Chief complaint: "My dog had a seizure."
I scratched my head and looked around. Was somebodypulling my leg? I scanned the chart: "Thirty-two-year-old female withhistory of seizures." What? Was she worried that epilepsy wascontagious, 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 alittle older. Usually a baby in a good mood can lift my spirits likenothing else. But the baby in this room was not happy. She sat in hermother'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, Idecided I didn't want to stay with the guy. I wanted to live with mymom, and my place was this dinky studio..."
The grandmother picked up seamlessly: "I was soexcited, but she couldn't live with me in that studio, so I bought aramshackle 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 daughtercontinued. "We overlooked a smelter, and there was an asphalt factorydown the road. Things went OK through the pregnancy, except I kepthaving morning sickness the whole time. I was even having morningsickness after I delivered. The baby was born three weeks premature.She was OK, though. Then about two months later, I had a seizure. Twoseizures—two in one day."
"There is no history of seizures in the family," the grandmother said.
Ithought of preeclampsia, a poorly understood hypertensive conditionthat can cause seizures in the late stages of pregnancy. But the timingwas wrong. A patient can experience symptoms as late as a few daysafter the delivery, but not two months later.
About a week later the patient dropped by with the testresults. Her lead level could have stopped a bull elephant dead in itstracks.
The daughter said that a workup had foundno cause for the seizures. "They told me it runs in families. Iprobably inherited it from somebody."
"Seizures do not run in our family," Grandmother repeated.
Two months after her first seizures, the daughter had athird. Her doctor started her on an anticonvulsant, phenytoin, and thenswitched her to a newer, more expensive drug. She was fine for morethan six months, and then another disaster struck: The baby, who hadjust 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 oftests—brain scans and heart scans and lung scans and what-all scans.And after everything, the doctor told me that there must be a familyhistory of seizures and that I just didn't know about it. But I knoweverybody back to my great-granddad, and I can tell you that there's afew 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 helooked just like my daughter when she had her seizure. So in a littleover a year, me, my daughter, and my dog got seizures. That ain'tright."
I didn't know where to begin.
Mom, however, offered apossible 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 thedisorders that can cause the patient's symptoms. The causes of seizuresrange from epilepsy to brain injury to electrolyte imbalance. The nextstep is to look for clues in the patient's medical history, thephysical exam, and results from laboratory tests to narrow the list.Our laboratory had a couple of gifted employees, and I had picked uptheir habit of searching the complete blood count for clues. The testresults for this patient showed a problem in her red blood cells.
Normal red blood cells have a uniform red blush. But mypatient's red blood cells contained bluish-purple staining granules,which are a form of nucleic acid protein. Their presence suggested atoxic insult to the bone marrow where the red blood cells are formed.Only a few conditions are known to cause this feature, which is calledbasophilic 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 arrangementsfor her daughter to see a pediatrician. I explained that lead poisoningwas a possibility.
About a week later the patient dropped by with the testresults. Her lead level could have stopped a bull elephant dead in itstracks. She had figured out the source of the lead—and it wasn't thesmelter. Although paints containing lead were banned for use inAmerican homes in 1978, older structures are still a worrisome sourceof exposure. Their home's interior had been painted with lead-basedpaint at some point, but it had been meticulously stripped away fromevery room except one. That room had been wallpapered, and it hadbecome the baby's room. The patient and her mother had stripped thewallpaper away and tried to sand down the leftover paint, but theyprobably hadn't done the job well enough.
Mom probably got her initial dose of lead when shestripped off the wallpaper while she was pregnant. The baby had beenrelatively protected until she started to crawl on the floor and cameacross leftover paint chips and lead dust. As for the dog, theveterinarian 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 chelationderives from the Greek word for claw. Imagine a giant molecular clawreaching out and grabbing a lead molecule and then spiriting it awayfor excretion. That's how a chelating agent works. The treatment, whichcan be given orally or intravenously, may require a weeklong hospitalstay.
I didn't know how this child and her mother wouldfare. What I did know is that infants and children are far morevulnerable to high levels of lead exposure than adults. Although leadpoisoning affects all organ systems, the nervous system is particularlysusceptible. The body mistakes lead for calcium, a mineral that iscrucial to cell signaling throughout the body. The metal so disruptscell communication in the brain that it causes subtle deficits ingrowing minds. Other environmental factors can heighten the insult. Ahigh-fat diet, for example, increases the body's vulnerability to leadtoxicity; a diet rich in green vegetables helps minimize the impact. Ihoped that catching the poisoning early would minimize the damage.
Preventing lead poisoning from the outset throughpublic-health measures and education is far easier than trying to undothe poison's damage after the fact. Identifying lead poisoning isn'twhat busy emergency room doctors do best. But sometimes the mostimportant clues to a case come where they are least expected—in thiscase, from man's best friend.
Read Frequently Asked Questions about lead poisoning from the CDC.
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