1. GI Disorder Part 1 of 4
Lawrence M. Formoso, M.D.

2. Normal Digestive Tract Phenomena
A fetus can swallow AF as early as 12 wk of gestation
nutritive sucking in neonates 1st develops at about 34 wk of gestation
The coordinated oral and pharyngeal movements necessary for swallowing solids develop within the 1st few months of life
By 1 mo of age, infants appear to show preferences for sweet and salty foods

3. Infants’ interest in solids increases at about 4 mo of age
The recommendation to begin solids at 6 mo of age is based on nutritional and cultural concepts rather than maturation of the swallowing process
Infants swallow air during feeding, and burping is encouraged to prevent gaseous distention of the stomach

4. Regurgitation, the result of gastroesophageal reflux, occurs commonly in the 1st year of life
volumes of emesis are commonly ≈15–30 mL but may occasionally be larger
Most often, the infant remains happy, although possibly hungry, after an episode of regurgitation
Episodes may occur from less than one to several times per day
resolves in 80% of infants by 6 mo of age and in 90% by 12 mo.
Complications of gastroesophageal reflux include failure to thrive, pulmonary disease (apnea or aspiration pneumonitis), and esophagitis with its sequelae

5. The earliest stools after birth consist of meconium, a dark, viscous material that is normally passed within the 1st 48 hr of life
With the onset of feeding, meconium is replaced by green-brown transition stools, often containing curds, and, after 4–5 days, by yellow-brown milk stools
Stool frequency is extremely variable in normal infants and may vary from none to seven per day
Breast-fed infants may have frequent small, loose stools early (transition stools), and then after 2–3 wk, may have very infrequent soft stools.

6. Toddler's diarrhea A pattern of intermittent loose stools
occurs commonly between 1 and 3 yr of age
These otherwise healthy growing children often drink excessive carbohydrate-containing beverages
The stools typically occur during the day and not overnight
The volume of fluid intake is often excessive
limiting sugar-containing beverages and increasing fat in the diet often leads to resolution of the pattern of loose stools.

7. Nondigestive Tract Causes of Gastrointestinal Symptoms in Children
ANOREXIA
Systemic disease (inflammatory, neoplastic)
Cardiorespiratory compromise
Iatrogenic—drug therapy, unpalatable therapeutic diets
Depression
Anorexia nervosa
VOMITING
Inborn errors of metabolism
Medications (erythromycin, chemotherapy)
Increased intracranial pressure
Brain tumor
Infection (urinary tract)
Labyrinthitis
Adrenal insufficiency
Pregnancy
Psychogenic
Abdominal migraine
Toxins

8. Nondigestive Tract Causes of Gastrointestinal Symptoms in Children
DIARRHEA
Infection (otitis media, urinary)
Uremia
Medications (antibiotics, cisapride)
Tumors (neuroblastoma)
Pericarditis
CONSTIPATION
Hypothyroidism
Spina bifida
Psychomotor retardation
Dehydration (diabetes insipidus, renal tubular lesions)
Medications (narcotics)
Lead poisoning
Infant botulism
ABDOMINAL PAIN
Pyelonephritis, hydronephrosis, renal colic  
Pneumonia  
Pelvic inflammatory disease  
Porphyria  
Angioedema  
Endocarditis  
Abdominal migraine  
Familial Mediterranean fever 
Sexual or physical abuse  
Systemic lupus erythematosus  
School phobia  
Sickle cell crisis  
Vertebral disk inflammation  
Medications (NSAIDs)  
Pelvic osteomyelitis

9. Nondigestive Tract Causes of Gastrointestinal Symptoms in Children
ABDOMINAL DISTENTION OR MASS
Ascites (nephrotic syndrome, neoplasm, heart failure)
Discrete mass (Wilms tumor, hydronephrosis, neuroblastoma, mesenteric cyst, hepatoblastoma, lymphoma)
Pregnancy
JAUNDICE
Hemolytic disease
Urinary tract infection
Sepsis
Hypothyroidism
Panhypopituitarism

10. Major Symptoms and Signs of Digestive Tract Disorders
Dysphagia, or difficulty swallowing, may be caused by a structural defect or motility disorder
Structural defects that cause a fixed impediment to the food bolus arise from narrowing within the esophagus
stricture, web, or tumor
Most nonstructural causes of dysphagia are caused by motility abnormalities of the oropharynx or the esophagus
transfer dysphagia
- Dysphagia during the oropharyngeal phase of swallowing
usually associated with neuromuscular disorders (cerebral palsy)
The sensation that something is stuck in the upper esophagus is globus (formerly termed globus hystericus)
associated with GER

