1. Acute Gastroenteritis in Children
infections of the gastrointestinal (GI) tract caused by bacterial, viral, or parasitic pathogens
most common manifestations :
diarrhea
vomiting
abdominal pain and fever.
fecal-oral route
Risk Factors : environmental contamination and increased exposure to enteropathogens
associated with poverty, poor environmental hygiene, and development indices
young age, immunodeficiency, measles, malnutrition, and lack of exclusive or predominant breast-feeding
he majority of cases of diarrhea resolve within the 1st wk of the illness. A smaller proportion of diarrheal illnesses fail to resolve and persist for >2 wk
Refer to tables to for common etiologic agents

2. Treatment oral rehydration therapy enteral feeding and diet selection,
zinc supplementation
additional therapies such as probiotics
Refer to table for antiobiotic therapy for infection

3. Persistent Diarrhea
episodes that began acutely but last for ≥14 days

4. Chronic Diarrhea diarrheal episode that lasts for ≥14 days
Refer to table for the etiology

5. STEPWISE DIAGNOSTIC WORK-UP FOR CHILDREN WITH CHRONIC DIARRHEA

6. General therapeutic approaches to management of chronic diarrhea

7. Treatment general supportive measures nutritional rehabilitation
elimination diet
drugs

8. DIARRHEA CAUSED BY NEUROENDOCRINE TUMORS

9. Functional Abdominal Pain (Nonorganic Chronic Abdominal Pain)
Recurrent abdominal pain (RAP) in children was defined as at least 3 episodes of pain over at least 3 mo that interfered with function
ROME III CRITERIA for H2d. CHILDHOOD FUNCTIONAL ABDOMINAL PAIN
Diagnostic criteria* must include all of the following:
Episodic or continuous abdominal pain
Insufficient criteria for other FGIDs
No evidence of an inflammatory, anatomic, metabolic or neoplastic process that explains the subject's symptoms

10. ROME III CRITERIA FOR CHILDHOOD FUNCTIONAL ABDOMINAL PAIN SYNDROME H2D1
Diagnostic criteria* must satisfy criteria for childhood functional abdominal pain and have at least 25% of the time one or more of the following:
Some loss of daily function
Additional somatic symptoms such as headache, limb pain, or difficulty sleeping.

12. Irritable Bowel Syndrome
characterized as a chronic functional bowel disorder associated with abdominal pain or discomfort and altered bowel function
Abdominal pain is episodic, cramping, or aching, usually in the lower abdomen and often relieved by defecation
abdominal discomfort, bloating, and flatulence
Diarrhea and constipation alone or in an alternating pattern must be present
The diarrhea is often watery and frequent and is associated with pain, the passage of mucus per rectum, and a feeling of incomplete emptying
The constipation is associated with a decreased stooling frequency and the passage of hard stools
Management:
Pain has been managed with cognitive-behavioral therapy, pain clinic referrals, peppermint, antispasmodic agents, and tricyclic antidepressant agents (amitriptyline).
Diarrhea has been managed with loperamide, oral nonabsorbable antibiotics, and 5-HT3 antagonists (alosetron).
Constipation is managed with fiber (psyllium), increased fluid intake, lactulose, 5-HT4 agonists (tegaserod), and selective C2 chloride channel–activating agents

13. Acute Appendicitis
most common acute surgical condition in children and a major cause of childhood morbidity
most common in older children, with peak incidence between the age of 12 and 18 yr; it is rare in children <5 yr of age (<5% of cases) and extremely rare (<1% of cases) in children <3 yr of age
Perforation is most common in young children, with rates as high as 82% for children <5 yr and approaching 100% in infants
Localized abdominal tenderness is the single most reliable finding in the diagnosis of acute appendicitis
The psoas sign is elicited with active right thigh flexion or passive extension of the hip and typically positive in cases of a retrocecal appendix.
The obturator sign is demonstrated by adductor pain after internal rotation of the flexed thigh and typically positive in cases of a pelvic appendix
mass in the RLQ representing an inflammatory phlegmon around the appendix or a localized abscess

14. Scores of ≤2 suggest a very low likelihood of appendicitis, while scores ≥8 are highly associated with appendicitis. Scores between 3 and 7 warrant further diagnostic studies

15. Plain Films sentinel loops of bowel and localized ileus,
scoliosis from psoas muscle spasm,
a colonic air-fluid level above the right iliac fossa (colon cutoff sign)
fecalith (5-10% of cases)
low sensitivity for appendicitis and are not generally recommended

16. Ultrasound CT Scan >90% sensitivity and specificity
ultrasound criteria:
wall thickness ≥6 mm, luminal distention,
lack of compressibility,
a complex mass in the RLQ, or a fecalith
CT Scan
gold standard
>95% sensitivity and specificity for acute appendicitis.

