In a case believed to be a United States first, the radiology team at
Lucile Packard Children's Hospital has used prenatal magnetic resonance
imaging to detect an often-misdiagnosed genetic disease.
“Dr. Barth’s experience with difficult cases and the depth of his
familiarity with the fetal imaging scientific literature really helped
our entire team provide the best possible care for this mother and
baby”
The disorder, congenital chloride diarrhea, can cause severe dehydration
and serious metabolic disturbances in newborns if not treated quickly.
"This is a disease where early diagnosis is the key to a good outcome,"
said Richard Barth, MD, the physician who recognized the unusual case.
Congenital chloride diarrhea is so rare, with only about 250 total cases
reported worldwide, that infants with the disease are often erroneously
treated for other diarrhea-causing ailments. "If the patient's
fortunate, you could stumble onto this diagnosis," said Barth, the chief
radiologist at Packard Children's and a professor of pediatric radiology
at the Stanford University School of Medicine. The case was the first
instance of CCD Barth had ever seen.
The diagnosis is one of only four known cases of CCD diagnosis ever made
via prenatal MRI. A scientific report on the four cases, including
Barth's case and three from France, was published online Dec. 9 in the
journal Ultrasound in Obstetrics & Gynecology. The report is
a collaboration between Barth and a team of French scientists in
Marseilles.
Barth made his diagnosis in February 2009 when an expectant mom was
referred to him for follow-up of an abnormal prenatal ultrasound. The
ultrasound showed classic signs of bowel obstruction, a fairly common
fetal problem. To get more information about the fetus, Barth ordered an
MRI scan, which gave him a surprise that could not have been detected by
ultrasound: Instead of showing the fetal colon filled with solid waste,
as in a bowel obstruction, it was filled with fluid. This important
clue, found thanks to the Packard team's expertise in fetal MRI, pointed
Barth toward the obscure diagnosis of CCD. "The baby's dad said, 'You're
coming up with a real zebra here,'" Barth recalls.
But that 'zebra' saved the new baby a lot of trouble when she was born
at Packard a few weeks later. Barth collaborated with obstetrics and
neonatology teams in the hospital’s Johnson Center for Pregnancy and
Newborn Services to ensure the infant's fluid and electrolyte levels
would be monitored starting at birth. This was needed because the gene
mutation that causes CCD damages a salt-transporting protein in the
intestine. The abnormality stops the body from absorbing essential
electrolytes, causing patients to have large amounts of watery,
high-salt diarrhea.
"These babies can go into shock and die because of the tremendous
electrolyte imbalance at birth," said Maurice Druzin, MD, professor and
service chief of obstetrics and gynecology at Packard Children's.
Without the prenatal diagnosis, it could easily have taken physicians a
few days to figure out what was going on, Druzin added. "The baby could
have been in serious trouble by that time," he said. Untreated patients
who survive early life may suffer permanent kidney damage, feeding
problems, severe malnutrition, and delays in growth and motor
development.
"In this case, the neonatology team was not just monitoring the baby's
electrolytes, but also taking special precautions in terms of feeding,"
said neonatologist Susan Hintz, MD, associate professor and medical
director of the Center for Comprehensive Fetal Health & Maternal and
Family Care at Packard Children's. "We took these steps due to the
strong possibility that this was CCD."