As I reflect back on the last four years of medical school, I am reminded of the ghosts of patients past. Those of you already entrenched in the dredges of patient care know what I mean. The images of their faces burned on your brain: the ones you couldn’t help, the promises you never meant to break, and the hope you weren’t able to give.

Those ghosts take on several shapes and sizes. They’re orphans in Thailand: victims of sexual abuse, who cried and clung to the doors of the van as my colleagues and I pulled away, headed back into the comfort of the American education system. They’re patients in the ICU, who despite your best efforts, get sicker and sicker everyday. Finally, and most painfully, they’re the individual faces of patients you felt powerless to help.

For me, one of those faces is Mrs. G, an elderly, uninsured immigrant who presented to the hospital for four months with ascending flaccid paralysis (a condition in which there is successive paralysis of the legs, then the trunk and arms, and finally the muscles of respiration). It was my first day rotating through an infectious disease elective, and I took her history and helped to admit her. I was filled with the excitement and naivety I think that is common among many medical students. She represented a mystery I couldn’t wait to solve.

I eagerly presented her story to my team along with a long list of potential causes: Guillan-Barre Syndrome, tick-related paralysis, CNS malignancy, poliomyelitis, etc. I continued to see her every morning. At first, our team was not discouraged by the negative test results we got back, and I reassured her that she shouldn’t be either. There was still a myriad of other possibilities and teams we could consult.

Her MRI indicated changes in her spinal cord, so we knew her paralysis was not psychogenic (related to emotional or mental stress). We ran nearly every blood test even loosely associated with paralysis, performed a lumbar puncture, sent cells to our own lab and to the CDC for analysis, ordered a full body MRI searching for elusive malignancies we could have missed, consulted neurology, hematology, oncology, rheumatology and infectious disease experts in other cities.

As the days dragged on, so did the number of negative test results and the size of the increasingly large pit in my stomach. This exhaustive barrage of tests and procedures had effectively resulted in nothing. Our best assessment was that she had contracted a remote viral infection that had caused permanent damage to her nervous system and was no longer detectable or treatable.

Mrs. G taught me something that no one seems to like to acknowledge: Sometimes, despite expensive and incredible technological advancements, nearly unlimited resources, brilliant, caring and dedicated physicians, the only answer we have to give is, “I’m sorry. I don’t know.” She also taught me that sometimes, that honest answer is exactly what patients need to hear.

As the days turned to weeks, I spent less time seeing her as a problem to solve and more time seeing her as the person she is. I would hold her hand and listen to her stories. Her extensive family visited everyday and would teach me medical Spanish. Their love for her was overwhelming and the acceptance they showed us was humbling. On my last day, her daughter thanked me for everything we had done as a team and told us that they were not angry. They knew we had cared for her as both a patient and a person and had done everything in our power to help her.

I write this reflection in an effort to give life and meaning to these experiences. To elevate the ones I couldn’t help to writing. To give them a voice and to hope that in some small way, someone might learn from them or relate to their experiences. My hope is for a single patient to learn that your physicians carry you home with them. You are not a number, a statistic, or a blip in our day. You are our day. You are our family, our friends, our teachers and our mentors and your presence is felt long after you leave us.

Sarah Mongiello Bernstein is a medical student. This article originally appeared in Aspiring Docs Diaries.