An Old Man's Liver Harbors Hundreds of Tapeworms

Unbeknownst to him, the patient has hosted a huge colony of larval tapeworms for decades.

By Claire Panosian Dunavan|Monday, April 07, 2014
Dog tapeworm larvae can form enormous cysts in the liver and other organs, causing a disease known as hydatidosis.
Sinclair Stammers/Science Source

What would you do if you had huge parasitic cysts? That could burst at any moment? And spill thousands of babies?

My new patient, an elderly Armenian who recently moved to the United States, didn’t speak much English. He didn’t need to. His penetrating gaze — anxious, wary and pleading all at the same time — revealed his inner thoughts. He had one overriding goal: to make his problem go away ASAP.

I also wanted to vanquish his parasitic invader and restore his peace of mind. But major abdominal surgery in a man nearing 80? About that, I wasn’t so sure.

After trading emails with a local radiologist, I was finally meeting Mr. Kazaryan face to face. From his CT scan, I already knew the bulging landscape of his liver. His X-rays revealed a textbook case of Echinococcus granulosus, or dog tapeworm infection. Within two huge sacs (called hydatid cysts) that occupied two-thirds of his liver, Kazaryan harbored hundreds, if not thousands, of budding tapeworm larvae. In my 30 years as an infectious diseases specialist, I had never seen such a huge cache of parasites.

“Is it true you’ve never experienced any discomfort?” I asked, marveling at the scope of his infection. Yes, he nodded, until a few weeks earlier when an internist discovered his massive, rubbery liver. At that point, Kazaryan started to suffer fretful, sleepless nights — not, as far as I could tell, from physical pain. Just old-fashioned fear.

I clipped Kazaryan’s X-ray films to the light box in my consultation room. Moments later, he and his wife and their daughter-in-law, who was his translator, huddled close as I pointed out the two watery gray-and-white silhouettes in his liver. The largest shadow was as big as an eggplant. Its nearby satellite resembled a ring of bell pepper. Scattered through the remaining tissue were other dots and blots. Were they more larvae waiting to bloom? I wished I knew. 

The most immediate threat to my patient was not continued invasion, but a forceful blow to his belly. I could picture him slamming his brakes in a big-city traffic jam, hitting the steering wheel, bursting the capsule of his megacyst and — seconds later — his blood pressure falling to zero. Rapid leakage of echinococcal parasite proteins into the human bloodstream can trigger dramatic allergic collapse, even death.

“Well, Mr. Kazaryan,” I began, feeling three pairs of eyes on me. “These certainly look like hydatid cysts. Just to make sure, we’ll do a blood test. Assuming it’s positive, you’ll then start an anti-parasitic drug called albendazole. The drug won’t cure you, but it should prevent further growth of the cysts.”

Kazaryan’s daughter-in-law, a nursing student, spoke up. “In Armenia, we have learned, they often operate on this condition. Is that another possibility?”

“Yes,” I replied. “But it could be risky. Let’s talk about surgery after we’ve confirmed the diagnosis, OK? We have time. I know it’s hard to believe,” I added. “But your father-in-law has had this disease for decades.”

She looked a bit dubious but remained polite. “Of course, doctor. We’ll start with the blood test.”

How to Vanquish a Worm

Mention tapeworms, and most people think of the fully grown variety: long, ribbonlike creatures slithering in someone’s gut. Most commonly contracted by eating undercooked pork, beef or freshwater fish containing larval blebs, adult intestinal tapeworms spark fanciful lore. Can they really scarf calories and make people svelte? Don’t count on it. They may absorb a few nutrients through their delicate skin, but their metabolic needs are surprisingly low.

Larval tapeworms, on the other hand, are acquired by ingesting tiny eggs passed in the stool of animals or humans carrying adult parasites. Silently breaching the intestinal lining, then morphing into juvenile stages, the microscopic parasites eventually find their way into a congenial organ. Then they slowly grow … and grow … and grow. Pork tapeworm larvae typically lodge in the human brain and can eventually cause seizures, severe headaches and blockage of cerebrospinal fluid. In contrast, larval dog tapeworms, the kind my patient harbored, most commonly seed the liver and lungs.

