PMID- 18284640
OWN - NLM
STAT- MEDLINE
DCOM- 20090723
LR  - 20081017
IS  - 1365-2265 (Electronic)
IS  - 0300-0664 (Linking)
VI  - 69
IP  - 3
DP  - 2008 Sep
TI  - Very low or undetectable intact parathyroid hormone levels in patients with 
      surgically verified parathyroid adenomas.
PG  - 382-5
LID - 10.1111/j.1365-2265.2008.03225.x [doi]
AB  - OBJECTIVES: To report and explore potential reasons for undetectable or 
      low-normal serum intact PTH levels in patients with surgically verified primary 
      hyperparathyroidism with parathyroid adenomas, review the relevant literature, 
      and offer suggestions for management of such patients occasionally encountered in 
      clinical practice. For future research, to help understand mechanisms underlying 
      'undetectable' or inappropriately low serum intact PTH levels. METHODS: Serum 
      intact PTH levels were measured pre- and postoperatively by 
      immunochemiluminescent assay (ICMA) and the results were confirmed by at least 
      two repeated measurements on different occasions in each patient. PATIENTS: We 
      encountered two unusual patients with primary hyperparathyroidism who had 
      suggestive biochemical and/or clinical features of primary hyperparathyroidism. 
      However, serum intact PTH levels were either very low or undetectable in the 
      context of hypercalcaemia, with no other obvious cause. A (99m)Tc sestamibi scan 
      showed increased uptake in one of the parathyroid glands, suggesting a single 
      adenoma in each case that was confirmed at surgery. RESULTS: In the first 
      patient, from India, mean +/- SD serum calcium was 2.6 +/- 0.32 mmol/l (reference 
      range 2.12-2.74 mmol/l) with intact PTH of 0.11 pmol/l (reference range 1.1-7.59 
      pmol/l). In the second patient, from the USA, mean +/- SD serum calcium and 
      intact PTH were 2.9 +/- 0.07 mmol/l (reference range 2.17-2.51 mmol/l) and 1.35 
      pmol/l (reference range 1.1-7.59 pmol/l), respectively. Following curative 
      parathyroidectomy, serum calcium levels normalized in both patients. By contrast, 
      serum intact PTH levels, which were either suppressed or very low before surgery, 
      rose into the low-normal reference range in all patients. CONCLUSIONS: When the 
      clinical suspicion is high, the diagnosis of primary hyperparathyroidism should 
      be pursued despite suppressed or low-normal serum intact PTH levels after 
      carefully excluding other causes of hypercalcaemia. Further research on various 
      intact PTH molecular species secreted by parathyroid adenomas or 
      post-translational changes in the intact PTH molecule that might interfere with 
      in vitro measurements should be undertaken to understand the precise reason(s) 
      for such anomalous findings.
FAU - Bhadada, S K
AU  - Bhadada SK
AD  - Department of Endocrinology, Postgraduate Institute of Medical Education and 
      Research, Chandigarh, India.
FAU - Cardenas, M
AU  - Cardenas M
FAU - Bhansali, A
AU  - Bhansali A
FAU - Mittal, B R
AU  - Mittal BR
FAU - Behera, A
AU  - Behera A
FAU - Chanukya, G V
AU  - Chanukya GV
FAU - Nahar, U
AU  - Nahar U
FAU - Rao, D Sudhaker
AU  - Rao DS
LA  - eng
PT  - Case Reports
PT  - Journal Article
DEP - 20080218
PL  - England
TA  - Clin Endocrinol (Oxf)
JT  - Clinical endocrinology
JID - 0346653
RN  - 0 (Parathyroid Hormone)
SB  - IM
MH  - Adenoma/*blood/complications/diagnosis/surgery
MH  - Adult
MH  - Aged
MH  - Female
MH  - Humans
MH  - Hyperparathyroidism/blood/complications
MH  - Male
MH  - Osmolar Concentration
MH  - Parathyroid Hormone/analysis/*blood
MH  - Parathyroid Neoplasms/*blood/complications/diagnosis/surgery
EDAT- 2008/02/21 09:00
MHDA- 2009/07/25 09:00
CRDT- 2008/02/21 09:00
PHST- 2008/02/21 09:00 [pubmed]
PHST- 2009/07/25 09:00 [medline]
PHST- 2008/02/21 09:00 [entrez]
AID - CEN3225 [pii]
AID - 10.1111/j.1365-2265.2008.03225.x [doi]
PST - ppublish
SO  - Clin Endocrinol (Oxf). 2008 Sep;69(3):382-5. doi: 
      10.1111/j.1365-2265.2008.03225.x. Epub 2008 Feb 18.