Patient presents with signs and symptoms suggestive of primary hyperparathyroidism.  Elevated calcium levels, hypercalcemia, were noted on routine laboratory workup or during investigation for presenting complaints such as fatigue, muscle weakness, bone pain, kidney stones, nephrolithiasis, or gastrointestinal issues including constipation, nausea, and abdominal pain.  The patient reports experiencing some combination of these symptoms, impacting their quality of life.  Differential diagnosis includes familial hypocalciuric hypercalcemia, malignancy-related hypercalcemia, and other causes of hypercalcemia.  Serum parathyroid hormone (PTH) levels are elevated, confirming the diagnosis of primary hyperparathyroidism.  Further evaluation including 24-hour urine calcium excretion, serum phosphate, vitamin D levels, and renal function tests were performed to assess the extent of the disease and potential complications.  Imaging studies such as a parathyroid sestamibi scan or ultrasound may be considered for localization of an adenoma.  The patient was counseled on the risks and benefits of parathyroidectomy, the definitive treatment for primary hyperparathyroidism.  Management options including observation, medical therapy with bisphosphonates for bone protection, and surgical intervention were discussed.  The treatment plan will be determined based on the patient's symptoms, severity of hypercalcemia, presence of complications, and patient preference.  Follow-up appointments are scheduled to monitor calcium levels, PTH levels, and kidney function.  Patient education regarding diet, hydration, and potential complications was provided.  ICD-10 code E21.0, primary hyperparathyroidism, is documented for billing and coding purposes.