Assessment of gastric emptying in children: Establishment of control values utilizing a standardized vegetarian meal.

BACKGROUND AND AIM: Disorders of gastric emptying constitute an important group of conditions in children. The diagnostic gold standard is scintigraphy, and recommendations for standardization have been published with adult normative data. Pediatric literature lacks standardized age specific normative values. Our aim was to establish normal values of solid phase gastric emptying utilizing scintigraphy in children (5-18 years) using the recommended imaging protocol and standardized meal. METHODS: Gastric emptying was assessed by scintigraphy of a (99m) Tc-labeled vegetarian meal. Image acquisition was dynamic for first hour and static at 2, 3, and 4 h. Results were reported as percent intragastric retention; lag phase defined as time to 5% emptying. RESULTS: Thirty (17 boys) healthy children, mean ages of 9.5 ± 3.1 (range 5 to 16) years, were enrolled. Median values (5th and 95th percentiles) for percent gastric retention at 30 min, 1, 2, 3 and 4 h were 90% (76 and 100%), 77% (56 and 96%), 33% (10 and 71%), 16% (3 and 44%), and 7% (0.5 and 22%). The median (5th and 95th percentiles) lag phase was 18 min (6 and 60 min). Lag phase had no correlation with gastric retention at 4 h. CONCLUSIONS: This study provides valuable normative ranges for solid phase gastric emptying in children. Using adult normative data in children may be inappropriate.

Serial evaluation of children with ALF with advanced MRI, serum proinflammatory cytokines, thiamine, and cognition assessment.

OBJECTIVES: This prospective, sequential study was done to understand changes in cerebral edema (CE) on magnetic resonance imaging and magnetic resonance spectroscopy, liver functions, and neurocognitive testing (NCT) in children with acute liver failure (ALF). METHODS: A total of 11 ALF and 8 healthy controls were evaluated with advanced magnetic resonance (MR) imaging, blood proinflammatory cytokines (PCs), thiamine levels, liver functions, and NCT. Reevaluation was done at 43.5 ±â€Š26.9 days (first follow-up, n = 8) and 157.3 ±â€Š52.3 days (second follow-up, n = 6) after discharge. RESULTS: At diagnosis, patients with ALF had vasogenic and cytotoxic CE, raised brain glutamine (23.2 ±â€Š3.4 vs. 15.3 ±â€Š2.7), and serum PCs (tumor necrosis factor [TNF]-α 40.1 ±â€Š8.9 vs. 7.2 ±â€Š2.7  pg/mL, interleukin [IL]-6 29.2 ±â€Š14.4 vs. 4.7 ±â€Š1.2  pg/mL). The mammillary bodies (MBs) were smaller, and brain choline (1.9 ±â€Š0.36 vs. 2.6 ±â€Š0.6) and blood thiamine (55.2 ±â€Š6.7 vs. 81.8 ±â€Š10.2  nmol/L) were lower than controls. At first follow-up, the brain glutamine and CE recovered. Brain choline and MBs volume showed improvement and thiamine levels normalized. Significant reduction in TNF-α and IL-6 was seen. The patients performed poorly on NCT, which normalized at second follow-up. Liver biochemistry and thiamine levels were normal and TNF-α and IL-6 showed further reduction at second follow-up. CONCLUSIONS: Patients with ALF have CE contributed by raised brain glutamine and PCs. MBs are small because of thiamine deficiency and show recovery in follow-up. CE and brain glutamine recover earlier than normalization of NCT and liver functions. Persistence of raised cytokines up to 6 months after insult suggests possible contribution from liver regeneration.

Encephalopathy assessment in children with extra-hepatic portal vein obstruction with MR, psychometry and critical flicker frequency.

BACKGROUND & AIMS: Mild cognitive and psychomotor deficit has been reported in patients with extra-hepatic portal vein obstruction. This prospective study was done to ascertain the presence of minimal hepatic encephalopathy by neuropsychological testing and its correlation with diffusion tensor imaging derived metrics, T1 signal intensity, brain metabolites in (1)H magnetic resonance spectroscopy, blood ammonia and critical flicker frequency in patients with extra-hepatic portal vein obstruction. METHODS: Neuropsychological tests, critical flicker frequency, blood ammonia, diffusion tensor imaging, T1 signal intensity and (1)H magnetic resonance spectroscopy were determined in 22 extra-hepatic portal vein obstruction and 17 healthy children. Bonferroni multiple comparison post hoc analysis was done to compare controls with patient groups. RESULTS: Based on neuropsychological tests, 7/22 patients had minimal hepatic encephalopathy, and significantly increased Glx/Cr ratio, blood ammonia, mean diffusivity and globus pallidus T1 signal intensity with decreased critical flicker frequency in comparison to controls and in those without minimal hepatic encephalopathy. Cho/Cr, mI/Cr ratio and fractional anisotropy were unchanged in patient groups compared to controls. A significant inverse correlation of neuropsychological test with mean diffusivity, Glx/Cr ratio and blood ammonia and a positive correlation among mean diffusivity, blood ammonia and Glx/Cr ratio was seen. CONCLUSIONS: Extra-hepatic portal vein obstruction is a true hyperammonia model with porto-systemic shunting and normal liver functions that results in minimal hepatic encephalopathy in one-third of these children. Hyperammonia results in generalized low grade cerebral edema and cognitive decline as evidenced by increased Glx/Cr ratio, mean diffusivity values and abnormal neuropsychological tests.