Primary Hyperparathyroidism as a Rare Cause of Unexplained Recurrent Abdominal Pain: Case Presentation and Literature Review.

Abdominal pain is a common symptom in surgical practice. Around 11%-45% of pediatric population present with abdominal pain. In 29%-87.5% of pediatric population diagnosed with primary hyperparathyroidism (PHPT), abdominal pain and other gastrointestinal (GI) symptoms were the presenting complaint. Hyperparathyroidism is a condition characterized by increased parathyroid hormone (PTH) secretion. It usually presents with nonspecific symptoms of fatigue, poor appetite, weight loss, abdominal pain, nausea, emesis, and bone pain. We present a case of a 13-year-old girl who experienced a recurrent abdominal pain associated with nausea and vomiting, which was diagnosed eight months later when her laboratory investigation revealed high amylase, calcium, and PTH, which raised a suspicion of pancreatitis secondary to hyperparathyroidism. Imaging studies showed retrosternal lesion within the thymus gland, most likely a thymic parathyroid adenoma. The patient's symptoms resolved following thoracoscopic thymectomy, which was performed in another center. To assess the relationship between GI symptoms and PHPT, we reviewed 13 articles published between 2007 and 2020 in the English literature which reported 331 cases of primary PHPT and found that GI symptoms are the fourth most common presentation in patients with PHPT. In those patients, the reported incidence of GI symptoms including abdominal pain was 18.67%. Out of the 331 cases included, only one case mimicked our case as abdominal pain was the main presenting symptom. Unexplained recurrent abdominal pain should raise the suspicion for rare causes. Hyperparathyroidism should be included in the differential diagnosis of recurrent abdominal pain.