim of this study was to examine the therapeutic effect of hypocalcemic stimulation caused by sevelamer hydrochloride (SH) administration on adynamic bone disease (ABD). The subjects were 28 maintenance hemodialysis (HD) patients who had remained in ABD state in spite of no administration of vitamin D(3) since HD induction (15 males and 13 females;12 diabetic patients and 16 non-diabetic patients). The mean age was 61.8+/-9.5 years and the mean HD duration was 5.5+/-3.9 years. The calcium concentration in the dialysate was 3.0 mEq/L. We made the final daily dose of SH after two months the same as the first daily dose of calcium carbonate (CC) in the following manner. At first we administered only CC at breakfast and lunch and SH at supper. And for the next two weeks we administered CC at breakfast and SH at lunch and supper. And for the final two weeks we administered only SH. After that we increased the dose of SH as much as possible. We evaluated the therapeutic effect of the above treatment on ABD using intact-osteocalcin (iOC) [Teijin. Tokyo] as a marker before and 6, 12 months after the beginning of the replacement. If iOC Ievel of 30 to 70 ng/mL showed normal tumover bone (NTB), 5 cases (17.9%) changed into NTB in 6 months. 9 cases (32.1%) changed into NTB in 12 months and one case (3.6%) changed into ostitis fibrosa in 12 months. It is thought that SH is effective for the treatment of ABD but we have to be careful for ostitis fibrosa.

[Lithium, a potentially dangerous drug]

Two patients with a bipolar disorder, a woman aged 56 and a woman aged 68, who had used lithium for more than 30 years, were seen with side effects from this medication. Both patients were treated by their general practitioner and had not visited a psychiatrist for many years. The first patient had a chronic lithium intoxication with cerebellar signs and eventually coma, diabetes insipidus, hyperthyroidism, hyperparathyroidism and psoriasis. After 6 weeks of treatment in the intensive-care unit she made a good recovery. The second patient had several lithium side effects. She was diagnosed with diabetes insipidus, hyperparathyroidism due to a parathyroid adenoma, hypothyroidism and a sick-sinus syndrome. A pacemaker was implanted 4 years earlier. The adenoma was surgically removed. After other medication was tried, the patient was once again given lithium, on which she was able to function well. The first patient had lithium concentrations above the therapeutic value for several years and both patients experienced a delay before their signs and symptoms were attributed to lithium. Lithium treatment should be monitored by an experienced psychiatrist.

Acute effect of pamidronate on PTH secretion in postmenopausal hemodialysis patients with secondary hyperparathyroidism

BACKGROUND

The purpose of this study is to evaluate the acute effect of pamidronate on plasma ionized calcium (iCa) level reduction and dynamic parathyroid hormone (PTH) secretion in postmenopausal hemodialysis-dependent women with secondary hyperparathyroidism.

METHODS

Twelve postmenopausal women undergoing regular hemodialysis with serum intact PTH levels greater than 200 pg/mL (200 ng/L) were included in this study. Pamidronate was administered intravenously as a single dose of 15 mg in the last hour of hemodialysis. PTH responses to hypocalcemia and hypercalcemia induced with 1 mEq/L (0.5 mmol/L) and 4 mEq/L (2 mmol/L) of dialysate calcium, respectively, were evaluated before and 1 week after pamidronate therapy.

RESULTS

Pamidronate therapy resulted in a decrease in predialysis basal plasma iCa (iCa(base); P < 0.05) levels and an increase in maximal serum PTH (PTHmax; P < 0.001), basal PTH (PTHbase; P < 0.001), and minimal PTH levels (P < 0.001). The set point of serum calcium and the slope of the PTH-calcium curve were not altered by pamidronate therapy. An inverse correlation was present between iCa(base) and the PTHbase-PTHmax ratio before (r = -0.66; P < 0.05) and after (r = -0.84; P < 0.001) pamidronate therapy.

CONCLUSION

Our study shows that pamidronate therapy is associated with reduced plasma iCa levels and increased PTH secretion, resulting in aggravated secondary hyperparathyroidism. These findings suggest that secondary hyperparathyroidism may worsen after the administration of pamidronate, at least in the short term, in postmenopausal hemodialysis patients.

