A rare instance of retrosternal goitre presenting with obstructive sleep apnoea in a middle-aged person.

INTRODUCTION: In endemic goitre areas, 20% of the population over 70 will have retrosternal goitre.(12) Obstructive sleep apnoea (OSA) occurs when there are repeated episodes of complete or partial blockage of the upper airway during sleep.

PRESENTATION OF CASE: A 55-year-old man was being treated for obstructive sleep apnoea, came with stridor worsening over the 2 and was advised CPAP ventilation. In our institution, he was diagnosed to have goitre with retrosternal extension with no hypo/hyperthyroidism. He was an obese (BMI - 30Kg/m(2)) male with a short, broad neck and clinically no obvious swelling in the neck. He had stridor, with positive Kocher's test as well as Pemberton's sign. His TFT's were normal and CT scan revealed widening of superior mediastinum. Patient was pre-medicated with low dose (0.1μg) fentanyl, and induced with inhalational anaesthesia (sevoflourane). Endotracheal intubation was done using 6 no. ET tube, without muscle relaxation, and the thyroid was removed through a conventional Kocher's incision. Thyroid was enlarged 25cm by 10cm in retrosternal position. Postoperatively, pt was reversed and shifted to ICU, was monitored for the next 24hours. He was extubated uneventfully the next morning. Patient had a good post-op recovery and was discharged on the 7th post-op day.

DISCUSSION: Terms such as retrosternal, substernal, intrathoracic, or mediastinal have been used to describe a goitre that extends beyond the thoracic inlet. However, there is a lack of consensus regarding the exact definition of a retrosternal goitre (RSG).(1) The majority of patients present with shortness of breath or asthma like symptoms (68.8%), as was the case in the studied patient. Other modes of presentation include neck mass (75%), hoarseness of voice (37.5%), dysphagia (31.3%), stridor/wheezing (19%), or SVC obstruction. Upper airway obstruction due to thyroid gland has been reported up to 31%(2) and difficulty in intubation has been reported in 11%.(3) Central airway obstruction produces symptoms of dyspnoea, stridor, or obstructive pneumonia and is often misdiagnosed as asthma.(4) The CT scan was the most useful tool showing the nature and extent of the lesion in the reported case. In a recent publication, the CT scan was considered the gold-standard preoperative radiological investigation.(5) Surgery is the only effective treatment for retrosternal goitres. In most cases, suppressive therapy with thyroxine is ineffective in reducing the size of multinodular goitres;(7,8) radio-iodine therapy is both generally ineffective in large goitres(8) and may induce acute inflammation and swelling of the gland with the potential for airway obstruction. The operation of choice is usually a total thyroidectomy. Only around 2% of patients undergoing thyroidectomy for retrosternal goitre will require surgical access other than a standard collar incision (either manubriotomy, sternotomy or thoracotomy).(9) CONCLUSION: Despite all the advances in investigative modalities, retrosternal goitre still exists in 20% of patients over 70 years in endemic regions. It has to be recognised that it can be a cause of obstructive sleep apnoea. Early detection and prompt management goes a long way in decreasing the morbidity and mortality in patients with RSG.