Calcium requests in a primary care; An observational audit of biochemical requests and frequency of abnormal results

BACKGROUND/AIMS

This aim of this audit was to assess the extent of serum calcium testing and the frequency of hypercalcaemia in the primary care setting. We also assessed the appropriateness of subsequent investigations with repeat serum calcium and PTH testing if hypercalcaemia was identified.

METHODS

All laboratory requests for adjusted calcium and PTH samples sent from primary care in Glasgow were analysed over a 12 month period. This covered approximately 125 GP practices and a patient population of over 590,000.

RESULTS

There were 78,845 requests for adjusted calcium and 2053 PTH requests from 62,745 patients aged 16-105 years (median age 57, IQ range 30 years). Of these requests 1423 (2.3%) of patients had biochemical evidence of hypercalcaemia (adjusted calcium ≥ 2.61 mmol/L). Of the 1423 patients with hypercalcaemia, 368 patients (45.8%) had a single raised calcium level that was within the normal range on repeat testing. Of the 400 patients with persistent hypercalcaemia on 2 or more samples, 210 (52.5%) had a PTH measured. Eight patients had a PTH < 2.0 pmol/L, whilst 202 (96.1%) had a PTH ≥ 2.0 pmol/L (range 2.1-106.1 pmol/L).

CONCLUSIONS

Serum calcium was checked in 10.6% of the population per year within primary care. In the 2.4% with a raised calcium on initial testing, approximately half (45.8%) will normalise on repeat testing. Of those who remained persistently hypercalcaemic, only half (52.5%) had a PTH measured and the majority (96.1%) were in keeping with primary hyperparathyroidism being the most common cause of hypercalcaemia.

Primary Hypoparathyroidism Resistant to Conventional Therapy

A 28 year old man with primary hypoparathyroidism failed to respond to treatment with calcium and vitamin D analogues. Despite extensive investigation no reason for this was found and he is now successfully treated with teriparatide (synthetic human PTH)

Using WHO-FRAX to describe fracture risk: experience in primary care

Ideally those at highest risk of fracture should be identified prior to fracture occurrence to reduce mortality, morbidity and costs. Case-finding strategies for those at high risk of first fracture or systematic case-finding strategies following fracture are recommended in the UK, rather than population-based screening to identify individuals at high fracture risk. General practices in the UK hold relevant data on individuals beyond fracture history that could allow identification of a wider group of patients at highest risk of fracture. The aim of the paper is to evaluate the feasibility of applying the WHO-FRAX fracture risk calculator to general practice populations using existing recorded data. A cross-sectional study of 2467 women aged 50 years and older (mean 66.2 years, standard deviation = 11.3) registered with two Scottish General Practices with low deprivation (one semi-rural, one urban) was undertaken. Patient data were extracted from the two general practices' patient information databases and the WHO-FRAX calculator was applied to these data. WHO-FRAX calculation was possible on 1872 patients. Of these, 687 patients were found to have a high fracture risk (risk of major facture ≥15% and or risk of hip fracture ≥3% - 37% of the WHO-FRAX assessed cohort) and should be considered for follow-up. In conclusion, use of the WHO-FRAX calculator using general practice-held data is feasible and can help to identify a patient group at higher fracture risk. Further evaluation and treatments can then be targeted at this group.

Impact of treatments for postmenopausal osteoporosis (bisphosphonates, parathyroid hormone, strontium ranelate, and denosumab) on bone quality: a systematic review

The objective of this systematic review was to examine the influence of treatments for postmenopausal osteoporosis (parathyroid hormone [PTH], bisphosphonates, strontium ranelate, and denosumab) on bone quality and discuss the clinical implications. Most bone-quality data for PTH is from teriparatide. Teriparatide results in a rapid increase in bone-formation markers, followed by increases in bone-resorption markers, opening an "anabolic window," a period of time when PTH is maximally anabolic. Teriparatide reverses the structural damage seen in osteoporosis and restores the structure of trabecular bone. It has a positive effect on cortical bone, and any early increases in cortical porosity appear to be offset by increases in cortical thickness and diameter. Bisphosphonates are antiresorptive agents which reduce bone turnover, improve trabecular microarchitecture, and mineralization. Concerns have been raised that the prolonged antiresorptive action of bisphosphonates may lead to failure to repair microdamage, resulting in microcracks and atypical fragility. Strontium ranelate is thought to have a mixed mode of action, increasing bone formation and decreasing bone resorption. Strontium ranelate improves cortical thickness, trabecular number, and connectivity, with no change in cortical porosity. Denosumab exerts rapid, marked, and sustained effects on bone resorption, resulting in falls in the markers of bone turnover. Evidence from bone-quality studies suggests that treatment-naive women, aged 60-65 years, with very low BMD T scores may benefit from PTH as primary therapy to improve bone substrate and build bone. Post-PTH treatment with bisphosphonates will maintain improvements in bone quality and reduce the risk of fracture.

The prevalence of vertebral fracture amongst patients presenting with non-vertebral fractures

INTRODUCTION

Despite vertebral fracture being a significant risk factor for further fracture, vertebral fractures are often unrecognised. A study was therefore conducted to determine the proportion of patients presenting with a non-vertebral fracture who also have an unrecognised vertebral fracture.

METHODS

Prospective study of patients presenting with a non-vertebral fracture in South Glasgow who underwent DXA evaluation with vertebral morphometry (MXA) from DV5/6 to LV4/5. Vertebral deformities (consistent with fracture) were identified by direct visualisation using the Genant semi-quantitative grading scale.

RESULTS

Data were available for 337 patients presenting with low trauma non-vertebral fracture; 261 were female. Of all patients, 10.4% were aged 50-64 years, 53.2% were aged 65-74 years and 36.2% were aged 75 years or over. According to WHO definitions, 35.0% of patients had normal lumbar spine BMD (T-score -1 or above), 37.4% were osteopenic (T-score -1.1 to -2.4) and 27.6% osteoporotic (T-score -2.5 or lower). Humerus (n=103, 31%), radius-ulna (n=90, 27%) and hand/foot (n=53, 16%) were the most common fractures. For 72% of patients (n=241) the presenting fracture was the first low trauma fracture to come to clinical attention. The overall prevalence of vertebral deformity established by MXA was 25% (n=83); 45% (n=37) of patients with vertebral deformity had deformities of more than one vertebra. Of the patients with vertebral deformity and readable scans for grading, 72.5% (58/80) had deformities of grade 2 or 3. Patients presenting with hip fracture, or spine T-score

CONCLUSIONS

Our results support the recommendation to perform vertebral morphometry in patients who are referred for DXA after experiencing a non-vertebral fracture. Treatment decisions will then better reflect any given patient's future absolute fracture risk. The 'Number Needed to Screen' if vertebral morphometry is used in this way would be seven to identify one patient with vertebral deformity, and 14 to identify one patient with two or more vertebral deformities. Although carrying out MXA will increase radiation exposure for the patient, this increased exposure is significantly less than would be obtained if X-rays of the dorso-lumbar spine were obtained.