[Fluoride toxicity]

Many years have passed since domestic water fluoridation was adopted to reduce the incidence of caries in developed countries; however, since there is an additional dose of fluorides ingested with foods and drinks prepared with such waters, the problem has emerged of possible adverse effects on health associated to them, so that in some countries fluorine integrator selling is allowed only with preventive medical prescription. Owing to the affinity for calcifited tissues, fluorine has a powerful effect on bone cellular order (mediated by growth factors' upregulation system IGF-2, TGF-beta, PDGF, bFGF, EGF, BMP-2 and PTH), on function and length, since it can provoke chronic joints-pain, ligaments-calcification, osteosclerosis. Moreover, sodium-fluoride may cause adverse effects on testicular activity (connected to oxidative-stress depending on increased activity of peroxidases and catalases) due to inhibition of 2 androgenesis-regulator enzymes DELTA(5)b-HSD and 17beta-HSD. Furthermore, insoluble gut formed calcium-fluoride may be responsible for hypocalcemia inducing a secondary hyperparathyroidism with bone matrix resorption, osteoporosis, osteomalacia and, perhaps, lowered level of phosphorus. At encephalic level, then, high doses of fluorine cause the onset of neurological symptoms and of a decreased spontaneous motor activity due to a reduction in the number of nicotinic acetylcholine receptors. Nevertheless, epidemiological studies about fluoride toxicity have established that such oligoelement may be safely used at odontoiatric dosages.

Pathophysiology of bone loss in patients receiving anticonvulsant therapy

Many studies have shown that patients taking antiepileptic drugs (AEDs) are at increased risk for metabolic bone disease and low bone mineral density. Although early reports of bone disease in patients with epilepsy often involved institutionalized patients, who may be at risk because of lack of physical activity, reduced sunlight exposure, and poor nutrition, low bone density has also been reported in well-nourished, ambulatory outpatients with epilepsy. Traditionally, attention to the problem of AED-induced bone loss has been focused on those drugs that induce the hepatic cytochrome P450 enzyme system, thereby increasing the metabolism of vitamin D. However, the mechanisms of AED-induced bone loss appear to be multiple, and all types of AEDs are potentially implicated. Besides hepatic enzyme induction, mechanisms may include direct effects of AEDs on bone cells, resistance to parathyroid hormone, inhibition of calcitonin secretion, and impaired calcium absorption. An understanding of bone biology and the pathophysiology of bone loss can aid in the identification and monitoring of patients at risk and in the planning of appropriate prophylactic and therapeutic measures, by which most of the morbidity associated with AED-induced bone loss can be prevented.

Hypertension in hypophosphatemic rickets--role of secondary hyperparathyroidism

Hypertension has been anecdotally reported in children with familial hypophosphatemic rickets (XLH). To better identify and characterize the clinical and laboratory features of hypertensive XLH children, we reviewed the medical records of 41 XLH children, all treated with phosphate and vitamin D analogues. Eight children, who were originally normotensive, developed hypertension during the 2nd decade of life. At diagnosis of hypertension all had persistent secondary/tertiary hyperparathyroidism (HPTD), defined as high serum parathyroid hormone (PTH) for 12 months or longer. Seven had nephrocalcinosis (NC). Analysis of data showed that of 11 children with HPTD, 8 developed hypertension compared with 0 among 30 without HPTD (P<0.001). Of 40 children studied, 18 had NC that was significantly associated with both HPTD (P<0.01) and hypertension (P<0.025). At diagnosis of hypertension, serum calcium was elevated in 2. Plasma renin activity was high in 3 of 4 patients in whom it was measured. Doppler ultrasonography or renal scan was normal in the 5 children studied. Early echocardiography showed left ventricular hypertrophy in only 2 of 5 children studied. In 3 patients who underwent parathyroidectomy, hypertension persisted and 1 progressed to renal failure. Serum creatinine remained normal in all others. Successful treatment of hypertension consisted of beta-adrenergic blockers, angiotensin converting enzyme inhibitors, and Ca channel blockers as monotherapy or in combination. We conclude that hypertension in treated XLH children is closely associated with HPTD. Emphasis should therefore be placed on prevention of the development of HPTD as a complication of XLH treatment, and close monitoring for hypertension in those who do develop HPTD.

