Asymptomatic hyperparathyroidism--need for multicentre studies

Preoperative and Intraoperative Methods of Parathyroid Gland Localization and the Diagnosis of Parathyroid Adenomas

Accurate pre-operative determination of parathyroid glands localization is critical in the selection of minimally invasive parathyroidectomy as a surgical treatment approach in patients with primary hyperparathyroidism (PHPT). Its importance cannot be overemphasized as it helps to minimize the harmful side effects associated with damage to the parathyroid glands such as in hypocalcemia, severe hemorrhage or recurrent laryngeal nerve dysfunction. Preoperative and intraoperative methods decrease the incidence of mistakenly injuring the parathyroid glands and allow for the timely diagnosis of various abnormalities, including parathyroid adenomas. This article reviews 139 studies conducted between 1970 and 2020 (49 years). Studies that were reviewed focused on several techniques including application of carbon nanoparticles, carbon nanoparticles with technetium sestamibi (99m Tc-MIBI), Raman spectroscopy, near-infrared autofluorescence, dynamic optical contrast imaging, laser speckle contrast imaging, shear wave elastography, and indocyanine green to test their potential in providing proper parathyroid glands' localization. Apart from reviewing the aforementioned techniques, this study focused on the applications that helped in the detection of parathyroid adenomas. Results suggest that applying all the reviewed techniques significantly improves the possibility of providing proper localization of parathyroid glands, and the application of indocyanine green has proven to be the 'ideal' approach for the diagnosis of parathyroid adenomas.

Efficacy of Scintigraphy, Ultrasound and Both Scintigraphy and Ultrasonography in Preoperative Detection and Localization of Primary Hyperparathyroidism

Objective: The aim of our study was to evaluate the efficacy of preoperative dual-phase 99mTc-methoxyisobutylnitrile (MIBI) parathyroid scintigraphy (PS), and ultrasound (US) in primary hyperparathyroidism (pHPT) diagnosis and compare the results with the surgical findings.

Methods: Forty-five patients were enrolled in this study. Preoperative serum parathyroid hormone (PTH) levels, calcium (Ca), phosphate (P), and alkaline phosphatase (AP) levels were measured. All parathyroid patients were evaluated by ultrasonography, dual phase 99mTc-MIBI. Surgical findings were used as a reference standard.

Results: Of the 45 patients included in this study, 30 were females (66.7%) with an age range between 30 years and 70 years (mean age 41± 13). The sensitivity and specificity of 99mTc-MIBI scintigraphy was 97.4% and 71.4%, respectively, while the sensitivity of ultrasound was 94.4% and specificity 44.4%. The sensitivity, specificity, and accuracy of combined scintigraphy and ultrasound was higher-97.4%, 83.3%, and 95.6%, respectively.

Conclusions: The combination of MIBI and US appears promising for localizing parathyroid pathology in patients with primary hyperparathyroidism. The concordance rate is high together with a lower chance of missing concomitant thyroid pathology, which might alter the surgical approach.

Clinical presentation and management of patients with primary hyperparathyroidism in Italy

PURPOSE

Evaluation of the phenotype of primary hyperparathyroidism (PHPT), adherence to International Guidelines for parathyroidectomy (PTx), and rate of surgical cure.

METHOD

From January 2014-January 2016, we performed a prospective, multicenter study in patients with newly diagnosed PHPT. Biochemical and instrumental data were collected at baseline and during 1-year follow-up.

RESULTS

Over the first year we enrolled 604 patients (age 61 ± 14 years), mostly women (83%), referred for further evaluation and treatment advice. Five hundred sixty-six patients had sporadic PHPT (93.7%, age 63 ± 13  years), the remaining 38 (6.3%, age 41 ± 17  years) had familial PHPT. The majority of patients (59%) were asymptomatic. Surgery was advised in 281 (46.5%). Follow-up data were available in 345 patients. Eighty-seven of 158 (55.1%) symptomatic patients underwent PTx. Sixty-five (53.7%) of 121 asymptomatic patients with at least one criterion for surgery underwent PTx and 56 (46.3%) were followed without surgery. Negative parathyroid imaging studies predicted a conservative approach [symptomatic PHPT: OR 18.0 (95% CI 4.2-81.0) P < 0.001; asymptomatic PHPT: OR 10.8, (95% CI 3.1-37.15) P < 0.001). PTx was also performed in 16 of 66 (25.7%) asymptomatic patients without surgical criteria. Young age, serum calcium concentration, 24 h urinary calcium, positive parathyroid imaging (either ultrasound or MIBI scan positive in 75% vs. 16.7%, P = 0.001) were predictors of parathyroid surgery. Almost all (94%) of patients were cured by PTx.

CONCLUSIONS

Italian endocrinologists do not follow guidelines for the management of PHPT. Negative parathyroid imaging studies are strong predictors of a non-surgical approach. PTx is successful in almost all patients.

