Pediatric Gastroenterology

Gastrointestinal Conditions

Diarrhea:
- Definition: three or more loose stools per day in children, and twice the usual number of stools per day in infants
- Types: acute (lasting fewer than 7 days and no longer than 14 days), chronic (lasting more than 4 weeks)
- Causes: GI tract infection, can lead to dehydration and malnutrition
- Prevention: access to safe drinking water and sanitation
- Treatment: hydration with hypotonic fluids, resumption of diet, nutrition/hydration support in severe cases
Constipation:
- Definition: difficulty emptying bowels, often with hard stool
- Common pediatric problem, often accompanied by irritability, abdominal pain, and decreased appetite
- Evaluation: diet for adequate fiber and fluids, consistent meal pattern, daily physical activity
- Treatment: laxatives and stool softeners as necessary
Reflux:
- Definition: gastroesophageal reflux (GER), passage of stomach contents into esophagus
- Normal physiological process, but can be accompanied by regurgitation, spitting up, or vomiting
- Diagnosis: identification of symptoms, weight loss, and poor weight gain
- Treatment: nutrition and feeding modifications, positional modifications, and medications
- Goal: decrease symptoms while promoting expected growth and development

Food Allergies and Sensitivities

Food allergy:
- Definition: adverse reaction to a food or ingredient involving the body's immune system
- Symptoms: nausea, stomach pain, diarrhea, vomiting
- Common allergens: cow's milk, egg, peanut, tree nut, soy, wheat, fish, and shellfish
- Diagnosis: skin prick test, radioallergosorbent test (RAST), and oral food challenge
- Treatment: removal of offending food, education, and nutrition management
Food intolerance:
- Definition: abnormal physical response to food or additive
- Examples: lactose and gluten intolerances
Food sensitivity:
- Definition: difficulty digesting a particular food
- Onset of symptoms: slower and may last longer

Malnutrition

Definition: inadequate nutrition leading to impaired growth, development, and function
Prevalence: common in developing countries, varying based on underlying condition
Etiology: multiple factors, including poor nutrition, disease, and chronic conditions
Assessment: anthropometric parameters, growth, chronicity, etiology, and developmental/functional status
Prevention: screening, nutrition education, and early intervention
Treatment: addressing specific causes, nutrition-focused physical exam, and nutrition education

Failure to Thrive

Definition: complex clinical syndrome describing infants and children who require nutrition intervention due to unexplained deficits in growth
Growth faltering: weight crossing 3 percentiles on standard growth charts over 3 months in infancy and 6 months in the second and third years of life
Etiology: multiple factors, including inadequate nutrition, feeding difficulties, and psychiatric disorders
Assessment: interdisciplinary approach, growth history, and feeding and nutrition assessment
Treatment: targeting suspected causes, addressing feeding difficulties, and providing nutrition therapy

Cancer

Etiology: interaction of multiple factors, including genetic composition, hormonal reactions, immune deficiencies, diet, and viral infections
Nutrition assessment: nutrition history, physical assessment, biochemical assessment, and calculations of energy and protein needs
Nutrition management: maximizing healthy food options, minimizing GI exposure to pathogens, and considering vitamins and minerals
Considerations: immunosuppressed or low-microbial diet, vitamin and mineral supplementation, and avoiding iron-containing vitamins