Prolonged high-dose phosphate treatment: a risk factor for tertiary hyperparathyroidism in X-linked hypophosphatemic rickets

OBJECTIVE

X-linked hypophosphatemic rickets is characterized by renal phosphate wasting, hypophosphatemia and defective bone mineralization. Treatment with oral phosphate (Pi) and calcitriol improves skeletal changes but associates with secondary hyperparathyroidism and nephrocalcinosis. Tertiary hyperparathyroidism is a rare complication of the treatment. The aim of the present study was to identify treatment-related factors that might be associated with the transition of secondary hyperparathyroidism to tertiary hyperparathyroidism in patients with X-linked hypophosphatemic rickets.

DESIGN

Thirteen patients with X-linked hypophosphatemic rickets and secondary or tertiary hyperparathyroidism were included in the study. Their hospital records were reviewed and compared for onset, duration and dosage of treatment, and for age of diagnosis and degree of secondary hyperparathyroidism.

RESULTS

Two patients developed tertiary hyperparathyroidism and 11 patients secondary hyperparathyroidism during the treatment. Patients with tertiary hyperparathyroidism had, on average, earlier onset and longer duration of treatment, higher dose of Pi and longer duration of treatment with very high Pi doses (> 100 mg/kg/day) compared to the 11 patients with secondary hyperparathyroidism. However, variation of all parameters was great with considerable overlap. Very high S-PTH levels > or = 42 pmol/l were observed in those who later developed tertiary hyperparathyroidism.

CONCLUSIONS

Prolonged very high dose oral Pi treatment is a major risk factor for the development of tertiary hyperparathyroidism in X-linked hypophosphatemic rickets.

[Lithium induced dysfunction of the parathyroid hormone]

The prevalence of hyperparathyroidism (HPT) in patients treated with lithium is higher than that in controls. Lithium seems to affect calcium metabolism, by acting directly parathyroid hormone cells, and distal tubuli in the kidneys. Because hypercalcaemic HPT can cause psychiatric symptoms mistakenly attributed to the lithium treatment, ionised calcium should be a standard control.

[Hyperparathyroidism secondary to anticonvulsant treatment]

Treatment with some anticonvulsants is known to lead to liver enzyme induction. Two cases suggest that this interaction is also the mechanism behind anticonvulsant osteomalacia, which is characterised by hypocalcaemia, elevated alkaline phosphatase, and low 25(OH) cholecalciferol.

Intravenous versus oral vitamin d therapy in dialysis patients: what is the question?

The debate regarding the administration of vitamin D (parenteral versus pulse oral) in dialysis patients has centered on the efficacy of parathyroid hormone (PTH) suppression while ignoring other questions related to complications and compliance. Past studies looking at efficacy showed no differences during short-term treatment, although the small number of patients studied reduces the significance of these findings. Long-term studies with larger populations have shown that parenteral calcitriol is more effective than pulse oral calcitriol in suppressing PTH. When considering the questions of complications and compliance the current literature demonstrates that parenteral vitamin D therapy is associated with fewer episodes of hypercalcemia and hyperphosphatemia and that patients receiving pulse oral calcitriol require more phosphate binders. Because of the documented high noncompliance rate with oral medications in the dialysis population, parenterally administered vitamin D is expected to more completely suppress PTH long term and result in fewer parathyroidectomies. Based on these considerations it is suggested that parenteral vitamin D analogs are superior to pulse oral calcitriol for the long-term control of hyperparathyroidism in dialysis patients.

[Lithium treatment and hyperparathyroidism]

BACKGROUND

Lithium treatment, which is extensively used in bipolar affective disorders, may give rise to hypercalcaemia and sometimes to irreversible hyperparathyroidism.

