title: Coexisting primary hyperparathyroidism and sarcoidosis cause increased angiotensin-converting enzyme and decreased parathyroid hormone and phosphate levels.
abstract: BACKGROUND
  Primary hyperparathyroidism (PHPT) and sarcoidosis may separately contribute to abnormal calcium and phosphate metabolism via different mechanisms, and their coexistence is infrequently reported.
  
  
  OBJECTIVE
  We sought to characterize a group of 50 patients with coexisting PHPT and sarcoidosis in our institution to evaluate their clinical and laboratory characteristics.
  
  
  METHODS
  This was a retrospective observational study of patients with both disorders at our institution between January 1980 and December 2011.
  
  
  RESULTS
  A cohort of 50 patients was identified, with mean ± SD age 59.6 ± 13.9 years and 86% women. Serum calcium in the cohort was 11.1 ± 1.1 mg/dL, phosphate was 3.3 ± 0.6 mg/dL, and PTH was 76 ± 42 pg/mL. Serum 25-hydroxyvitamin D was 25 ± 9 ng/mL, and serum 1,25-dihydroxyvitamin D was 51 ± 20 pg/mL; 24-hour urine calcium was 275 ± 211 mg. In subjects with sarcoidosis, serum angiotensin-converting enzyme (ACE) was 47.2 ± 37.4 U/L. Sarcoidosis was diagnosed first in 50% of patients, PHPT was diagnosed first in 16% of patients, and sarcoidosis and PHPT were both diagnosed within 6 months of each other in 30% of patients. The interval between the 2 diagnoses when sarcoidosis was diagnosed first was 15.5 ± 12.4 years and was 5.5 ± 6.0 years when PHPT was diagnosed first. Patients with PHPT who had active sarcoidosis had higher serum ACE levels (60.9 ± 38.1 vs 20.2 ± 14.0 U/L, P <.0001), lower PTH levels (60 ± 24 vs 96 ± 41 pg/mL, P = .01), and lower phosphate levels (2.7 ± 0.6 vs 3.2 ± 0.5 mg/dL, P = .02).
  
  
  CONCLUSIONS
  Fifty patients with coexisting PHPT and sarcoidosis are described, with patients with PHPT coexisting with clinically active sarcoidosis having increased serum ACE levels and decreased serum PTH and phosphate levels compared with those with inactive sarcoidosis.
authors.affiliation: Mayo Clinic Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Rochester, Minnesota 55905, USA.
authors.forename: Vivien
authors.initials: V
authors.lastname: Lim
authors.forename: Bart L
authors.initials: BL
authors.lastname: Clarke
mesh_terms: D000368:Aged; D002118:Calcium / Q000097:blood / Q000652:urine; D015331:Cohort Studies; D015536:Down-Regulation; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000150:complications* / Q000503:physiopathology / Q000652:urine; D017674:Hypophosphatemia / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D010758:Phosphorus / Q000097:blood; D012189:Retrospective Studies; D012507:Sarcoidosis / Q000097:blood / Q000150:complications* / Q000503:physiopathology / Q000652:urine; D012720:Severity of Illness Index; D013997:Time Factors; D015854:Up-Regulation; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: C470125:PTH protein, human; D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A; D002118:Calcium