Lisa Marie Presley, the singer-songwriter and only child of Elvis Presley, died in January as a result of “a small bowel obstruction” caused by scar tissue that developed after bariatric surgery years ago, the Los Angeles County Medical Examiner’s office said on Thursday.

Presley had been complaining on January 12 of severe abdominal pain, according to an autopsy report released on Thursday by the medical examiner’s office. Later that day, she was found unresponsive at her home in Calabasas, California, by her ex-husband, who was not named in the report.

Presley, 54, was taken by paramedics to a hospital, where she went into cardiac arrest and died that afternoon.

The report stated that although Presley had a previous history of drug use, she was sober “for the past few years”. Still, health problems appeared to have occurred after her bariatric surgery, which is generally considered a treatment option for people with a high body mass index who failed to lose weight with diet and exercise alone.

Juan M. Carrillo, a deputy medical examiner in Los Angeles county, described Presley’s health problems after the bariatric surgery as a “known long-term complication of this type of surgery”.