Metabolic bone disease in patients with coeliac disease is commonly associated with secondary hyperparathyroidism due to impaired vitamin D and calcium absorption. However, primary, tertiary and quaternary hyperparathyroidism, characterised by hypercalcaemia, have also been reported in coeliac disease. Tertiary or quaternary hyperparathyroidism result from the chronic stimulation of the parathyroid glands secondary to longstanding vitamin D and calcium deficiency. Quaternary hyperparathyroidism suggests parathyroid adenoma emerge from transformation of pre-existing gland hyperplasia.
We present a patient who had re-operative parathyroidectomy on a background of coeliac disease. A 53-year-old Caucasian female was referred to an endocrinologist for severe osteoporosis with multiple fractures. Screening for secondary causes of osteoporosis revealed positive gliadin and tissue transglutaminase antibodies as well as high PTH (8.0pmol/L), calcium levels between 2.45 and 2.63mmol/L and vitamin D of 59nmol/L. The urine ca/cr ratio was 0.014. Coeliac disease was confirmed on duodenal biopsy. No adenoma was localised on ultrasound, sestamibi scan and 4-dimensional CT. She was referred to ENT with provisional diagnosis of primary hyperparathyroidism and underwent a neck exploration where the enlarged left superior parathyroid gland (200mg) was removed. The biopsy was unable to distinguish between parathyroid hyperplasia and adenoma histologically. Her PTH and calcium levels only temporary improved and therefore a second operation was performed. The right superior and a part of the right inferior parathyroid gland were removed, and histology confirmed a superior parathyroid adenoma. Her PTH and corrected calcium levels normalised after the second operation at 5.6pmol/L and 2.33mmol/L, respectively.
Tertiary and quaternary hyperparathyroidism in coeliac patients are important considerations especially with negative localisation studies and a high chance of prolonged undiagnosed coeliac disease. If hyperplasia is present, a different surgical technique may need to be applied, and patients may need to consent to more than one parathyroid resection pre-operatively.