The early-morning light wakened the middle-aged man early on a Saturday morning in 2003. He felt his 51-year-old wife move behind him and turned to see her whole body jerking erratically. He was a physician, a psychiatrist, and knew immediately that she was having a seizure. He grabbed his phone and dialed 911. His healthy, active wife had never had a seizure before. But this was only the most recent strange episode his wife had been through over the past 18 months.
A year and a half earlier, the man returned to his suburban Pittsburgh home after a day of seeing patients and found his wife sitting in the kitchen, her hair soaking wet. He asked if she had just taken a shower. No, she answered vaguely, without offering anything more. Before he could ask her why she was so sweaty, their teenage son voiced his own observations. Earlier that day, the boy reported, “She wasn’t making any sense.” That wasn’t like her.
Weeks later, his daughter reported that when she arrived home from school, she heard a banging sound in a room in the attic. She found her mother under a futon bed, trying to sit up and hitting her head on the wooden slats underneath. Her mother said she was looking for something, but she was obviously confused. The daughter helped her mother up and brought her some juice, which seemed to help. With both episodes, the children reported that their mother didn’t seem upset or distressed. The woman, who had trained as a psychiatrist before giving up her practice to stay with the kids, had no recollection of these odd events.
The Problem Is Sugar
Her husband persuaded her to see her primary-care doctor. Upon hearing about these strange spells, the physician said she suspected that her patient was having episodes of hypoglycemia. Very low blood sugar sends the body into a panicked mode of profuse sweating, shaking, weakness and, in severe cases, confusion. She referred her to a local endocrinologist.
The specialist agreed that the patient was probably suffering from hypoglycemia. Having the right amount of glucose — the body’s preferred sugar — in the bloodstream is essential for the body to run normally. If it drops too low, the brain shuts down. Too much glucose in the system, which is what those with untreated diabetes face, will injure blood vessels, nerve fibers, the heart and the kidneys. And extreme excesses in either direction can sometimes be fatal.
The endocrinologist gave the patient a glucometer and asked her to check her sugar when she felt these symptoms. It indicated that when the patient felt bad, her sugars were often low. But sometimes she checked when she felt fine, and her sugars would be low then too. Normal measurements for women are above 60. Many of her measurements were in the 40s, and some were as low as the 20s. Patients will often be confused or even unconscious when their blood-glucose levels go as low as hers did.
Why was her glucose dropping this way? The most concerning possibility was that she had a rare insulin-producing tumor, known as an insulinoma. Insulin, produced by the pancreas, helps cells take up the glucose they need for fuel from the bloodstream. Too much insulin leaves too little glucose in the circulation. But insulinomas are rare — with just four cases per one million patients in a given year.
Illness Script
To make a diagnosis, especially of a rare ailment, doctors often turn to illness scripts — detailed mental pictures of a disease that doctors develop based on what they’ve learned about it. The typical patient with an insulinoma, we are taught, is female and overweight from eating extra food to keep her blood glucose up. Symptoms are often the worst in the middle of the night, when sugars are naturally the lowest. Labs will show a low glucose and a high insulin level. Despite these mental pictures, insulinoma is often misdiagnosed as a neurological or a psychological problem before the right diagnosis is made. In one Mayo Clinic study, it took a year and a half for patients with an insulinoma to get the diagnosis, on average — and a few had been sick for decades.
The woman didn’t fit this profile of a patient with an insulinoma. She was female but quite fit and not at all overweight. Most of her episodes of low sugars came during the day. And when the endocrinologist checked the patient’s glucose and insulin levels in the lab, they were in the normal range.
If she didn’t have an insulinoma, the endocrinologist explained to the patient, she probably had an unusual disorder known as reactive hypoglycemia. In this condition, the hormonal machinery that controls insulin tells the pancreas to release too much of it into the system after eating or exercising, which causes glucose levels to plummet.
The treatment for this oddity is mostly dietary. Patients are told to eat small, frequent meals containing more proteins and fats and fewer carbs. The patient and her husband were skeptical. They thought she had an insulinoma. Still, the patient did her best to implement her doctor’s treatment plan for more than a year. It didn’t work; she continued to have these occasional episodes of sweating and confusion.
The Day of the Seizure
The husband still recalls the fear he felt waiting for the ambulance to arrive the morning his wife had a seizure. When the E.M.T.s checked her sugar, it was down to 30. They quickly placed an IV and gave her a concentrated solution of sugar water. By the time she got to the local emergency room, her sugar was in the 50s. Reactive hypoglycemia shouldn’t produce sugars low enough to cause a seizure. So again her doctors searched for evidence of an insulinoma. And once again, her glucose and insulin levels were in the normal range when checked in the hospital. Neither a CT scan nor an M.R.I. showed any sign of an insulin-producing tumor.
A Second Opinion
The patient and her husband decided to get a second opinion, this time at the University of Pittsburgh Medical Center. The gold standard for diagnosing an insulinoma involves a 72-hour fast in the hospital. Dr. Mary Korytkowski, an endocrinologist on the faculty there, would be running the test. When the patient and her husband explained her story, Korytkowski thought that this woman just might have one of the four in a million tumors. But she didn’t say anything; first they needed evidence. During the fast, the patient’s blood sugar is checked every few hours to see if it drops. The theory is that if you have a tumor producing insulin and don’t eat and provide your system with glucose, blood-sugar levels will decrease, and you’ll have symptoms of hypoglycemia.
Once the clock started, the patient’s glucose hovered in the mid-50s to the mid-60s, and she felt fine. Sixteen hours in, her glucose dropped into the 40s, but still she had no symptoms. She wasn’t sweaty; she wasn’t confused. Nineteen hours in, with glucose still in the 40s, she finally started to feel that familiar sweaty shakiness. The test was stopped. Finally her sugar was low, and her insulin was too high.
Finding the Culprit
She probably did have an insulinoma, Korytkowski told the patient and her husband. Now they just had to find it. The endocrinologist ordered a special CT scan with very fine visual slices of the pancreas. If she had a tumor, there was a very good chance that’s where they’d find it. And they did. A tiny mass, about the size of a green pea, located at the tail of the pancreas near the spleen.
A laparoscopic surgery was done to remove the tumor. And a week later, she was back to normal. Playing tennis. Running. Eating normally. For years after this diagnosis, the woman checked her sugars; she knew from her own medical-school training that this tumor could come back. But it hasn’t; and after this much time, she hopes that it won’t.
