A Deadly Backache

The patient's symptoms seem simple, but their cause might prove far more serious

By Tony Dajer|Monday, January 01, 2001
RELATED TAGS: HEART DISEASE
He caught my eye the minute he strolled into the emergency room, just before midnight. He had wrapped both hands around his lower back and kept straightening up, as if to work out a kink. The resident examined him first.

"Seventy-one-year-old man with back pain," he reported. "Began six hours ago, and it's getting worse. Funny thing is, he didn't lift anything heavy, or fall. Should I give him something for the pain?"

"Can you find where it hurts?" I asked.

"I checked along his back. Nothing."

"Pulses?" I continued.

He frowned. "I forgot to check."

"Maybe," I said, "it isn't his back."

I went over to say hi. The patient had the weathered mien of a smoker.

"Hello, doctor," he said in a gravelly voice. "I need something for this pain."

I pressed up and down his back: no sore muscles or tender vertebrae. His belly hurt a little in the left lower quadrant. Above his navel, I felt carefully for a pulsing, painful fullness but found none. The pulses in his groin seemed a little uneven—: the right stronger than the left—: but I couldn't be sure. Most intriguing was the appearance of his legs. A lacy pattern of blue seemed to play over them, a mottling that suggested his blood wasn't circulating well.

"I'm not sure what's causing your pain," I confessed. "Until I am, I can't give you anything for the pain. It would only mask things."

"It hurts. Hurts like a bear, doctor."

"Soon as I can. I promise."

The resident and I stepped away.

"What are you thinking?" he asked.

"Triple-A: abdominal aortic aneurysm."

"But shouldn't we be able to feel it?"

"Not always. He needs a diagnosis," I said. "Preferably in the next five minutes."

It's easy to forget that the aorta arches off the heart, diving down through the diaphragm and running along the left side of the spinal column. At the level of the navel, it forks into two big arteries, the iliacs, to feed the lower body. Buried beneath the abdominal wall and the intestines, shielded from the rear by ribs and back muscles, the abdominal aorta lies at our very pith. Thick and resilient, it swells with every squeeze of the heart's left ventricle, then smoothly recoils to keep the pressure wave moving along. This elasticity is its Achilles' heel. Age, combined more often than not with the insults of cigarette smoking and atherosclerosis, can weaken the aortic wall in the upper abdomen until it balloons like a worn inner tube.

When an aneurysm gets too big or too weak, it bursts. If the tear is recognized and repaired immediately, about half of these patients survive. But aneurysms can also leak, ooze, or expand in so many ways that a good third of them end up misdiagnosed. Clinicians often expect to find a tender mass in the upper abdomen, but that clue isn't always present. Worse, the belly may not be particularly sensitive to an examining hand. In fact, aneurysms are usually asymptomatic until they start leaking, especially in overweight patients. As the blood oozes slowly into the tough tissues around the spinal cord, the symptoms can mimic anything from a kidney stone to diverticulitis to a slipped disk.

To exclude the possibility of an aneurysm, you need an ultrasound or a CAT scan. My hospital has no ultrasound at night, and the CAT scan was down. Moreover, our operating room could not handle major vascular surgery.

My hazy impression would have to do: He had to be transferred fast.

I called uptown for the vascular surgery resident. It took 10 minutes to get an operator, then another 10 for a sleepy voice to answer. "Vascular."

"Hi, this is Dr. Dajer," I said. "I've got a 71-year-old man, smoker, with increasingly severe back pain for six hours. His abdomen shows left lower quadrant tenderness. The left femoral pulse is clearly diminished. His legs are mottled."

Silence.

"I think he has a triple-A," I prompted.

"I can't accept him," he said in a dismissive tone. "Only the attending can."

My patient was grimacing. It had to be an aneurysm. Nothing else could account for such pain. I had no more time for dead-end calls.

But I couldn't transfer him yet. Federal laws make it illegal to ship out a patient without an accepting physician and a guaranteed bed on the other end. I called Don, who runs our hospital's ambulance service, and explained the situation.

"You really need this? I'll send one."

An emergency like this doesn't have to happen. Sometimes a doctor can detect an abdominal aortic aneurysm during a routine physical before it leaks and take preventive steps. Many doctors now recommend periodic ultrasounds for high-risk patients. Among people over 65, smokers have four to eight times the average person's risk; those with high blood pressure have double the risk.

A normal abdominal aorta measures 2 centimeters in diameter. When an aneurysm hits 5.5 centimeters, the risk of rupture is 5 to 11 percent. At 6.5 cm, the risk more than doubles.

Surgeons can mend the weakened aorta by clamping it, cutting out the ballooned section, and replacing it with a synthetic vessel. Still, this is an operation with a death rate of 2 to 11 percent. Large hospitals with extensive vascular experience give the best odds. It is a soul-searing choice: maybe die now, or probably die later. As a result, many experts recommend holding off on surgery until the aneurysm reaches 6 cm or grows more than a centimeter a year or starts causing symptoms.

Researchers are studying a less invasive method. In 1991, surgeons devised a graft that reinforces the aorta from within. First, a catheter is threaded through the groin artery to the level of the aneurysm. Then a sheath on the catheter is pulled back to let the tubular graft spring open and latch onto the vessel's wall with tiny hooks. When all goes according to plan, the new conduit then seals off the aneurysm from the circulation.

If this method works out, the 200,000 patients diagnosed each year could be spared major surgery, and perhaps smaller aneurysms could be repaired sooner. So far, the verdict is good but not definitive. Over a thousand have been inserted, with mortality rates ranging from 0 to 6 percent. One drawback is that many patients do not have the right plumbing for the graft. Their aortas are too heavily calcified or narrowed by blockages to hold the graft. More worrisome is the grafts' tendency to leak blood around their seals. This can occur in up to a third of the cases, often causing the aneurysm to keep on expanding. The follow-up time for most of these endovascular grafts has been six to 18 months, too short to know if there are long-term disasters looming. Moreover, a stampede to the new procedure might make it impossible to enroll patients in a clinical trial that fairly compares it to traditional surgery.

But for our patient, the question was no longer whether, or what, but when.

Just then the ambulance crew arrived.

In a last-ditch attempt at legality, I called the emergency room uptown. By luck, I stumbled on an acquaintance.

"Lauren, I'm not sure," I began, "but I think it's a leaking triple-A. The vascular resident gave me the runaround. I have no CAT scan or ultrasound ... or accepting physician."

"I'll deal with the surgeons. Send him."

Five hours later, she called back.

"Infrarenal triple-A," she said without preamble. "They're almost done."

"Whew," I exhaled. "Thanks so much for taking him."

"My pleasure," she replied, "but tell me something. How did you know?"
ADVERTISEMENT
Comment on this article
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
DSC-CV1218web
+