Dear Dr. Roach: My 83-year-old sister underwent the simple procedure of replacing her pacemaker battery. She’s also been diagnosed with early signs of dementia. They gave her propofol, and when she woke up, she had extreme vertigo. Since it was an outpatient facility, they dumped her in the emergency room. She spent four days in the ER because there weren’t any beds in the hospital.

On the second day, she developed a bad case of delirium. After four days, she had to be transferred to a nursing home, where she spent 17 days trying to recover. She still isn’t 100% as this delirium has progressed her dementia. Prior to the procedure, she lived alone and drove. Now she requires a caregiver and can’t drive.

Please make your readers aware that the elderly with dementia need to make sure their doctor is aware and prepared to deal with any aftereffects immediately. Apparently, her doctor didn’t read her medical history (or didn’t care), or he would’ve never allowed her to be stuck in a dark, windowless ER room for four days. — C.S.

Answer: I understand why you’re angry about the poor care that your sister received. What happened to her is almost a textbook example of how not to care for someone who’s at risk for delirium. Delirium is sometimes called an “acute confusional state.” It can happen to anyone, but people who are older than 65 (especially older than 75) are at a high risk.

Delirium is common during hospitalization, especially after a surgical procedure — even relatively simple ones like a pacemaker battery change or a colonoscopy. Propofol isn’t particularly risky for delirium, at least when compared to general anesthesia, but dizziness or vertigo after propofol is common. Being in an isolation-type room with poor lighting and no clocks, like an ER, absolutely is a risk factor for delirium.

People with delirium have a poor prognosis, as they’re at a higher risk for worsened brain function, have more of a need to go into a nursing home, and even have a higher mortality risk. After an episode of delirium, persistent confusion and difficulty thinking can last for a year or sometimes more. People who may have had very mild problems before, such as early dementia or even mild cognitive impairment, are at a particularly high risk for developing dementia, so prevention is key in these cases.