Endocrine Abstracts

Primary hyperparathyroidism (PHPT) is being more and more frequently diagnosed.

Objective

to describe the clinical presentation and the main laboratory and imaging findings in a group of patients with PHPT diagnosed during the last 10 years. Materials and Methods: This was a retrospective cross-sectional study with data review from the last 10 years. Secondary causes for elevated PTH were excluded. The symptoms and signs of hypercalcemia/HPT were reviewed. Serum calcium (total, albumin-corrected and ionized; sCa, corrCa, iCa +), phosphates (P), magnesium, creatinine, alkaline phosphatase, beta-crosslinks were measured. The intact parathyroid hormone (iPTH) and 25(OH)-vitamin D were determined by electro-hemi-luminescence (Elecsys, Roche Diagnostics). Neck ultrasound (US) was used as first localization study. Half of the participants underwent fine-needle aspiration biopsy (FNAB) with cytology and needle-washouts for iPTH. One fourth was assessed by Single-Photon Emission Tomography (SPECT-CT). Data on bone density (from DXA), fractures and renal stones (from renal US) were collected.

Results

100 patients met the study criteria – 95 were women. Most of them were in their 5th and 6th decades. The median corrected sCa was 2.73 mmol/l, iCa + – 1.39 mmol/l, P – 0.88 mmol/l, iPTH – 14.5 pmol/l and 25(OH)D – 54.0 nmol/l. Normal sCa was registered in 20 participants (20%), while normal sP – in 67.0%. The neck US located single lesions (parathyroid adenoma) in 81% - behind or below the left inferior pole of the thyroid gland in 33 cases (33%) and contra-laterally in another 33%. FNAB of the suspicious lesion had been performed in 51% of the study subjects. The cytology confirmed the presence of parathyroid cells in 22 cases (43.1%), Bethesda II thyroid nodules in 21 cases (41.2%), Bethesda III nodules in 2 cases (3.9%) and insufficient samples (Bethesda I) in 5 cases (9.8%). SPECT-CT from 27 patients identified a suspicious left parathyroid in 11 cases, as well as three ectopic locations. Reduced eGFR and low bone mass were more prevalent than in the general population. Fractures however were not more frequent. Data from renal ultrasound were available in 77% and revealed chronic pyelonephritis without stones in 8 patients (10.4%) and renal stone disease – in 37 patients (48.0%).

Conclusion

Mild to moderate hypercalcemia is frequently the first clue to the diagnosis of PHPT. SPECT-CT seems to be replaced by US-guided FNAB with needle washout measurements of iPTH. Altogether the picture of PHPT is shifting towards milder and asymptomatic (and probably earlier) forms of the disease.