A 33-year-old woman comes to the office for evaluation of hypercalcemia. Her Serum calcium was 12.1mg/dl on routine laboratory testing performed for a life insurance application. The patient feels well and has had no excessive urination, bone pain, abdominal pain, headache or constipation. Medical history is significant for upper gastrointestinal hemorrhage secondary to a gastric ulcer a year ago, for which she is on oral proton pump inhibitor. She has a 10-pack-year smoking history but does not use alcohol or illicit drugs. The patient’s menstrual cycles are regular; she has never been pregnant, is sexually active with one partner, and uses barrier contraception to prevent pregnancy. The patient’s mother underwent parathyroid surgery for symptomatic hypercalcemia and takes a pill twice a day for an unspecified pituitary tumor. Blood pressure is 120/80 mm Hg and pulse is 78/min. BMI is 27 kg/m2. Neck examination is unremarkable. A few small subcutaneous lipomas are present on the patient’s back. The rest of her physical examination is unremarkable. Laboratory results are as follows:
Serum chemistries:
Calcium: 12 mg/dl
Phosphorus: 1.9 mg/dl
Creatinine: 0.8 mg/dl
Parathyroid hormone: 100 pg/ml (normal 10-65 pg/ml)
25-hydroxyvitamin D: 31 ng/ml (normal: 30-50 ng/ml)
24-hour urine calcium: 415 mg
Bone mineral density by DEXA is normal.
Which of the following is the best next step in the management of this patient?
- A. Parathyroidectomy
- B. Plasma Metanephrine assay
- C. Serum Calcitonin and plasma Metanephrine assays
- D. Serum Calcitonin and gastrin assay
- E. Reassurance and close observation
Answer is A.
This patient has significant hypercalcemia with an elevated parathyroid hormone level consistent with primary hyperparathyroidism. In light of her young age, history of gastric ulcer, and family history of parathyroid and pituitary disease, this constellation of clinical features is highly suggestive of multiple endocrine neoplasia type 1 (MEN1).
Indications for parathyroidectomy in patients with MEN1, similar to those for sporadic primary hyperparathyroidism, include symptomatic hypercalcemia (or calcium >1 mg/dL above normal), end-organ complications (eg, osteoporosis, chronic kidney disease, nephrolithiasis), and increased risk for complications (eg, urinary calcium excretion >400 mg/day). Patients age <50 are likely to develop complications later in life and should also undergo parathyroidectomy; as patients with MEN1 typically present at a relatively young age, most should be offered surgery.