Post-Surgical Hypoparathyroidism (PoSH): Causes, consequences and novel preventative techniques

Abstract
Post-surgical hypoparathyroidism (PoSH) is a significant cause of hypocalcaemia following thyroid and parathyroid surgery. Hypocalcaemia can be temporary or long-term and reported incidences vary greatly in the literature. PoSH is associated with significant morbidity and requires ongoing treatment. Several studies have found that patients with PoSH experience a lower quality of life.
Management of post-thyroidectomy hypocalcaemia is guided by recommendations from the British Association of Endocrine and Thyroid Surgeons UK. However, the management of post-parathyroidectomy hypocalcaemia has little evidence to support guidance. This thesis evaluates the epidemiology of post-surgical hypoparathyroidism after parathyroid surgery and its current management in Sheffield Teaching Hospitals NHS Foundation Trust. This showed that low post-operative parathyroid hormone levels, rather than calcium itself, was a good indicator for the development of PoSH.
Although several studies report on quality of life in post-surgical hypoparathyroidism they are either not matched to appropriate controls or are small studies and recommendations from a systematic review was that further studies considering co-morbidities and aetiology should be performed. For this thesis, a cross-sectional observational study of four hundred and thirty-nine participants including matched controls showed that patients with PoSH reported significantly more fatigue and loss of energy.
Intra-operative preservation of parathyroid glands is key to the prevention of PoSH, and especially long-term PoSH. Parathyroid gland identification has largely relied on surgical technique and experience. Several novel technologies are being investigated to aid the intra-operative identification of the glands and assessment of viability. Two of these technologies are investigated in this thesis – near infrared fluorescence and electrical impedance spectroscopy. Two Phase I clinical trials were conducted to evaluate the feasibility of these technologies in thyroid and parathyroid surgery. Both technologies showed potential but near infrared fluorescence was the most promising with an important and interesting observation of parathyroid auto-fluorescence.