An active 13-year-old middle school student complains to her
parents of increasing thirst, frequency of urination, and fatigue
that has persisted for a week. The following morning, the girl and her
parents visit their family pediatrician. While taking the history,
the physician notes the above-mentioned symptoms, as well as a decrease
in the girl’s academic performance over the previous week.
She is consuming more than 3 liters of liquid a day and urinating
approximately eight times during a 24-hour period; at least one
of those times requires her to awaken from sleep. On physical examination,
she is found to be afebrile, with a pulse of 80, which is slightly
elevated for the patient, a normal blood pressure lying and sitting,
and a normal respiratory rate. The pediatrician notes that the girl’s
weight has dropped 2 kg since a visit 3 months earlier. The remainder
of the physical examination is unremarkable.
In the office, the pediatrician performs a urinalysis, which
reveals a normal microscopic examination; the dipstick examination
of the urine is negative for blood, white blood cells, and bilirubin, but
is 4+ positive for glucose and 1+ positive for
ketones. The pediatrician expresses concern to the parents that
the girl may have diabetes mellitus. A complete blood count and
blood chemistries are sent to a local laboratory, and the doctor
arranges for the patient and her parents to see a pediatric endocrinologist
within the hour.
In the endocrinologist’s office, the results of the
blood tests confirm that the girl has a markedly ...