Disorders: More and more children and adults are struggling to do what should come naturally
May 17, 2004
The Baltimore Sun
Asingle act of swallowing is a symphony of perfectly timed events: muscles tightening and relaxing, holes opening and closing, signals flashing from brain to throat and back.
So when 2-month-old Hana Pitt vomited with every feeding and rasped with every breath, doctors were left to wonder: What in the complex sequence was going wrong?
"Swallowing problems can result in a disruption anywhere from the mouth to the stomach," said Maureen Lefton-Greif, a speech-language pathologist at the Johns Hopkins Children's Center who helped solve the mystery.
"There is no one domain that swallowing belongs to."
Specialists say they are seeing increasing numbers of children and adults who have trouble managing a task that most people never think about because it comes so naturally.
Though the reasons aren't completely clear, the increase appears at least partly to be the price paid for the survival of premature babies and elderly stroke patients who might have died just a decade or two ago. Many survive with impairments that make swallowing difficult or impossible.
The U.S. Centers for Disease Control and Prevention recently estimated that up to 10 million older Americans suffer from swallowing disorders. Most are victims of stroke, though some suffer from neurodegenerative disorders, including amyotrophic lateral sclerosis (Lou Gehrig's disease), multiple sclerosis and Parkinson's disease.
Head injuries, cancer and dementia are also sometimes to blame.
Among children, cerebral palsy - a brain injury that interferes with the proper signaling of muscles - is a leading culprit. Also, an estimated 40 percent of children with developmental problems, including autism and mental retardation, have trouble swallowing.
Children who are born prematurely are frequently at risk because myriad muscles and nerves required for swallowing haven't had time to develop properly. But problems also arise in the neonatal intensive care unit, where breathing and feeding tubes that help babies overcome the tumultuous first weeks of life can produce damage.
Dr. Anil Darbari, a gastroenterologist at Baltimore's Kennedy Krieger Institute, said the tubes can cause structural damage to muscles and tissues needed for healthy swallowing.
Mechanical life support can also deprive muscles of the exercise they need to work properly on their own. "The way we develop muscles is to use them," Darbari said.
To understand what can go wrong when a person swallows, consider what must happen for everything to go right.
The first part is deliberate: As a person chews, the tongue pushes food from the center of the mouth to the side and back. When the food is sufficiently softened, the tongue rises and the palate presses down to force food into the throat.
"From the point where the bolus hits the back of the throat, the rest is involuntary," said Darbari, using the term for a softened ball of food.
As soon as the food hits the back of the palate and begins its descent, a piece of elastic cartilage known as the epiglottis closes like a lid over the airway. A wrong turn into the windpipe can cause severe irritation or infection in the upper airway or lungs.
But with the lid properly closed, the food has nowhere to go but on its correct path into the esophagus, the passageway to the stomach.
The esophagus isn't a simple tube, but a series of muscles that contract and relax in wavelike action called peristalsis. (Think of a snake digesting its prey.) When working properly, this ensures that the food is pushed, accepted and pushed again.
Finally, as the bolus approaches the stomach, a muscle called the lower esophageal sphincter opens and lets it drop inside.
None of this would happen without communication between nerves that sense the bolus' progress along the way and the brain, which receives the information and signals muscles to contract and relax in a precise timing.
Specialists use various tests to determine whether a patient is suffering from a swallowing disorder and, if so, what part of the anatomy isn't functioning. One important tool is video fluoroscopy, which uses X-rays to produce a moving picture of a patient swallowing.
For Hana Pitt, fluoroscopy provided a quick answer.
Almost from birth, she emitted a raspy, rattling sound with every breath and regurgitated practically every ounce of breast milk that she swallowed. At first, her pediatrician blamed a sinus infection and, later, asthma, prescribing medication to take with a mechanical misting machine.
That only seemed to make the problem worse.
"The first night, she was absolutely horrible," said her mother, Terry Pitt of Woodbine. "You could see her struggling to breathe."
At Howard County General Hospital, an emergency room doctor suspected that she was drawing formula into her windpipe - setting her up for dangerous infections - and referred her to the swallowing disorders program at Hopkins.
Lefton-Greif, who works in the program, observed the swallowing test and immediately saw wisps of milk entering the airway. The problem stemmed from a soft spot that caused her upper airway to collapse upon itself and produce a disturbing sound every time she exhaled. To make matters worse, she breathed rapidly during feeding and couldn't hold her breath - as people who swallow properly do - with every gulp of formula.
For the little girl, the temporary solution was to attach a feeding tube directly through the abdominal wall into her stomach. This gave her anatomy additional time to mature while she received sufficient nutrition to help her grow.
To exercise her sucking muscles, Hana's parents frequently gave her a pacifier dipped in milk. Later, they spoon-fed her moistened bits of cracker. Finally, when she was 13 months old, doctors withdrew her feeding tube.
Hana, now 4, is healthy. She was among the many babies who, though carried to term, needed extra time to mature.
Last Thursday, Lefton-Greif watched the video screen as Joshua Foxwell, a premature infant whose family lives in West River, sucked formula from a bottle. Though the milk usually steered clear of his windpipe, a sizable stream took a wrong turn less than a minute into the study.
Lefton-Greif had seen enough and called a halt to the exam. The infant, who was born 12 weeks early and suffers from chronic lung disease, may also need a feeding tube to give his nervous system more time to develop.
"What other babies do in utero, [premature babies] do afterward, and they are a little bit slow in doing it," she said.
Darbari said he sees older children who experience pain upon swallowing because of abdominal growths that press on the esophagus. Others suffer from achalasia, the failure of the lower esophagus to relax and let food enter the stomach.
Though medication and surgery can correct some problems, others yield to therapy.
Therapists can help children learn to use utensils and coordinate chewing and swallowing. In some cases, therapists will introduce small quantities of food with initial feedings, then increase the amount as the child becomes more adept.
Swallowing experts stress the importance of early intervention, which can prevent lung infections and help children grow. There may be a long-term reason, too.
"Swallowing disorders in childhood might cause lasting damage that shows
up in adulthood," Lefton-Grief said.
Copyright © 2004, The Baltimore Sun