11. Major Symptoms and Signs of Digestive Tract Disorders
Nontransfer Dysphagia
Esophageal web, tracheobronchial remnant, or vascular ring may cause dysphagia in infancy.
A Schatzki ring, a thin ring of tissue near the lower esophageal sphincter, is another mechanical cause of recurrent dysphagia presenting after infancy
An esophageal foreign body or a stricture secondary to a caustic ingestion also causes dysphagia
REGURGITATION
effortless movement of stomach contents into the esophagus and mouth
infants with regurgitation are often hungry immediately after an episode
Regurgitation is a result of GER through an incompetent or, in infants, immature lower esophageal sphincter
regurgitation or “spitting” resolves with maturity

12. Differential Diagnosis of Emesis During Childhood
Gastroenteritis
Gastritis
Systemic infection
Toxic ingestion
Pertussis syndrome
Medication
(GERD)
Sinusitis
Otitis media
INFANT
Gastroenteritis
Gastroesophageal reflux
Overfeeding
Anatomic obstruction
Systemic infection
Pertussis syndrome
Otitis media

13. Differential Diagnosis of Emesis During Childhood
ADOLESCENT
Gastroenteritis
GERD
Toxic ingestion
Systemic infection
Gastritis
Sinusitis
Inflammatory bowel disease
Appendicitis
Migraine
Pregnancy
Medication
Ipecac abuse/bulimia

14. Major Symptoms and Signs of Digestive Tract Disorders
ANOREXIA
Hunger and satiety centers are located in the hypothalamus
The afferent nerves from the gastrointestinal tract to these brain centers are important determinants of the anorexia that characterizes many diseases of the stomach and intestine
Satiety is stimulated by distention of the stomach or upper small bowel, the signal being transmitted by sensory afferents, which are especially dense in the upper gut

15. Major Symptoms and Signs of Digestive Tract Disorders
Vomiting
is a highly coordinated reflex process that may be preceded by increased salivation and begins with involuntary retching
Violent descent of the diaphragm and constriction of the abdominal muscles with relaxation of the gastric cardia actively force gastric contents back up the esophagus
coordinated in the medullary vomiting center, which is influenced directly by afferent innervation and indirectly by the chemoreceptor trigger zone and higher central nervous system (CNS) centers

16. Cyclic vomiting
is a syndrome with numerous episodes of vomiting interspersed with well intervals
onset is usually between 2 and 5 yr of age
the frequency of vomiting episodes is variable (average of 12 episodes per yr)
with each episode typically lasting 2–3 days, with four or more emesis episodes per hour
Patients may have a prodrome of pallor, intolerance of noise or light, nausea, lethargy, and headache or fever
Precipitants include infection, stress, and excitement

17. Cyclic vomiting
Laboratory evaluation is based on a careful history and physical examination and may include, if indicated, endoscopy, contrast gastrointestinal radiography, brain MRI, and metabolic studies (lactate, organic acids, ammonia)
Treatment includes hydration and ondansetron
Prevention may be possible with the antimigraine agent amitriptyline or cyproheptadine

18. Pharmacologic Therapies for Vomiting Episodes
Reflux
Dopamine antagonist: metoclopramide (Reglan) (0.1–0.2 mg/kg qid PO/IV)
Peripheral dopamine antagonist: domperidone (Motilium) (0.2–0.6 mg/kg tid–qid PO)
Chemotherapy
Metoclopramide; (0.5–1.0 mg/kg qid IV, with antihistamine prophylaxis of extrapyramidal side effects)
Serotoninergic 5-HT3 antagonist: ondansetron (Zofran) (0.15–0.3 mg/kg tid IV/PO)
Phenothiazines:(extrapyramidal, hematologic side effects)
   
Prochlorperazine (Compazine) (≈0.3 mg/kg bid–tid PO)
Chlorpromazine (Thorazine) (>6 mo of age: 0.5 mg/kg tid–qid PO/IV)
Steroids:dexamethasone (Decadron) (0.1 mg/kg tid PO)
Cannabinoids:nabilone (tetrahydrocannabinol) (0.05–0.1 mg/kg bid–tid PO)

19. Pharmacologic Therapies for Vomiting Episodes
Motion sickness/vestibular disorder
Antihistamine:dimenhydrinate (Dramamine) (1 mg/kg tid–qid PO)
Anticholinergic:scopolamine (Transderm Scōp) (adults: 1 patch/3 days)
Adrenal crisis
Steroids:cortisol (2 mg/kg bolus IV followed by 0.2–0.4 mg/kg/hr IV [± 1 mg/kg IM])

