White object found moving in infant’s diaper
What’s your diagnosis?
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A 1-year-old boy is brought to your urgent care clinic after his mother found a white object similar to a grain of rice in his stool during a diaper change.
She was alarmed when she saw this object move slightly, which prompted her visit. There are no other complaints of current or recent illnesses, and his stools have been consistently normal in appearance. The baby’s immunizations are up to date for his age, and there are no sick contacts at home or elsewhere of whom the mother is aware. The baby’s diet consists of store-bought baby foods, including rice cereal. Also, the mother occasionally feeds the baby pureed vegetables that she makes at home.
The baby’s past medical history and family history are unremarkable, and there has been no travel. There are two healthy school-age siblings and both parents in the home. No other family members have noticed anything unusual with their stools. The only animal exposure is to the family dog and two cats, all of which are both indoor and outdoor pets.
Examination of the baby is that of a normal, healthy-appearing infant male. The mother brought in the diaper with normal, yellow stool. She had removed the oblong white object, shown in Figure 1, along with some uncooked grains of rice for comparison.
The object was taken to the lab, where it was carmine stained (Figure 2), showing two openings and containing numerous objects.
What’s your diagnosis?
A. Ascaris lumbricoides
B. Dipylidium caninum
C. Enterobius vermicularis
D. Partially digested rice
Answer and discussion:
The answer is B, Dipylidium caninum, which is the dog tapeworm. The word Dipylidium is the name of the genus of this tapeworm, which comes from the Greek word dipylon, meaning having two entrances, which presumably comes from having a genital pore at each lateral margin of the proglottid. Of course, the species caninum comes from the Latin word for dog. This tapeworm is fairly common among dogs and some cats; however, human disease is uncommon and is usually confined to young children and infants, although adults can also acquire it — essentially anyone who comes in face-to-face contact with their dogs, as noted below.
Each proglottid contains a variable number of egg packets, as shown in Figure 3. Each egg packet contains five to 15 eggs, and each egg containing an oncosphere (a tapeworm embryo). In nature, the proglottid is found in the soil where dogs defecate. Once liberated from the proglottid, the eggs in the soil are ingested by the larvae of the dog flea. As the larvae of the flea matures, the tape worm also goes through larval stages. Therefore, the flea serves as the intermediate host. When the flea bites the dog, the dog nips at the flea, thereby crushing it between its teeth, and the tapeworm cysticercoid larvae are then swallowed, which in the gut goes on to develop into an adult, intermittently releasing proglottids filled with egg packets. The usual way a human swallows a cysticercoid larvae is to “French kiss” their dog soon after the dog has crushed the flea in its mouth, with accidental transfer from the dog’s mouth to the happy, unsuspecting family member. By the way, the word cysticercoid is derived from the Greek words “kystis,” meaning bladder, plus “kerkos,” meaning tail. This term is generally used to describe the larval form of tapeworms, which are enclosed in a bladderlike cyst, before transforming into the adult.
Most children have no symptoms of the dog tapeworm, and it comes to their attention just as the case shown here. However, some may have mild abdominal discomfort or diarrhea, in which case praziquantel can be used in children as young as 6 months of age. It has been shown to be safe and effective, although not approved for this indication. Alternatively, doing nothing causes no harm, and because the worms are not adapted to thrive in the human gut, they are usually eliminated within 6 weeks. They may be eliminated intact, as shown in Figure 4.
Another roundworm (nematode) is Ascaris lumbricoides, the largest of common human worms, found mostly in tropical and subtropical regions, including the Southern United States. This migrating worm may cause no symptoms at all, or it may present with cough during the pulmonary phase (Lffler syndrome, aka eosinophilic pneumonia). A low worm burden may cause no gastrointestinal symptoms but may be discovered by passing a worm in the stool. Figure 5 shows a large adult Ascaris worm suitable for fish bait, found in the toilet after an asymptomatic child passed it. Intestinal obstruction is very uncommon but possible with a high worm burden.
The very small, humble pinworm (Enterobius vermicularis) is usually diagnosed by seeing this tiny roundworm about the anal opening, when they migrate out to deposit their eggs, or within a stool sample during diaper changes (Figure 6).
Sometimes they are diagnosed by seeing the eggs (Figure 7) using the simple “tape test” that we were all taught to do in residency.
Lastly, I am not sure what undigested rice would look like but not likely as shown in Figure 1.
Columnist comments:
With winter upon us, children are spending more time playing inside their home, and thus more likely to be in close proximity to their dogs. At least, that was the case when the patient in this scenario found their way to my infectious disease clinic at Brooke Army Medical Center in Fort Sam Houston, Texas, in the mid-1980s. I eventually showed this case in the March 1995 issue of Infectious Diseases in Children — over 28 years ago. With regard to diagnosis and treatment, not much has changed since then. As a child, I never let my dog, Ginger, lick me about the face. She was a friendly dog, but I was never inspired to get that close to her. However, I can understand why some children and adults seem to enjoy allowing their dog to lick them about the face and mouth. It appears to be a fairly harmless activity, and as some claim, an activity with possible benefits to one’s immune system. Nonetheless, I’ll take my chances with immunizations over the tongue of a dog.
Happy holidays from my family to yours, stay safe while traveling and please keep in touch.
For more information:
Brien is a member of the Healio Pediatrics Peer Perspective Board and an adjunct professor of pediatric infectious diseases at McLane Children's Hospital, Baylor Scott & White Health, in Temple, Texas. He can be reached at jhbrien@aol.com.