Iron Deficiency

Definition: most common single-nutrient deficiency among children in the developing world
Prevalence: 6.6% to 15.2% of toddlers, increasing to 40% without dietary fortification
Risk factors: developing countries, insufficient dietary intake, and intestinal blood loss
Symptoms: fatigue, weakness, irritability, pallor, and dizziness
Diagnosis: series of specific blood tests, including hemoglobin concentration measurement
Prevention: breastfeeding, iron supplementation, and introduction of iron-containing solid foods
Treatment: supplementation with 3 to 6 mg/kg of body weight for at least 3 months### Newborn Screening and Genetics
Amino acid metabolism disorders:
- Inability to correctly metabolize specific amino acids
- Results in accumulation of neurologically toxic amino acids
- Examples: Phenylketonuria (PKU), maple syrup urine disease (MSUD), and tyrosinemia type 1 (TYR1)
- Require metabolic formulas that restrict/limit offending amino acids
Organic acid metabolism disorders:
- Characterized by errors in metabolism of branched chain amino acids
- Result in accumulation of non-amino organic acids and buildup of toxic intermediates
- Can cause metabolic crises and increases in blood acids and ammonia
- Examples: Isovaleric acidemia (IVA), Glutaric acidemia type 1 (GA1), Methylmalonic acidemia (MMA), Propionic acidemia (PA)
Fatty acid oxidation disorders:
- Characterized by inability to use stored fat for energy
- Can lead to dangerously low blood glucose levels during times of increased energy needs
- Examples: Medium-chain acyl-CoA dehydrogenase deficiency (MCAD), Long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHAD), Very long chain acyl-CoA dehydrogenase deficiency (VLCAD)
Carbohydrate metabolism disorders:
- Characterized by errors in metabolism of certain carbohydrates
- Example: galactosemia, a disorder of galactose metabolism treated with a galactose-restricted diet
Other disorders screened for:
- Endocrine disorders: Congenital adrenal hyperplasia, Congenital hypothyroidism
- Hemoglobinopathies
- Cystic fibrosis (CF)

Cystic Fibrosis

Autosomal recessive genetic disorder
Result of a defective cystic fibrosis transmembrane conductance regulator (CFTR) protein
Characterized by:
- Sticky and thick secretions that affect the GI tract, lungs, pancreas, liver, sinuses, and reproductive system
- Poor weight gain and growth
- Nutritional management includes:
  - Nutritional assessment
  - Increasing caloric, protein, and fat intake
  - Management of pancreatic insufficiency and pancreatic enzyme replacement
  - Fat-soluble vitamin replacement
  - Monitoring for evidence of vitamin deficiency

Down Syndrome

Characterized by an extra chromosome 21
Risk impacted by maternal age
Can be detected through prenatal screening or blood test after birth
Affects one in every 700 newborns
Characterized by:
- Hypotonia
- Developmental delay
- Short stature
- Mild to moderate intellectual disability
Infants may have feeding issues and increased risk for overweight/obesity

Spina Bifida

Neural tube defect characterized by abnormal development of spinal canal
Lesion location determines severity of weakness or paralysis
Associated with folate status of mother
Neonates typically have lesions repaired immediately after birth
Increases energy, protein, and vitamin/mineral requirements to promote optimal wound healing
Energy needs similar in infancy to those of healthy infants, but decreased by as much as 50% by 1 year of age
Often have feeding issues and bladder/bowel dysfunction

Cerebral Palsy

Caused by brain injury or abnormal brain development
Results in difficulties with motor control and muscle tone
Can occur during the prenatal, perinatal, or postnatal period
Increased risk for cognitive impairment, learning difficulties, intellectual disabilities, hearing and vision problems
Common nutrition-related problems:
- Dysphagia
- Difficulty gaining weight
- GI problems
- Drug-nutrient interactions
Oral motor function affected by decreased jaw, tongue, and lip control
Reduces ability to chew, swallow, and eat
May increase risk of aspirating food

Cleft Lip and Palate

Congenital anomalies that result in incomplete closure of the skin, muscle, and bone of the upper lip and gum line (cleft lip) and incomplete closure of the tissues that form the roof of the mouth (cleft palate)
Etiology can be genetic, environmental, or idiopathic
Risk factors:
- Family members with an orofacial cleft
- Prenatal exposure to teratogens
Increases risk of:
- Feeding difficulties with subsequent poor growth
- Increased energy requirement
- Eustachian tube dysfunction
- Dental, orthodontic, and/or speech problems
- Gastroesophageal reflux
- Breathing difficulty (Pierre Robin sequence)
- Endocrine dysfunction (midline clefting)

Autism Spectrum Disorders

Neurologically based developmental disorder
Characterized by difficulties in social interactions and communication
Often coexist with restricted and repetitive behaviors
Prevalence/etiology:
- Reportedly 1 in 68 children in the United States
- Etiology unknown, but strong likelihood of genetic component
Risk factors:
- 50% to 90% have feeding problems
- Avoidant eating behaviors
- Sensory-based feeding difficulties
- Behavioral rigidity around food and food routines
- Food selectivity by type, texture, and/or presentation
- Greater prevalence of reported GI symptoms