MADRID – In March, as the coronavirus was tearing across Spain, Lídia Bayona Gómez started to suffer bouts of vomiting and coughing.

A nursing home worker, she treated herself as a potential COVID-19 case, isolating and getting tested. The results came back negative, twice. With her weight dropping and her urine turning red, she made repeated attempts to see a doctor and in late April, on a phone consult, one prescribed medicine for gastroenteritis and a urinary tract infection.

But the pain kept getting worse and in late June, her sister took her to an emergency hospital unit. In mid-July, she underwent a 12-hour surgery to remove two cancerous tumors. She died in the hospital nine days later, at age 53. It was not an isolated tragedy.

Hospitals and other health care centers have been forced to devote most of their resources to COVID-19 patients, and doctors are warning that a growing number of cases of cancer and other serious illnesses are going undetected. That toll is beginning to be reflected in lawsuits.

The details of Bayona Gómez’s care are part of a lawsuit brought by her sister, Fátima Bayona. Prosecutors said they would investigate.

Several other suits have been filed just in Burgos, including one by a woman who learned she had terminal cancer after trying for seven months to get access to a hospital.

Carmen Flores, president of an association that helps patients or their relatives take legal action, said her association had helped file more than 50 lawsuits since September. Some lawsuits accuse doctors of refusing to see patients. But others assert that doctors rushed to the wrong conclusions or did not want to risk touching patients as part of their examinations because of the risk of catching COVID-19.

For the most part, doctors say they are just overworked. Doctors in many countries have warned that the pandemic may have exacerbated other health problems. The main doctors’ body in Britain said its hospitals received more than 250,000 fewer urgent cancer referrals than normal in April, May and June. A survey of U.S. cancer patients published in April found nearly 1 in 4 reporting delays to their care.

But Spanish medics say the crisis has exposed particular weaknesses.

“This pandemic is now also making us realize how much we have neglected our primary health care,” said César Carballo, an emergency care doctor in Madrid. “We have had thousands of our professionals who have left to work overseas.”