1. Symptoms

“I don’t feel well.” The middle-aged man could feel sweat running down his face as he stood, getting ready to leave a restaurant with his aunt and 13-year-old daughter. He was visiting his family in Jamaica, where he grew up, and had been enjoying his time there, but now he felt dizzy and lightheaded. He wondered if he was going to faint. He quickly sat back down. His daughter sat next to him, her eyes wide with concern and fear. Her father’s dark skin looked gray, and his T-shirt was drenched with sweat. His aunt handed him a cool glass of water, and after he drank it he began to feel a little better. He looked at his daughter’s worried face and smiled. He was O.K. now, he told her. “Let’s go.”

For the rest of the day he felt a little confused. He couldn’t get his mind to focus. But the next day he felt fine, and the rest of his two-week stay in Jamaica was uneventful. He almost forgot about his spell of lightheadedness, until it happened again during a trip to Toronto soon after. A powerful surge of nausea and dizziness almost knocked him to the ground. He told his wife about it when he got back to their home in Oakland, but he didn’t call his doctor until it happened a third time.

This time, it was early in the morning, and as he was getting ready for work, he suddenly felt hot and cold. His heart raced. He felt dizzy, faint, nauseated and strangely hungry. A friend had left a glucometer in his house, and he wondered suddenly if this was what it felt like to have diabetes. He checked his blood sugar. It was 35. He wasn’t certain what normal was, but he checked a book and realized that it was low. He quickly ate breakfast then called his doctor, Albert Yu, and made an appointment to see him.

2. Investigation

In the doctor’s office the patient’s blood sugar was 146, expected for someone who’d eaten breakfast an hour before. Yu quickly reviewed his chart. The patient was a healthy 38-year-old. He had mild kidney disease, for which he took one medicine. He was health-conscious  ate a mostly vegetarian diet, worked out every day. His exam turned up nothing. Yu worried that perhaps the pharmacy had given the patient the wrong medication when he refilled his prescription and that he might be having a reaction. Yu gave the patient an order for blood tests and told him to take the pills to the pharmacy to make certain there was no mistake. But shortly after he left the office, his symptoms returned, worse than ever. He quickly checked his blood sugar again; it was 27. He contacted his doctor. Blood sugar that low can cause seizures, even a coma. “You need to go to the emergency room,” Yu told him.