17. Treatment prompt appendectomy
For simple nonperforated appendicitis: one preoperative dose of a single broad-spectrum agent (cefoxitin)
In perforated or gangrenous appendicitis: “triple” antibiotics (ampicillin, gentamicin, and clindamycin or metronidazole) or a combination such as ceftriaxone-metronidazole or ticarcillin- clavulanate plus gentamicin, continued postoperatively for 3-5 days
Interval Appendectomy
For appendicitis complicated by a walled-off inflammatory mass or abscess
intended to avoid a predictable higher surgical complication
The vast majority of pediatric surgeons perform interval appendectomy routinely (4-6 wk interval) after nonoperative management of perforated appendicitis
Complications
nonperforated appendicitis,: 5-10%
perforated appendicitis,: %.
The most common complications are wound infections (3-10%) and intra-abdominal abscesses

18. Anorectal Malformations
defined by the relationship of the rectum to this complex and include varying degrees of stenosis to complete atresia
Incidence: 1/3,000 live births
Sphincter complex:
puborectalis, levator ani
external and internal sphincters
superficial external sphincter muscles
Normal anorectal anatomy in relation
to pelvic structures.

19. Imperforate anus
Low lesions: rectum has descended through the sphincter complex
In boys, low lesions usually manifest with meconium staining somewhere on the perineum along the median raphe
Low lesions in girls also manifest as a spectrum from an anus that is only slightly anterior on the perineal body to a fourchette fistula that opens on the moist mucosa of the introitus distal to the hymen
High lesions: rectum has not descended through the sphincter complex
Boys: no apparent cutaneous opening or fistula, but it usually has a fistula to the urinary tract, either the urethra or the bladder
Girls: cloacal anomalies in which the rectum, vagina, and urethra all empty into a common channel or cloacal stem of varying length
Associated anomalies:
Caudal regeression syndrome: most common
anomalies of the kidneys and urinary tract in conjunction with abnormalities of the sacrum
VATERR (vertebral, anal, tracheal, esophageal, radial, renal)
VACTERL (vertebral, anal, cardiac, tracheal, esophageal, renal, limb)

20. Diagnostic approach
Prone cross-table lateral plain x-ray at 24 hr of life (to allow time for bowel distention from swallowed air) with a radioopaque marker on the perineum can demonstrate a low lesion by showing the renal gas bubble <1 cm from the perineal skin
A plain x-ray of the entire sacrum, including both iliac wings, is important to identify sacral anomalies and the adequacy of the sacrum
An abdominal-pelvic ultrasound and voiding cystourethrogram (VCUG) must be performed
NGT
ECG
Treatment:
Simple dilation (Hegar dilator) for perineal fistula
High lesion: double-barrel colostomy
PSARP: definitive; performed at about 1 yr of age

21. Anal fissure laceration of the anal mucocutaneous junction
mainly seen in infants <1 yr of age
may be the consequence and not the cause of constipation
Treatment:
goal is to ensure that the patient has soft stools to avoid overstretching the anus
dietary and behavioral modification and a stool softener is indicated
healing process can take several weeks or even several months
Chronic Anal Fissure:
Initial treatment: stool softeners, hot sitz bath
Topical 0.2% glyceryl trinitrate reduces anal spasm and heals fissures, but it is often associated with headaches
local anesthetics such as 10% lidocaine or EMLA (5% prilocaine, 5% lidocaine) may be effective.
Non-responders: local injection of botulinum toxin to treat the associated contraction of the sphincter

22. Perianal Abscess and Fistula
Usually manifest in the first year of life
Unknown etiology
Clinical manifestations: low-grade fever, mild rectal pain, and an area of perianal cellulitis
spontaneously drain and resolve without treatment
Treatment
Treatment is rarely indicated in infants with no predisposing disease because the condition is often self-limited
With extreme patient discomfort, abscesses may be drained under local anesthesia
Fistulas requiring surgical intervention may be treated by fistulotomy (unroofing or opening), fistulectomy (excision of the tract leaving it open to heal secondarily), or placement of a seton
Antibiotics are not useful
Surgery:
Surgical treatment is reserved for patients failing conservative management.
Techniques described include rubber band ligation, open excision, and use of a transanal stapling device

