Introduction
Primary hyperparathyroidism (PHPT) is a rare condition in children, with an incidence of approximately 2 to 5 per 100,000. The most common cause of PHPT in children is solitary parathyroid adenoma (PTA), accounting for 70% to 80% of cases. Unlike adults, where PHPT often presents as asymptomatic hypercalcemia, children and adolescents typically exhibit symptoms. The recommended treatment for PHPT secondary to adenoma is excision of the adenoma. This article presents a case of a pediatric patient with asymptomatic hypercalcemia, later diagnosed with PTA and successfully treated with parathyroidectomy.
Case Report
A previously healthy 13-year-old African American boy was admitted for intravenous antibiotics due to left orbital cellulitis. Initial laboratory tests revealed elevated calcium levels (total calcium corrected for albumin: 14.8 mg/dL, ionized calcium: 6.73 mg/dL). Despite these findings, the patient was asymptomatic, denying symptoms such as constipation, anorexia, nausea, polydipsia, polyuria, muscle weakness, or bone pain. The patient’s mother reported no family history of hypercalcemia. The patient had a history of attention-deficit/hyperactivity disorder and was on medications including amphetamine, dextroamphetamine, guanfacine, and trazodone.
On examination, the patient appeared well-hydrated with normal vital signs. Repeat calcium levels remained elevated, prompting further investigations. Elevated parathyroid hormone (PTH) levels, elevated 1-25 hydroxyvitamin D, low 25-hydroxyvitamin D, and a normal urine calcium-to-creatinine ratio suggested PHPT secondary to PTA. Thyroid ultrasound and Tc-99m-Sestamibi scintigraphy confirmed the presence of a right PTA measuring 2.3 x 0.8 cm. The renal ultrasound was negative for nephrolithiasis and nephrocalcinosis.
Management and Outcome
The patient underwent parathyroidectomy of the right superior parathyroid gland. The remaining parathyroid glands were normal in size and left intact. Pathology confirmed a PTA weighing 1.3 g. Postoperatively, PTH levels were undetectable, and the patient was treated with calcitriol and calcium supplementation. Calcitriol was discontinued after one month, and calcium supplementation was stopped after four months. The patient continues to take a maintenance dose of Vitamin D 1000 units daily. Genetic testing for multiple endocrine neoplasia (MEN) and rearranged during transfection (RET) gene mutations was negative.
Discussion
PTA is the most common cause of PHPT, with a higher prevalence in women. However, our patient was an adolescent boy. PTAs are usually sporadic but can be part of syndromes such as MEN types 1, 2A, and 4, hyperparathyroidism-jaw tumor syndrome (HPT-JT), and familial isolated hyperparathyroidism syndromes. PHPT can also result from CaSR mutations, such as familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism, characterized by decreased calcium excretion and hypocalciuria. Genetic mutations account for approximately 10% of PHPT cases.
Symptomatic PHPT in children often presents with nephrolithiasis, polydipsia, polyuria, bone pain, muscle weakness, anorexia, nausea, constipation, fatigue, depression, anxiety, and memory issues. The critical biochemical features of PHPT due to PTA include high or inappropriately normal PTH levels and elevated serum calcium levels. Urinary calcium excretion is usually normal or high. Preoperative localization of PTA is achieved through neck ultrasound and Tc-99m-Sestamibi scintigraphy, with high sensitivity. Parathyroidectomy is the standard treatment, with a cure rate of approximately 97%. Postoperative hypocalcemia is a potential complication that requires monitoring.
Conclusion
Although PHPT is common in adults, it is rare in pediatric patients. The most common cause of PHPT in children is single PTA. Early diagnosis and treatment are crucial to prevent complications related to hypercalcemia, such as arrhythmia, pancreatitis, and nephrolithiasis.
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