Collapse

Key Words

• low trauma fracture
• number needed to screen
• osteoporosis
• vertebral fracture
• vertebral morphometry

Collapse

MESH Headings

• Absorptiometry, Photon/methods
• Age Factors
• Aged
• Body Mass Index
• Female
• Fractures, Bone/diagnosis
• Fractures, Bone/epidemiology
• Humans
• Lumbar Vertebrae/abnormalities
• Lumbar Vertebrae/injuries
• Male
• Middle Aged
• Osteoporosis/diagnosis
• Osteoporosis/epidemiology
• Prevalence
• Prospective Studies
• Recurrence
• Risk Factors
• Scotland/epidemiology
• Spinal Fractures/diagnosis
• Spinal Fractures/epidemiology
• Thoracic Vertebrae/abnormalities
• Thoracic Vertebrae/injuries

Collapse

Grants Collapse

Peri-prosthetic bone mineral density after total knee arthroplasty

We compared peri-prosthetic bone mineral density between identical cemented and cementless LCS rotating platform total knee arthroplasties. Two matched cohorts had dual energy x-ray absorptiometry scans two years post-operatively using a modified validated densitometric analysis protocol, to assess peri-prosthetic bone mineral density. The knee that was not operated on was also scanned to enable the calculation of a relative bone mineral density difference. Oxford Knee and American Knee Society scores were comparable in the two cohorts.

Statistical analysis revealed no significant difference in absolute, or relative peri-prosthetic bone mineral density with respect to the method of fixation. However, the femoral peri-prosthetic bone mineral density and relative bone mineral density difference were significantly decreased, irrespective of the method of fixation, particularly in the anterior distal portion of the femur, with a mean reduction in relative bone mineral density difference of 27%.

There was no difference in clinical outcome between the cemented and cementless LCS total knee arthroplasty. However, both produce stress-shielding around the femoral implants. This leads us to question the use of more expensive cementless total knee components.

Osteoporosis risk assessment and treatment intervention after hip or shoulder fracture. A comparison of two centres in the United Kingdom

This study compares the investigation of and treatment for osteoporosis in two groups of fracture patients at two orthopaedic centres in the UK. One centre had a formal fracture liaison service (FLS) responsible for screening fracture patients for osteoporosis. The other centre relied upon individual clinicians to initiate investigation or treatment for osteoporosis in patients following fracture. Patients who had been treated in either centre for a proximal humeral or hip fracture during a 6-month period were followed up 6 months later to identify how many had received screening or treatment for osteoporosis. Information was retrieved from a prospectively compiled database or by postal questionnaire. The study revealed that in the centre with an FLS 85% of patients with a proximal humeral fracture and 20% with a hip fracture had been offered a dual-energy X-ray absorptiometry (DEXA) scan. Approximately 50% and 85%, respectively, were receiving treatment for osteoporosis 6 months following their fracture. This compared with DEXA being offered to only 6% and 9.7% of humeral and hip fracture patients, respectively, and 20% (hip) and 27% (proximal humerus) receiving osteoporosis treatment in the other centre. The presence of an FLS resulted in a considerably higher proportion of patients receiving investigation and treatment for osteoporosis following a hip or proximal humeral fracture.

Prevalence of vitamin D inadequacy in Scottish adults with non-vertebral fragility fractures

BACKGROUND

It is well established that vitamin D levels are sub-optimal in the elderly and that adults with fragility fracture are more likely to have serum vitamin D levels either lower than those of control patients of similar age, or below the normal range.

OBJECTIVES

To investigate the prevalence of vitamin D inadequacy in an elderly population presenting to the South Glasgow Fracture Liaison Service with non-vertebral fragility fractures in order to assess the extent of the problem.

RESEARCH DESIGN AND METHODS

The retrospective arm of this study used data from an established database to identify patients aged over 50 years admitted to South Glasgow University Hospitals over the previous 4 years with hip fracture. The prospective arm identified the first 50 patients aged over 50 presenting with a clinical non-vertebral fragility fracture with osteoporosis as measured by axial spine and/or hip DEXA (T-score < -2.5) after November 2004.

RESULTS

In the retrospective arm, 626 patients were identified from the database: mean age 80.5 years; 94% were aged over 60 and 74% were aged over 75. Data analysis was limited to 548 patients aged over 60 years with vitamin D recordings and not receiving supplementation with calcium and vitamin D. The mean vitamin D level was 24.7 nmol/L (9.9 ng/ml) SD = 17, however, it is likely that the true mean is lower since in approximately 25% of cases vitamin D levels were reported as < 15 nmol/L (effectively unrecordable). These were transcribed as 15 nmol/L in order to permit a numerical value to be calculated. In the absence of an agreement on what should constitute a diagnostic serum level of vitamin D inadequacy, a number of thresholds were considered--97.8% had vitamin D levels below 70 nmol/L and 91.6% had vitamin D levels below 50 nmol/L. There were no significant differences by patient sex, age or season of presentation. The mean age of patients in the prospective arm was 65.8 years (range 50.6-83.8), 72% were aged over 60 and 16% were aged over 75. The mean vitamin D level was 44.1 nmol/L (18.4 ng/ml) SD = 25.3; 82% had vitamin D levels below 70 nmol/L and 72% had vitamin D levels below 50 nmol/L. Although numbers were too small to justify extensive subgroup analyses, the mean vitamin D level in the 13 patients with hip fracture (34.5 nmol/L) was lower than in the 37 with non-hip fractures (48.2 nmol/L).

CONCLUSIONS

This study confirms almost universal vitamin D inadequacy among 548 elderly patients admitted to hospital with hip fracture, regardless of whether a threshold of 50 nmol/L or 70 nmol/L was used. However, among a prospective subset of 50 patients with clinical fragility fractures, especially those with non-hip fractures, the prevalence of inadequacy was substantially lower. It may be that vitamin D represents a correctable risk factor for fragility fracture in the elderly, possibly specifically for the hip.

DXA body composition studies are not affected by extracellular water measurements using stable sodium bromide dilution

Body composition studies using dual energy x-ray absorptiometry (DXA) are being increasingly reported in the literature. When DXA body composition measurements are combined with body water studies, stable bromide is often administered to measure extracellular water. Bromine attenuates x-rays significantly more than soft tissue and so could affect DXA body composition analysis. DXA scans were performed on 26 adults (12 F, 14 M) before and after the intravenous injection of 3 g sodium bromide (NaBr). No significant differences were noted pre- and post-NaBr infusion for whole-body fat mass, fat-free soft tissue mass and bone mineral content. These findings were supported by a simple mathematical analysis of the likely effect of the sodium bromide infusion. This showed that when 3 g NaBr was introduced into the body, the effect on fat mass estimates was expected to be marginally less than the precision of the DXA technique.

