Current status and treatment of primary hyperparathyroidism

4D SPECT/CT: A Hybrid Approach to Primary Hyperparathyroidism

Our rationale was to review the imaging options for patients with primary hyperparathyroidism and to advocate for judicious use of 4-dimensional (4D) SPECT/CT to visualize diseased parathyroid glands in patients with complex medical profiles or in whom other imaging modalities fail. We review the advantages and disadvantages of traditional imaging modalities used in preoperative assessment of patients with primary hyperparathyroidism: ultrasound, SPECT, and 4D CT. We describe a scheme for optimizing and individualizing preoperative imaging of patients with hyperfunctioning parathyroid glands using traditional modalities in tandem with 4D SPECT/CT. Using the input from radiologists, endocrinologists, and surgeons, we apply patient criteria such as large body habitus, concomitant multiglandular disease, multinodular thyroid disease, confusing previous imaging, and unsuccessful previous surgery to create an imaging paradigm that uses 4D SPECT/CT yet is cost-effective, accurate, and limits extraneous radiation exposure. 4D SPECT/CT capitalizes on the strengths of SPECT and 4D CT and addresses limitations that exist when these modalities are used in isolation. In select patients with complicated clinical parameters, preoperative imaging with 4D SPECT/CT can improve accuracy yet remain cost-effective.

Role of 18F-Fluorocholine Positron Emission Tomography (PET)/Computed Tomography (CT) in Diagnosis of Elusive Parathyroid Adenoma

Accurate localization of parathyroid adenomas is paramount in hypercalcemia and elevated parathyroid hormone (PTH) levels. This narrative of a 56-year-old female diagnosed with primary hyperparathyroidism underscores the intricacies faced when conventional imaging falls short. Despite a series of diagnostic and surgical endeavors, including an initial nuclear sestamibi scan and diverse imaging examinations like ultrasound, 4D CT, and MRI, it was the 18F-Fluorocholine positron emission tomography (PET)/computed tomography (CT) scan that illuminated the presence of the elusive adenoma in the left para esophageal superior mediastinum. The surgical outcome reinforced the diagnosis, marking the resolution of the adenoma. This case accentuates the necessity of a multifaceted diagnostic methodology, especially in convoluted primary hyperparathyroidism presentations. It highlights the yet-to-be widely adopted 18F-Fluorocholine PET/CT scan, emphasizing its prospective significance awaiting Food and Drug Administration (FDA) endorsement.

Symptomatic versus asymptomatic primary hyperparathyroidism: a systematic review and meta-analysis

Purpose

Primary hyperparathyroidism (PHPT) is the underlying etiology for 90% of patients with hypercalcemia. PHPT patients have traditionally been characterized as being symptomatic or asymptomatic. However, we submit that even "asymptomatic" patients may still have clinical features, posing the idea of coining asymptomatic disease as a misnomer. This paper presents a systematic review and meta-analysis elucidating the differences between asymptomatic and symptomatic PHPT in the literature.

Methods

A comprehensive literature search was conducted in PubMed, Cochrane, and Web of Science databases for articles published from 2012 to 2022. Inclusion criteria consisted of all studies comparing symptomatic and asymptomatic PHPT patients. Two reviewers independently evaluated the literature using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The level of evidence was determined using the Oxford Center for Level of Evidence-Based Medicine. Data were extracted, and a meta-analysis was performed. I² index was employed for heterogeneity.

Results

There were 18 studies included, with a total of 4238 patients. The average age of patients included was 56.37, with 25.7% of the cohort being male. Several studies reported clinical features even for the "asymptomatic" group. Patients in the symptomatic group tended to have higher levels of PTH and calcium. The asymptomatic group had greater levels of vitamin D. There was observed heterogeneity between the studies.

Conclusions

More extreme PTH, calcium values, and low vitamin D levels were seen in patients with symptomatic disease. However, asymptomatic patients occasionally exhibited clinical features. Therefore, the terminology of "asymptomatic" disease is likely inappropriate for these patients.

Preoperative Localization for Primary Hyperparathyroidism: A Clinical Review

With increasing use of minimally invasive parathyroidectomy (PTx) over traditional bilateral neck exploration in patients with primary hyperparathyroidism (PHPT), accurate preoperative localization has become more important to enable a successful surgical outcome. Traditional imaging techniques such as ultrasound (US) and sestamibi scintigraphy (MIBI) and newer techniques such as parathyroid four-dimension computed tomography (4D-CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) are available for the clinician to detect the diseased gland(s) in the preoperative workup. Invasive parathyroid venous sampling may be useful in certain circumstances such as persistent or recurrent PHPT. We review the diagnostic performance of these imaging modalities in preoperative localization and discuss the advantages and weaknesses of these techniques. US and MIBI are established techniques commonly utilized as first-line modalities. 4D-CT has excellent diagnostic performance and is increasingly performed in first-line setting and as an adjunct to US and MIBI. PET and MRI are emerging adjunct modalities when localization has been equivocal or failed. Since no evidence-based guidelines are yet available for the optimal imaging strategy, clinicians should be familiar with the range and advancement of these techniques. Choice of imaging modality should be individualized to the patient with consideration for efficacy, expertise, and availability of such techniques in clinical practice.