23. Hemorrhoids related to a diet deficient in fiber and poor hydration
In younger children, the presence of hemorrhoids should also raise the suspicion of portal hypertension
External hemorrhoids occur below the dentate line
Internal hemorrhoids are located above the dentate line and manifest primarily with bleeding, prolapse, and occasional incarceration
The natural course of the disease involves increasing pain, which peaks at hr, with gradual remission as the thrombus organizes and involutes over the next 1- 2 wk
Treatment :
dietary modification,
decreased straining
avoidance of prolonged time spent sitting on the toilet
thrombectomy may be indicated for excrutiating pain

24. Rectal Mucosal Prolapse
Exteriorization of the rectal mucosa through the anus
Procidentia : all of the layers of the rectal wall are included
Onset is often between 1 and 5 yr of age
Predisposing factors: intestinal parasites (particularly in endemic areas), malnutrition, diarrhea, ulcerative colitis, pertussis, Ehlers-Danlos syndrome, meningocele (more often associated with procidentia owing to the lack of perineal muscle support), cystic fibrosis, and chronic constipation
Conservative treatment : careful manual reduction of the prolapse after defecation, attempts to avoid excessive pushing during bowel movements (with patient's feet off the floor), use of laxatives and stool softeners to prevent constipation, avoidance of inflammatory conditions of the rectum, and treatment of intestinal parasitosis when present
Surgical treatment for failed conservative management:

25. Pilonidal Sinus and Abscess
3 hypotheses :
trauma, such as can occur with prolonged sitting, impacts hair into the subcutaneous tissue, which serves as a nidus for infection
hair follicles exist in the subcutaneous tissues, perhaps due to some embryologic abnormality, and that they serve as a focal point for infection, especially with secretion of hair oils
motion of the buttocks disturbs a particularly deep midline crease and works bacteria and hair beneath the skin
Treatment:
acute abscess should be drained and packed open with appropriate anesthesia
Oral broad-spectrum antibiotics covering the usual isolates (Staphylococcus aureus and Bacteroides species)
Once the wound is healed, elective excision should be scheduled to avoid recurrence

26. Juvenile Polyposis Syndrome
multiple juvenile polyps, ≥5 but typically
autosomal dominant pattern
Most malignancy is colorectal, though gastric, upper GI, and pancreatic tumors
The risk of malignancy is greater in patients with >3 polyps and a positive family history
routine esophagogastroduodenoscopy, colonoscopy, and upper GI contrast studies
Serial polypectomy or polyp biopsy should be undertaken if possible
If dysplasia or malignant degeneration is found, a total colectomy is indicated
Juvenile polyposis of infancy :
early polyp formation (<2 yr of age) and may be associated with protein-losing enteropathy, hypoproteinemia, anemia, failure to thrive, and intussusception
Early endoscopic or surgical intervention may be needed

27. Peutz-Jeghers Syndrome
Autosomal dominant disorder (incidence, ∼1 : 120,000)
characterized by mucocutaneous pigmentation and extensive GI hamartomatous polyposis
Polyps are primarily found in the small intestine (in order of prevalence: jejunum, ileum, duodenum) but may also be colonic or gastric
Diagnosis:
positive family history with an autosomal dominant inheritance pattern
mucocutaneous hyperpigmentation
small bowel polyposis
Up to 50% of patients develop cancer, usually by middle age: Colorectal, breast, and reproductive tumors
Polyps >1.5 cm should be removed.
Screening for breast, gynecologic, and testicular cancers should be routine after age 20 yr

28. Apc-Associated Polyposis Syndromes
Familial Adenomatous Polyposis : most common genetic polyposis syndrome (incidence 1 : 5,000 to 1 : 17,000 persons)
numerous adenomatous polyps throughout the colon, as well as extraintestinal manifestations
Treatment of FAP requires prophylactic proctocolectomy to prevent cancer
Colorectal Carcinoma:
most common primary GI carcinoma in children
may be asymptomatic, or they present with nonspecific signs and symptoms such as abdominal pain, constipation, and vomiting
Surgical resection is the primary treatment modality
Lymphoma
most common GI malignancy in the pediatric population
occur anywhere in the GI tract, but it most commonly occurs in the ileocecal region and small bowel
Lymphoma should be considered in patients >3 yr old who present with intussusception

