Her “Deep Sleep” Was a Late-Presenting Urea Cycle Disorder

The notebook

The notebook began in October 2018, after Mara’s mother found her asleep on the bathroom floor.

Mara, a composite drawn from several patient experiences, was 14. She had vomited after waking and then lay down without remembering that she had done it. By the time they reached the primary care doctor, she could answer questions and complained only of a headache. The examination was unremarkable.

A recent stomach illness seemed possible.

Her mother bought the notebook that week. She wrote the month at the top of each page, then recorded what happened in the plainest language she could manage: “hard to wake,” “didn’t know school day,” “vomited.” She also noted what Mara had eaten the evening before because the episodes appeared to follow some meals, although the pattern did not hold every time.

At the next appointment, the primary care doctor looked through four entries and said, “Teenagers can be almost impossible to wake.” Mara had started high school, stayed up late and sometimes slept through alarms. The vomiting was less easily explained, but it was intermittent. She had grown several inches.

Her basic blood work was within the ranges the office expected.

For a while, adolescence covered the whole case.

Over the next nine months, the notebook acquired 26 entries. Some mornings Mara was merely slow. On others, she seemed awake but could not follow a sentence, and her answers came several beats after the question. She once tried to put on clothes she had already taken off.

Another morning, she insisted it was Saturday and became angry when shown her school schedule.

The confusion usually cleared. That mattered. By an afternoon appointment, Mara could describe the headache and the nausea, but she could not reproduce the state that had frightened her mother before school. An urgent care clinician called one episode “probably a stomach virus.

” A later visit raised the possibility of migraine.

A neurologist ordered imaging after the episodes became more frequent in early 2020. The scan showed no structural explanation. “The normal scan is reassuring,” the neurologist said. It was reassuring about the conditions the scan could detect.

It did not explain the notebook.

School made the problem visible in another way. Mara missed 18 mornings during one semester, enough that an administrator asked for documentation. Her mother copied two notebook pages and attached them to a general letter from the primary care office. The absences were excused, but the practical change was small: Mara still had to recover work she did not remember being assigned.

She began calling the episodes “sleep attacks,” although sleep was not quite right. During some of them, her eyes were open. She could walk with help. Later, she remembered nothing.

The emergency admission

In February 2021, 28 months after the first notebook entry, Mara did not return to herself.

She had complained of nausea the previous evening and gone to bed early. The next morning, she could not sit upright without assistance. Her speech was unclear, and she vomited while her mother was gathering the notebook and her insurance card. At the emergency department, she became less responsive rather than more alert.

The first questions followed familiar paths. Staff asked about medications, substances and a possible head injury. Her mother answered, then opened the notebook to the recent pages. There were five episodes in six weeks.

One entry said Mara had seemed better by lunch. This time she was not better.

An emergency physician ordered broader blood testing after the usual early explanations did not fit. One result changed the admission: ammonia in Mara’s blood was markedly elevated. The team repeated the test, and the second result confirmed that the first was not a collection error.

“This is not ordinary sleepiness,” the physician told her mother.

Ammonia is produced as the body processes nitrogen. The liver normally converts it through a sequence of reactions known as the urea cycle so it can leave the body. A problem at one step can allow ammonia to accumulate, affecting the brain and causing symptoms that may include confusion, vomiting or reduced consciousness.

Many severe urea cycle disorders are identified in infancy. Others retain enough enzyme function that a person can reach childhood or adulthood before a major episode, particularly when the underlying change affects people unevenly. That later presentation was the part no one had been looking for during Mara’s normal afternoons in clinic.

The hospital treated the elevated ammonia while metabolic testing continued. Her mother sat beside the bed with the notebook closed in her lap. By the following day, Mara was speaking more clearly. She remembered feeling sick before bed.

She did not remember arriving at the hospital.

A metabolic specialist reviewed the old history alongside the new laboratory findings. The specialist did not claim that every headache or difficult morning had been the same event, but the repeated episodes now formed a plausible record of earlier metabolic instability. Follow-up biochemical testing and genetic analysis supported a urea cycle disorder that had presented later than expected.

“People expect these disorders in newborns,” the specialist said. “That expectation can delay recognition in someone older.”

After the name

The diagnosis reorganized the notebook without making it perfect evidence. Meals that appeared important on one page had no visible effect on another. Illness preceded some episodes but not all of them. The notebook could show sequence and duration; it could not establish the biochemical cause on its own.

Still, it documented what office visits had repeatedly missed. Mara’s condition fluctuated, and the most alarming evidence often disappeared before she reached a clinician. Her mother’s short entries preserved the difference between being reluctant to wake and being unable to understand where she was.

The months after discharge were occupied by specialist visits, laboratory checks and negotiations with school. The most consequential accommodation was not a long schedule of exceptions. Mara was allowed to make up work without waiting for each absence to be evaluated separately, which ended the repeated argument over whether a morning episode counted as illness.

There was anger, although it arrived without a single target. The early symptoms overlapped with common problems. The routine tests had been normal. Yet “teenager” had become an explanation rather than a description, broad enough to absorb vomiting and periods of altered awareness for more than two years.

Mara also disliked the cleaner version of the story, the one in which the emergency admission solved everything. A diagnosis identified the disorder and changed how clinicians interpreted her episodes. It did not restore the missed semester or make her comfortable with sleep. For months, she checked the notebook after waking to see whether anything had happened that she could not recall.

By fall 2021, there were fewer entries. Her mother no longer recorded every slow morning, only events that seemed meaningfully different from Mara’s baseline and information requested by the specialist. Blank pages accumulated.

One weekday, Mara woke late, read the last notebook entry and put it into her backpack. Then she left for school with a piece of toast in her hand.

Questions people ask

Can a urea cycle disorder first appear during adolescence?

Some urea cycle disorders are recognized soon after birth, while milder or variable forms may not become apparent until later. In Mara’s case, the diagnosis followed years of intermittent symptoms and an emergency episode in adolescence, when elevated ammonia prompted metabolic testing that had not been part of her earlier evaluations.

Why can a metabolic crisis look like unusually deep sleep?

Elevated ammonia can affect brain function, producing confusion, unusual behavior or reduced consciousness. Mara sometimes appeared asleep, but during other episodes her eyes were open and she could not process ordinary questions. The distinction became clearer in her mother’s notebook than it had during appointments after the symptoms passed.

Why did normal earlier tests not settle the problem?

Mara’s routine blood work and brain imaging addressed several common explanations but did not capture the abnormality found during her emergency admission. Her symptoms also fluctuated, so she often looked well by the time she was examined. The normal results were meaningful within their limits; they were not an explanation for the recurring episodes.

What part of the family’s record mattered most?

The notebook showed dates, duration and changes in awareness across 28 months. It did not diagnose the disorder, but it helped the hospital team see that the emergency was part of a longer pattern rather than an isolated event. By the next school year, the same notebook traveled in Mara’s backpack.