3. Physiology of Gastric Acid Secretion
• Stomach is divided into four
areas: Cardia, Fundus, Body
• It has two valve-like sphincters
1. LES –Lower esophageal sphincter
2. Pyloric sphincter
• These sphincters regulate the entry
and exit of food from the stomach.
• Acid secreted in stomach causes
hydrolysis, sterilizes the meal
content & activates pepsinogen to
• Acid secretion:
Regulation of acid secretion
• Parietal cells in the gastric glands secrete
hydrochloric acid, which is needed for digestion.
• The parietal cells have 3 kinds of receptors
on their surface. These include:
1. Histamine (H2) receptor
2. Gastrin (G) receptor
3. Muscarinic (M3) receptor
• Stimulation by any one of these receptors
causes stimulation of HCl secretion from the
Acid Peptic Disease (APD)
• Acid peptic disorders include a number of conditions
whose patho-physiology is believed to be the result of
damage from acid and pepsin activity in the gastric
– Gastric Ulcer
– Duodenal Ulcer
– Hyper acidity etc…….
GER & GERD in Children
• Gastroesophageal reflux (GER), defined as passage of
gastric contents into the esophagus, is normal
physiological process that occurs throughout the day in
healthy infants, children and adults. The terms:
– Regurgitation is defined as passage of refluxed gastric
contents into the oral pharynx.
– Vomiting is defined as expulsion of the refluxed gastric contents
– Gastroesophageal reflux disease (GERD) occurs when gastric
contents reflux into the esophagus or oropharynx and produce
GER & GERD in Children
Most infants occasionally spit up throughout the day ,when
regurgitation causes other problems or is associated with other
symptoms, it may be due to Gastroesophageal Reflux Disease
(GERD), which can also occur in older children.
The difference between GER and GERD is a matter of severity
and associated consequences to the patient.
GER differs from vomiting in that it is generally not associated with
a violent ejection.
Causes of GERD
– Genetic predisposition
– Increased pressure on the abdomen (over eating, obesity, straining with
stool due to constipation, etc.).
– Decreased gastric emptying and reduced acid clearance from esophagus.
– Supine position
– Medications: diazepam, theophylline, methylxanthines (decrease
– Poor dietary habits: like overeating, eating late at night….
– Food allergies, certain foods like greasy highly acidic..
– Some beverages may also be implicated in facilitating such
– Neurodevelopmental disabilities: like cerebral palsy, Down syndrome etc..
– Tracheo-esophageal fistula
14. Symptoms of GERD
• symptoms directly related to the consequences of
emesis (eg, poor weight gain) or
• exposure of the esophageal epithelium to the gastric
• typical symptoms (eg, heartburn, vomiting, regurgitation)
in adults cannot be readily assessed in infants and
• Pediatric patients with GER cry and report sleep
disturbance and decreased appetite.
15. Gastroesophageal reflux in infants and young children
• Weight loss or poor growth (failure to thrive)
• Typical or atypical crying and/or irritability
• Poor appetite
• Chronic cough, Apnea and/or bradycardia
• Wheezing, Stridor, Sore throat
• Hoarseness and/or laryngitis
• Recurrent pneumonia
• Apparent life-threatening event (ALTE)
• Sandifer syndrome - Ie, posturing with opisthotonus or
• Abdominal and/or chest pain
16. Diagnostic Approaches
• History and Physical Examination
• Barium Contrast Radiography
• Esophageal pH Monitoring
• Multichannel Intraluminal Impedance (is a catheter-based
method to detect intraluminal bolus movement within the esophagus.
MII is performed in combination with manometry or pH testing.)
• Endoscopy and Biopsy
• Scintigraphy (radioactive tracer to obtain an image of a bodily organ
or a record of its functioning.)
• Empiric Therapy (medical treatment or therapy based on
experience ) 15
22. Does Asthma Trigger GERD?
Across The LES
23. Does GERD Trigger Asthma?
Direct contact between
gastric refluxate and
Inflammation of the
– Elevating the head of the baby's crib
– Holding the baby upright for 30 minutes after a feeding
– Thickening bottle feedings with cereal
– Changing feeding schedules
For older children:
– Elevating the head of the child's bed
– Keeping the child upright for at least two hours after eating
– Serving several small meals throughout the day, rather than
– Limiting foods and beverages that seem to worsen the reflux
– Encouraging your child to get regular exercise
– Basic compounds which neutralizes gastric acid
– Used in symptomatic management of acid disorders
– Do not reduce volume of HCl secreted
– Most commonly used antacids are Aluminium &
– Most common side effect of magnesium salts is
diarrhea and with aluminum salts is constipation
– Inconvenient in children
– Chronic antacid therapy is not recommended.1
Proton Pump Inhibitors (PPI):
– Acts by blocking enzyme system i.e. H+K+ATPase,
which is found at acid secretory surface of parietal cells
that mediates final transport of H+ ions in exchange of
K+ into gastric lumen.
– These drugs inhibit H+K+ATPase which activate proton
– E.g are Omeprazole, lansoprazole and pentoprazole
H2RA (H2 Receptor Antagonist):
– These block H2 receptors on parietal cells, and
antagonize normal stimulatory effect of histamine
on acid secretion e.g. Ranitidine, Famotidine
30. Why Ranitidine in Children
– Ranitidine 5 mg/kg per dose orally has been shown to increase
gastric pH for 9 to 10 hours in infants, very useful for infants
who need persistent acid suppression1.
– First line of therapy for GERD in pediatrics
– Efficacy in suppressing nocturnal acid secretion
– No activation required in parietal cell: Ease of
administration in pediatric patients; better response
– Safety established from 1 month onwards.
– Fast onset of action with sustainable duration of action