Dr. Lowell has struggled to obtain treatment for his own wife. Shortly before the virus hit New York, she had back surgery and then developed a complication called a seroma, which flooded her abdomen with several liters of fluid. The specialist who could drain the fluid did not want to bring her in, afraid of exposing her to the virus. Finally, it was scheduled for April 21. She has waited more than a month.

“Any other time, this would have been done the same day,” he said.

Some of his patients have had far more serious problems, he said.

One called him, saying she felt depressed and weak, and couldn’t eat.

They were communicating via telemedicine, which Dr. Lowell — like many other doctors in the New York region — has been using to avoid in-person visits that could spread the virus.

In the past, her tests suggested that she was prone to a blood cancer, multiple myeloma. Listening to her, seeing her on his screen and knowing her history, Dr. Lowell suspected a serious illness, possibly the cancer. He told her that, and urged her to go to the hospital. The patient, who was 60, declined, fearing she would contract the coronavirus.

Five or six days passed, and her husband called, saying she felt even worse. Again, Dr. Lowell implored them to go to the hospital. Again, she refused.

A few hours later, she died.

“I have no idea why,” Dr. Lowell said.

Some of his other patients with serious illnesses have also refused to go to the hospital, for the same reason. One who wanted to go, and whose family called 911, was urged by paramedics to stay home because the hospital was overwhelmed by coronavirus cases. He did stay home, and died a few days later.

Many colleagues share similar stories.

“I’m a primary care doctor,” Dr. Lowell said. “I’m totally hogtied trying to take care of people. It’s sad. It brings tears. We’re all on the front line.”

Jan Hoffman contributed reporting.