Her doctors should be checking her heart, kidney or adrenal glands and diabetes to determine the cause of decreasing sodium levels. An intravenous solution with sodium or salting her food should keep her sodium levels within norms which are 135 – 147 mEq / L in the US. Her level is not low at 143 and within norms. Would suggest you re-check this value if you have been told that her sodium is low.
The kidneys are responsible for regulating sodium levels in the blood. Other factors could make her sodium levels drop including:
- Bacterial infection or inflammation of the kidneys which occurs because of a kidney infection;
- Insufficient or non-functioning adrenal glands (these glands sit on top of the kidneys);
- Fluid retention due to congestive heart failure – the pumping ability of the heart can decrease and result in dilution of the blood including sodium levels because there is more water in the blood;
- High blood pressure prescribed drugs (diuretics) that are intended to reduce sodium levels and fluid retention;
- Severe burns of the skin that would result in large losses of fluid and sodium;
- Diarrhea or vomiting;
- Water intoxication possibly due to excess intravenous fluids;
- Diabetic acidosis (high levels of ketones due to starvation or decreased elimination in persons with diabetes that is not controlled) or her body may be losing sodium when her blood sugar goes above normal while attempting to remove the excess sugar;
- Malabsorption of sodium.