ESPE Abstracts

Background: Hypoparathyroidism (HP) and pseudohypoparathyroidism (PHP) are conditions associated with basal ganglia calcification (BGC) which is thought to be caused by high serum calcium-phosphorus product and inadequate management of hypocalcemia. Novel mechanisms have recently been proposed for phosphate sensing and transport. However, the exact pathophysiology of BGC remains to be elucidated.

Objective: To gain further insight into the relationships between the presence of BGC and clinical and laboratory findings.

Participants and Methods: We analyzed the presence of BGC on initial cranial Computed Tomography (CT) scans and clinical and laboratory features at presentation in 47 patients (23 male, 49%) who were followed up with a diagnosis of HP (n = 20) or PHP (n = 27; 17 of PHP-1b type).

Results: The mean age at presentation was 9.2±4.2 years. CT was performed at initial diagnosis in 12 patients (4/8:HP/PHP), of whom seven had BGC (4/3:HP/PHP). BGC was detected in 11 (38%) patients on first cranial CT performed 6.3±5.7 year after diagnosis. Among 11 patients, three (27%) were diagnosed with HP, six (55%) with PHP-1a, and two (18%) with PHP-1b; 29 patients showed no BGC when first CT was performed. There was no statistically significant difference in the probability of BGC between the patients with PHP-1a and 1b (P =0.26). There were no significant differences between patients with and without BGC regarding the primary diagnosis, sex, presence of epileptic seizures/syncope, or nephrocalcinosis/nephrolithiasis or initial biochemical parameters. However, only differences in age at presentation and seizure incidence were observed when comparing patients with BGC at diagnosis to those without BGC. First group was older at presentation and had a higher seizure incidence (P =0.007 and P =0.003, respectively).

Conclusion: This study highlights the prevalence of BGC in children with HP and PHP. Our findings suggest that length of time before disease diagnosis and treatment, and thus duration of hyperphosphatemia and/or hypocalcemia, is the only risk factor for BGC. Additionally, the absence of a substantial relationship with other variables suggests that BGC development may involve complex and multifactorial mechanisms.