20. Pharmacologic Therapies for Vomiting Episodes
Cyclic vomiting syndrome (CVS)
Supportive:
Analgesic:meperidine (Demerol) (1–2 mg/kg q4–6h IV/IM)
 Anxiolytic, sedative: Lorazepam (Ativan) (0.05–0.1 mg/kg q6h IV)
Antihistamine, sedative: diphenhydramine (Benadryl) (1.25 mg/kg q6h IV)
Abortive:
Serotoninergic 5-HT3 antagonist:
Ondansetron:(0.15–0.3 mg/kg tid IV/PO)
Granisetron (Kytril) (10 μg/kg q4–6h IV)
Nonsteroidal antiinflammatory agent (GI ulceration side effect):
Ketorolac (Toradol) (0.5–1.0 mg/kg q6–8h IV)
Serotoninergic 5-HT1D agonist: sumatriptan (Imitres) (>40 kg; 20 mg intranasally/25 mg PO, one time only)
Prophylactic:(if >1 CVS bout/month;taken daily)
Antimigraine, β-adrenergic blocker: propranolol (Inderal) (0.5–2.0 mg/kg bid PO)
Antimigraine, antihistamine: cyproheptadine (Periactin) (0.25–0.5 mg/kg/day ÷ bid–tid PO)
Antimigraine, tricyclic antidepressant: amitriptyline (Elavil) (0.33–0.5 mg/kg tid PO, and titrate to maximum of 3.0 mg/kg/day as needed; obtain baseline ECG at start of therapy, and consider monitoring drug levels)
Antimigraine antiepileptic: Phenobarbital (Luminal) (2–3 mg/kg qhs)
Erythromycin:
Low estrogen oral contraceptives: consider for catamenial CVS episodes

21. Causes of Gastrointestinal Obstruction
ESOPHAGUS
Congenital
Esophageal atresia  
Vascular rings 
Schatzki ring  
Tracheobronchial remnant
Acquired
Esophageal stricture  
Foreign body  
Achalasia  
Chagas disease  
Collagen vascular disease

22. Causes of Gastrointestinal Obstruction
STOMACH
Congenital
Antral webs  
Pyloric stenosis
Acquired
Bezoars/foreign body  
Pyloric stricture (ulcer)  
Chronic granulomatous disease of childhood  
Eosinophilic gastroenteritis  
Crohn disease  
Epidermolysis bullosa

23. Causes of Gastrointestinal Obstruction
SMALL INTESTINE
Congenital
Duodenal atresia  
Annular pancreas  
Malrotation/volvulus 
Malrotation/Ladd bands  
Ileal atresia  
Meconium ileus  
Meckel diverticulum with volvulus or intussusception  
Inguinal hernia  Intestinal duplication
Acquired
Postsurgical adhesions  
Crohn disease  
Intussusception  
Distal ileal obstruction syndrome (cystic fibrosis)  
Duodenal hematoma  
Superior mesenteric artery syndrome

24. Causes of Gastrointestinal Obstruction
COLON
Congenital
Meconium plug  
Hirschsprung disease  
Colonic atresia, stenosis  
Imperforate anus  
Rectal stenosis  
Pseudo- obstruction  
Volvulus 
Colonic duplication
Acquired
Ulcerative colitis (toxic megacolon)  
Chagas disease  
Crohn disease  
Fibrosing colonopathy (cystic fibrosis)

25. Major Symptoms and Signs of Digestive Tract Disorders
DIARRHEA
excessive loss of fluid and electrolyte in the stool.
Normally, a young infant has ≈5 g/kg of stool output per day; the volume increases to 200 g/24 hr in an adult
The greatest volume of intestinal water is absorbed in the small bowel; the colon concentrates intestinal contents against a high osmotic gradient
The basis for all diarrhea is disturbed intestinal solute transport

26. Mechanisms of Diarrhea
Secretory
Decreased absorption, increased secretion, electrolyte transport
Cholera, toxigenic E. coli; carcinoid, VIP, neuroblastoma, congenital chloride diarrhea, Clostridium difficile, cryptosporidiosis (AIDS)
Persists during fasting; bile salt malabsorption may also increase intestinal water secretion; no stool leukocytes
Osmotic
Maldigestion, transport defects ingestion of unabsorbable
Lactase deficiency, glucose-galactose malabsorption, lactulose, laxative abuse
Stops with fasting; increased breath hydrogen with carbohydrate malabsorption; no stool leukocytes
Primary mechanism, Defect, Examples

