Abstracts/Presentation Description
Anila Hashmi1,2
1NSW Health Pathology, Liverpool, NSW, Australia; 2University of Technology Sydney, Sydney, NSW, Australia
1NSW Health Pathology, Liverpool, NSW, Australia; 2University of Technology Sydney, Sydney, NSW, Australia
Background:
Primary hyperparathyroidism (pHPT) is characterised by excessive secretion of parathyroid hormone (PTH), leading to hypercalcaemia. The treatment of choice is the surgical excision of the hyperfunctioning gland. Noninvasive localisation has limited sensitivity, particularly in patients requiring revision surgery. Although not often thought by laboratorians, selective venous sampling (SVS) for PTH has demonstrated high sensitivity and specificity in localising hyperfunctioning parathyroid tissue. This review evaluated the diagnostic accuracy of SVS for lateralising parathyroid adenomas where non-invasive radiological diagnostic methods yielded inconclusive results.
Primary hyperparathyroidism (pHPT) is characterised by excessive secretion of parathyroid hormone (PTH), leading to hypercalcaemia. The treatment of choice is the surgical excision of the hyperfunctioning gland. Noninvasive localisation has limited sensitivity, particularly in patients requiring revision surgery. Although not often thought by laboratorians, selective venous sampling (SVS) for PTH has demonstrated high sensitivity and specificity in localising hyperfunctioning parathyroid tissue. This review evaluated the diagnostic accuracy of SVS for lateralising parathyroid adenomas where non-invasive radiological diagnostic methods yielded inconclusive results.
Case Study:
A 51-year-old female with a complex medical history, including end-stage renal disease, prior thyroidectomy, thymectomy, and multiple parathyroid surgeries, presented with persistently elevated PTH levels and hypercalcaemia. Non-invasive imaging, including bone scans and SPECT-CT, suggested possible adenomas but failed to provide definitive localisation.
A 51-year-old female with a complex medical history, including end-stage renal disease, prior thyroidectomy, thymectomy, and multiple parathyroid surgeries, presented with persistently elevated PTH levels and hypercalcaemia. Non-invasive imaging, including bone scans and SPECT-CT, suggested possible adenomas but failed to provide definitive localisation.
Methodology:
SVS was employed to localize the source of elevated PTH levels. A total of 20 samples were drawn from the internal jugular, subclavian, and brachiocephalic veins, and kept on ice immediately after collection. PTH levels were measured using the Roche Cobas immunoassay. The criterion for a positive result was a significant gradient of PTH levels in the sampled veins compared with peripheral levels.
SVS was employed to localize the source of elevated PTH levels. A total of 20 samples were drawn from the internal jugular, subclavian, and brachiocephalic veins, and kept on ice immediately after collection. PTH levels were measured using the Roche Cobas immunoassay. The criterion for a positive result was a significant gradient of PTH levels in the sampled veins compared with peripheral levels.
Results:
SVS identified significantly elevated PTH levels in the left superior and inferior jugular veins, indicating a hyperfunctioning parathyroid adenoma in the left superior parathyroid region. Surgical intervention confirmed the presence of an adenoma, which was successfully excised. Postoperative PTH levels normalized, and the patient experienced substantial improvement in bone pain. Several studies have demonstrated the benefit of SVS before reoperation for hyperparathyroidism. SVS alone has a positive predictive value (PPV) of approximately 75%, which increases to 95% when combined with positive ultrasound findings. Previous studies have reported that combining 4D CT with SVS increased sensitivity from 50% to 95% and accuracy from 55% to 91%.
SVS identified significantly elevated PTH levels in the left superior and inferior jugular veins, indicating a hyperfunctioning parathyroid adenoma in the left superior parathyroid region. Surgical intervention confirmed the presence of an adenoma, which was successfully excised. Postoperative PTH levels normalized, and the patient experienced substantial improvement in bone pain. Several studies have demonstrated the benefit of SVS before reoperation for hyperparathyroidism. SVS alone has a positive predictive value (PPV) of approximately 75%, which increases to 95% when combined with positive ultrasound findings. Previous studies have reported that combining 4D CT with SVS increased sensitivity from 50% to 95% and accuracy from 55% to 91%.
Conclusion:
Our case demonstrated the diagnostic value of SVS in localizing parathyroid adenomas, particularly when non-invasive imaging methods yield inconclusive or negative results. SVS is a valuable adjunct to preoperative localisation strategies. Increasing the recognition of the test by laboratorians and clinicians may help with the management of challenging pHPT cases.
Our case demonstrated the diagnostic value of SVS in localizing parathyroid adenomas, particularly when non-invasive imaging methods yield inconclusive or negative results. SVS is a valuable adjunct to preoperative localisation strategies. Increasing the recognition of the test by laboratorians and clinicians may help with the management of challenging pHPT cases.
Speaker/Presenting Authors
Authors
Submitting/Presenting Authors
Anila Hashmi - NSW Health Pathology (NSW, Australia)