MATERIAL AND METHODS

We present a patient who developed hyperparathyroidism following long-term treatment with lithium.

RESULTS

After 15 years on lithium the patient was diagnosed with hypercalcaemia; at the same time the patient stopped her lithium medication. Two years later she developed depression with psychotic symptoms and was given electroconvulsive treatment. Measurements of serum calcium and parathormon showed that she had developed hyperparathyroidism. Neck exploration was performed, and two parathyroid adenomas (weight 650 mg and 880 mg), which had been detected by scintigraphy, were removed. Lithium treatment was restarted. One year later she was normocalcaemic and her mood was normal.

INTERPRETATION

In lithium-induced hyperparamyroidism, lithium should be replaced with other mood stabilizers, preferably an antiepilepticum. If cessation of lithium therapy does not lead to normocalcaemia, parathyroidectomy is indicated.

Secondary hyperparathyroidism exacerbation: a rare side-effect of interferon-alpha?

Recombinant human interferon alpha (alpha IFN) is the only treatment with proven benefit for chronic hepatitis C virus (HCV) infection. Nevertheless its use in some susceptible individuals has led to the development or aggravation of different autoimmune conditions. We report the case of a 20 year old woman on peritoneal dialysis with chronic lobular hepatitis secondary to HCV infection who developed de novo psoriasis 9 months after starting treatment with alpha-IFN. In addition to psoriasis, alpha-IFN prescription was also concurrent with an unexpected and refractory secondary hyperparathyroidism exacerbation initially characterized by a marked reduction of serum calcium levels and a consequential increase of PTH. Both complications disappeared after drug withdrawal. The clinical sequence makes an alpha-IFN-induced autoimmune side effect the most plausible hypothesis. The case is discussed and some possible etiopathogenic factors are briefly reviewed.

Intact parathyroid hormone levels are not elevated in glucocorticoid-treated subjects

To assess whether chronic glucocorticoid therapy results in a compensatory increase in parathyroid hormone (PTH), we measured intact PTH levels and other indices of mineral metabolism in 13 postmenopausal glucocorticoid-treated women and 16 normal age-matched controls. The glucocorticoid-treated women received a mean prednisone dose of 15.8 +/- 3.1 mg/day for 12.9 +/- 3.1 years. A linear regression analysis between intact PTH levels and a wide range of prednisone doses in these 13 glucocorticoid-treated women and 26 additional male and female subjects receiving chronic glucocorticoid therapy for a variety of rheumatic and pulmonary disorders (n = 39) was also performed. Intact PTH levels using the sensitive immunoradiometric assay (IRMA, Nichols Institute, San Juan Capistrano, CA) were comparable in the glucocorticoid-treated and normal control women (35.3 +/- 4.4 vs 31.3 +/- 3.2 ng/l, respectively) as wee the total calcium concentrations (9.67 +/- 0.12 vs 9.52 +/- 0.11 mg/dl). In the glucocorticoid-treated women, the 25-hydroxyvitamin D levels, measured by competitive protein assay were similar to those of the control subjects (29.2 +/- 2.8 vs 29.1 +/- 2.3 mg/ml), and no patient was treated with vitamin D in excess of 400 IU daily. In the combined 39 male and female patients, there were also no significant regression relationships between daily prednisone dose and intact PTH levels. Thus, secondary hyperparathyroidism does not accompany chronic oral glucocorticoid therapy in women on low to moderate doses of oral glucocorticoids. The lack of an elevation in intact PTH levels in the presence of chronic glucocorticoid therapy may represent an increased sensitivity of bone to PTH, or an alteration in the relationship between calcium and PTH, or both.

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)

Lithium-induced alterations in parathyroid cell function: insight into the pathogenesis of lithium-associated hyperparathyroidism

BACKGROUND

Reduced parathyroid sensitivity to changes in calcium (Ca2+) has been observed in patients treated with lithium (Li+). In order to investigate this desensitization phenomenon, the effect of Li+ on cytosolic calcium (Cai2+) regulation was examined.

