Episode 19 Part 2: Pediatric Gastroenteritis, Constipation and Bowel Obstruction

In Part 2 of this pediatric abdominal pain Episode – Pediatric Gastroenteritis, Constipation & Bowel Obstruction, Dr. Anna Jarvis, Canada’s “mother of pediatric emergency medicine” and  Dr. Stephen Freedman, one of Canada’s pre-eminent researchers in pediatric GI emergencies, discuss the assessment, work-up and treatment of pediatric gastroenteritis, with particular attention to gastroenteritis & acute abdomen mimics, how best to assess hydration status, the nuances of the use of ondansetron and the prose and cons of various rehydration methods. A detailed discussion of the most common and lethal causes of acute abdomen bowel obstruction in pediatrics follows, including intussesception and midgut volvulus. Finally, the differential diagnosis and best management of the most common cause of pediatric abdominal pain, constipation, is reviewed.

Anna Jarvis and Stephen Freedman answer such questions as: Does Ondansetron mask serious illness? Should we be sending home children with scripts for Ondansetron? What are the contra-indications to Ondansetron? What is the role of anti-diarrhea medications like probiotics in the pediatrics? How good are we at clinically assessing hydration status in children? What is any easy way to remember oral rehydration doses? Which, if any, lab tests are indicated for children with gastroentritis and why? When should we suspect Hemolytic Uremic Syndrome in a child with diarrhea? What is the value of Abdominal X-rays in pediatrics? What are the clinical pearls that can help us diagnose intussusception in a timely manner before gut ischemia sets in? Which is better to diagnose intussusception – ultrasound or enema? In what situations can should children with intussusception go directly to surgery without a barium or air enema? What is the best medication for treatment of pediatric constipation? and many  more Pediatric Gastorenteritis, Constipation & Bowel Obstruction pearls…….

Written summary and blog post written by Claire Heslop edited by Anton Helman January 2012

Pediatric Gastroenteritis

  • Common diagnosis but may hide sinister pathology, so consider it a diagnosis of exclusion
  • In cases of isolated vomiting, especially if prolonged, consider alternate diagnoses: intracranial mass, meningitis, strep throat, pneumonia, myocarditis, appendicitis, UTI etc.

History

  • Sick contacts (siblings, day care, travel or relatives visiting from abroad), contact with farm‐products (eg, unpasteurized milk), unclean water exposure, prior episodes (if chronic or recurrent, might need out‐ patient work‐up r/o IBD), new animals or foods

Physical examination

  • Dehydration:
    • Highly sensitive but non‐specific, with clinicians poor at differentiating the different degrees of severity and usually over‐estimating dehydration leading to over‐aggressive resuscitation
    • Only 3 findings have significant LR+: prolonged cap refill, abnormal skin turgor, tachypnea
    • Classification
      • 1. NO OR MILD DEHYDRATION: None of the features below
      • 2. SOME DEHYDRATION: Some components of ‐ unwell general appearance (eg, fussy, leathargic), mucous membranes dry, absence of tears, sunken eyes, prolonged capillary refill, abnormal skin turgor and tachypnea –PO rehydration indicated (safer than IV)
      • 3. SEVERE DEHYDRATION: Most or all of the above features, with abnormal vital signs –IV or NG rehydration indicated

Investigations

  • Majority of children do NOT need investigations, except for: accucheck if lethargy for hypoglycemia secondary to poor oral intake); to rule out other diagnoses ‐ urinalysis in polyuria/polydipsia for DKA or in children with fever and prior UTIs to rule out same
  • Electrolyte abnormalities are usually minor and rarely impact management, however if starting IV rehydration, then electrolytes are important to monitor to avoid iatrogenic electrolyte imbalances
  • Indications for stool cultures: travel to endemic countries, >10 diarrhea episodes in 24hrs, >5d duration and not resolving, blood and/or mucous in stools, and unremitting fever

 

