It's early evening, the pediatricians’ offices are all closed, and the waiting room is filling up. Typical crunch time for the Pediatric ED at your hospital. You look up at the board and see that a possible sexual assault just got placed in a room. No way you’re going to proceed very quickly on that one. And what is this world coming to anyway, the kid’s only 6 years old! You send the resident down the hall to get started.
The resident gives you that deer-in-headlights look. They are very uncomfortable with the forensic exam. You reassure her that you’ll be there to back her up and dispatch her to the patient’s room. A while later, she returns with the story.
The child was at her usual babysitter’s house this afternoon. The babysitter walked into a bedroom and found the child alone with her pants pulled down to her knees, touching her genitals. The babysitter didn’t question the child but brought it up when the mother came to get her. The babysitter is female. She keeps the patient, and two toddlers, all female. There have been no other people at the house today. Mom is very concerned that her daughter has been "messed with".
The past medical history and family history are unremarkable and there are no flags in the social history. The household consists of the mother, father and 18-month-old sister. The father would "never do anything like that" per Mom. The child’s been with the same babysitter for over a year. There are no adults in the household except the babysitter.
You ask the resident about the physical exam and get a blank stare. She thought you were going to be there for that. And don’t you need to page the Sexual Abuse Nurse Examiner (SANE) on call?
Your hospital just instituted a SANE program a few years ago. As a tertiary referral center, you were always being sent forensics cases. Before the SANE program started, there was too much variation in the way evidence was collected and documented. The SANES are very good at getting high quality evidence with good charting and follow-up. But after hours, the SANE has to be called in from home. You tell the resident that you need to do your own physical exam before making someone come in. Off you go to see the patient.
The child is calm and looks clean and well cared-for. After talking for a bit to build up some rapport, you ask the child if you can speak to her alone, but she clings to her mother and you decide not to push the issue. You give her a gown to change into "like a big girl", so there won’t be any drama associated with undressing her later. Then, in a calm and unhurried manner, you give her a check-up, just like her regular doctor does, so she can get used to you. After spending the customary time looking in her ears, listening to her heart, and all the usual things, you have bought her trust and you matter-of-factly proceed to the genital exam, reminding her that it’s ok for the doctor and her parents to check her there, but nobody else.
The first position you exam her in is the frog-leg position, lying flat on her back with her legs apart and her heels together. After inspecting her, you gently retract her labia to look at her vaginal opening. And there, wiggling around and practically waving at you, is a pinworm. There are no notches, bruising or tears. Her hymen is a half-moon or crescentic shape and looks normal. By now you’re pretty sure that you know why she had her pants down at the babysitters. But just to be sure (especially as you’re teaching the resident), you have the child get into the knee-chest position. To do this, you have the patient get on all fours and then sink her chest down on her bent forearms, leaving her rear end in the air. In this position, again with a little, gentle labial traction, you can see the vaginal area in a different way, in case you missed anything the first time. Nope, same worm, no tears or notches. This position is also good for viewing the anus. And to no surprise, her peri-anal region is teeming with worms.
You show the mom, who is a bit grossed out, but hugely relieved that there is a clear explanation for her daughter’s behavior at the sitter’s. It seems that the only one who has molested her daughter is enterobius vermicularis. You explain that pinworms are a common infestation of young children. They get it by ingesting eggs, which are carried on fingernails, bedding and clothing. The larvae migrate to the colon where they set up shop, emerging every evening to lay their eggs in the anal region. This causes intense itching. They are then supposed to migrate back up the rectum, but in about 20 percent of cases, a worm goes into the vagina instead, causing vulvovaginitis. Obviously, if you see a worm the diagnosis is straight-forward. If you don’t, you can use the old "scotch tape test". Have the parent put a piece of scotch tape over the anal opening at bedtime. In the morning, remove it and you’ll see the egg, which looks like a slightly flattened football.
Mom then has one of those "come to think of it" moments, and reports the child has been scratching her bottom at night and not sleeping well lately.
You send her home with Mebendazole 100 mg—one to take tonight and repeat in two weeks. You prescribe enough for the entire household, as there may be others who are infected. They are also advised to wash the sheets, bedding, underwear and pajamas in hot water, to trim the child’s nails so the eggs can’t collect there, to reinforce hand washing after toileting and before eating or handling food, and send her on her way.