The barrier is her doctor's own reluctance to talk to patients through e-mail.
"It makes sense to me to have the words laid out, to be able to re-read, to go back to it at a convenient time," the 34-year-old Milwaukee woman recently wrote on a social networking site. "If I were able to ask my physician questions this way, it would make my own health care much easier."
Kreuziger's experience is shared by most Americans: They want the convenience of e-mail for non-urgent medical issues, but fewer than a third of U.S. doctors use e-mail to communicate with patients, according to recent physician surveys.
"People are able to file their taxes online, buy and sell household goods, and manage their financial accounts," said Susannah Fox of the Pew Internet & American Life Project. "The health care industry seems to be lagging behind other industries."
Doctors have their reasons for not hitting the reply button more often. Some worry it will increase their workload, and most physicians don't get reimbursed for it by insurance companies. Others fear hackers could compromise patient privacy - even though doctors who do e-mail generally do it through password-protected Web sites.
There are also concerns that patients will send urgent messages that don't get answered promptly. And any snafu raises the specter of legal liability.
Many patients would like to use e-mail for routine matters such as asking for a prescription refill, getting lab results or scheduling a visit. Doing so, they say, would help avoid phone tag or taking time off work to come in for a minor problem.
Still, a survey conducted early last year by Manhattan Research found that only 31 percent of doctors e-mailed their patients in the first quarter of 2007.
Two major health insurers, Cigna Corp. and Aetna Inc., this year expanded pilot programs that compensate doctors who use a secure Internet site to make virtual house calls with patients. That includes the ability to send encrypted e-mail, a move some hope will increase the number of doctors who go digital.
Dr. Daniel Z. Sands, an assistant clinical professor at Harvard Medical School, is among the early adopters who doesn't get paid for e-visits. He sees communicating with patients online as no different from phoning them, a practice that also is not billable.
Since 2000, Sands has answered patient questions by logging onto a password-protected Web site of the Harvard-affiliated Beth Israel Deaconess Medical Center. He also sets his Treo to retrieve new messages every four hours. He mostly gets e-mails from patients seeking advice for new symptoms or updates from chronic disease sufferers.
Although Sands has had mostly positive experiences, one patient bombarded him with e-mails. She became "pushy" and her messages were sometimes threatening.
"We sort of had this fight back and forth through electronic communication, which is absolutely the wrong thing to do. I should have picked up the phone and called her. Any message that takes more than two volleys back and forth should not be done by e-mail," Sands said.
The American Medical Association says e-mail should not replace face-to-face time with patients. The group's etiquette guidelines recommend talking to patients about the technology's limitations.
Most studies have shown patients don't abuse e-mail. They generally don't deluge doctors with rambling messages, and Internet exchanges may even help doctors' productivity and cut down on office visits.
For example, a 2007 University of Pittsburgh study published in the journal Pediatrics followed 121 families who e-mailed their doctors. Researchers found 40 percent of e-mails were sent after business hours and only about 6 percent were urgent. Doctors received on average about one e-mail a day and responded 57 percent faster than by telephone.
A separate study by health care giant Kaiser Permanente published in the American Journal of Managed Care last year found patients who used its secure Web system were 7 to 10 percent less likely to schedule an office visit. Patients also made 14 percent fewer phone calls than those who did not use the online services.
Before e-mail can become as routine as a physical, doctors need to be trained to handle confidential patient messages in the digital age, some experts say. That would include learning to file e-mails in patients' health records and instructing patients in the risks of electronic messaging.
Kreuziger, the nurse who can't e-mail her doctor, works in a large practice that also doesn't offer e-mail services. She often has to phone patients to check on their blood-sugar levels or track them down about an abnormal lab test - a chore for a person who prefers e-mail over the phone.
"I hate a ringing phone. It's an interruption," she said in an interview.
Kreuziger and her colleagues recently asked patients about their Internet needs. Of the 76 patients who responded to the questionnaire, most said they would like e-mail access to their doctors.
It's not the first time the medical field has been slow to embrace technology. When the first telephones became widely available in the late 1800s, doctors were concerned about being swamped with calls.
Dr. Tom Delbanco, a primary care doctor at Beth Israel who e-mails patients, believes it is just a matter of time before the technology becomes a routine part of patient care.
"Medicine is very conservative. It changes slowly," he said.