Improving diagnostic recognition of primary hyperparathyroidism with machine learning

BACKGROUND

Parathyroidectomy offers the only cure for primary hyperparathyroidism, but today only 50% of primary hyperparathyroidism patients are referred for operation, in large part, because the condition is widely under-recognized. The diagnosis of primary hyperparathyroidism can be especially challenging with mild biochemical indices. Machine learning is a collection of methods in which computers build predictive algorithms based on labeled examples. With the aim of facilitating diagnosis, we tested the ability of machine learning to distinguish primary hyperparathyroidism from normal physiology using clinical and laboratory data.

METHODS

This retrospective cohort study used a labeled training set and 10-fold cross-validation to evaluate accuracy of the algorithm. Measures of accuracy included area under the receiver operating characteristic curve, precision (sensitivity), and positive and negative predictive value. Several different algorithms and ensembles of algorithms were tested using the Weka platform. Among 11,830 patients managed operatively at 3 high-volume endocrine surgery programs from March 2001 to August 2013, 6,777 underwent parathyroidectomy for confirmed primary hyperparathyroidism, and 5,053 control patients without primary hyperparathyroidism underwent thyroidectomy. Test-set accuracies for machine learning models were determined using 10-fold cross-validation. Age, sex, and serum levels of preoperative calcium, phosphate, parathyroid hormone, vitamin D, and creatinine were defined as potential predictors of primary hyperparathyroidism. Mild primary hyperparathyroidism was defined as primary hyperparathyroidism with normal preoperative calcium or parathyroid hormone levels.

RESULTS

After testing a variety of machine learning algorithms, Bayesian network models proved most accurate, classifying correctly 95.2% of all primary hyperparathyroidism patients (area under receiver operating characteristic = 0.989). Omitting parathyroid hormone from the model did not decrease the accuracy significantly (area under receiver operating characteristic = 0.985). In mild disease cases, however, the Bayesian network model classified correctly 71.1% of patients with normal calcium and 92.1% with normal parathyroid hormone levels preoperatively. Bayesian networking and AdaBoost improved the accuracy of all parathyroid hormone patients to 97.2% cases (area under receiver operating characteristic = 0.994), and 91.9% of primary hyperparathyroidism patients with mild disease. This was significantly improved relative to Bayesian networking alone (P < .0001).

CONCLUSION

Machine learning can diagnose accurately primary hyperparathyroidism without human input even in mild disease. Incorporation of this tool into electronic medical record systems may aid in recognition of this under-diagnosed disorder.

Epidemiology of Primary Hyperparathyroidism and its Non-classical Manifestations in the City of Recife, Brazil

Before the introduction of routine measurements of serum calcium in ambulatory services, PHTP (primary hyperparathyroidism) was symptomatic with classic bone disease (known as osteitis fibrosa cystica) nephrolithiasis, and acute neuropsychiatric syndrome with severe hypercalcemia. Currently, PHPT presents few unspecific symptoms. This cross-sectional study was conducted from December 1, 2007, through August 31, 2008 to estimate the prevalence of primary hyperparathyroidism and to describe the clinical and laboratory characteristics of patients receiving ambulatory care. From 4207 patients, we found a prevalence of PHTP of 0.78 (95% confidence interval [CI], 0.52–1.04) of which 81.8% were asymptomatic and 18.2% symptomatic. The female:male ratio was 7.2:1, and 89.7% of the women were postmenopausal. Mean age was 61.12 ± 15.73 years, mean serum calcium was 10.63 ± 1.33 mg/dL, and mean serum parathyroid hormone (PTH) was 182.48 ± 326.51 pg/mL. We found a high prevalence of PHTP at reference centers and a high prevalence of hypertension and type 2 diabetes.

Primary hyperparathyroidism: an overview

Primary hyperparathyroidism is a common condition that affects 0.3% of the general population. Primary and tertiary care specialists can encounter patients with primary hyperparathyroidism, and prompt recognition and treatment can greatly reduce morbidity and mortality from this disease. In this paper we will review the basic physiology of calcium homeostasis and then consider genetic associations as well as common etiologies and presentations of primary hyperparathyroidism. We will consider emerging trends in detection and measurement of parathyroid hormone as well as available imaging modalities for the parathyroid glands. Surgical indications and approach will be reviewed as well as medical management of primary hyperparathyroidism with bisphosphonates and calcimimetics.

What symptom improvement can be expected after operation for primary hyperparathyroidism?

BACKGROUND

The only cure for primary hyperparathyroidism (pHPT) is operative resection of the parathyroid gland(s) responsible for the disease. The 1990 National Institute of Health's (NIH) consensus development conference on asymptomatic pHPT and its subsequent workshop in 2001 established which clinical criteria warranted parathyroidectomy (PTx) versus observation. While there is no debate that these NIH criteria capture a group of patients likely to benefit from PTx, there is concern that these guidelines miss a significant percentage of pHPT patients who actually are symptomatic. Unfortunately, these additional symptoms are often subtle, nonspecific, not traditionally measured, frequently not assessed or considered in this patient population, and are usually attributed to other diagnoses or simply advanced age.

METHODS

An evidence-based literature review was performed assessing symptoms and clinical conditions associated with bone, neuropsychiatry, cognition, quality of life, and the neuromuscular system. The level of evidence and grade of recommendations were assigned to key studies to help determine recommendations regarding indications and potential benefits of parathyroidectomy (PTx).

