Fluid and electrolyte HELP!!

As I understand it, he would dehydrated and hyponatremic because he is vomiting. He is losing fluid and losing sodium together

But I thought when a patient was in hyponatremia, their cells swell with water? and to be dehydrated shouldn't the cells be shriveled?

It can be caused by dehydration OR fluid volume overload and dilution of the sodium.

But I thought when a patient was in hyponatremia, their cells swell with water? and to be dehydrated shouldn't the cells be shriveled?

Hyponatremia and dehydration would be measured by the ECF, not what's in the cells.

Salt always follows water. What your thinking of is when u put a cell in a hypertonic/hypotonic solution what happens to the cell (it swells or lysis). Vomiting = water loss = electrolyte loss

when a patient vomits they lose both water and sodium. there are many other medical conditions that cause a decrease in one but not the other. when confused, always look at the big picture. if a patient is vomiting repeatedly, they are losing both fluid and electrolytes, and they need both to be replaced.

The danger of hyponatremia is that the cells swell because the tonicity of the ECF is lower than the ICF. A hyponatremic patient can be at serious risk for seizures due to brain cell swelling. The cells swelling did not cause the hyponatremia. As it was mentioned, things like cerebral salt-wasting syndrome, SIADH and vomiting can cause hyponatremia. What do you think is in gastric fluid? Only hydrochloric acid??? Potassium chloride and sodium chloride are also present to help things like proton pumps function and deal with mucus viscosity. Therefore, if someone is vomiting, electrolytes are leaving and the concentrations of electrolytes in the ECF and ICF can become disrupted. Make sense?