Primary hyperparathyroidism mimicking vaso-occlusive crises in sickle cell disease

We report a case of bone pain associated with primary hyperparathyroidism in a patient with sickle cell disease. A 17-year-old girl with sickle cell disease (SS phenotype) was seen for bilateral knee and back pain. She had had recurrent severe vaso-occlusive crises and acute chest syndrome in the course of her disease. In the last 2 years, she had frequent visits to the emergency department for severe bone pain. She complained of long-standing fatigue and lethargy. Her physical examination was normal. Hydroxyurea treatment, as well as and long- and short-acting narcotics were given, with little improvement in symptoms. Poor compliance with medication, family dysfunction, and potential narcotic addiction were felt to be significant contributors to the patient's symptoms. She was incidentally found to have an extremely elevated total calcium level of 3.19 mmol/L (range: 2.25-2.76) with an ionized calcium level of 1.9 mmol/L (range: 1.15-1.35). Phosphorus level was 0.82 mmol/L (range: 0.90-1.50), alkaline phosphatase level was elevated at 519 U/L (range: 10-170), and parathyroid hormone level was extremely high at 1645 pg/mL (range: 10-60). Her renal function was normal. Ultrasonography of the neck and a Sestamibi scan revealed a single left inferior parathyroid adenoma adjacent to the thyroid lobe. There was no evidence of an underlying multiple endocrine neoplasia. The patient was diagnosed with primary hyperparathyroidism. Fluid hydration, hydrocortisone, calcitonin, and bisphosphonates were initiated for acute hypercalcemia management before surgical excision of the left parathyroid adenoma. On review of previous blood work, a borderline calcium level of 2.72 was present 18 months before this admission. Two years postsurgery, she has normal renal function, calcium, and parathyroid hormone levels. The weekly visits to the emergency department for pain episodes decreased to 1 every 2 months within the first few months after her surgery. The decrease in pain episodes, even if it coincided with the treatment of primary hyperparathyroidism, may still reflect the natural evolution of sickle cell disease in this patient. However, the high morbidity associated with primary hyperparathyroidism was successfully prevented in this patient. Primary hyperparathyroidism is rare in childhood. In a recent study, it occurred more commonly in female adolescents and was because of a single adenoma, as in our patient. Significant morbidity, mainly secondary to renal dysfunction, was because of the delay in diagnosis after the onset of symptoms (2.0-4.2 years), emphasizing the need for a rapid diagnosis. Sickle cell disease affects approximately 1 of every 600 blacks in North America. Acute episodes of severe vaso-occlusive crisis account for > 90% of sickle cell-related hospitalizations and are a significant cause of morbidity in patients. There is no known association between sickle cell disease and primary hyperparathyroidism, and this case is most probably a random occurrence. However, as emphasized by this case report, pain may also be a harbinger of other disease processes in sickle cell disease. Because management may vary, we suggest that care providers consider the diagnosis of vaso-occlusive crisis as the diagnosis of exclusion and that other etiologies for pain be envisaged in this patient population, especially in the presence of prolonged pain or unusual clinical, radiologic, or biological findings.