640 likes | 689 Views
Pediatric Gastrointestinal Diseases. By Dr.Ashraf Radwan, MD Pediatric Department. DIARRHOEA. Diarrhea. Definition Diarrhea is defined as excessive loss of fluid and electrolyte in the stool Clinically Diarrhea is an increase in the number ,volume And Fluidity
E N D
Pediatric Gastrointestinal Diseases By Dr.Ashraf Radwan, MD Pediatric Department
Diarrhea Definition Diarrhea is defined as excessive loss of fluid and electrolyte in the stool Clinically Diarrhea is an increasein the number,volumeAnd Fluidity of stools relative to the usual habits of each individual
DIARRHOEA Morbidity The average child ( <5 years ) suffers 3 bouts of diarrhea per year
High Childhood Morbidity In children under 5 years of age 1.3 billion episodes/year
DIARRHOEA Mortality Responsible for about 12 % of deaths in children <5 years
High Childhood Mortality 3.2 million deaths/ year In children under 5 years of age
Small Intestinal Morphology The small intestinal mucosa comprises 2 main structures: Villi: Covered by absorptive cells (enterocytes) having a microvillar( brush border) Crypts : Covered mainly by secretory cells without brush border
Intestinal Physiology Two important physiologic processes occur in the small intestine 1- Absorption 2-Secretion
Normal intestinal Fluid Balance Balance between absorption and secretion with NET ABSORPTION
Intestinal Physiology +++ NET ABSORPTION ++
Intestinal Absorption of Na+ 1-Coupled with Chloride absorption 2-Direct absorption down concentration gradient 3-Exchanged to H- ion 4-Coupled to absorption of organic substances like Glucose or Amino acids
Absorption of Na+ Coupled absorption of Na+ with Glucose or Amino acids is NOT AFFECTED during diarrhea
DIARRHOEA (Pathophysiology ) Physiologically diarrhea is considered as imbalance between absorption and secretion. There are two physiologic mechanisms of diarrhea 1-Secretory diarrhea 2-Osmotic diarrhea However other mechanisms play a role 1- Increased GIT motility 2- Short bowl
Secretory diarrhea There is increased net secretion of water and salts into the small intestine through activation of the intracellular mediators such as cAMP, cGMP which 1-Stimulate active chloride secretion from the crypt cells 2- Inhibit the sodium chloride absorption .
Pathogenesis of Secretory Diarrhoea 1-EnterotoxigenicBacteria secrete an Enterotoxin that stimulates the production of C-AMP (cyclic adenosine mono-phosphate) • 2-Increased C-AMP leads to: • Inhibition of absorption of Na+ & Cl- from the cells of villi • Stimulation of secretion of Cl- from crypt cells
Pathogenesis of Secretory Diarrhoea ----- NET SECRETION +++++
Secretory diarrhea The major causes of secretory diarrhea are 1-Bacterial toxins 2-Vasoactive intestinal peptide
Osmotic diarrhea Osmotic diarrhea is caused by the presence of nonabsorbable materials in the gastrointestinal tract these nonabsorbable materials will generate an osmotic load and cause water to be secreted into the lumen
Osmotic diarrhea The classic example of osmotic diarrhea is lactose intolerance 1- lactase enzyme deficiency 2-lactose is not absorbed in the small intestine and reaches the colon intact 3-The colonic bacteria ferment the lactose to short-chain organic acids, generating an osmotic load
Osmotic diarrhea Other examples include ingestion of excessive amounts of 1-carbonated fluids 2-magnesium hydroxide 3-sorbitol 4-Lactulose( a synthetic therapeutic disaccharide composed of galactose and fructose)
II- Chronic diarrhea Duration >14 days Types of Diarrhea I –Acute diarrhea Duration < 14 days
DIARRHOEA Consequences 1-Dehydration 2-Electrolyte disturbances 3-Acid base disturbances
DEHYDRATION Definition is the loss of body water and electrolytes Importance the most dangerous event in diarrhea Degrees Minimal or NO dehydration < 3% loss of body weight Mild to Moderate 3 – 9 % loss of body weight Severe > 9 %loss of body weight
DEHYDRATION Types 1- Isonatremic ( isotonic ) 2- Hypernatremic ( hypertonic ) 3-Hyponatremic ( Hypo tonic)
Isonatremic ( isotonic )dehydration -The most common type -Equal loss of water and sodium -Serum sodium and the osmolality of the extracellular fluid are normal
Hyponatremic ( Hypo tonic )dehydration - loss of sodium is more than that of water - Serum sodium and osmolality of the extracellular fluid are decreased
Hypernatremic ( Hypertonic )dehydration - loss of sodium is less than that of water - Serum sodium and osmolality of the extracellular fluid are increased
Hypernatremic ( hypertonic ) dehydration -Very serious ( Intracellular dehydration -Common in 1-young infants 2-Formula fed infants 3- The use of fluid with excess electrolyte in treatment of diarrhea
DEHYDRATION (manifestations) 1-Thirst 2- Oliguria 3- Depressed anterior fontanel 4- Sunken eyes 5- Decreased or absent tears 6- Dry tongue 7- Loss of skin turgor
DEHYDRATION (manifestations) ) 8- Shock a – Tachycardia b- Hypotension c-Cold extremities d- Impaired consciousness Lethargy Coma
Skin Pinch Normal — it goes back immediately Slowly — the fold is visible for less than 2 second Very slowly — the fold is visible for more than 2 seconds.
