A baby's troubled breathing puzzles doctors

Jack's cry was so weak that Laura wouldn't have heard it if she hadn't already been awake.

Earlier that evening, the new mother had noticed that Jack seemed less interested in nursing, but didn't make much of it. But when she heard his soft cry at 2 a.m., she ran to gather him from his crib. There was something different about this cry, and Laura found Jack limp and struggling to breathe.

She immediately woke up her husband, Glenn, and rushed their 2-month-old son to the hospital.

The doctors found that Jack had poor muscle tone, and were concerned about the long pauses in his breathing. Also, he had been constipated for the last four or five days. Initially, Laura thought this was probably because Jack was exclusively breastfed. Now she wasn't so sure.

His breathing worsened, and Jack was admitted to the intensive care unit.

Laura and Glenn were asked many questions as the doctors and nurses tried to determine the cause of Jack's illness.

They were most concerned about an infection, even though Laura and Glenn had been extra careful to protect Jack from any germs. The baby's older brother and sister were attending school, but they hadn't been sick since Jack was born, and they weren't allowed to hold him without washing their hands; the kids always seemed to be bringing viruses home from school.

Glenn, a contractor, had spent the last few weeks working at home on an addition to their house - the extra space would allow Jack to have his own room. Nothing had seemed out of the ordinary until that night.

Jack's doctors started by testing his blood and urine. They performed a spinal tap to look for any signs of inflammation or infection in the fluid surrounding the brain and spinal cord.

Test after test came up negative. Jack's muscle weakness, though, continued to worsen before their eyes.

Stumped, Jack's doctors called the hospital's neurology team.

Without much to go on, the neurologists who saw two-month-old Jack decided to perform electromyography, a technique used to evaluate electrical activity produced by skeletal muscles. The results showed something unusual: Jack's nerves were not able to stimulate his muscles normally.

Based on these findings, the doctors were immediately worried about a rare but serious condition: infant botulism. If Jack wasn't treated immediately, his disease could get worse. Much worse. He could eventually stop breathing, requiring a breathing tube and a ventilator.

Infant botulism occurs when a baby swallows spores produced by the bacterium Clostridium botulinum. Once in a baby's intestine, the spores grow into bacteria that produce the world's most powerful toxin; as little as billionths of a gram can cause disease. In Jack's case, the toxin circulated around his body and blocked the ability of his nerves to cause his muscles to contract.

Infant botulism occurs only in babies less than one year old. And it's different from the kind of botulism found in children and adults, who typically ingest the toxin from contaminated foods - not the spores that make the bacteria, which make the toxin.

The reason for the difference isn't known. It could be that infant stomachs don't make as much acid as adult stomachs, so babies aren't able to kill the spores as easily. Another possibility is that it takes a while for "good" bacteria to begin to inhabit the gut as babies grow, which might in turn protect against growth of C. botulinum even if the spores are ingested.

Many parents are told to avoid giving honey to babies under a year, because this is the only known, preventable source of the spores that appear to cause the disease. Most cases of infant botulism now, however, are believed to occur when babies swallow the spores from invisible particles of dust or dirt in the environment.

Pennsylvania has some of the highest soil levels of C. botulinum spores in the United States. It's not clear why, but Pennsylvania also reported the second-highest number of cases of infant botulism (21), behind California (36), in 2012, according to the U.S. Centers for Disease Control and Prevention. There were only 122 cases reported nationwide; New Jersey (six) was fourth-highest.

Jack's doctors believed that he had likely swallowed spores that entered the air during the recent construction on his family's home.

Once the diagnosis was made, Jack was treated with antibodies that inactivate the toxin. The powerful antitoxin (called Baby BIG, for botulism immune globulin) is one of the most expensive drugs on the market. A single dose costs about $42,000.

After receiving just one dose, Jack quickly began to move normally again, and no longer required any help with breathing. Three days later, he was doing so well that he was discharged home from the hospital.

These days, Jack is developing like any other six-month-old. And there are no lasting effects from his illness, other than his parents' memories of how frightening a case of infant botulism can be.

- Amelia Keaton