Struck with sudden paralysis in his legs, a 26-year-old man had to go through two ambulance calls, an ICU stay, and one determined physician to discover the unusual cause—and regain his ability to walk, Lisa Sanders reports for the New York Times Magazine.

Expedite patient diagnosis

A sudden onset of paralysis

The patient first experienced the paralysis in his legs when, after several hours working at his computer, he realized he couldn't stand up. His legs looked and felt normal, but simply wouldn't move.

After he used his desk to leverage himself into a standing position, he simply collapsed.

"I can't move my legs," he told his younger brother.

The brother called an ambulance, and when EMTs arrived, they asked the man about his recent activities. He said he had been getting into shape the past few weeks, cutting out junk food, drinking a protein drink to build muscle, and working out every day—ultimately leading him to lose 20 pounds, Sanders reports.

The EMTs felt that, given the diet and exercise regimen, the man likely was dehydrated and simply needed fluids and electrolytes. But despite drinking water and Gatorade, the patient remained unable to move his legs.

By the following afternoon, he noticed a growing weakness in his arms, and he asked his younger brother to call an ambulance again.

An early explanation raises more questions than answers

This time, the EMTs took the patient to a nearby ED at Metropolitan Hospital, where he was assessed by Getaw Worku Hassen, an emergency medicine doctor on duty that night.

After asking about the patient's medical history and conducting an exam, Hassen discovered the patient had a heart rate of 110 beats per minute and had high blood pressure. And a test found the man's potassium levels were dangerously low.

According to Sanders, potassium is instrumental in "for every cell in the body, and its movement in and out of cells is key to many of the body's functions"—including the heart's operations. In fact, too much or too little potassium can lead to a dangerous heart arrhythmia, Sanders writes.

Hassen ordered potassium to be given to the man both orally and intravenously. The patient, who by then had been admitted to the ICU, said he started feeling stronger almost immediately afterward.

By the next day, the man could stand and even walk. He was discharged from the hospital after regaining his strength, with instructions to take potassium tablets for the next week.

Yet despite this apparent success, Hassen remained puzzled. Why was the man's potassium so low in the first place? And why had his heart rate—which had remained high even after his potassium levels improved—never calmed down?

How Hassen ultimately cracked the medical mystery

Taking his search to the internet, Hassen eventually discovered a case report that resembled his patient's story: a young man who had low potassium levels, a high heart rate, and weak legs.

That patient ultimately had been diagnosed with thyrotoxic periodic paralysis, a muscle weakness stemming from low potassium caused by an excess of thyroid hormone.

Hassen ordered a new round of tests for his own patient, which revealed that his thyroid hormone levels were very high. Hassen then advised the young man to see an endocrinologist.

Ultimately, the patient was diagnosed with Graves' disease, an autoimmune disease in which a person's antibodies cause the thyroid gland to produce too much hormone, Sanders reports. Although the disease is usually treated with radioactive iodine, the patient opted instead to take a medication that inhibited the thyroid gland from producing its hormone.

In the four years since his diagnosis, the man has given up his intensive diet and exercise regimen and is instead just attempting to eat well, stay in shape, and take his medication each day, Sanders reports. And whenever he starts feeling tired or weak, he eats a banana or avocado to get a boost of potassium, Sanders writes, "determined to never relive that kind of helplessness again" (Sanders, New York Times Magazine, 5/12).