Dr. Roach: Diuretic use common low blood sodium cause

Keith Roach
To Your Health

Dear Dr. Roach: Please discuss low sodium? My last blood sodium shows 129 on a scale of 136 to 146. I have been on a 50-mg hydrochlorothiazide water tab once a day for 15 years, along with two benazepril 40-mg tabs each day. My sodium has been running 129 to 133 for five years. I am 71.


Dear S.G.: The diuretic hydrochlorothiazide is a very common cause of low sodium levels. With HCTZ, especially at the higher 50-mg dose and especially in the elderly, the kidney is unable to get rid of all the free water we drink, and the sodium in the urine can exceed the sodium in blood, leading to a lowering of the blood sodium level. The body will reach a new set point for sodium, as yours has done for at least the past five years.

It’s important to note that low sodium levels are NOT treated by increasing dietary sodium. That would counteract the blood pressure effect of the diuretic. Since low sodium is almost always about excess water, treatment, if necessary, must either deal with the underlying problem or reduce water intake.

In your case, with very mild, apparently asymptomatic and stable low sodium, I would talk to your doctor about whether a lower dose of the HCTZ, or changing it for a different class of medication, is necessary.

In people with very severely low sodium levels, raising them too quickly can cause severe neurologic disease, so these are corrected slowly, under observation.

Dear Dr. Roach: My sister has had rectal prolapse for two years. She does not exercise or walk regularly, and eats TV dinners. She takes stool softeners. She is afraid of surgery. The rectal prolapse is getting harder to retract back. I am worried because she is losing weight. What is the cause? What are the outcomes with surgery?


Dear I.T.: Rectal prolapse is the protrusion of the rectum through the anal opening. It happens most often in older women, and often is complicated by pain, bleeding, constipation and incontinence. It can have a dramatic effect on overall quality of life. It is caused by weakness in the pelvic floor, which is most common in women with multiple children and in people with chronic constipation and straining. Severe rectal prolapse is most common in people with dementia or stroke.

There are few treatments outside surgery, but these include a healthy diet (not TV dinners) and plenty of water and fiber. There are several surgical treatments, which generally have a good success rate and low rates of recurrence, but pose significant risk for complications of incontinence and constipation, though this depends on the function of the bowel prior to surgery. It takes several weeks to recover from the surgery. Odds are, however, that surgery is likely to improve your sister’s quality of life, perhaps dramatically so.

Email questions to ToYourGoodHealth@med.cornell.edu.