Classification of dehydration 1- MINIMAL OR NO DEHYDRATION 2- MILD TO MODERATE DEHYDRATION 3- SEVERE DEHYDRATION
MINIMAL OR NO DEHYDRATION 1-Thirst Drinks normally 2-Urine output Normal to decreased 3- Skinfold Instant recoil 4-Mouth and tongue Moist 5-Eyes Normal 6-Tears Present 7-Heart rate Normal 8- Pulse Normal 9-Extremities Warm 10- Mental statusAlert
1-Thirst Thirsty (eager to drink) 2-Urine output Decreased 3-SkinfoldRecoil in <2 sec 4-Mouth and tongue Dry 5-Eyes Slightly sunken 6-Tears Decreased 7-Heart rate Normal to increased 8- Pulses quality Normal to decreased 9-Extremities Cool 10- Mental status, restless or irritable MILD TO MODERATE DEHYDRATION
SEVERE DEHYDRATION 1-Thirst Drinks poorly 2-Urine output Minimal 3-SkinfoldRecoil in >2 sec 4-Mouth and tongue Parched 5-Eyes Deeply sunken 6-Tears Absent 7-Heart rate Tachycardia 8- Pulses quality Weak or impalpable 9-Extremities Cold; mottled or cyanotic 10-Mental status Apathy, lethargy or unconsciousness
II - infectious diarrhea (Gastroenteritis ) Causes of Diarrhea I –Non infectious diarrhea
Gastroenteritis The term gastroenteritis denotes infections of the gastrointestinal tract Etiology Organisms 1-Viral 2- Bacterial 3- Parasitic
GastroenteritisViral pathogens 1- Rotavirus ( 30 – 50 % ) 2- Noroviruses 3- Others Enteric adenoviruses Astroviruses
GastroenteritisBacterial pathogens 1- Escherichia coli 2-Shigella 3- Salmonella 4- Others -Vibrio cholera -Campylobacter -Yersinia enterocolitica -Clostridium difficile
GastroenteritisParasitic pathogens 1-Cryptosporidium 2 –Giardia lamblia 3- Entameba histolytica
Gastroenteritis Transmission 1- Fecal-Oral Transmission 2- Personal Transmission
EtiologyFecal-Oral Transmission Infected animal Infected Person Food Water
EPIDEMIOLOGY Age incidence Between 3 months and 3 years Peak incidence is 6-24 months Season Present allover the year Bacterial ( More in Summer ) Viral ( More in winter )
Gastroenteritis Pathogenesis Enteropathogens can lead to either an inflammatory or noninflammatory response in the intestinal mucosa.
Inflammatory diarrhea Inflammatory diarrhea is usually caused by bacteria that 1-Directly invade the intestine 2- Produce cytotoxins with consequent passage of fluids, protein, and cells (erythrocytes, leukocytes) into the intestinal lumen
Noninflammatory diarrhea Noninflammatory diarrhea through 1-Enterotoxin production ( some bacteria) 2- Destruction of villus cells ( viruses) 3- Adherence ( parasites)