Dear Dr. Roach: My mother’s blood test has a sodium level of 130 mEq/L. She is not on diuretics, and she does not have heart or kidney problems. She is on thyroid medication and omeprazole. Do I need to be concerned? Due to the heat, I was encouraging her to drink more water. Should I have her add more salt to her diet and drink less water? I am concerned about the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Any advice is appreciated.
M.S.
There are many causes for a low blood sodium level. While you are probably right that your mother has one common cause (SIADH), she should have an evaluation before any treatment is started.
High levels of sugar can interfere with the measurement of serum sodium levels, and once in a while, diabetes can be the cause of a low serum sodium level in a person who doesn’t even know they have it. But most of the time, the blood sugar is checked at the same time as the sodium, so this probably isn’t the issue. However, high immunoglobulin levels, extremely high cholesterol, and jaundice may cause a similar issue (“pseudohyponatremia” — falsely low blood sodium).
A person with fluid overload, usually from heart failure, can often have low sodium, while volume depletion form poor water intake or shock can sometimes cause a low sodium level. But a person who has the appropriate amount of volume should have their urine tested. A high urine sodium level will confirm the diagnosis of SIADH, meaning that the kidney is holding on to more water than it should.
SIADH can occur by itself, but sometimes occurs as a result of infections (especially in the brain or lung). Your mother’s thyroid tests should be rechecked because the wrong dose of thyroid hormone can cause SIADH. Low adrenal gland activity may also cause SIADH.
With mild SIADH and a sodium level of 130 mEq/L, treatment may not be necessary beyond moderate fluid restriction (i.e., drinking less water) and increased sodium intake with salt tablets or salty foods.
Dr. Roach Writes: A recent column on GLP-1 drugs led to many letters. Despite me using these drugs on a daily basis, I miswrote one of the brand names. Semaglutide given for diabetes is Ozempic by injection or Rybelsus orally. The same exact drug used for weight loss is Wegovy, which is given by injection. (The oral version has been tested for weight loss at a very high dose, but it isn’t approved for weight loss. The high dose is not available as a single tablet.)
Tirzepatide’s brand name is Mounjaro when used for diabetes and Zepbound when used for weight loss. Oral tirzepatide is not approved. (Although I see ads for compounded oral tirzepatide, I don’t recommend these.)
Several readers asked why I am cautious about using these medicines for weight loss. The reason is that although these drugs are very useful for the treatment of obesity, especially when there are weight-related medical problems, I do not recommend them for healthy people who just want to “look better.” I don’t recommend them for cosmetic reasons, but I do recommend them to reduce the risk of heart disease, when appropriate, and to help manage metabolic diseases associated with obesity.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected]u