Alteration of the circadian rhythm of intact parathyroid hormone and serum phosphate in women with established postmenopausal osteoporosis

Several studies have established that the circulating concentration of intact parathyroid hormone, PTH (1-84), over 24 h follows a circadian rhythm. The importance of this circadian rhythm is not known although some authors have detected alterations in the rhythm in metabolic bone disease and following dietary manipulation. We have studied the circadian rhythm of PTH (1-84) in 8 premenopausal women, 8 postmenopausal women with established osteoporosis and 8 postmenopausal women with no evidence of osteoporosis. Blood samples were obtained at 30-min intervals over a 24-h period and significant differences were found in the profiles of PTH (1-84) and serum phosphate in the three groups studied. Premenopausal women possessed a nocturnal/early morning increase in PTH (1-84) and phosphate (between 2200 and 0700 hours), as did postmenopausal women without osteoporosis. In postmenopausal women with osteoporosis the nocturnal increase in PTH (1-84) and serum phosphate was absent and PTH (1-84) decreased during the period 2200-0700 hours. A shift in acrophase is observed between premenopausal and postmenopausal women without osteoporosis. No acrophase was found in postmenopausal women with osteoporosis for either PTH (1-84) or serum phosphate. No circadian rhythm, acrophase or significant amplitude was observed in serum adjusted calcium or ionized calcium in any group studied. Alterations in the circadian rhythms for PTH (1-84) and serum phosphate occur in patients with postmenopausal osteoporosis that suggest that normal dynamics of PTH (1-84) secretion may play a role in both calcium and phosphate metabolism and the bone remodelling process. Whether these changes are causative or a response to the pathology will require further investigation.

Attenuated neutrophil respiratory burst following acute hypoglycaemia in diabetic patients and normal subjects

The effects of insulin-induced hypoglycaemia on the neutrophil respiratory burst were investigated in six patients with type 1 diabetes and six non-diabetic control subjects. Plasma glucose reached similar nadirs in control subjects (0.9 +/- 0.1 mmol 1(-1); mean +/- SEM) and diabetic patients (1.2 +/- 0.2 mmol 1(-1)) (NS). The resting neutrophil respiratory burst was similar in control subjects (1.26 +/- 0.15 mV) and diabetic patients (1.03 +/- 0.18 mV) (NS). The neutrophil respiratory burst fell following hypoglycaemia in control subjects and diabetic patients to 0.38 +/- 0.05 mV (P < 0.001) and 0.54 +/- 0.09 mV (P < 0.05), respectively. This fall was significantly greater in control subjects (ANOVA; P < 0.001). Resting neutrophil counts were not significantly different in control subjects (3.2 +/- 0.3 x 10(9) 1(-1)) and diabetic patients (6.1 +/- 1.5 x 10(9) 1(-1)). Following hypoglycaemia, neutrophil numbers increased in control subjects and diabetic patients to 11.5 +/- 1.4 x 10(9) 1(-1) (P < 0.01) and 9.7 +/- 1.7 x 10(9) 1(-1) (P < 0.05), respectively. This increase was significantly greater in control subjects (ANOVA; P < 0.001). These results suggest that the neutrophil respiratory burst is suppressed in response to hypoglycaemia and that this phenomenon is more pronounced in non-diabetic subjects.

Formulary management of drugs for cancer-associated hypercalcaemia

Hypercalcaemia associated with cancer is seen not infrequently in hospital practice and can be a source of considerable morbidity. Over the past decade, our understanding of the pathogenesis of this syndrome has advanced, allowing improved treatment protocols. Because one of the principal abnormalities relates to an increase in bone resorption, antiresorptive agents such as calcitonin and the bisphosphonates have been shown to be of value. In the medium to longer term, the bisphosphonates -particularly pamidronic acid[pamidronate;aminohydroxypropylidene bisphosphonate (APD)] and clodronic acid [clodronate; dichloromethyl bisphosphonate (Cl2MDP)]¿ appear to be more efficacious in terms of their calcium-lowering effect than calcitonin, and also appear to be associated with fewer adverse effects than most other agents. However, the importance of energetic re-expansion of the extracellular space with 0.9% sodium chloride before bisphosphonate therapy is extremely important. Cancer-associated hypercalcaemia, especially with squamous cancer, is often associated with the production of parathyroid hormone-related protein (PTHrP). Where this is the case, it usually reflects the presence of more advanced disease with shortened life expectancy, and poorer response to calcium-lowering therapy. Multiple treatments with larger doses of bisphosphonate may be required for these patients.

Neutrophil bactericidal function in diabetes mellitus: evidence for association with blood glucose control

Neutrophil bactericidal activity was assessed in patients with type 1 (n = 45) and Type 2 diabetes mellitus (n = 68) and non-diabetic control subjects (n = 40) by measurement of whole blood chemiluminescence. Though chemiluminescence values tended to be highest in the non-diabetic subjects these differences were not statistically significant (mean +/- SD) (2.73 +/- 1.65 mV (controls), 2.33 +/- 1.41 mV (Type 1 diabetes) and 2.38 +/- 1.12 mv (Type 2 diabetes), F = 1.12, p = 0.33). Significant negative correlations were evident, however, in patients with both Type 1 and Type 2 diabetes between chemiluminescence and glycated haemoglobin (rs = -0.35, p = 0.005 (Type 1), rs = -0.45, p = 0.002 (Type 2), fructosamine (rs = -0.36, p = 0.003 (Type 1), r = -0.42, p = 0.004 (Type 2)), and random blood glucose (rs 0 -0.25, p = 0.04 (Type 1), rs = -0.48, p = 0.001 (Type 2)). Changes in whole blood chemiluminescence in a further group of 10 patients with Type 2 diabetes mellitus commenced on insulin therapy were followed for 21 days. Serum fructosamine concentrations fell significantly over this time (524 +/- 58 mumol l-1 to 405 +/- 47 mumol l-1, p < 0.001), however, although chemiluminescence values tended to rise these changes were not statistically significant (1.01 +/- 0.38 mV to 1.60 +/- 0.91 mV, S = 4.24, df = 5, p = 0.52). These results suggested that impaired neutrophil bactericidal function is associated with poor blood glucose control. While it is likely that neutrophil bactericidal function will improve as blood glucose control improves, further studies are required both to confirm this and to demonstrate a reduction in the incidence of clinical bacterial infection.

Changes in calciotrophic hormones and biochemical markers of bone turnover in normal human pregnancy

Plasma concentrations of parathyroid hormone-related protein (PTHrP), parathyroid hormone, alkaline phosphatase, osteocalcin and albumin-adjusted calcium were measured along with nephrogenous cyclic adenosine monophosphate (NcAMP) in 10 normal women longitudinally through pregnancy. In addition, an assessment of bone resorption was made in these same subjects by the measurement in true fasting urine specimens of the calcium/creatinine ratio (Ca/Cr), hydroxyproline/creatinine ratio (HP/Cr), pyridinoline/creatinine ratio (Pyr/Cr) and deoxypyridinoline/creatine ratio (Dpyr/Cr). The PTHrP level rose through pregnancy from (mean +/- SEM) 0.8 +/- 0.2 pmol/l in the first trimester to 2.7 +/- 0.2 pmol/l 6 weeks postpartum (p < 0.0001). Serum alkaline phosphatase rose from 94 +/- 8 U/l (first trimester) to 347 +/- 25 U/l at term (p < 0.0001). A significant positive correlation was evident between PTHrP and alkaline phosphatase up to term (r = 0.44, p < 0.005). Parathyroid hormone concentrations remained unchanged during pregnancy but rose significantly postpartum from 1.8 +/- 0.2 pmol/l (first trimester) to 3.1 +/- 0.5 pmol/l (p < 0.0001). Similarly, osteocalcin, a marker of bone formative activity, remained unchanged through pregnancy but rose significantly at 6 weeks after delivery to 0.38 +/- 0.05 nmol/l from 0.19 +/- 0.03 nmol/l (first trimester) (p = 0.019). No significant change was noted in serum-adjusted calcium or NcAMP, either through pregnancy or at the postpartum assessment. Fasting urinary Ca/Cr fell through pregnancy from 0.70 +/- 0.11 (first trimester) to a nadir of 0.19 +/- 0.04 6 weeks postpartum (p = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokine and growth factor expression in Paget's disease: analysis by reverse-transcription/polymerase chain reaction

