Five-year Retrospective Study on Primary Hyperparathyroidism in South India: Emerging Roles of Minimally Invasive Parathyroidectomy and Preoperative Localization with Methionine Positron Emission Tomography-Computed Tomography Scan.

Background: Primary hyperparathyroidism (PHPT) is a common endocrine disease with a variable clinical presentation. PHPT is usually symptomatic at presentation in majority of the patients, especially in developing countries. As the accessibility to investigations, advanced imaging methods and surgical procedures are improving, the clinical profile of the patients with PHPT has undergone a palpable change compared to the earlier description. Hence we decided to look for a change in clinical, imaging and surgical outcomes of PHPT patients from South India.

Methods: We collected the data on clinical presentation, biochemistry, radiological features and operative findings of patients with PHPT treated in our hospital from 2011-2015. Cases of PHPT were identified from the laboratory values using the biochemical criteria, after the exclusion of secondary and tertiary hyperparathyroidism cases.

Results: Our study identified 54 patients (19 males and 35 females) with age ranging from 16 to 71 years. A Significant proportion(38.9%) of the patients were asymptomatic. Musculoskeletal symptoms (40.7%), renal manifestations (27.7%) and gastrointestinal system involvement (27.7%) constituted the other common modes of presentation. CNS involvement was seen in 3 patients. A palpable nodule in the neck was detected in 4 patients. Interestingly 4 patients were managed for parathyroid crisis at presentation. Biochemical features included hypercalcaemia (100%) and hypophosphatemia (59%) with a mean intact PTH level of 602.0±721.3 pg/ml. Sensitivity of Ultrasonography and Tc99M Sestamibi was 72% and 70.6% respectively for detecting a parathyroid adenoma. Sensitivity of C11 methionine PET-CT was 71.4% in those patients who were negative for other imaging modalities. Forty three patients (79.6%) underwent minimally invasive parathyroidectomy.

Conclusion: In South India we have a notable change in the clinical presentation of PHPT from a symptomatic to an asymptomatic state. C11 Methionine PET - CT is an emerging modality for preoperative localisation especially when other imaging modalities are negative and when a minimally invasive parathyroidectomy is desired.