Accidental ketosis-induced polyuria in a toddler: a case report.

Background: In the pediatric population, parental concern of recent onset frequent or large volume urination in young children is common.
Case Presentation: A 2-year-old male with no significant past medical history and unremarkable family history was brought to his pediatrician by his mother who reports that the child had been "soaking through his diapers" for the previous two to 3 days. Mother states that patient has not had an appreciable change in the number of wet diapers per day, just the perceived weight/volume of each diaper. The patient's mother denied any recent illness, apparent abdominal pain, dysuria, or recent changes in his bowel movements. She similarly denied polydipsia, polyphagia, or gross hematuria in the patient. Patient's diet consists of eating a low carbohydrate with mostly high protein and fat diet that was similar to the paleo-type diet consumed by her and her husband. Meals over the recent days were even lower in carbohydrates than usual as the family was actively trying to consume healthier food options. On physical exam the child was found to be afebrile with a normal physical exam. A urine dipstick was performed and was positive for 2+ ketones and 1+ protein. Urine leukocytes and nitrites were negative, as was urinary glucose. A fingerstick blood glucose sample was 83 mg/dL. Based on the patient's physical examination, laboratory findings, and the history which revealed a very-low carbohydrate diet, a preliminary diagnosis of ketosis-induced polyuria was made. The patient's mother was advised to incorporate a greater portion of carbohydrates into her son's diet, with a follow-up scheduled for the following week. At the follow-up appointment the mother reports that she had continued the patient's carbohydrate intake and the excessive urine amount per wet diaper has not returned. Repeat urine dipstick confirmed the resolution of the ketonuria and proteinuria.
Conclusion: This case illustrates the inadvertent consequences that can occur when parents impose new fad diets on their young children. The recent increase in the popularity of fad diets makes the consideration of alternative diets important to review in the patient history and subsequently include in the differential diagnosis of polyuria.