Another close call with hyponatremia

By Michelle Hillman
Tuesday, April 22, 2003


BOSTON -- Katherine Guevara, an experienced marathoner who
didn't follow doctors' recommendations, said if there had
been a bowl of pretzels at the finish line, she would have
eaten them to recoup the salt she lost by drinking two cups
of water at each station along the 26-mile route.
Guevara, who finished in 3 hours and 38 minutes, was the
first case of hyponatremia in the Boston Marathon medical
tent yesterday -- a condition that killed charity runner
Cynthia Lucero of Waltham last year.
Three other cases followed Guevara, and one of them was
hospitalized.
Hyponatremia is caused by overloading the body with fluids,
which dilute sodium levels in the blood.
"She's a real case," said Dr. Arthur Siegel. "A woman who
could've been a Cynthia Lucero this year. It proves how
important the testing is."
Siegel, a physician at McLean Hospital in Belmont, has been
studying blood samples from cases like Lucero's to determine
what other factors cause hyponatremia, or water
intoxication.
Most runners aren't aware of the dangers of hyponatremia,
but Guevara, 26, of Virginia knew she needed salt because
she felt dizzy and disorientated. Her blood test showed she
was right, and she was immediately given salty, hot broth to
drink by Siegel.
"She's a classic case," he said. "She's a full-blown case."
Hyponatremia is common in petite women, and charity runners
who are on the course for five or six hours and drink
continuously during the race.
The condition is also common among ultra-marathoners, who
run as many as 50 to 100 miles, and tri-athletes, who
compete for long periods of time. These athletes are
encouraged to take sports drinks to replace electrolytes.
But Guevara, who is an ultra-marathoner, said she doesn't
like Gatorade, and loaded up on three liters of water before
the race and drank throughout. She still entered the tent in
a treatable condition.
Lucero's death -- only the second in Marathon history and
the first from hyponatremia -- has changed the way medical
officials treat runners.
Each registered Marathoner and charity runner received
information about how to properly hydrate themselves.
They were told to weigh themselves on practice runs before
Marathon day -- if they gained weight they were drinking too
much; if they lost weight, they needed more fluids.
Guevara did not follow these directions and actually had
gained 2 pounds on the course, coming into the tent at 118
pounds.
Runners can suffer from hyponatremia hours after running the
Marathon, said Siegel.
If blood sodium levels indicate runners are hyponatremic,
they should not drink any fluids until they urinate, he
said, so the condition won't worsen.
Once urination resumes, runners should drink no more than 6
to 8 ounces of fluids per hour for the next six hours. If
they are nauseous or vomit or faint, they should immediately
visit an emergency room.
Runners can confuse the condition with dehydration, which
has similar symptoms, and often continue drinking, worsening
their conditions.
In severe cases, hyponatremia causes seizures, coma and
death as a result of brain swelling. Lucero drank 16 ounces
of fluid five minutes before she collapsed, Siegel said.
Lucero collapsed at mile 22 and later died at Brigham &
Women's Hospital.
Siegel believes an antidiuretic hormone that prevents the
kidney from secreting fluid is also at play when runners
develop hyponatremia.
In addition to testing blood sodium levels before
administering IV fluids, Siegel was conducting a pilot study
yesterday using a test called an osmolality. The test
measures how concentrated or diluted a runner's body fluids
are and if there is more of the suspected antidiuretic
hormone present.
If the test is shown to work -- connecting hyponatremics
with elevated levels of the hormone, called arginine
vasopressin -- it could become a new standard at marathons
across the country.
The hormone is made in the brain and is in charge of
regulating water excretion by the kidney.
Siegel was in charge yesterday of determining who had
dangerous sodium levels and delivering test results to
physicians who tailor the amount of fluids given to runners
based on the results.
Terry Shirey, director of scientific affairs at Nova
Biomedical of Waltham, said for the last four years the
company has provided equipment at the medical tent to test
blood sodium levels.
"The idea is to get a sodium result on the runner's blood as
fast as we can after they've crossed the finish line,"
Shirey said.
Joan Casey, medical coordinator for the Boston Athletic
Association, said a couple of years ago -- before Lucero's
death -- Guevara might have been treated for dehydration
with more fluids.