We investigated expression of several cytokines and growth factors in explants of Pagetic and non-Pagetic bone samples using the technique of reverse-transcription/polymerase chain reaction (RT/PCR). Transcripts for IL-1 alpha and IL-1 beta, TNF-alpha, TNF-beta, IL-6, basic fibroblast growth factor (bFGF), transforming growth factor beta (TGF-beta) and insulin-like growth factor-I (IGF-I) were found to a variable degree in both Pagetic and non-Pagetic bone samples, but there was no significant difference in the patterns of expression for these factors in Pagetic bone (n = 18) as compared with non-Pagetic bone (n = 51). There was furthermore, no significant difference in the patterns of expression for the various factors studied when patients were subdivided into mild and severe categories of disease activity using markers of bone formation (serum alkaline phosphatase) or bone resorption (osteoclast counts on adjacent biopsy specimens). Although IL-6 and IL-1 have previously been implicated as bone resorbing factors in Pagetic bone, 40% of our patients with severe disease had not detectable IL-6 transcripts, 70% had no detectable IL-1 alpha transcripts and 50% no IL-1 beta transcripts. We conclude that patterns of expression for cytokine and growth factor mRNAs are not disturbed in Paget's disease. Although we cannot exclude the possibility that post-transcriptional processing of the mRNAs may differ in Pagetic and normal bone cells, our data raise the possibility that the abnormalities of bone turnover which are characteristic of active Paget's disease may be due to local elaboration of other, possibly novel osteotropic factors, which stimulate bone formation and resorption.

Association of severe haemophilia A with osteoporosis: a densitometric and biochemical study

Following a femoral neck fracture and vertebral compression fractures in two patients with severe haemophilia A, bone density and turnover were measured in 19 males with severe haemophilia A (all HIV negative, 18/19 hepatitis C antibody positive) and in 19 age/sex matched controls. Bone density at the lumbar spine (L2-4), measured by dual energy X-ray absorptiometry, was significantly lower in the haemophiliac patients (HPs) at (mean +/- SEM) 1.109 +/- 0.042 g/cm2 vs. 1.234 +/- 0.027 in controls; p = 0.018. Femoral neck density was also lower at 0.877 +/- 0.034 g/cm2 (HPs) vs. 1.067 +/- 0.032; p < 0.0005. No significant differences were evident between the groups for serum calcium, parathyroid hormone, luteinizing hormone, follicle-stimulating hormone or 1,25 dihydroxyvitamin D3, nor for fasting urinary hydroxyproline, pyridinoline or deoxypyridinoline excretion. Serum total alkaline phosphatases was elevated in HPs at 200 +/- 10 U/l vs. 158 +/- 8; p = 0.004. Similarly, gamma-glutamyl transferase was elevated at 42 +/- 7 U/l (HPs) vs. 20 +/- 2; p = 0.007. Serum total testosterone and sex-hormone-binding globulin (SHBG) were higher in HPs at 26 +/- 2.5 nmol/l vs. 17.4 +/- 1.6 (p = 0.009) and 56 +/- 6 nmol/l vs. 27 +/- 3 (p = 0.0005), respectively. Free androgen index, however, was lower in HPs at 44 +/- 5 vs 69 +/- 7; p = 0.008. These results suggest significant osteopenia associated with haemophilia A. This may be partly due to liver dysfunction in HPs, but other factors, e.g. relative immobilization, may also be relevant.

Acute effects of intravenous 1 alpha-hydroxycholecalciferol on parathyroid hormone, osteocalcin and calcitriol in man

The acute effects of a single intravenous injection of 2 micrograms of 1 alpha-hydroxycholecalciferol (alfacalcidol) were studied for a 24-h period in six normal males (mean age 33 years), six women with primary hyperparathyroidism (mean age 72 years) and six women with established osteoporosis (mean age 63 years). In all three groups, serum calcitriol levels rose to a peak 2-3 h after administration of alfacalcidol. Basal levels were highest in the primary hyperparathyroidism group at (mean +/- SEM) 81 +/- 2 vs 62 +/- 12 (normal males) (p < 0.05) and 56 +/- 5 pmol/l (osteoporosis) (p < 0.01). Highest peak levels were found also in the primary hyperparathyroidism group at 150 +/- 15 vs 114 +/- 15 (normal males) (p < 0.05) and 127 +/- 15 pmol/l (osteoporosis) (p < 0.01). The rise in calcitriol was higher in the primary hyperparathyroidism group than either the normal males or osteoporotic patients (p < 0.05). No significant differences were evident in basal serum calcidiol concentrations among the three treatment groups. As might be expected, highest basal concentrations of parathyroid hormone (PTH), serum calcium and serum osteocalcin were noted in the primary hyperparathyroid group (PTH: 17.1 +/- 7.7 vs 1.9 +/- 0.5 (normal males) (p < 0.01) and 2.1 +/- 0.3 pmol/l (osteoporosis) (p < 0.01); calcium: 3.06 +/- 0.08 vs 2.50 +/- 0.02 (normal males) (p < 0.01) and 2.43 +/- 0.02 mmol/l (osteoporosis) (p < 0.01); osteocalcin: 1.10 +/- 0.08 vs 0.56 +/- 0.16 (normal males) (p < 0.05) and 0.53 +/- 0.21 nmol/l (osteoporosis) (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Mineralisation defects with pamidronate therapy for Paget's disease

Bone biopsy samples were taken from 20 patients with Paget's disease before and after intravenous pamidronate therapy. In 10 patients given 180 or 360 mg during 6 or 9 weeks, bone turnover decreased as measured biochemically and histologically, but osteomalacia developed in 1 patient and mineralisation defects in 3. 10 other patients received 45 mg every 3 months for 1 year. Bone turnover decreased biochemically but not histologically, and osteoid thickness increased, suggesting impaired mineralisation. Despite overall efficacy, pamidronate has a narrow therapeutic range between resorption inhibition and mineralisation defects. Short courses given to achieve biochemical remission should be administered with caution.

