|Year : 2018 | Volume
| Issue : 1 | Page : 46-47
Redefining hypocalcemia for surgeons
Karthik K Prasad, Debanshu Bhaduri, Manish S Bhatia
Department of Surgical Oncology, M. N. Budhrani Cancer Institute, Pune, Maharashtra, India
|Date of Web Publication||18-Jun-2018|
Dr. Karthik K Prasad
M. N. Budhrani Cancer Institute, 7-9 Koregaon Park, Pune - 411 001, Maharashtra
Source of Support: None, Conflict of Interest: None
Hypocalcemia is a well-known complication of parathyroidectomy. Although biochemical hypocalcemia denotes serum levels of total calcium below the lower limit of the reference range, symptoms of hypocalcemia occur even with normal/high calcium levels in postparathyroidectomy patients. Understanding the pathophysiology of hypocalcemia, rather than just treating the biochemical parameters, is more important in the management of these patients.
Keywords: Hyperparathyroidism, hypocalcemia, postparathyroidectomy
|How to cite this article:|
Prasad KK, Bhaduri D, Bhatia MS. Redefining hypocalcemia for surgeons. J Curr Oncol 2018;1:46-7
| Introduction|| |
Primary hyperparathyroidism (PHPT) is a generalized disorder of calcium metabolism from abnormally high levels of serum calcium and increased level of parathormone (PTH). Adenoma is the most common cause of PHPT. Parathyroidectomy is the only definitive treatment. Hypocalcemia is one of the most dangerous complications of parathyroidectomy, occurring in 10%–46% of patients.
Postparathyroidectomy, a decline in calcium level is expected. However, the unusual phenomenon of occurrence of symptoms of hypocalcemia at normal/above normal serum calcium levels was observed and is described in this case report.
| Case Reports|| |
A 70-year-old male, who was a known case of chronic kidney disease and multiple renal calculi, presented with vomiting and pain abdomen for 1 week. Ultrasound of the neck revealed a 30 mm × 30 mm round hypoechoic lesion along the posterior margin of lower pole of thyroid gland on the right side, which was confirmed by Sestamibi scan to be a functioning parathyroid adenoma. Serum calcium was 17 mg/dl and serum PTH was 2077 IU/L. The patient underwent right inferior parathyroidectomy. Intraoperative serum PTH (IOPTH) sent after 5 min of removal of the gland was 618.5 IU/L (70% fall). The histopathological report was parathyroid adenoma.
On postoperative day 1, the patient developed signs and symptoms of hypocalcemia such as tremors, tingling and numbness of hands, tachycardia, and tachypnea. However, the serum calcium was 15.3 mg/dl (8.5–11.0 mg/dL).
A 28-year-old male presented with generalized weakness for 6 months and a lesion in the right upper gingivobuccal sulcus (GBS) for 2 months.
Orthopantomogram (OPG) showed multiple well-defined radiolucencies with a soap bubble appearance. Biopsy of GBS lesion revealed Brown tumor of hyperparathyroidism. Well-defined lytic lesions were noted in the cervical and dorsal vertebrae and ribs. The serum calcium was 12.5 mg/dl and PTH was 1415.9 IU/L.
A well-defined enhancing lesion approximately 29 mm × 19 mm on the inferior surface of the thyroid gland on the left side was seen on computed tomography of the neck and was confirmed by Sestamibi scan to be a functioning parathyroid adenoma. The patient underwent left inferior parathyroidectomy. IOPTH sent after 5 min of removal of the gland was 135 IU/L (90% fall). The histopathological report was parathyroid adenoma.
On postoperative day 1, the patient developed circumoral tingling and numbness with positive Chvostek's sign. However, the serum calcium was 10.1 mg/dL.
Both the patients were symptomatic and were treated with intravenous calcium gluconate and supplemented with oral calcium, in spite of serum calcium level being normal/high and were relieved of symptoms.
| Discussion|| |
Hypocalcemia occurs when there is an inappropriate compensation or even a failure of the PTH-controlled homeostasis mechanisms that protect against a hypocalcemic stimulus. The symptoms of hypocalcemia include acral or generalized numbness and paresthesia, muscle cramps, or, in more severe cases, laryngeal stridor, tetany, generalized seizures, and cardiac arrhythmias may develop.
Hypocalcemia is a common, expected, and sometimes dangerous parathyroidectomy complication because of the sudden drop in PTH levels and the increased shift of calcium from the circulation to the bones and in more extreme cases presents as the “hungry bone” syndrome.
Postparathyroidectomy, the prevalence of hypocalcemia is 52%. Transient hypocalcemia occurs in 15%–30% of patients and permanent hypocalcemia is reported in only 0.5%–3.8% of cases.
The long-term hypercalcemic suppression of nonadenomatous parathyroid tissue makes remaining parathyroid tissue somewhat “stunned” when having to suddenly control calcium levels postoperatively. One sees a gradual recovery of the secretion of PTH by the remaining parathyroid glands that are no longer suppressed by the adenoma. It is during this period that a decrease in serum calcium is expected. The body which has attained homeostasis at higher calcium levels experiences an imbalance in calcium homeostasis due to sudden drop in calcium level. Most studies have found that a significant drop in calcium is not evident until the 3rd and 4th postoperative day. If patients are discharged before this point, they should be aware that hypocalcemia can develop even if the initial course was uneventful. It is difficult to identify patients at risk of developing hypocalcemia. Moore et al. and Adams et al. proposed a model based on the slope between the first two serum calcium level determinations. Patients who develop hypocalcemia have a more negative slope than those remaining normocalcemic.,
Ionized calcium is the exact measure of symptom manifestation. To avoid clinical manifestations of hypocalcemia, serum calcium level monitoring is mandatory in postparathyroidectomy patients. A readily available perioperative method to identify patients at risk of developing hypocalcemia would be beneficial. A drop of >80% in IOPTH at 10 min was a significant factor for postoperative hypocalcemia.
Although biochemical hypocalcemia denotes serum levels of total calcium below the lower limit of the reference range, symptoms of hypocalcemia occur even with normal/high calcium levels in postparathyroidectomy patients. Calcium supplementation is indicated if there is >10% drop in serum calcium level.
| Conclusion|| |
Postparathyroidectomy hypocalcemia is a well-known complication. Decrease of serum calcium more than 10%, even if serum calcium is within normal range/higher, is an indication for calcium supplementation. Hypocalcemia is not just serum calcium level below the lower limit of reference range.
Changes in biochemical parameters may take longer than the clinical events. The rate of fall of serum calcium is more important than the actual serum calcium level. Treatment should be based on the understanding of the pathophysiology and recognition of symptoms of hypocalcemia rather than the biochemical values.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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