METHODS

Transmembrane signal transduction and Ca2+ sequestration were investigated in bovine parathyroid cells by measuring changes in [Cai2+] in response to 5 mmol/L magnesium (Mg2+), 0.5 to 2.5 mmol/L Ca2+, 25 mumol/L adenosine triphosphate (ATP), and 1 mumol/L ionomycin in cells pretreated with 1 to 10 mmol/L lithium chloride (LiCl) and control cells. Measurement of Cai2+ was made using fura-2.

RESULTS

Increases in [Cai2+] in response to Ca2+ and Mg2+ were blunted following overnight culture with as low as 1 mmol/L LiCl. In normocalcemic medium, 1 mmol/L Ca2+ produced an 81% increase in [Cai2+] in control cells compared with a 58% increase in cells pretreated with LiCl (P < 0.01), whereas in hypocalcemic medium, increases in [Cai2+] were similar in lithium-treated and control cells (78% versus 82%, P > 0.1). The ATP produced increases in [Cai2+] from 225 +/- 9 nmol/L to 366 +/- 10 nmol/L in control cells, compared with 221 +/- 7 nmol/L to 308 +/- 10 nmol/L in cells pretreated with 5 mmol/L LiCl (P < 0.01). Ionomycin-induced increases in [Cai2+] were unaffected by Li+.

CONCLUSIONS

We concluded that the in vitro desensitizing effects of Li+ occur at therapeutic concentrations, but only in the presence of Ca2+ in concentrations that induce transmembrane signaling; and that Li+ blunts increases in [Cai2+] related to cation and ATP-induced transmembrane signal transduction without affecting ionomycin-releasable Ca2+ stores.

Calcium mass balance and behavior of intact immunoreactive parathyroid hormone in acetate-free biofiltration: acute and one-year evaluation

The present study evaluated calcium mass balance (MB) during acetate-free biofiltration (AFB) with a dialysate calcium concentration of 2 mmol/l and different ultrafiltration rates (UF; 42.5 ml/min in schedule 1 and 48.5 ml/min in schedule 3), and with a calcium concentration of 1.75 mmol/l but an UF of 43 ml/min (schedule 2). We also examined the effects of these schedules on the behavior of intact parathyroid hormone (I-PTH). AFB according to schedule 1 and 3 achieve a positive calcium MB (8.49 +/- 1.56 and 5.59 +/- 1.06 mmol, respectively), while in schedule 2 calcium MB merely balanced (0.07 +/- 2.29 mmol/l). A significant acute intradialytic I-PTH decrease was observed with all schedules; after 1 month, however, predialytic PTH values were unchanged in schedules 1 and 3, but worsening was noted in schedule 2. Subsequently, AFB was performed for 12 months employing a dialytic schedule (No. 1) involving a positive calcium balance. A year later I-PTH was significantly lower, thus proving that AFB may play an additional part in controlling secondary hyperparathyroidism.

Single-dose intravenous pamidronate is effective alternative therapy for Paget's disease refractory to calcitonin

We have conducted an open, prospective study to investigate the efficacy of a single 60 mg infusion of pamidronate as alternative therapy in 15 subjects with severe Paget's bone disease refractory to calcitonin. Disease activity was assessed with a visual-analogue score of symptom severity, plasma alkaline phosphatase and quantitative estimation of 99mTc-methylene biphosphonate uptake on bone scan. All indices of disease activity fell after pamidronate, reaching a nadir at 3 months. Although disease activity increased thereafter, only 3 subjects required retreatment within 12 months. Plasma calcium fell after 3 days and remained below baseline levels for 6 months associated with evidence of secondary hyperparathyroidism. Pamidronate was well tolerated; femoral neck fractures occurred in 2 subjects with severe local Paget's disease but were unlikely to be due to the drug. We conclude that pamidronate is an effective and promising alternative for treatment of patients with severe Paget's disease no longer adequately controlled by calcitonin. Calcium supplementation may be prudent to prevent secondary hyperparathyroidism associated with the use of this agent.

