Hypernatraemia management involves the careful correction of elevated serum sodium levels, typically above 145 mmol/L, to prevent neurological complications. It is crucial in clinical practice as rapid correction can lead to cerebral oedema, while inadequate treatment may result in dehydration and cellular dysfunction. A key association is with conditions such as diabetes insipidus, where hypernatraemia can occur due to excessive water loss, necessitating targeted fluid replacement strategies.