Clinical presentation of type 1 diabetes

To identify the presenting features of type 1 diabetes in a national incident cohort aged under 15 yr, the duration of symptoms, the occurrence of diabetic ketoacidosis (DKA) at presentation, and the frequency of a family history of diabetes.

A prospective study was undertaken of incident cases of type 1 diabetes using an active monthly reporting card system from January 1, 1997 to December 31, 1998 in the Republic of Ireland. Follow-up questionnaires were distributed to pediatricians nationally.

Two hundred and eighty-three incident cases were identified. Polyuria, polydipsia and weight loss were the main presenting symptoms in all age categories. Nocturnal enuresis was reported in 19% under 5 yr and in 31% aged 5-9.99 yr. Constipation was noted in five patients and in 10.4% under 5 yr of age. The median duration of symptoms was highest in the youngest (under 2 yr) and oldest (10-14.99 yr) age categories. Presentation in moderate/severe DKA occurred in 25% overall and six of nine of those aged under 2 yr. A family history of type 1 diabetes in a first-degree relative was found in 10.2%.

This study confirms the abrupt onset of type 1 diabetes, the absence of a family history, and the importance of the classical symptoms of polyuria, polydipsia, and weight loss in the majority of cases. It reveals secondary enuresis as an important symptom, especially in those under 10 yr, and constipation in the under 5 yr age group. The very young (under 2 yr) are more difficult to diagnose, have more variability of symptom duration, and are more likely to present in moderate/severe DKA. A high index of suspicion aids early diagnosis.