Final answer:
Hypernatremia is a high sodium level in the blood that can occur after a head injury, leading to various effects on the body.
Step-by-step explanation:
Sodium level of 160 after a head injury refers to a high sodium level in the blood, known as hypernatremia. Hypernatremia can occur due to dehydration or hormonal imbalances involving ADH and aldosterone. Increased blood sodium levels can have various effects on the body, including hemoconcentration and potential brain damage.