While our world was being reduced to the size of ceaseless dread, Ella’s was expanding. Illustration by GUY BILLOUT

On July 15, 2010, my wife, Teri, and I took our younger daughter, Isabel, to the doctor for a regular checkup. She was nine months old and appeared to be in perfect health. Her first teeth had come in, and she was now regularly eating with us at the dinner table, babbling and shovelling rice cereal into her mouth. A cheerful, joyous child, she had a fondness for people, which she had not, the joke went, inherited from her congenitally grumpy father.

Teri and I always went together to our children’s doctor’s appointments, and this time we also took Ella, Isabel’s big sister, who was almost three. The nurse at Dr. Armand Gonzalzles’s office took Isabel’s temperature and measured her weight, height, and head circumference, and Ella was happy that she didn’t have to undergo the same ordeal. Dr. G., as we called him, listened to Isabel’s breathing and checked her eyes and ears. On his computer, he pulled up Isabel’s development chart: her height was within the expected range; she was a little underweight. Everything seemed fine, except for her head circumference, which was two measures of standard deviation above her last measurement. Dr. G. was concerned. Reluctant to send Isabel for an MRI, he scheduled an ultrasound exam for the following day.

Back at home that evening, Isabel was restless and cranky; she had a hard time falling and staying asleep. If we hadn’t gone to Dr. G.’s, we would have assumed that she was simply overtired, but now we had a different interpretative framework, one founded on fear. Later that night, I took Isabel out of our bedroom (she always slept with us) to calm her. In the kitchen, I sang her my entire repertoire of lullabies: “You Are My Sunshine,” “Twinkle, Twinkle, Little Star,” and a Mozart piece I’d learned as a child, whose lyrics in Bosnian I miraculously remembered. Singing the three lullabies in a relentless loop usually worked, but this time it took a while before she laid her head on my chest and quieted down. When she did this, it felt as though she were somehow comforting me, telling me that everything would be all right. Worried as I was, I imagined a future in which I would one day recall that moment and tell other people how Isabel had calmed me down. My daughter, I would say, took care of me, and she was only nine months old.

The following morning, Isabel underwent an ultrasound exam of her head, crying in Teri’s arms throughout the procedure. Shortly after we got home, Dr. G. called to tell us that Isabel was hydrocephalic and we needed to go to an emergency room immediately—it was a life-threatening situation.

The examination room in the E.R. at Chicago’s Children’s Memorial Hospital was kept dark, as Isabel was about to have a CT scan and the doctors were hoping she’d fall asleep so that they wouldn’t have to drug her. But she wasn’t allowed to eat, because there was the possibility of a subsequent MRI, and she kept crying from hunger. A resident gave her a colorful whirligig and we blew at it to distract her. She finally fell asleep. As the scan was performed, we waited for something to reveal itself, too afraid to imagine what it might be.

Dr. Tadanori Tomita, the head of pediatric neurosurgery, read the CT scans for us: the ventricles of Isabel’s brain were enlarged, full of fluid. Something was blocking the draining channels, Dr. Tomita said, possibly “a growth.” An MRI was urgently needed.

Teri held Isabel in her arms as the anesthetics were administered, then we handed her over to the nurses for an hour-long MRI. The cafeteria in the hospital’s basement was the saddest place in the world, with its grim neon lights and gray tabletops and the diffuse foreboding of those who had stepped away from suffering children to have a grilled cheese sandwich. We didn’t dare speculate about the results of the MRI; we were anchored in the moment, which, terrifying as it was, hadn’t yet extended into a future.

Called up to medical imaging, we ran into Dr. Tomita in the overlit hallway. “We believe,” he said, “that Isabel has a tumor.” He showed us the MRI images on his computer: right at the center of Isabel’s brain, lodged between the cerebellum, the brain stem, and the hypothalamus, was a round thing. It was the size of a golf ball, Dr. Tomita suggested, but I’d never been interested in golf and couldn’t envision what he meant. He would remove the tumor, and we would find out what kind it was only after the pathology report. “But it looks like a teratoid,” he said. I didn’t comprehend the word “teratoid,” either—it was beyond my experience, belonging to the domain of the unimaginable and incomprehensible, the domain into which Dr. Tomita was now guiding us.

Isabel was asleep in the recovery room, motionless, innocent. Teri and I kissed her hands and her forehead and wept through the moment that divided our life into before and after. Before was now and forever foreclosed, while after was spreading out, like an exploding twinkle star, into a dark universe of pain.

Still unsure of the word that Dr. Tomita had uttered, I looked up brain tumors on the Internet, and found an image of a tumor that was nearly identical to Isabel’s. Its full name was, I read, “atypical teratoid/rhabdoid tumor” (A.T.R.T.). It was highly malignant and exceedingly rare, occurring in only three in a million children and representing about three per cent of pediatric cancers of the central nervous system. The survival rate for children younger than three was less than ten per cent. There were even more discouraging statistics available for me to ponder, but I recoiled from the screen, deciding instead to talk to and trust only Isabel’s doctors; never again would I research her condition on the Internet. Already I understood that it would be necessary to manage our knowledge and our imaginations if we were not to lose our minds.

On Saturday, July 17th, Dr. Tomita and his neurosurgical team implanted an Ommaya reservoir in Isabel’s head, to help drain and relieve the pressure from the accumulated cerebrospinal fluid. When Isabel was returned to her hospital room on the neurosurgery floor, she kicked off her blanket, as she was wont to do; we took this as an encouraging sign, a hopeful first step on a long journey. On Monday, she was released from the hospital to wait at home for the surgery that would remove the tumor, which was scheduled for the end of the week. Teri’s parents were in town, because her sister had given birth to her second son on the day of Isabel’s checkup—too concerned about Isabel, we had hardly paid attention to the new arrival in the family—and Ella had spent the weekend with her grandparents, barely noticing the upheaval or our absence. Tuesday afternoon was sunny, and we all went out for a walk, Isabel strapped to Teri’s chest. That night, we rushed to the emergency room, because Isabel had developed a fever; it was likely that she had an infection, which is not uncommon after the insertion of a foreign object—in this case, the Ommaya—in a child’s head.