Non-familial primary hyperparathyroidism

Is plasma calcium concentration implicated in the development of critical illness polyneuropathy and myopathy?

Introduction

This prospective study investigated whether plasma ionized calcium concentration abnormalities and other electrolyte disturbances represent risk factors for the development of critical illness polyneuromyopathy (CIPNM) in ICU patients.

Methods

One hundred and ninety consecutive adult critically ill patients with prolonged ICU stay (longer than 7 days) were prospectively evaluated. Patients with acute weakness and/or weaning difficulties were subjected to extensive electrophysiological measurements in order to establish the diagnosis of CIPNM. All recognized and/or possible risk factors for development of CIPNM were recorded.

Results

The diagnosis of CIPNM was confirmed in 40 patients (21.05%). By applying a logistic regression model, hypocalcemia (P = 0.02), hypercalcemia (P = 0.01) and septic shock (P = 0.04) were independently associated with the development of CIPNM in critically ill patients.

Conclusions

We found that septic shock and abnormal fluctuations of plasma Ca²⁺ concentration represent significant risk factors for the development of CIPNM in critically ill patients.

Indian primary hyperparathyroidism patients with parathyroid carcinoma do not differ in clinicoinvestigative characteristics from those with benign parathyroid pathology

INTRODUCTION

No foolproof preoperative diagnostic indicators of parathyroid carcinoma (PC) exist in absence of nonskeletal metastases. Palpable parathyroid tumor, advanced skeletal and renal manifestations, and very high serum calcium and parathyroid hormone levels are considered strong predictors. Most of these features are common in Indian primary hyperparathyroidism (PHPT) patients although only few have PC. The aim of this study was to identify dependable clinicoinvestigative predictors of PC in Indian PHPT patients.

MATERIALS AND METHODS

Clinical, biochemical, radiological, and densitometric attributes of 100 PHPT patients who underwent successful parathyroidectomy (1990-2004) were studied. Various parameters of patient groups with parathyroid adenoma (n = 84), primary hyperplasia (n = 12), and carcinoma (n = 4) were compared using ANOVA, with P value < 0.05 considered significant.

RESULTS

Mean age of patients was 37.4 years, with no difference in the 3 groups (P = 0.92). Patients in 3 groups had comparably severe bone disease; 36 had coexistent renal disease. Two patients with PC and 27 (32%) with adenoma had palpable parathyroid tumor. None of the biochemical parameters predicted malignant pathology. Mean tumor weight (milligram) in carcinoma patients (15,080 +/- 5,638.02) was significantly higher than those with adenoma (5,724 +/- 1,257.9) (P = 0.002). Postoperative course and recovery in carcinoma patients were similar to those with adenoma. In follow-up (mean: 33 months), none of the adenoma patients were found to have persistent/recurrent PHPT attributable to missed PC.

CONCLUSION

Indian patients with parathyroid adenoma, hyperplasia, and carcinoma were not found to differ in their clinical, biochemical, and pathological characteristics except for significantly higher tumor weight in the carcinoma group.

Parathyroid glands in calcium regulation and human disease

In humans and other land-living vertebrates, the parathyroids are known to have an overall regulatory role with action as a thermostat in the systemic calcium homeostasis to ensure tight regulation of serum calcium concentrations and appropriate skeletal mineralization. Parathyroid hormone (PTH) is an 84-amino-acid peptide, synthesized and released by parathyroid chief cells in response to hypocalcemia. PTH mobilizes calcium by increasing calcium resorption from bone and by raising calcium reabsorption in the proximal kidney tubule. Treatment with active vitamin D can increase vitamin D receptor expression, inhibit growth of parathyroid tumors, and reduce PTH levels in patients with hyperparathyroidism (HPT). Newly developed vitamin D analogues with reduced calcemic effects and with more pronounced antiproliferative effect may provide new favorable treatment for reversal of HPT.

Risk of renal stone events in primary hyperparathyroidism before and after parathyroid surgery: controlled retrospective follow up study

AIM

To study the risk of renal stone episodes and risk factors for renal stones in primary hyperparathyroidism before and after surgery.

DESIGN

Register based, controlled retrospective follow up study.

SETTING

Tertiary hospitals in Denmark.

PARTICIPANTS

674 consecutive patients with surgically verified primary hyperparathyroidism. Each patient was compared with three age- and sex-matched controls randomly drawn from the background population. Hospital admissions for renal stone disease were compared between patients and controls. Risk factors for renal stones among patients were assessed.

MAIN OUTCOME MEASURES

Number of renal stone episodes; comparison of hospital admissions for renal stones in patients and controls; assessment of risk factors for renal stones.

RESULTS

Relative risk of a stone episode was 40 (95% confidence interval 31 to 53) before surgery and 16 (12 to 23) after surgery. Risk was increased 10 years before surgery, and became normal more than 10 years after surgery. Stone-free survival 20 years after surgery was 90.4% in patients and 98.7% in controls (risk difference 8.3%, 4.8% to 11.7%). Patients with preoperative stones had 27 times the risk of postoperative stone incidents than controls. Before surgery, males had more stone episodes than females and younger patients had more stone episodes than older patients. Neither parathyroid pathology, weight of removed tissue, plasma calcium levels, nor skeletal pathology (fractures) influenced the risk of renal stones. After surgery, younger age, preoperative stones and ureteral strictures were significant risk factors for stones.

CONCLUSIONS

The risk of renal stones is increased in primary hyperparathyroidism and decreases after surgery. The risk profile is normal 10 years after surgery. Preoperative stone events increase the risk of postoperative stones. Stone formers and non-stone formers had the same risk of skeletal complications.