Very high parathormone levels may not always be due to primary hyperparathyroidism

INTRODUCTION: Secondary hyperparathyroidism is a disease characterized by parathyroid gland hyperplasia originating from a localization other than the parathyroid gland. Common causes of this condition are kidney failure and vitamin D deficiency. Here, we presented a case of secondary hyperparathyroidism to sleeve gastrectomy. CLINICAL CASE: A 46-year-old female patient who applied to an external medical center with fatigue, weight loss, and muscle and joint pain was referred to our clinic with a diagnosis of primary hyperparathyroidism. In the examinations of the patient, PTH 455 pg/mL (normal range 15–65 pg/mL), 25-hydroxy vitamin D 4,95 uq/L, Ca total 8,8 mg/dL (normal range 8,5–10,5 mg/dL), phosphorus 7,4 mg/dL (normal range 2,5–4,5 mg/dL), Ca 24h urine 9,5 mg/day. No anomaly was detected in the neck USG imaging of the patient. In the detailed history, it was learned that a sleeve gastrectomy was performed in December 2016. It was understood that the PTH level was well above normal due to insufficient vitamin D absorption, leading to secondary hyperparathyroidism. We made a treatment plan for the patient diagnosed with secondary hyperparathyroidism. For six weeks, the patient was given cholecalciferol, 50,000 IU per week. Treatment was continued with daily maintenance of 2,000 IU. During the follow-up of the patient, parathormone levels reached normal values. CONCLUSION: After sleeve gastrectomy, vitamin and mineral deficiencies are frequently encountered due to malabsorption. Very high parathormone levels may not always be due to primary hyperparathyroidism. Vitamin D deficiency can sometimes raise parathormone levels too high.