RESULTS

Symptoms ranging from decreased bone mineral density, increased fracture risk, neuropsychiatric symptoms and cognitive changes, lower quality of life, and neuromuscular symptoms were found to be associated with pHPT. The effects of PTx on these symptoms was addressed in a variety of studies that varied in quality.

CONCLUSION

Although there are few Level I randomized clinical trials addressing the benefit of PTx in patients with pHPT, there are supportive data to suggest that most patients with pHPT would benefit from operative cure.

Persistent symptomatic improvement in the majority of patients undergoing parathyroidectomy for primary hyperparathyroidism

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism (PHPT) is followed by a decrease in the severity of symptoms reported on the Pasieka's parathyroid symptoms score (PPSS) and SF-36 questionnaires. Some argue that such benefits are short-lived. This study investigates the severity of symptoms at more than 12 months after parathyroidectomy.

METHODS

A prospective database collected clinical/operative data on consecutive patients with PHPT. PPSS was calculated as the sum of the 13 parameters self-assessed using a visual analog scale. SF-36(v2) was analyzed using commercially available software (QualityMetric Inc., Lincoln, USA).

RESULTS

Over 3-year interval, 166 patients (119 F/47 M, age 15-89 years) were operated for with PHPT (Ca 2.90 ± 0.25 mmol/L, PTH 21.64 ± 23.05 pmol/L). Their preoperative PPSS ranged 0-1,260 (median 413) and did not correlate with the severity of hypercalcemia. One hundred and seven patients responded when contacted by post at 18 ± 6 months postoperatively. Their postoperative PPSS was significantly lower (398 ± 226 to 231 ± 203, p < 0.001) and in 55 of 107 patients the severity of symptoms reduced by at least 50%. Most significant improvements were for mood (36 ± 33 vs. 16 ± 23), weakness/tiredness (37 ± 32 vs. 17 ± 23), irritability (35 ± 31 vs. 17 ± 21), and thirst (37 ± 32 vs. 18 ± 25; p < 0.0001). Physical and mental component scores of SF-36 questionnaire improved in patients whose PPSS decreased postoperatively.

CONCLUSION

Symptomatic benefits persist for at least 1 year after parathyroidectomy in the majority of patients with PHPT.

Expanding boundaries of endocrinology

There have been huge advances in endocrine care as a consequence of improved biochemistry and diagnostic techniques as well as improved imaging. Specialist transethmoidal endoscopic surgery has improved results in pituitary tumour patients and minimally invasive parathyroid surgery has had the same consequence in patients with parathyroid disease. Multidisciplinary teams have improved outcomes in a number of areas and, as described above, endocrinologists are dealing with more in the way of endocrine disease to expand boundaries. Much work remains to be done particularly concerning the care of children and adults with late endocrine effects of cancer treatment and obesity.

Pasieka's parathyroid symptoms scores correlate with SF-36 scores in patients undergoing surgery for primary hyperparathyroidism

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism (PHPT) is expected to trigger an improvement in the quality of life. This has been demonstrated previously by using the SF-36 questionnaire, whose interpretation is difficult in routine clinical practice. As an alternative, the 13-item questionnaire developed by Pasieka et al. can be used to assess the severity of symptoms on a visual analogue from which a parathyroid assessment of symptoms score (PAS) can be calculated. The purpose of this study was to correlate results of these two assessment tools.

METHODS

Prospective case-series study recruiting consecutive unselected patients who underwent successful parathyroidectomy for PHPT. SF-36(v2) and Pasieka's questionnaires were collected before parathyroidectomy and at 3, 6, and 12 months postoperatively.

RESULTS

Between November 2005 and December 2006, 101 patients were diagnosed with PHPT (30 men; aged 18-89 years). Preoperative PAS ranged 0-1040 and did not correlate with the severity of hypercalcemia (2.91+/-0.25; range, 2.56-3.4 mmol/l). Scores from the SF-36 questionnaire were under the 50th percentile for the normal population in three domains (vitality, emotional role, and physical role). Minimally invasive parathyroidectomy was performed in 69 patients and bilateral cervical exploration in 32 patients. All were found to have a single parathyroid adenoma and were normocalcemic at 3-12 months after parathyroidectomy. At follow-up, there was a significant reduction of PAS from 460+/-257 preoperatively to 254+/-234 at 3 months postoperatively (n=72), to 245+/-215 at 6 months (n=50), and 249+/-212 at 12 months (n=63) (p<0.05, Student's t-test). There was a significant and persistent improvement in five domains of SF-36 questionnaire: bodily pain, general health, vitality, social functioning and mental health. Overall analysis of 244 assessments using both questionnaires demonstrated a negative correlation between increasing PAS and decreasing mental component scores and physical component scores of the SF-36 assessment (r2=0.372 and 0.301, respectively).

CONCLUSIONS

Pasieka's parathyroid assessment of symptom scores (PAS) correlate with SF-36 questionnaire scores. Because PAS allows easier and faster analysis, we advocate that Pasieka's questionnaire should be integrated into the assessment of patients with PHPT as a reliable tool to identify symptomatic changes that correlate with improved quality of life.