Central nervous system histiocytosis X--imaging and responses to chemotherapy

Histiocytosis X is the term first coined by Lichtenstein in 1953 to describe a heterogeneous group of disorders which is considered now to include Hand-Schuller-Christian disease, Letterer-Siwe disease and Eosinophilic Granuloma of bone. Gagel, in 1941, first described involvement of the central nervous system (CNS) in Histiocytosis X--in this case the hypothalamus and posterior pituitary were the areas principally affected. CNS involvement outwith these areas is rare, generally difficult to diagnose, and little information on treatment is available. In this case we describe a man with cranial histiocytosis X who was treated with intrathecal and systemic chemotherapy and cranial irradiation, and we comment upon the value of magnetic resonance imaging (MRI) in this condition.

Paget's disease of bone

In this review, recent studies on the etiology and pathogenesis of Paget's disease, with particular attention to the apparent familial clustering of cases and the possibility of a causal role for viral infection, are discussed. The role of biochemical markers of bone turnover is explored, as well as the value of imaging in confirming the diagnosis, monitoring the effects of therapy, and assessing complications. The bisphosphonates are widely used in the treatment of Paget's disease; experience with newer, more potent second- and third-generation bisphosphonates, as well as potential future roles for calcitonin, are described. Studies on some of the orthopedic effects of Paget's disease are also presented.

A comparison of 10 MHz ultrasound and 201-thallium/99m-technetium subtraction scanning in primary hyperparathyroidism

Both high resolution (10 MHz) ultrasound and 201-thallium/99m-technetium subtraction scanning (Tl/Tc) were carried out preoperatively in 25 patients with primary hyperparathyroidism. Operative findings were the standard against which these two imaging methodologies were compared. Tl/Tc scanning showed a sensitivity of 42% and a specificity of 97%. By comparison, sensitivity of ultrasound was 38% and specificity 89%. Both techniques were positive together in nine instances and correctly localized the parathyroid adenoma in eight of these. In 44% of cases, however, both methods together failed to localize any abnormal parathyroid tissue. The ability of these modalities to localize abnormal parathyroid tissue correctly tended to vary with gland size. Where both ultrasound and Tl/Tc scans were negative, median gland size was smaller at 170 mg (range 50-2,500 mg), compared with where Tl/Tc scanning was correct (750 mg, 150-6,820 mg; P < 0.03), ultrasound was correct (960 mg, 100-6,820 mg; P < 0.03) and both techniques together were correct (980 mg, 600-6,820 mg; P = 0.002). These results suggest that neither Tl/Tc scanning or ultrasound has sufficient sensitivity or specificity to be used routinely in the preoperative evaluation of patients with primary hyperparathyroidism.

Coincidental occurrence of primary hyperparathyroidism and cancer-associated hypercalcaemia in a middle-aged man

Primary hyperparathyroidism (PHPT) is found not uncommonly in patients with cancer. In this report, however, we describe a patient where both humoral hypercalcaemia of malignancy and PHPT were present coincidentally. A 47-year-old man was found to have PHPT due to parathyroid hyperplasia. Serum parathyroid hormone (PTH) levels, which were elevated before parathyroidectomy, were undetectable post-operatively; however, hypercalcaemia persisted. Nephrogenous cyclic adenosine monophosphate was elevated along with this undetectable PTH, indicative of the presence of a PTH-like factor in the serum. This was confirmed by the finding of an elevated level of PTH-related protein (PTHrP) in plasma (9.1 pmol/l, normal < 2.6 pmol/l). Secondary carcinoma was identified in a lesion in the region of the manubrium sternii. This stained positively for PTHrP by immunocytochemistry and PTHrP messenger RNA was detected by in-situ hybridization. This case illustrates the value of sensitive PTH assays in distinguishing PHPT from other causes of hypercalcaemia and also shows the importance of considering primary hyperparathyroidism in the differential diagnosis of the patient with cancer and hypercalcaemia.

Clinical and laboratory studies of a new immunoradiometric assay of parathyroid hormone-related protein

Parathyroid hormone-related protein (PTHrP) was measured in plasma by a new immunoradiometric assay (IRMA) from Nichols Institute. The assay is specific for PTHrP and shows excellent parallelism when measuring keratinocyte fluid, samples with high PTHrP content, and PTHrP-supplemented plasma. A precision profile established the assay detection limit at 0.7 pmol/L. PTHrP was unstable in plasma, but the degradation rate was patient-specific. Because delay in separation resulted in loss of PTHrP immunoreactivity, samples were collected into tubes containing protease inhibitors (aprotinin, leupeptin, pepstatin, and EDTA) and separated within 30 min. Among normal subjects, 78% had PTHrP values greater than the detection limit; the reference range established was < 0.7-2.6 pmol/L. Of patients with hypercalcemia associated with malignancy, 46% had PTHrP > 2.6 pmol/L. PTHrP was increased in patients with breast (73%), genitourinary (64%), or lung (46%) malignancy but was rarely above normal in patients with hematological (29%) or gastrointestinal (33%) malignancy. PTHrP and nephrogenous cyclic adenosine monophosphate (NcAMP) were strongly correlated (r = 0.63, P < 0.01) in 37 patients with PTHrP values greater than the detection limit, but 8 patients had PTHrP and parathyroid hormone [PTH(1-84)] values below the limit of detection with inappropriate or increased NcAMP. Five of these eight patients had small cell carcinoma of lung. These patients may have secreted a factor that is not detected by the IRMAs of PTHrP or PTH used in this study but that produces hypercalcemia by means of cAMP-mediated mechanisms.

An evaluation of bone density and turnover in premenopausal women with type 1 diabetes mellitus

Measurement of bone density and turnover was assessed in 20 premenopausal females with Type 1 diabetes mellitus and 27 age-sex-matched controls. Measurement was made of spinal (L2-4) and neck of femur bone density by dual-energy X-ray absorptiometry. L2-4 density was significantly higher in the diabetic patients compared with controls (1.224 +/- 0.021 g cm-2 vs. 1.161 +/- 0.020 g cm-2: p = 0.016). No significant difference was noted between the groups in neck of femur density. Measurement of bone formation was assessed by serum alkaline phosphatase and bone resorption by fasting urinary hydroxyproline/creatinine ratio. Alkaline phosphatase was significantly higher in the diabetic patients (185 +/- 16 Ul-1 vs 135 +/- 10 Ul-1: p < 0.01) as was hydroxyproline/creatinine ratio (0.028 +/- 0.003 vs 0.017 +/- 0.002: p = 0.002). No significant correlation was found between L2-4 density and glycated haemoglobin, duration of diabetes or daily dose of insulin taken. These data suggest that osteopenia is not associated with Type 1 diabetes mellitus; however these patients do have evidence of increased bone turnover and may therefore be at risk of osteoporosis in later life, particularly after the menopause.