[Effect of fluoride on the skeletal system]

The chronic fluoride intoxication in man and animal may cause so different diseases of the bones as osteosclerosis, osteomalacia, secondary hyperparathyroidism and osteoporosis--partly in combination. On the basis of own examinations and of literature an own theory is developed which tries to explain these 4 contrary findings on the bone. According to this theory the fluor dosage, the calcium and vitamin D deficiency, differences of the species, duration of the fluoride supply and an individual sensitiveness to fluoride play an important role. Fluor has an effect on the 3 constituents of bones: osteoblasts, osteoclasts and the bone material.

Bone ultrastructure and x-ray microanalysis of aluminum-intoxicated hemodialyzed patients

In hemodialyzed patients aluminum (Al) intoxication may induce osteomalacic lesions which are mainly observed when plasma immunoreactive parathyroid hormone (iPTH) concentrations are low, and osteitis fibrosa absent. In this study, the bone tissue of eight hemodialyzed patients with elevated plasma and bone Al concentrations was examined by histomorphometry, electron microscopy, and x-ray microanalysis. Five patients (group 1) had osteomalacia and minimal osteitis fibrosa, three patients (group 2) had severe osteitis fibrosa. In group 1, Al was concentrated at the mineralizing front, in hexagonal structures measuring 200 to 1,000 A which also contained phosphorus, but not calcium. Hydroxyapatite needles had a normal aspect. Osteoblasts appeared inactive. In group 2, Al was also present at the mineralizing layer of osteoid, but, in these cases, in small clusters next to abnormal calcium deposits. Osteoblasts appeared very active. Their mitochondria contained calcium and phosphorus granules, or amorphous material, measuring 1,500 to 2,000 A, emitting x-rays characteristic for Al and phosphorus. These results suggest that secondary hyperparathyroidism, by stimulating the cellular activity, may increase the uptake and release of Al by the osteoblasts. The presence of Al within the mitochondria of these cells may be one of the factors inducing the mineralization defect.

Secondary hyperparathyroidism and bone disease in infants receiving long-term furosemide therapy

Four preterm infants receiving long-term furosemide therapy were examined for hypercalciuria, hyperparathyroidism, renal calcification, and bone demineralization. All four infants had increased urinary calcium excretion. Three infants had high serum concentrations of parathyroid hormone, and in these three infants, bone mineral content was below the mean of "osteopenic" preterm infants of comparable gestational and postnatal age. In two of these infants, there was ultrasound evidence of renal calcification. In one infant, autopsy disclosed bone changes of hyperparathyroidism, gallstones, and calcification in the heart and kidney.

Importance of increased urinary calcium excretion in the development of secondary hyperparathyroidism of patients under glucocorticoid therapy

Parathyroid function and calcium metabolism were studied in 44 patients under glucocorticoid therapy (steroid group) and in 25 control subjects. Nephrogenous cAMP and serum immunoreactive parathyroid hormone levels in the steroid group were significantly higher than those in control subjects (p less than 0.001). Nephrogenous cAMP in the steroid group correlated positively with prednisolone dosage (r = 0.424, p less than 0.01), and most patients who showed obvious elevations of nephrogenous cAMP had received over 10 mg/day of prednisolone for at least 2 mo. Fasting urinary calcium in the steroid group [166.1 +/- 78.5 (+/- SD) mg/g creatinine] was about 2 times greater than that in control subjects (74.1 +/- 35.6) (p less than 0.001). Fasting urinary calcium in control subjects correlated negatively with nephrogenous cAMP (r = -0.486, p less than 0.02). In contrast, these values in steroid group showed significant positive correlation (r = 0.631, p less than 0.001), suggesting that increased urinary calcium excretion is an important factor in the development of secondary hyperparathyroidism. Elevated nephrogenous cAMP and serum immunoreactive parathyroid hormone levels decreased after the administration of trichlormethiazide and/or 1 alpha hydroxy-vitamin D3. We conclude that increased urinary calcium excretion plays an important role in the development of secondary hyperparathyroidism in patients under glucocorticoid therapy and that the administration of thiazide and/or vitamin D could improve the secondary hyperparathyroidism caused by glucocorticoid therapy.