Sudden Odynophagia and Globus-A Unique Presentation of a Nonsecreting Parathyroid Adenoma: A Case Report and Literature Review

Parathyroid adenomas are most commonly diagnosed when symptoms consistent with primary hyperparathyroidism arise. However, certain parathyroid glands may enlarge without such symptoms. Described here is a case in which a patient presented with acute signs of unilateral cervical point tenderness, dysphagia, and odynophagia. Calcium and parathyroid hormone levels tested within normal range. Imaging revealed an enlarged right-sided mass, with compression of the trachea-esophageal groove and potentially the right recurrent laryngeal nerve. Surgical excision was performed, and final pathology revealed an infarcted parathyroid adenoma. Clinical symptoms promptly resolved thereafter. Current NIH criteria for parathyroidectomy include various symptoms of hyperparathyroidism but do not include the above findings. Nonsecreting parathyroid adenomas rarely cause laryngeal symptoms, as this has only been documented once before.

Persistence of "non-dipping" pattern in blood pressure after curative parathyroidectomy in apparently normotensive patients with symptomatic primary hyperparathyroidism

BACKGROUND

The prevalence of hypertension in primary hyperparathyroidism (PHPT) varies from 20-80% with data being based on office-based blood pressure measurements. Little is known about ambulatory monitoring of blood pressure (AMBP) in PHPT and changes in blood pressure (BP) variables post-curative parathyroidectomy. Hence, we conducted a prospective study wherein we performed AMBP in apparently normotensive patients with PHPT and reevaluated them 3 months post-curative parathyroidectomy.

METHODS

Consecutive patients with symptomatic PHPT aged 20 years and above underwent 24 hours AMBP at enrollment and at 3 months after successful parathyroidectomy. Pre- and postoperative BP variables were compared and correlated with serum calcium, creatinine and intact parathyroid hormone (iPTH) levels.

RESULTS

After exclusion, 17 symptomatic PHPT patients were enrolled in the study. AMBP detected hypertension in 4 (23.5%) patients. There was a significant reduction in the average nighttime systolic (P=0.007) and diastolic BP (P=0.034) after parathyroidectomy. However, the average 24 hours systolic/diastolic BP, daytime systolic/diastolic BP and average 24 hours mean arterial pressure did not differ before and after surgery. Non-dipping blood pressure pattern was seen in 53% of patients at presentation and persisted in 50% of cases after successful surgery. None of the biochemical parameters significantly correlated with any BP variable.

CONCLUSIONS

AMBP can help detect hypertension in patients with PHPT that remains unrecognized with routine office-based blood pressure measurement. In addition, AMBP detects loss of normal dipping pattern in BP that persists in almost half of the patients even after successful parathyroidectomy, perhaps because of permanent vascular damage induced by PHPT.

11C-Choline PET/CT for Detection and Localization of Parathyroid Adenomas

OBJECTIVE

The purpose of this study is to determine the efficacy of ¹¹C-choline PET/CT for the detection of parathyroid adenomas by retrospectively reviewing a large patient population.

MATERIALS AND METHODS

In this single-institution retrospective study, 7088 ¹¹C-choline PET/CT scans performed of 2933 men with prostate cancer from January 2005 through February 2016 were evaluated. Patients with suspected parathyroid adenomas were identified through a review of the electronic medical record and relevant imaging. Patient demographics, laboratory results, and lesion characteristics were noted. Pathologically proven parathyroid adenomas and lesions in patients with imaging or laboratory findings consistent with the diagnosis were considered positive.

RESULTS

Thirteen men (mean [± SD] age, 72 ± 7 years) with pathologically or laboratory-proven parathyroid adenomas were identified. All had abnormally elevated serum calcium and parathyroid hormone levels. All adenomas were tracer avid on ¹¹C-choline PET/CT (maximum standardized uptake value, 5.6 ± 3.0), with activity averaging 4.2 times that of the blood pool and 2.1 times that of the adjacent thyroid. One case of an ectopic adenoma was identified. Of the six pathologically confirmed cases, none displayed high-grade features such as capsular, vascular, or adjacent tissue invasion. Three additional patients with possible parathyroid adenomas at ¹¹C-choline PET/CT were ultimately found to have thyroid lesions on the basis of tissue diagnosis; however, none of these patients had abnormal calcium or parathyroid hormone levels.