Clinical and laboratory studies of a new immunoradiometric assay of parathyroid hormone-related protein

Parathyroid hormone-related protein (PTHrP) was measured in plasma by a new immunoradiometric assay (IRMA) from Nichols Institute. The assay is specific for PTHrP and shows excellent parallelism when measuring keratinocyte fluid, samples with high PTHrP content, and PTHrP-supplemented plasma. A precision profile established the assay detection limit at 0.7 pmol/L. PTHrP was unstable in plasma, but the degradation rate was patient-specific. Because delay in separation resulted in loss of PTHrP immunoreactivity, samples were collected into tubes containing protease inhibitors (aprotinin, leupeptin, pepstatin, and EDTA) and separated within 30 min. Among normal subjects, 78% had PTHrP values greater than the detection limit; the reference range established was &lt; 0.7-2.6 pmol/L. Of patients with hypercalcemia associated with malignancy, 46% had PTHrP &gt; 2.6 pmol/L. PTHrP was increased in patients with breast (73%), genitourinary (64%), or lung (46%) malignancy but was rarely above normal in patients with hematological (29%) or gastrointestinal (33%) malignancy. PTHrP and nephrogenous cyclic adenosine monophosphate (NcAMP) were strongly correlated (r = 0.63, P &lt; 0.01) in 37 patients with PTHrP values greater than the detection limit, but 8 patients had PTHrP and parathyroid hormone [PTH(1-84)] values below the limit of detection with inappropriate or increased NcAMP. Five of these eight patients had small cell carcinoma of lung. These patients may have secreted a factor that is not detected by the IRMAs of PTHrP or PTH used in this study but that produces hypercalcemia by means of cAMP-mediated mechanisms.

Factors predicting the acute effect of pamidronate on serum calcium in hypercalcemia of malignancy

In this study we retrospectively reviewed results of the first 9 days of treatment with pamidronate at doses of 30 mg (n = 13), 45 mg (n = 9), and 90 mg (n = 13) in an attempt to see what factors influenced the response of serum calcium to pamidronate. The nadir of serum calcium obtained post treatment was correlated with pretreatment levels of nephrogenous cyclic adenosine monophosphate (NcAMP), the renal tubular threshold for phosphate reabsorption (TmPO4), and the renal tubular threshold for calcium reabsorption (TmCa). Using the post treatment serum calcium levels, patients were divided into "good" and "poor" responders depending on whether a normal serum calcium was obtained. Pretreatment NcAMP was significantly correlated with the magnitude of the response of serum calcium (r = 0.45, P = 0.0001). Pretreatment NcAMP was significantly higher in the poor responders (mean +/- SEM): 65.0 +/- 9.4 nmol/liter GF (poor responders) versus 29.6 +/- 6.3 (good responders), P = 0.004. NcAMP as a predictor of the acute response of serum calcium showed a sensitivity of 93% and a specificity of 72%. Pretreatment TmPO4 was negatively correlated with the serum calcium response post treatment (r = -0.41, P = 0.003). However, though TmPO4 tended to be lower in the poor responders, this was not statistically significant [0.65 mmol/liter GF +/- 0.09 (poor responders) versus 0.76 mmol/liter GF +/- 0.06 (good responders)]. As a predictor of the acute response of serum calcium, TmPO4 was less good with a sensitivity of 70% and specificity of 58%. No significant correlation was present between TmCa and the serum calcium response.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous pamidronate in the treatment of osteoporosis associated with corticosteroid dependent lung disease: an open pilot study

BACKGROUND

Bisphosphonates have been shown to be effective agents in the treatment of postmenopausal osteoporosis. Because corticosteroid associated osteoporosis is often associated with increased bone turnover, the effect of intermittent intravenous infusions of pamidronate on this condition has been investigated.

METHODS

Seventeen patients (five male) with chronic corticosteroid dependent lung disease (15 asthma, two sarcoidosis) were treated with infusions of 30 mg pamidronate once every three months for one year. These patients had been taking an average of 14 (range 7.5-40) mg prednisolone a day for an average of 14 (range 3-30) years. Bone density measurements, by dual energy x ray absorptiometry, and radiography of the dorsolumbar spine were carried out before and one year after treatment. Bone formation was assessed by measurement of serum alkaline phosphatase and bone resorption by measurement of the fasting urinary hydroxyproline: creatinine ratio at the same time as densitometry and radiography were performed.

RESULTS

Pretreatment density of L2-4 and the neck of the femur was significantly lower in these patients compared with a cohort of 100 age and sex matched controls (L2-4 (mean (SEM)): 0.906 (0.050) g/cm2 v 1.142 (0.016) g/cm2; neck of femur: 0.793 (0.030) g/cm2 v 0.936 (0.013)) g/cm2. After treatment there was a significant fall in serum alkaline phosphatase activity from (mean (SEM)) 220 (16) U/1 to 174 (9) U/1 (normal 80-280 U/1) and in the fasting urinary hydroxyproline:creatinine ratio from (mean (SEM) 0.040 (0.006) to 0.024 (0.003) (normal < 0.033). A significant rise was noted in L2-4 density to 0.927 (0.047) g/cm2; mean rise of 3.4%). No change was noted in density of the neck of the femur.

CONCLUSIONS

Intermittent infusions of intravenous pamidronate would seem to be effective in both reducing turnover of bone and increasing bone density in corticosteroid induced osteoporosis associated with chronic lung disease. Longer term controlled studies are indicated.

A comparison of low versus high dose pamidronate in cancer-associated hypercalcaemia

Pamidronate has been demonstrated to be an effective agent in the treatment of cancer-associated hypercalcaemia. The dose regime, however, remains controversial. In this study 16 patients with cancer-associated hypercalcaemia were given 30 mg pamidronate by intravenous infusion and 16 were given 90 mg also by infusion. Groups were well-matched in terms of tumour types, bone metastases, pre-treatment serum calcium and creatinine, fasting urinary calcium/creatinine ratio, nephrogenous cAMP and the renal tubular threshold for phosphate reabsorption (TmPO4). The calcium lowering effect was similar in both treatment groups with nadir at day 6 of mean (+/- SEM) 2.48 mmol/l (+/- 0.06) in the 30 mg group and at day 9 in the 90 mg group of 2.51 mmol/l (+/- 0.03) (P less than 0.01). 10 patients in the 30 mg group and 8 in the 90 mg group were normocalcaemic at this point. Similarly when those patients with more severe hypercalcaemia (greater than 3.30 mmol/l, n = 7 in each group) were analysed separately, no significant difference was evident between the two groups. Urinary calcium/creatinine ratios fell to a nadir at day 6 in both groups of 0.33 (+/- 0.05) (30 mg group) and 0.37 (+/- 0.10) (90 mg group) (P less than 0.01). Follow-up results after the initial 9 days showed the mean time to relapse to be 38 days (range 18-90) in the 30 mg group and 34 days (11-105) in the 90 mg group.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical experience with pamidronate in the treatment of Paget's disease of bone

Bisphosphonates have been shown to be effective in treating the increased bone turnover associated with Paget's disease of bone. In this study two groups of patients were treated with pamidronate by intravenous infusion. In group 1 (n = 15) 30 mg of pamidronate was given once a week for six weeks. A subgroup (group 1A, n = 6) of more severely affected patients (pretreatment serum alkaline phosphatase (ALP) greater than 1000 U/l, normal range 80-280 U/l) received a further 60 mg weekly for three weeks. Group 2 (n = 24) received 45 mg of pamidronate every three months for one year. In both groups the level of ALP in serum samples decreased steadily throughout the year. In group 1 the level decreased to a mean value of 230 U/l (95% confidence interval 188-281) and in group 2 to 297 U/l (227-389). Four of the six patients in group 1A achieved normal ALP, whereas ALP remained at an increased level in all of the 10 patients in group 2 whose pretreatment ALP was greater than 1000 U/l, suggesting that a dose-response effect exists. The lowest hydroxyproline to creatinine ratios (normal ratio less than 0.033) were observed at the end of treatment in group 1, with a mean ratio of 0.022 (range 0.015-0.033) and at three months after the start of treatment in group 2 with a mean ratio of 0.029 (range 0.022-0.037). There was a significant decrease in the turnover of bone, as measured by whole body retention of radiolabelled bisphosphonate, from a mean of 49.3 to 41.0% (p less than 0.01). These data confirm that pamidronate is effective in the management of Paget's disease of bone. For patients with levels of ALP in serum samples of up to four times above the upper limit of the normal reference range, an effective and convenient regimen is 45 mg every three months for one year. For patients with higher levels of ALP higher doses may be more effective.

