Diane Keaton, Oscar-Winning Actress, Dies at 79

Diane Keaton died from pneumonia, a lung infection that inflames the air sacs in the lungs, caused by bacteria or viruses, and can be severe or fatal, especially in the elderly or those with underlying health conditions. Symptoms include cough, fever, chest pain, and difficulty breathing, and it can lead to complications like sepsis or ARDS. Prevention includes good hygiene and vaccines for certain types of pneumonia.