Five Doctors, Stumped

But he could not explain why Bettie Munro's tremor had become so bad.

By December, Bruce Munro said, his wife was "shaking uncontrollably. She'd get up in the middle of the night to go to the bathroom and be unable to find the bed. Or she would try to sit on the edge of the bed, miss, and fall on the floor."

In mid-December her internist saw her. He checked her cholesterol and blood sugar levels and recommended that the couple seek a second opinion from a neurologist. Maybe, he suggested, they should consider a procedure called deep-brain stimulation, surgery that involves implanting a pacemaker-like device in the brain to reduce involuntary movements.

Less than two weeks later, Bruce Munro, who has had open-heart surgery and was feeling overwhelmed, called 911.

He still vividly remembers the ER doctor's first words: "He said, 'She's got a lithium level of 2.1,' " Munro recalled. "I knew that was toxic." A normal level is between 0.5 and 1.2 millimoles per liter.

At high levels, lithium, which is used to treat mood disorders including manic depression, can cause tremor, convulsions, confusion, memory problems, coma and even death. The drug has a narrow therapeutic range: A bit too much can be toxic and too little can be ineffective, which is one reason people taking it receive blood tests to check their levels.

Bruce Munro was flabbergasted, then chagrined. Despite multiple work-ups, nobody had thought to order the simple but essential blood test. Normally, Bettie Munro had her level checked about twice a year; her most recent test had been performed several months before her first fall. Gastrointestinal illness is known to increase the concentration of lithium in the blood, especially in elderly patients. The Parkinson's drugs she took boosted the concentration even further, her husband said.

The symptoms of Parkinson's disease and persistent intestinal problems were in fact indicators of lithium intoxication. Her therapeutic dose had become toxic.

"Everyone knew she was taking lithium, but nobody thought to check it," Munro said. "If they had, they would have figured out what was going on" and saved about $100,000 he estimates the tests and hospitalization cost.

Munro's case is not unusual. In 2001, Italian doctors writing in the Journal of Clinical Neuroscience reported the case of a 72-year-old woman who had been taking lithium and suddenly developed severe Parkinson's symptoms after a stomach virus. She was hospitalized with a lithium level of 3.7; within a few days, after her lithium was discontinued, her tremor and other symptoms disappeared.

Two days after Bettie Munro was admitted to Inova Loudoun Hospital, she was able to feed herself and walk using a walker. She was transferred to a rehab facility for a few weeks, just in time for a severe outbreak of norovirus, the highly contagious intestinal virus, which she contracted.

A few weeks later she was back home, fully recovered. "I feel great," she said. "I'm back to where I was."

Bruce Munro said that when he informed his wife's doctors that her problem had been lithium intoxication, they expressed surprise. One physician said he thought another had checked her level, so he didn't bother.

"It's the simple things," Munro noted, saying he wishes he'd thought of it.

Bettie Munro is philosophical. "Having five doctors -- a psychiatrist, internist, Bruce, a neurologist and a gastroenterologist -- well, I thought they knew what they were talking about."

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