CONCLUSION

In our patient population, ¹¹C-choline PET/CT identified parathyroid adenomas with high specificity. Prospective investigation is warranted to validate this result and delineate the utility of ¹¹C-choline PET/CT relative to other modalities.

Primary hyperparathyroidism associated to thrombocytopenia: an issue to consider?

Primary hyperparathyroidism (PHPT) is probably the most common endocrine disorder of the parathyroid glands, causing hypercalcemia. It is diagnosed often in persons with elevated serum calcium levels. However, hematological manifestations, such as thrombocytopenia are less known. In this case we describe the possible association of PHPT with reversible thrombocytopenia after parathyroidectomy. This hematological abnormality can be included in the spectrum of possible causes, including seemingly non-specific symptoms, in the decision tree towards surgical assessment.

No Need to Abandon Focused Unilateral Exploration for Primary Hyperparathyroidism with Intraoperative Monitoring of Intact Parathyroid Hormone

BACKGROUND

We investigated the rate of persistent and recurrent hyperparathyroidism after focused unilateral exploration (UE) with intraoperative monitoring of intact parathyroid hormone (IOPTH).

STUDY DESIGN

A prospective cohort of 915 patients with primary hyperparathyroidism (PHP) underwent parathyroid surgery by a single surgeon from January 2003 to September 2013. A total of 556 patients with at least a single positive preoperative localization by ultrasound (US) and/or sestamibi scan (STS) underwent UE with IOPTH. The criterion for completion of surgery was an IOPTH fall of 50% from the highest intraoperative level and into the normal range 5 to 10 minutes after resection of the localized gland.

RESULTS

Fifteen patients had either persistent or recurrent PHP, yielding a 2.7% (95% CI 1.6% to 4.4%) overall recurrence rate based on the refined Wilson method with continuity correction. Four patients had persistent PHP. Three of these patients were cured with reoperation, and the fourth patient was followed nonoperatively. Eleven patients had recurrent PHP, with 5 corrected by surgery and 6 patients followed nonoperatively. The mean postoperative serum calcium (Ca) level was 9.4 mg/dL over a mean follow-up interval of 44.0 months. Preoperative localization rates by each localization study were: US 74.3% (n = 413), STS 86.9% (n = 483), and US and STS 71.4% (n = 397). There was no difference in the preoperative study that localized the hyperfunctional parathyroid gland in recurrent vs nonrecurrent patients by the Fisher's exact test (US, p =1.00; STS, p =0.65; US and STS, p =1.00).

CONCLUSIONS

The low rate of recurrent PHP after focused unilateral exploration with IOPTH suggests that this procedure should not be abandoned.

Surgical management of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) is a common endocrine disorder in which the inappropriate elevation in serum parathyroid hormone level results in hypercalcemia. Most cases are caused by a single adenomatous parathyroid gland and less than 15% are caused by multiglandular disease. The incidence of PHPT appears to be increasing. More patients are being identified earlier and often before symptoms develop. Parathyroidectomy is the only definitive management; with it, the patient can achieve biochemical homeostasis and symptom relief, and sequelae are prevented. Even for asymptomatic patients with PHPT, there is a growing trend to recommend early surgical intervention. Controversy continues regarding the role of and reliance on various technologies, such as preoperative localization imaging, intraoperative parathyroid hormone level measurements, and minimally invasive surgery. Although both traditional bilateral 4-gland exploration and targeted approaches are accepted surgical techniques, there is a growing trend in unilateral targeted operations often using these technologies. Regardless of surgical approach, the expected success rate is greater than 95%. This article provides an overview of the contemporary surgical management of PHPT.

Cinacalcet for the treatment of primary hyperparathyroidism

The objective of this article is to review the literature regarding the treatment of primary hyperparathyroidism (PHPT) with a focus on cinacalcet. A MEDLINE (1965-June 2009) and bibliographic search of the English-language literature was conducted using the search terms cinacalcet, calcimimetics, primary hyperparathyroidism, and treatment. All articles identified in the search were included. Parathyroidectomy is curative for patients with PHPT; however, there are few options for patients who are not surgical candidates, who refuse surgery, or those with refractory PHPT after parathyroidectomy. Possible treatment options include estrogens, raloxifene, bisphosphonates, calcitonin, and cinacalcet. Cinacalcet has been shown to decrease serum calcium and parathyroid hormone serum levels in patients with PHPT. These trials, however, have not studied the effect of cinacalcet on patient-oriented outcomes such as bone mineral density, nephrolithiasis, or other complications of PHPT. Cinacalcet may be considered to reduce serum calcium and parathyroid hormone serum levels in patients with PHPT who cannot or will not undergo surgery and those with refractory PHPT after parathyroidectomy. Because the effects of cinacalcet on bone mineral density are uncertain, more frequent monitoring of bone mineral density may be required along with a medication proven to improve bone mineral density. Future studies should evaluate the effect of cinacalcet on complications of PHPT.