Gastroenteritis Management

  • Oral vs IV Rehydration: Compared with IV rehydration, oral rehydration therapy is associated with a lower risk of complications such as electrolyte imbalances, cerebral edema, phlebitis and cellulitis; therefore oral rehydration therapy is recommended as the treatment of choice for children with acute gastro who are in the category of ‘some’ dehydration
  • Pearls for oral rehydration with Pedialyte
  • Pedialyte  dose:  5cc  if  3yo  q5mins,  for  a  goal  of  around  30cc (1oz) per kg per hour for the first 3‐4hrs; Dr. Jarvis recommends starting slower during the first 30‐ 60min  to  minimize  the  chance  of  emesis
  • Continue to breastfeed at the same time, and add 10cc/kg/stool for diarrhea
  • Ondansetron (see Freedman, NEJM 2006 and Fedorowicz, Cochrane Review 2011)
  • Compared to placebo, oral Ondansetron (Zofran©) stops vomiting more frequently (NNT 5) and prevents IV insertion (NNT 5) – which is traumatic for both children and parents – and reduces immediate admission rates without masking serious disease or leading to worse outcomes in the long run; no change in hospitalizations at 72hrs, likely because children who have serious pathology will come back regardless
  • Given as single dose (repeat if vomiting within 15min, and keep patient NPO for 15 minutes before starting pedialyte, as it takes that long to be effective); Dr. Freedman suggests no prescription for home
  • – no benefit shown and increases diarrhea, and if child suffers from worsening vomiting, he/she needs a formal reassessment
  • Do NOT use as a diagnostic tool (i.e. if a child stops vomiting with Ondansetron, it does NOT rule out alternate more sinister diagnoses such as appendicitis; use it therapeutically only)
  • Ondansetron may prolong QTc interval, so do not use in patients with known prolonged QTc, hypokalemia or hypomagnesemia, congenital heart disease or CHF as it may cause arrhythmias
  • Antibiotics are rarely required, even for bacterial gastro; consider antibiotics when child is persistently ill and is high‐risk (immunocompromised , sickle cell disease, or use of corticosteroids or chemotherapy), or risk factors for C.diff are present (neonates and graduates of NICU, IBD patients, or immunosuppressed recently on antibiotics)

 

Gastroenteritis Discharge instructions

  • Early introduction of solids in addition to fluids, with small frequent feeds limited in complex sugars (eg, fruit juices); diarrhea may increase initially, so give pedialyte in addition to food
  • Return to care if child has bloody stool, increasing pain or fever, is lethargic (“too sleepy”) or behaves unusually for him/her
  • Antidiarrheals: Do NOT use loperamide (may cause lethargy, paralytic ileus, case reports of death), and bismuth is not recommended by our experts, but probiotics may be used given their relative safety (except in children with central lines, congenital heart disease or short gut, as they lead to higher infection rates) and somewhat improved outcomes (1d less of diarrhea, but only in severe cases)

 

INTUSSUSCEPTION

  • Prolapse of a segment of intestine into the lumen of an immediately adjacent part, and is the most common surgical emergency of the abdomen in children from 6mo to 6yo (peak at 18‐30mo)
  • Classic triad of intermittent crying, bloody stools and sausage‐shaped mass in the abdomen seen in
    <40% of cases

 

History for Intussusception

  • Crying is often severe and different than usual crying, with the child dropping into fetal or knee‐chest position, and behaving normally a few minutes later
  • 2 presentations: either vomiting (sometimes due to pain, and bilious only if prolonged) ± abdominal pain in older children, or lethargy with paleness (especially in younger infants, where parents might describe the child’s condition as “all the life got sucked out of them”)
  • May elicit a history of recent viral illness, given that intussusception often requires a lead point such as enlarged lymph glands (eg, Peyer’s patch), Meckel’s diverticulum, or mesenteric duct remnant
  • Classic currant jelly stool (loose stool with mucous and blood) is a LATE finding and only present in 10% of cases

 

Physical for Intussesception

  • The necessity of performing a rectal exam cannot be overstated, as fecal occult blood will appear before gross blood (by which time it is “too late” given that there is likely already bowel ischemia)
  • May feel an “empty” RLQ or a sausage‐shaped mass in the RUQ just below the liver
  • Examination should focus on ruling out inguinal hernia, testicular torsion, midgut volvulus (80% present in first year of life, where bowel turns around ligament of Treitz and causes bilious vomiting), as well as child abuse, sepsis, meningitis, bacterial gastroenteritis, UTI (intermittent crying when the child urinates due to irritation)

