Trouble in the Nursery

The dog provides a clue to a family's puzzling seizures.

By Pamela Grim|Friday, September 01, 2006
RELATED TAGS: SEIZURES

Chief complaint: "My dog had a seizure."

I scratched my head and looked around. Was somebody pulling my leg? I scanned the chart: "Thirty-two-year-old female with history of seizures." What? Was she worried that epilepsy was contagious, like the avian flu, and that the dog had caught it?

Three generations sat in the room—grandmother,daughter, and granddaughter. The granddaughter was a year old, maybe a little older. Usually a baby in a good mood can lift my spirits like nothing else. But the baby in this room was not happy. She sat in her mother's lap, head dangling, looking at nothing. Mom was stick thin,worn looking and with disheveled hair.

"Something is just not right," were the first words she said to me.

I had to agree. "Well then, tell me your story."

She began at an odd place. "When I got pregnant, I decided I didn't want to stay with the guy. I wanted to live with my mom, and my place was this dinky studio..."

The grandmother picked up seamlessly: "I was so excited, but she couldn't live with me in that studio, so I bought a ramshackle old house."

Her daughter broke in. "But it's big, big enough for a room for me and a room for the baby..."

"And the dog," the grandmother added.

"The only problem was the view," the daughter continued. "We overlooked a smelter, and there was an asphalt factory down the road. Things went OK through the pregnancy, except I kept having morning sickness the whole time. I was even having morning sickness after I delivered. The baby was born three weeks premature. She was OK, though. Then about two months later, I had a seizure. Two seizures—two in one day."

"There is no history of seizures in the family," the grandmother said.

I thought of preeclampsia, a poorly understood hypertensive condition that can cause seizures in the late stages of pregnancy. But the timing was wrong. A patient can experience symptoms as late as a few days after the delivery, but not two months later.

The daughter said that a workup had found no cause for the seizures. "They told me it runs in families. I probably inherited it from somebody."

"Seizures do not run in our family," Grandmother repeated.

Two months after her first seizures, the daughter had a third. Her doctor started her on an anticonvulsant, phenytoin, and then switched her to a newer, more expensive drug. She was fine for more than six months, and then another disaster struck: The baby, who had just started to crawl, had a seizure.

"Did she have a fever?" I asked. High fevers are a common cause of seizures in children.

"No," the daughter said. "They did all sorts of tests—brain scans and heart scans and lung scans and what-all scans. And after everything, the doctor told me that there must be a family history of seizures and that I just didn't know about it. But I know everybody back to my great-granddad, and I can tell you that there's a few horse thieves out there, but nobody with seizures.

"Today, just one month later, our dog got the fits," she tacked on. "Flossie was just stiff-legged and shaking, and he looked just like my daughter when she had her seizure. So in a little over a year, me, my daughter, and my dog got seizures. That ain't right."

I didn't know where to begin.

Mom, however, offered a possible cause. "Could it be the smelter down the road?" she asked. "We've got the smelter smell most of the time."

I didn't know, so I ordered a standard set of laboratory tests.

Diagnosing a disease begins with making a list of the disorders that can cause the patient's symptoms. The causes of seizures range from epilepsy to brain injury to electrolyte imbalance. The next step is to look for clues in the patient's medical history, the physical exam, and results from laboratory tests to narrow the list.Our laboratory had a couple of gifted employees, and I had picked up their habit of searching the complete blood count for clues. The test results for this patient showed a problem in her red blood cells.

Normal red blood cells have a uniform red blush. But my patient's red blood cells contained bluish-purple staining granules,which are a form of nucleic acid protein. Their presence suggested a toxic insult to the bone marrow where the red blood cells are formed. Only a few conditions are known to cause this feature, which is called basophilic stippling. The causes are severe bacterial infection,exposure to certain drugs, end-stage alcoholism, bad hereditary anemia,and lead poisoning.

The patient had been on the right track. Somehow this family—the dog included—had been exposed to lead. But do dogs even get lead poisoning? I went online to Google and tapped out "dogs" and "lead poisoning." There were 3,150,000 hits.

I ordered a lead level on Mom and made arrangements for her daughter to see a pediatrician. I explained that lead poisoning was a possibility.

About a week later the patient dropped by with the test results. Her lead level could have stopped a bull elephant dead in its tracks. She had figured out the source of the lead—and it wasn't the smelter. Although paints containing lead were banned for use in American homes in 1978, older structures are still a worrisome source of exposure. Their home's interior had been painted with lead-based paint at some point, but it had been meticulously stripped away from every room except one. That room had been wallpapered, and it had become the baby's room. The patient and her mother had stripped the wallpaper away and tried to sand down the leftover paint, but they probably hadn't done the job well enough.

Mom probably got her initial dose of lead when she stripped off the wallpaper while she was pregnant. The baby had been relatively protected until she started to crawl on the floor and came across leftover paint chips and lead dust. As for the dog, the veterinarian confirmed that he, too, had lead poisoning.

The only treatment for high levels of lead poisoning—and it is far from a perfect cure—is chelation therapy. The word chelation derives from the Greek word for claw. Imagine a giant molecular claw reaching out and grabbing a lead molecule and then spiriting it away for excretion. That's how a chelating agent works. The treatment, which can be given orally or intravenously, may require a weeklong hospital stay.

I didn't know how this child and her mother would fare. What I did know is that infants and children are far more vulnerable to high levels of lead exposure than adults. Although lead poisoning affects all organ systems, the nervous system is particularly susceptible. The body mistakes lead for calcium, a mineral that is crucial to cell signaling throughout the body. The metal so disrupts cell communication in the brain that it causes subtle deficits ingrowing minds. Other environmental factors can heighten the insult. A high-fat diet, for example, increases the body's vulnerability to lead toxicity; a diet rich in green vegetables helps minimize the impact. I hoped that catching the poisoning early would minimize the damage.

Preventing lead poisoning from the outset through public-health measures and education is far easier than trying to undo the poison's damage after the fact. Identifying lead poisoning isn't what busy emergency room doctors do best. But sometimes the most important clues to a case come where they are least expected—in this case, from man's best friend.

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