241: Temporal Dynamics of Visceral Pain After Fructose Ingestion in Fructose-Sensitive Children

Topic: Clinical Science
Subtopic: Non-specific to any diagnosis, Pain in special populations (e.g. neonates, children, teens, elderly, neurodegenerative diseases)

Background and Aims: Children with chronic abdominal pain often undergo evaluation for symptoms induced by carbohydrates, including those triggered by fructose ingestion. Although fructose sensitivity is widely recognised, the temporal pattern of pain and associated symptoms remains poorly characterised. A deeper understanding of symptom trajectories could provide valuable insights into the underlying nociceptive mechanisms and enhance diagnostic accuracy. Our aim was to characterise the timing and progression of visceral pain and non-painful gastrointestinal symptoms in paediatric patients identified as fructose-sensitive following fructose ingestion.

Methods: A standardised fructose breath hydrogen test was performed on sixty children/adolescents (aged 10–15) (1g/kg fructose up to 25 gram) who presented with chronic abdominal pain, after an organic cause of the symptoms had been ruled out. Their symptoms were recorded using a 0–5 visual analogue scale at regular intervals for up to nine hours. Fructose sensitivity was defined as an increase of at least two points in one or more symptom categories on a 11-point Likert scale. Temporal symptom profiles were analysed using the mean ± standard error of the mean (SEM); p < 0.05 was considered significant.

Results: Twenty-one children met the criteria for fructose sensitivity. Baseline abdominal pain was minimal and comparable between the sensitive and non-sensitive groups. For fructose-sensitive patients, pain remained unchanged for the first 120 minutes, rising significantly at around 150 minutes before spontaneously resolving without recurrence. Non-painful symptoms exhibited clear temporal clustering: nausea emerged within 30 minutes and persisted for up to two hours, bloating increased between 120 and 150 minutes, and excessive rectal gas passage occurred between three and six hours. No diarrhoea was observed during the nine-hour monitoring period.

Conclusions: Children who are sensitive to fructose exhibit a characteristic delay in the onset of visceral pain after ingesting fructose, whereas non-painful symptoms follow separate and symptom-specific timelines. These findings emphasise the importance of extended observation and symptom profiling when evaluating abdominal pain in children related to carbohydrate sensitivity.

References: + Hammer J, Hammer HF. Beyond Malabsorption: The Need for Symptom-Based Assessment in Suspected Lactose Intolerance. Lessons From a Test-Specific Symptom Assessment. Neurogastroenterol Motil. 2025 Sep 17:e70167
+ Hammer K, et al. Comparative analysis of hydrogen breath test devices for the diagnosis of carbohydrate malabsorption: fructose tests lack reliability. Eur J Gastroenterol Hepatol. 2025 Jun 1;37(6):733-737
+ Hammer K, et al. Relevance of Methane and Carbon Dioxide Evaluation in Breath Tests for Carbohydrate Malabsorption in a Paediatric Cohort. J Pediatr Gastroenterol Nutr. 2021 Mar 1;72(3):e71-e77

Presenting Author: Johann Hammer
Submitting Author: Johann Hammer

Senior Author: Johann Hammer

IASP 2026 Global Year theme of Neuropathic Pain: No

• Johann Hammer: Dr. - Medical University of Vienna
• Karin Hammer: Dr. - St. Anna Kinderspital