Failure to detect paramyxovirus sequences in Paget's disease of bone using the polymerase chain reaction

It is widely believed that Paget's disease of bone is due to a "slow virus" infection of osteoclasts with one of the paramyxovirus group. Controversy continues to surround the identity of the virus involved, however, since at different times evidence has been presented implicating measles virus (MV), respiratory syncytial virus (RSV), and canine distemper virus (CDV) as putative infective agents. In this study we used the technique of reverse transcription and polymerase chain reaction (PCR) to screen for paramyxovirus sequences in ribonucleic acid (RNA) extracted from pagetic bone. We were able to detect viral amplification products of the appropriate size in RNA extracted from as few as 50 cells experimentally infected with a wide range of paramyxoviruses, including measles, canine distemper, parainfluenza 3, and respiratory syncytial virus, but we found no evidence of viral products in RNA extracts of affected bone from 10 consecutive patients with Paget's disease. This study fails to support the hypothesis that active infection with one of these or a related paramyxovirus is involved in the pathogenesis of Paget's disease.

Augmentation of parathyroid 201Tl/99Tcm scanning by infusion of trisodium edetate

A significant number of patients with primary hyperparathyroidism have negative preoperative 201Tl/99Tcm subtraction localization scans. In this study an attempt was made to improve scan localization by creating a period of relative hypocalcaemia and increased parathyroid hormone (PTH) secretion before scanning. Six patients with primary hyperparathyroidism were studied (mean serum calcium 2.80 mmol l-1; range 2.70-2.95). All had had a negative standard 201Tl/99Tcm scan carried out within the 6 months prior to this study. Patients were commenced on an intravenous infusion of the calcium chelating agent trisodium edetate at a dose of 24 mg kg-1 h-1 given in 500 ml 0.9% saline over 90 min. Immediately thereafter a 201Tl/99Tcm scan was carried out in the usual way. Three patients showed areas of discordant thallium uptake consistent with the presence of a parathyroid adenoma. Two of these patients had surgery and an adenoma was found at the site corresponding to the scan appearances. It would appear that creating relative hypocalcaemia and increasing PTH secretion may allow increased thallium uptake, possibly secondary to the increased cellular metabolic activity, and thus creating a positive scan.

Pseudogout associated with the use of cyclical etidronate therapy

Recently the use of etidronate in a cyclical fashion has been shown to be of value in the treatment of osteoporosis. Like all bisphosphonates etidronate is structurally similar to pyrophosphate, further it is also known to interfere with phosphate handling by the kidney resulting in elevated plasma phosphate levels. This report describes the case of a patient with established osteoporosis who developed pseudogout associated with cyclical etidronate use. The possible mechanism responsible for this is discussed.

Direct and indirect assessment of the parathyroid hormone response to pamidronate therapy in Paget's disease of bone and hypercalcaemia of malignancy

In patients with either Paget's disease or hypercalcaemia associated with malignancy (HCM) we have assessed the parathyroid response to pamidronate therapy, both by immunoassay of serum intact parathyroid hormone PTH (1-84) and by measurement of indirect parameters of PTH bioactivity, tubular maximum reabsorption of phosphate (TmPO4/GFR) and nephrogenous cyclic AMP (NcAMP). In 12 patients with Paget's disease, therapy with pamidronate produced a small but significant decrease in adjusted serum calcium within the reference interval which was accompanied by a progressive increase in PTH (1-84) secretion and a corresponding fall in TmPO4/GFR and increase in NcAMP. In 12 patients with HCM pretreatment, PTH (1-84) concentrations were suppressed, whilst mean TmPO4/GFR was reduced and NcAMP was increased, compatible in most patients, with parathyroid hormone-related peptide (PTHrP) driven hypercalcaemia. Therapy with pamidronate produced the expected fall in serum calcium but caused an increase in PTH (1-84) secretion in the presence of absolute hypercalcaemia. The initial subnormal TmPO4/GFR decreased further to a nadir on day 5, and there was a corresponding further increase in NcAMP. By day 7, however, when PTH (1-84) concentrations were maximal, there was a significant paradoxical rise in TmPO4/GFR and a corresponding decrease in NcAMP. These data are consistent with a variable trigger point for PTH (1-84) secretion, one consequence of which is a reduction in the risk of hypocalcaemia following pamidronate. The results have major clinical implications for the interpretation of PTH (1-84) measurements in patients who are being treated or about to be treated for bone disease or for hypercalcaemia of malignancy (HCM).(ABSTRACT TRUNCATED AT 250 WORDS)

Serial bone scans in Paget's disease: development of new lesions, natural variation in lesion intensity and nature of changes seen after treatment

Serial radionuclide bone scans (n = 96) of 40 patients with Paget's disease were studied and tracer uptake graded using a four-point subjective scale. In nine patients studied without treatment the serial scan appearance improved in some, remained unchanged in others and deteriorated in yet others. Similarly individual lesions demonstrated increased, decreased or unchanged tracer uptake. One lesion disappeared without treatment but no new lesions developed. After treatment with aminohydroxypropylidene bisphosphonate (APD) or ethanehydroxy bisphosphonate (EHDP) the overall scan appearance improved in the majority of patients treated (n = 34), but individual lesions demonstrated increased (n = 20), unchanged (n = 79) or decreased uptake (n = 86). The mean reduction in tracer was 32% and 20 lesions reverted to normal intensity. The site of the lesion or the initial intensity of tracer uptake did not influence response to therapy. New lesions developed in five patients after therapy. There was variable correspondence between scintigraphic changes and biochemical parameters of response. From our study we conclude that serial bone scans must be used with caution when interpreting the response of Paget's disease to therapy.

