ABSTRACT
Chylous leak is a documented complication of radical neck dissection with well recognised morbidities, including wound breakdown, hypovolaemia and hypoalbuminaemia. Other less well-documented electrolyte imbalances can also ensue. We aim to raise awareness about hypo-osmotic hyponatraemia as a potentially fatal, commonly overlooked complication of high-output chylous leaks. Following identification of his hyponatraemia, this patient underwent successful management in the intensive therapy unit, followed by surgical repair of his chylous leak. Hypo-osmotic hyponatraemia as a complication of chylous leak is not well documented, is likely to be overlooked when present, and is potentially life-threatening. It should be sought after in any patient with a high-output chylous leak following neck dissection.