Nurse helps diagnose an uncommon parasitic infection
Two Ascaris lumbricoides nematods, i.e., roundworms. Photo credit: CDC
It was summertime in our pediatric office — typically a time for staff to begin recovering from the hectic winter season. My first patient was a two-year-old Hispanic female with “worms.” The family lives on a farm in the county and water is supplied via well. The mother is five months pregnant, and there are two cows and a horse on the property, as well as farm cats and dogs.
The mother states that she has saved the diaper from two days ago to show me the worm. The child's history of present illness is unremarkable. She denies nausea, vomiting, constipation, and abdominal pain and is afebrile. Her physical exam is normal. There is no redness around the rectum. Pinworms were at the top of my differential diagnosis.
The diaper is taken out of the exam room and opened to reveal a white-yellow colored, 2-inch long, 1 mm in diameter, cylindrical string-like specimen. The specimen is sent to lab for evaluation and Ascaris lumbricoides — a roundworm that can invade a human host — is identified as the culprit.
The typical symptoms of A. lumbricoides are mild digestive symptoms, nausea, and worms in either stool or emesis. We consulted with an infectious disease physician, and the recommendations were to obtain serum complete blood count with the differential for an eosinophil count. The eosinophil count would increase in response to a large parasitic burden.
Since A. lumbricoides may also invade the lung and brain tissue in the human host, we discussed whether to obtain brain MRI or chest x-ray but without any other symptoms, we chose not to pursue imaging studies at that time. Complete blood count with normal white count and eosinophil count were within normal range.
We initiated a county health department referral, and the county went to the farm to test well water for parasites. The well water was negative for A. lumbricoides. The parents were quite concerned about source of worm, and their concerns were discussed with a veterinarian.
The vet stated that it was unlikely that A. lumbricoides parasites in farm cows or horses would seek a human host. However, the father recalled that a farm pig had died earlier in the year from worms — so the pig, being that pig anatomy parallels human anatomy, was the most likely source of the current A. lumbricoides infection. The soil from around the house was the most likely source of the A. lumbricoides parasite, which invaded this child as a host.
The recommended treatment for A. lumbricoides is mebendazole, and the entire family was to be treated. The mother was five months pregnant, and we consulted her obstetrician to determine whether treatment was safe. The decision was that the benefit of treatment outweighed the risk that the A. lumbricoides posed to the fetus; the mother was also prescribed mebendazole.
One week later, the mother again brings in diaper with a live A. lumbricoides. The child was retreated with mebendazole without further incidence.
What an interesting day in the life of a pediatric nurse practitioner!