There’s a good reason why dog tapeworm infections are relatively rare in industrialized nations. The surprisingly puny adult E. granulosus (in a dog’s gut, it measures a mere quarter-inch) is found mainly in rustic locales throughout the world where dogs still herd sheep and sometimes consume their viscera. Eating the parasitized sheep flesh allows canines to acquire their own intestinal worms. 

Paradoxically, Kazaryan told me, he never liked dogs. Of course, he didn’t have to. To acquire his blight, he needn’t nuzzle one; he merely needed to swallow a tiny egg passed in the animal’s stool. That egg, in turn, might have lived for weeks or months in soil or vegetation before it ever entered him. I was sure of one fact, however: The fateful swallow of the wee ovum occurred in Kazaryan’s native Armenia.

After his blood test came back showing he was indeed infected with E. granulosus, I started him on daily albendazole to halt the progression of his disease, as we had discussed. But that was just a prelude to a more definitive solution. Over the next week or two, I weighed the latest data and treatment options for a massive E. granulosus liver cyst. 

Recent studies confirmed that anti-parasitic drugs like albendazole could sometimes melt smallish echinococcal cysts without further intervention. Alternatively, combining albendazole with trans-abdominal cyst puncture followed by a killing flush of alcohol or concentrated saline had successfully shrunk cysts of various sizes in several thousand sufferers residing in low- and middle-income countries. But albendazole plus classic surgical excision remained the treatment of choice for patients with really large or complex masses — especially those whose cysts were on the verge of rupture.

Well, I decided: That describes Mr. K. It was time for him to meet my colleague, Ron Busuttil, a surgeon at the University of California at Los Angeles.

Mass Exit

Living in the United States, it’s easy to take surgery for granted. By surgery, I don’t just mean the elegant craft itself, but all the ancillary care — from anesthesia to blood replacement to skilled post-op management — that helps assure a happy surgical outcome. Surgeons in developing countries often lack such support, while patients in rural areas where E. granulosus is endemic may lack access to hospitals altogether. This explains the ongoing need for less-invasive treatments for many of the 2 million to 3 million echinococcal sufferers worldwide.

Mr. Kazaryan was lucky. He was not only at a gleaming, modern medical center — he was about to become a patient of the best of the best, a world-famous liver transplant surgeon who over the years has operated on dozens of echinococcal patients. Busuttil didn’t blanch at Kazaryan’s advanced age or his enormous cysts. On the other hand, he never forgot a paramount risk of any echinococcal operation: During surgery, even a spatter of cyst contents could plant many more.

“We go on red alert as soon as we’re in the OR and take every precaution against spillage,” my colleague told me recently. He also described his careful search for the fibrous plane separating cyst wall from healthy liver. When a surgeon dissects along that plane, his scalpel is far less likely to trigger bleeding.

In Kazaryan’s case, the operation went as planned. After surgically exposing the liver, Busuttil vacuumed 2.5 liters of larvae-laced fluid from the huge carbuncle distending the organ’s surface. He then irrigated the cyst cavity with concentrated saline to kill additional embryonic larvae, trimmed tissue from the inner so-called “brood” lining of the cyst and, finally, using an argon laser device, he vaporized the remaining parasite membrane. Then he removed the second, smaller cyst entirely. 

Before closing, he repaired minor bile leaks and controlled bleeding vessels. Kazaryan returned to the recovery room in stable condition.

Five days later, Kazaryan suffered a cardiac setback, corroborating my fear that major surgery in a man his age might have unintended consequences. Fortunately, a delicate procedure corrected the problem, and he soon left the hospital.

Today, I see him every few months, admire his well-healed scar, check his blood tests and refill his prescription. When we meet, he always smiles and gives me a firm handshake. God willing, he’ll now live well into his 90s, just like his dad.

Claire Panosian Dunavan is a professor of medicine and infectious diseases at UCLA. The cases described in Vital Signs are real, but names and certain details have been changed. 

[This article originally appeared in print as "Unknowing Host."]

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