Cash, 69, suffers from autonomic neuropathy, which makes him susceptible to pneumonia. The famed vocalist and guitarist has been hospitalized with the condition four times since 1998. Cash's was last hospitalized in January.
Autonomic neuropathy is a group of symptoms caused by damage to nerves supplying the internal body structures.
The Grammy award-winning singer was elected to the Country Music Hall of Fame in 1980 and inducted into the Rock and Roll Hall of Fame in 1992. A six-time winner of Country Music Association awards, Cash has sold more than 50 million records during a career that has spanned over 5 decades.