29. Nodular Lymphoid Hyperplasia
Lymphoid follicles in the lamina propria and submucosa of the gut normally aggregate in Peyer's patches, most prominently in the distal ileum. These follicles can become hyperplastic, forming nodules that protrude into the lumen of the bowel
etiologies are infectious (classically Giardia), allergic, or immunologic
resolves spontaneously and rarely requires therapy
In severe pain or bleeding, corticosteroids may be effective.
Carcinoid Tumor
neuroendocrine tumors of enterochromaffin cells, typically found in the appendix
diagnosis is confirmed by elevated urinary 5-hydroxyindoloacetic acid (5-HIAA)
Symptomatic relief of carcinoid symptoms may be achieved with administration of somatostatin analogs (octreotide).
Gastrointestinal Stromal Cell Tumors
Intestinal mesenchymal tumors that probably arise from interstitial cells of Cajal or their precursors
tumors are most commonly found in the stomach, though they can occur anywhere in the GI tract or even the mesentery or omentum
Treatment consists of surgical en bloc resection of local disease

30. Inguinal Hernias
occurs when intra-abdominal contents escape the abdominal cavity and enter the inguinal region through a patent processus vaginalis
Incidence:
full-term newborn infants: %
preterm and low birthweight infants: 9% to 11%,
30% in very low birthweight infants (<1,000 g) and preterm infants <28 wk of gestation
male : female ratio of ~6 : 1.
About 60% of inguinal hernias occur on the right side
Hallmark signs: smooth, firm mass that emerges through the external inguinal ring lateral to the pubic tubercle and enlarges with increased intra-abdominal pressure
“silk glove sign”
Ultrasonography can help distinguish between a hernia and a hydrocele
Incarcerated Hernia
contents of the hernia sac cannot be reduced into the abdominal cavity

31. Management
The timing of operative repair depends on several factors including age, general condition of the patient, and comorbid conditions
<1 yr of age: repair should proceed promptly because as many as 70% of incarcerated inguinal hernias requiring emergency operation for reduction and repair occur in the 1st year of life
>1 yr, the risk of incarceration is less and the repair can be scheduled with less urgency

32. Exocrine Pancreas Anatomic Abnormalities
Pancreatic agenesis: associated with severe neonatal diabetes and usually death at an early age
Annular pancreas:
incomplete rotation of the left (ventral) pancreatic anlage
treatment of choice is duodenojejunostomy
Pancreas divisum:
most common pancreatic developmental anomaly
Result of failure of the dorsal and ventral pancreatic anlagen to fuse, the tail, body, and part of the head of the pancreas drain through the small accessory duct of Santorini rather than the main duct of Wirsung
Diagnosis is made by endoscopic retrograde cholangiopancreatography (ERCP) or by magnetic resonance cholangiopancreatography (MRCP)
Treatment of choice of recurrent pancreatitis: endoscopic insertion of an endoprosthetic stent
If the episodes stop occurring, surgical sphincterotomy is indicated
Choledochal cyst
dilatations of the biliary tract
diagnosis is usually made with ultrasonography, CT or biliary scanning, or MRCP

33. Acute Pancreatitis most common pancreatic disorder in children
Most common etiologies: blunt abdominal injuries, multisystem disease, biliary stones or microlithiasis (sludging), and drug toxicity (valproic acid, L- asparaginase, 6-mercaptopurine, and azathioprine )
CM: severe abdominal pain, persistent vomiting, and possibly fever
pain can increase in intensity for hr, during which time vomiting may increase and the patient can require hospitalization for dehydration and might need fluid and electrolyte therapy

34. Severe Acute Pancreatitis
CM: acutely ill with severe nausea, vomiting, and abdominal pain
Cullen sign : bluish discoloration around the umbilicus
Grey Turner sign: bluish discoloration in the flanks
Shock, high fever, jaundice, ascites, hypocalcemia, and pleural effusions can occur.
Diagnosis:
serum lipase and amylase
Other laboratory abnormalities: hemoconcentration, coagulopathy, leukocytosis, hyperglycemia, glucosuria, hypocalcemia, elevated γ-glutamyl transpeptidase, and hyperbilirubinemia
Abdominal x-rays might demonstrate a sentinel loop, dilation of the transverse colon (cutoff sign), ileus, pancreatic calcification (if recurrent), blurring of the left psoas margin, a pseudocyst, diffuse abdominal haziness (ascites), and peripancreatic extraluminal gas bubbles
Treatment: relieve pain and restore metabolic homeostasis
Recovery is usually complete within 4-5 days

35. Chronic Pancreatitis
genetic mutations or due to congenital anomalies of the pancreatic or biliary ductal system