Making patients aware is very important because hypoparathyroidism is the commonest complication of bilateral thyroid surgery. It may be temporary or permanent. Rates of hypoparathyroidism vary hugely in the literature, partly due to a lack of standardization of definitions. Outcomes from national audits are probably a better reflection of the true incidence. In Scandinavia 16 % of patients take calcium 6 weeks after surgery. In the UK, nearly 30 % are taking calcium at discharge and rates are even higher for those with Graves’ disease and those who underwent a central nodal dissection. At long-term follow-up between 4 % (Scandinavia) and 7 % (UK) are taking calcium/Vitamin D at long-term follow-up. These rates are much higher than reported series and may be over reporting as patients may be taking Vitamin D or calcium for other reasons. Nevertheless this presents a challenge to thyroid surgeons.

The best approach to post-operative hypoparathyroidism is prevention. Surgical technique is of utmost importance whereby the surgeon must make every effort to identify the parathyroid glands prior to dissection and ligation of the branches of the inferior thyroid artery (see Part III). In circumstances when the blood supply cannot be preserved, autotransplantation should be undertaken. This involves excising the parathyroid gland, mincing it into 1 mm cubes and either directly placing it in a pocket of muscle or making a suspension of parathyroid cells in normal saline and then inoculating the fluid directly into muscle.

Hypocalcaemia is the consequence of this complication and is associated with paraesthesiae of extremities (face, hands, toes) exacerbated by compression of the limbs (such as crossing one’s legs, sitting on the toilet). In profound hypocalcaemia patients will suffer with tetany manifest as carpopedal spasm, altered mental state, chest pain, bronchospasm and heart failure. In extreme cases there can be seizures and cardiac arrhythmia. Physical signs of hypocalcaemia include Chvostek’s and Trousseau’s. Whilst the severity of the symptoms often mirrors the degree of hypocalcaemia, this is not always the case.

All Units should have a written protocol for the management of post-operative hypocalcaemia (Table 22.2). Essentially this involves prescribing doses of calcium and/or Vitamin D titrated against the severity of the hypocalcaemia and symptoms. Blood calcium tests should be regularly repeated until a stable state of normocalcaemia has been achieved. When intravenous calcium is delivered, it is essential that extravasation is avoided and cardiac monitoring is needed to identify arrhythmias.