What disease did Enrico Caruso have?

caruso usually smoked one to two packs of Egyptian cigarettes/day from his early twenties onward. We assume as he got older he suffered from

chronic obstructive pulmonary disease.His voice was noted to have gotten much darker during the last ten years of his life. What finally killed him was pleurisy. After the illness which nearly killed him, he began smoking again, probably in Mar or April of 1921... He died in August of 1921, in Naples, Italy, a mere 48 years old.