The neatnik side of my patient’s personality, his obvious preference for cleanliness and order, made his infestation especially poignant. No one likes the idea of harboring worms, but highly meticulous people suffer most of all. Finally, on top of everything else, the man was having on-and-off stomach pain. Before the colonoscopy, he’d had two emergency CT scans. When I asked why, he replied, “Frankly, doc, I was sure I had appendicitis
.” Then he gingerly pressed his abdomen. “Sometimes I still do.”
Ouch, another curveball. In my experience, the localized tenderness in his lower right quadrant didn’t fit either parasite.
OK, enough second-guessing, I finally decided; there was no mystery about the next step. The ultimate proof of infection resided on microscope slides at another laboratory. After two or three phone calls, they were en route to my hospital for a second opinion.
A week later, our senior parasitology tech reported back. “Well, there’s no strongyloides in these specimens,” she said in a voice faintly tinged with regret, “but he’s sure loaded with pinworms, including really young larvae. I can see how the other folks got confused.” Soon a blood test negative for strongyloides confirmed her finding.
Now it was time to tell the patient. Not surprisingly, anger was his first reaction to the news that he’d been misdiagnosed. After all, by then he had spent many a sleepless night picturing evil strongyloides swarming his internal organs. His mood quickly brightened once he grasped that he had only pinworms, a far less ominous pathogen.
There was just one more mystery to solve: my patient’s continuing abdominal pain. Once in a while the attacks were so severe he felt he had no choice but to page me late at night. I was not about to rouse a surgeon from bed. But I started to wonder: Could a really bad case of pinworms mimic appendicitis? I went online and began to read.
Yes and no, according to recent research studies. In surveys published between 1991 and 2006, as many as 4 percent of surgically removed appendixes contained pinworms—an impressive statistic until one recalls that, in the United States alone, up to 20 million people are thought to harbor them. In other words, in terms of cause and effect, merely finding enterobius in an excised human appendix proves nothing.
But before abandoning my hypothesis altogether, I had one more mission—a trip to our medical school library. There, in a lonely corner of the stacks, I hit pay dirt: a 1950 paper titled “Pathology of Oxyuriasis: With Special Reference to Granulomas Due to the Presence of Oxyuris vermicularis (Enterobius vermicularis) and Its Ova in the Tissues,” by W. S. Symmers, an early 20th-century dean of tropical medicine pathologists.
In his masterful paper Symmers reviewed the autopsy findings of patients with incidental pinworm infection diagnosed after death, describing several whose postmortem tissues revealed inflammatory nodules around worms that had “strayed from their usual haunts and died, and around ova deposited in the course of such anomalous wanderings.”
Symmers’s elegant prose provided just the insight I had been seeking. After all, who could say my patient’s gut had not harbored stray, wandering pinworms for decades since childhood—just as Symmers’s subjects had harbored their worms up to and beyond the grave? And surely, after so long an infestation, I reasoned, cast-off eggs, dying worms, and little patches of inflammation near the appendix would trigger periodic pain in at least a few pinworm victims, right?
It was hardly proof positive, but, thus armed, I felt ready to tell my patient two things. First of all, that he should be thankful that his colonoscopy had revealed his strange case. And second, that with modern drugs and the tincture of time, I believed his painful attacks would slowly subside.
I like to think I was right. In any event, over the past year his midnight pages have stopped.
Claire Panosian Dunavan, an infectious diseases specialist at UCLA Medical Center, is president of the American Society of Tropical Medicine and Hygiene. The cases described in Vital Signs are real, but the patients’ names and other details have been changed.