27. Mechanisms of Diarrhea
Increased motility
Decreased transit time
Irritable bowel syndrome, thyrotoxicosis, postvagotomy dumping syndrome
Infection may also contribute to increased motility
Decreased motility
Defect in neuromuscular unit(s)
Stasis (bacterial overgrowth)
Mucosal invasion
Inflammation, decreased colonic reabsorption, increased motility
Salmonella, Shigella, infection; amebiasis; Yersinia, Campylobacter infections
Dysentery evident in blood, mucus, and WBCs
Blood and increased WBCs in stool

28. Differential Diagnosis of Diarrhea
INFANT
Common:
Gastroenteritis
Systemic infection
Antibiotic associated
Overfeeding
Rare:
Primary disaccharidase deficiency
Hirschsprung toxic colitis
Adrenogenital syndrome
Neonatal opiate withdrawal
CHILD
Gastroenteritis
Food poisoning
Systemic infection
Antibiotic associated
Toxic ingestion
ADOLESCENT
Hyperthyroidism

29. Major Symptoms and Signs of Digestive Tract Disorders
CONSTIPATION
is relative and depends on stool consistency, stool frequency, and difficulty in passing the stool
A normal child may have a soft stool only every 2nd or 3rd day without difficulty; this is not constipation
A hard stool passed with difficulty every 3rd day should be treated as constipation
Constipation can arise from defects either in filling or emptying the rectum
A nursing infant may have very infrequent stools of normal consistency; this is usually a normal pattern
True constipation in the neonatal period is most likely secondary to Hirschsprung disease, intestinal pseudo-obstruction, or hypothyroidism.

30. Major Symptoms and Signs of Digestive Tract Disorders
ABDOMINAL PAIN
Visceral pain
tends to be experienced in the dermatome from which the affected organ receives innervation
Painful stimuli originating in the liver, pancreas, biliary tree, stomach, or upper bowel are felt in the epigastrium
pain from the distal small bowel, cecum, appendix, or proximal colon is felt at the umbilicus
pain from the distal large bowel, urinary tract, or pelvic organs is usually suprapubic
Parietal pain impulses travel in C fibers of nerves corresponding to dermatomes T6–L1; such pain tends to be more localized and intense than visceral pain.

31. Major Symptoms and Signs of Digestive Tract Disorders
GASTROINTESTINAL HEMORRHAGE
Bleeding can occur anywhere along the gastrointestinal tract, and identification of the site may be challenging
Evaluation of the small intestine is facilitated by capsule camera endoscopy
Erosive damage to the mucosa of the gastrointestinal tract is the most common cause of bleeding, also variceal bleeding secondary to portal hypertension occurs frequently
bleeding originating in the esophagus, stomach, or duodenum, it may cause hematemesis

32. GASTROINTESTINAL HEMORRHAGE
When exposed to gastric or intestinal juices, blood quickly darkens to resemble coffee grounds; massive bleeding is likely to be red
Red or maroon blood in stools, hematochezia, signifies either a distal bleeding site or massive hemorrhage above the distal ileum.
Moderate to mild bleeding from sites above the distal ileum tends to cause blackened stools of tarry consistency (melena); major hemorrhages in the duodenum or above can also cause melena

33. Differential Diagnosis of Gastrointestinal Bleeding in Childhood
INFANT
Common:
Bacterial enteritis
Milk protein allergy
Intussusception
Swallowed maternal blood
Anal fissure
Lymphonodular hyperplasia
Rare:
Volvulus
Necrotizing enterocolitis
Meckel diverticulum
Stress ulcer, stomach
Coagulation disorder (hemorrhagic disease of newborn)

34. CHILD Common: Bacterial enteritis Anal fissure Colonic polyps
Intussusception  
Peptic ulcer/gastritis  
Swallowed epistaxis  
Prolapse (traumatic) gastropathy 2° emesis  
Mallory-Weiss syndrome
Rare:
Esophageal varices
Esophagitis
Meckel diverticulum
Lymphonodular hyperplasia
Henoch-Schönlein purpura
Foreign body
Hemangioma, arteriovenous malformation
Sexual abuse
Hemolytic-uremic syndrome
Inflammatory bowel disease
Coagulopathy

35. ADOLESCENT Common: Bacterial enteritis Inflammatory bowel disease
Peptic ulcer/gastritis
Prolapse (traumatic) gastropathy 2° emesis
Mallory-Weiss syndrome
Colonic polyps
Rare:
Hemorrhoids
Esophageal varices
Esophagitis
Telangiectasia-angiodysplasia
Gay bowel disease
Graft versus host disease