Immobilization-related hypercalcaemia--a possible novel mechanism and response to pamidronate

Immobilization-related hypercalcaemia is an uncommon but important condition being associated not infrequently with both urolithiasis and osteoporosis. In this study 5 patients who had been immobilized for a mean of 3 months and had a mean adjusted serum calcium of 3.15 mmol/l were treated with doses of intravenous pamidronate ranging between 10 mg and 45 mg. All patients became normocalcaemic by day 3. Patients 1-3 mobilized shortly after treatment and remained normocalcaemic. In those patients who continued to be immobile hypercalcaemia recurred after an interval of several weeks. Retreatment with pamidronate again resulted in normocalcaemia. No side effects were noted with treatment. All of the patients studied had increased rates of bone resorption as shown by elevated urinary hydroxyproline/creatinine ratios (median:range) of 0.101:0.045-0.180 (normal less than 0.033) and elevated calcium/creatinine ratios of 2.50:0.69-3.63 (normal less than 0.50). None of the patients in this study had any of the usual risk factors for developing immobilization-related hypercalcaemia though all 5 patients had problems with significant sepsis which we postulate may have lead to cytokine release which in turn contributed to the development of hypercalcaemia. We conclude that pamidronate (at doses as low as 10 mg) is safe and effective in immobilization-related hypercalcaemia and suggest that sepsis should be added to the list of risk factors for development of this syndrome.

Breast cancer-associated hypercalcaemia: a reassessment of renal calcium and phosphate handling

The mechanisms of hypercalcaemia were assessed in 20 hypercalcaemic patients with breast cancer. Abnormalities suggestive of a PTH-related peptide (PTHrP) mechanism were observed in up to 60% of cases; urinary cyclic adenosine monophosphate (UcAMP) was elevated in nine patients (45%), renal tubular reabsorption of calcium (RTRCa) was elevated in nine (45%) and the renal tubular threshold for phosphate reabsorption (TmPO4) depressed in 12 (60%). While TmPO4 was lower in patients with high UcAMP, there was no consistent relationship between RTRCa and UcAMP or UcAMP and the extent of bone metastases. In a control group of nine normocalcaemic breast cancer patients, bone resorption as assessed by urinary calcium/creatinine ratio was slightly increased but UcAMP, RTRCa and TmPO4 were generally normal. These observations indicate that a PTHrP-mediated mechanism of hypercalcaemia may be operative in up to 60% of patients with breast cancer, irrespective of the presence or extent of bone metastases.

Cancer-associated hypercalcemia: morbidity and mortality. Clinical experience in 126 treated patients

STUDY OBJECTIVE

To review the effects of antihypercalcemic treatment on morbidity and mortality in cancer-associated hypercalcemia.

DESIGN

Retrospective study of 126 consecutive patients with cancer-associated hypercalcemia.

SETTING

Inpatient referrals from a teaching hospital in the United Kingdom.

INTERVENTION

Medical antihypercalcemic therapy supplemented by specific anticancer therapy where possible.

MEASUREMENTS AND MAIN RESULTS

Median survival was 30 days. Survival did not differ in patients treated with different antihypercalcemic regimens but was longer (median, 135 days; P less than 0.001) in a subgroup of 26 patients for whom specific anticancer therapy was available. Polyuria and polydipsia improved after therapy in 83% of cases, central nervous system symptoms in 71%, constipation in 70%, nausea and vomiting in 56%, anorexia in 50%, and malaise and fatigue in 47% (all significant, P less than 0.001, pre-treatment compared with post-treatment). Pain control improved in only 23% of cases (not significant). Only 7% of patients with post-treatment serum calcium values above 3.50 mmol/L improved clinically compared with 80% whose calcium values fell below 2.80 mmol/L (P less than 0.001). Corresponding figures for the proportion of patients discharged from the hospital were 0% and 68% (P less than 0.001).

CONCLUSIONS

Life expectancy is poor in cancer-associated hypercalcemia even in patients who are actively treated. Antihypercalcemic therapy has an important palliative role, however, because symptoms are usually improved and, in many cases, patients may be made well enough to be discharged from the hospital during the terminal stages of their illness.

The loss of circadian rhythm for intact parathyroid hormone and nephrogenous cyclic AMP in patients with primary hyperparathyroidism

The measurement of serum intact parathyroid hormone (PTH) (1-84) over a 24-h period has shown the existence of a circadian rhythm in normal males which is absent in patients with primary hyperparathyroidism. The physiological significance of this observation is reflected in the presence of parallel changes in nephrogenous cyclic adenosine monophosphate (N-cAMP) in normals which are also absent in primary hyperparathyroidism. Serum calcium, adjusted for variations in albumin concentrations, showed a transient fall in normal subjects prior to the nocturnal rise in PTH (1-84). A similar transient fall in serum adjusted calcium was observed in the hyperparathyroid patients. Serum phosphate showed a circadian rhythm in normal subjects, and an attenuated rhythm persisted in primary hyperparathyroidism. These data suggest that both ionic factors and higher centres play important roles in the fine control of PTH (1-84) secretion.

Comparison of three intravenous bisphosphonates in cancer-associated hypercalcaemia

Three intravenous bisphosphonates were compared in the treatment of cancer-associated hypercalcaemia. 48 patients were randomly allocated to one of three treatment groups (each with 16 subjects)--30 mg pamidronate or 600 mg clodronate, both as single intravenous infusions; or etidronate as three infusions of 7.5 mg/kg per day for three consecutive days. Patients were rehydrated with normal saline before bisphosphonate treatment. All three bisphosphonates lowered serum calcium by inhibiting bone resorption; pamidronate was the most potent in this respect. By comparison with the other groups, more patients in the pamidronate group became normocalcaemic, and the effect on serum calcium was apparent sooner and lasted longer.

The hyperthyroidism of polyostotic fibrous dysplasia--a possible autoimmune aetiology

Endocrine disorders are a relatively common accompaniment of polyostotic fibrous dysplasia. Considerable debate has taken place concerning possible responsible mechanisms. This case demonstrates that the hyperthyroidism associated with the condition is of thyroidal origin and of probable autoimmune aetiology.

Clinical experience with aminohydroxypropylidene bisphosphonate (APD) in the management of cancer-associated hypercalcaemia

Fifty-five patients with symptoms caused by hypercalcaemia associated with cancer were treated with varying regimens of intravenously-administered aminohydroxypropylidene bisphosphonate after initial rehydration. Of 48 patients where adequate data were available, 32 (66 per cent) were rendered normocalcaemic and 16 (33 per cent) remained mildly hypercalcaemic. In these cases, failure to restore normocalcaemia was attributable to elevated renal tubular reabsorption of calcium in nine (18 per cent) and to inadequate suppression of bone resorption in seven (14 per cent). There was no significant difference in response and duration of effect (median 20 days) between single doses of 15, 25 and 45 mg, or when the 45 mg dose was administered over three, six or 24 h. These single dose regimens were similar in terms of effect on calcium levels and duration of action, to multiple daily doses of 15 mg for a mean of six days. While the effect of 5 mg dose was not significantly different from the higher doses, suppression of serum calcium levels was less marked and the effect on duration of action significantly shorter than with the 45 mg dose. In seven cases, treatment with a second course was less effective even with higher doses because suppression of bone resorption was poorer. These data indicate that there is little difference between the therapeutic effects of multiple 15 mg and single 15-45 mg intravenous infusions of aminohydroxypropylidene bisphosphonate in hypercalcaemia associated with cancer. A single intravenous infusion of a moderate dose (for example 15-30 mg) would be a convenient and effective way of treating most patients.