 

Investigations and management for Intussusception

  • Abdominal xray
    • Used mainly to rule out other or concomitant diagnoses (bowel obstruction or perforated viscus), but may see subtle target sign in
      • RUQ (subtle just below last rib and to side of spine)
      • Lack of air in RLQ, or
      • Crescent sign in LUQ – only 23% of cases have these signs

intussuseption target sign

Target sign of intussusception

intussusception

Crescent sign of intussusception

  • Ultrasound in Intussusception
  • Diagnostic test of choice, with sensitivity 99%
  • Less painful than enema, which is, however, also therapeutic

 

For step by step identification of intussusception using POCUS go to Episode 53 Pediatric POCUS

 

  • Treatment on Instussesception
  • Air or barium enema – center‐dependent; air may cause compartment syndrome in case of perforation due to high pressures, but barium may cause chemical peritonitis if it gets into the perineum
  • Direct to surgery in very young patients, prolonged symptoms (>15hrs), acidotic child, evidence of ongoing ischemia, gross blood per rectum getting worse, or hemodynamically unstable

 

PEDIATRIC CONSTIPATION

Definition as per RomeIII criteria

  • ≤2 stools per week for a duration of 2mo if patient >2yo and for duration of 4mo if patient <2yo, or with evidence of overflow incontinence (no stool, then diarrhea, then no stool, etc), or stools that clog toilet
  • Functional constipation is the most common cause of abdominal pain in children, but consider it a diagnosis of exclusion as severe underlying disease may be present

 

Differential diagnoses of Pediatric Constipation

  • Hirschprung’s disease: severe obstipation with overflow diarrhea and abdominal distention in non‐ thriving and cranky child, which may present with toxic megacolon
  • Cystic fibrosis and hypothyroidism: assess family history, and whether screening was performed
  • Others: Down syndrome, myelomeningocele or neuromuscular problems (slow to walk, walking “funny”), celiac disease (family history), child abuse

 

Management

  • Oral medications work better when combined with enemas in the ER, but explain to the parents that it takes time to re‐train the bowel (sometimes years)
  • Enemas: if child <2yo, use saline enema 20cc/kg, and if child >20‐25kg, use adult fleet enema
  • At home: our experts prefer PEG 3350 (OTC Laxaday©) at dose of 1.5g/kg/d (rounded to the nearest
    ½cup of 17g) dissolved in 8ounces of juice, then titrate dose up or down for 1 soft stool per day, and with goal to slowly taper down

 

High-Yield Associations and Pearls in Pediatric Abdominal Pain

  • Intermittent pain with change in stools (esp. bloody) ‐  intussusception
  • Bilious vomiting in neonate ‐  malrotation of the gut
  • Scrotal  swelling  or  discoloration ‐   testicular  torsion
  • Polyuria  +  Polydypsia ‐   DKA
  • Recent  Mononucleosis ‐    spleen  rupture
  • Petechial rash to  buttocks  and  legs ‐   HSP
  • Hematuria  +  proteinuria ‐   HSP
  • Sterile  pyuria ‐   appendicitis
  • Glucosuria  and  ketonuria ‐   DKA
  • Occult blood in stools ‐  intussusception or advanced volvulus
  • “Adult diagnoses” such as cholecystitis, renal colic, and incarcerated hernia can also all occur in children

 

Hemolytic Uremic Syndrome (HUS)

  • Triad of microangiopathic hemolytic anemia, thrombocytopenia and renal insufficiency caused by E.coli O157:H7, leading to bacterial enteritis
  • Clinical features: bloody stool and abdominal pain, lethargy, low‐grade fever, paleness and tachycardia due to anemia, petechiae, and tea‐colored urine due to blood, periorbital edema (esp. upon waking)
  • HUS Pearls: the haemolytic component may present after the diarrhea has resolved; do not give antibiotics on spec if you suspect HUS because it may worsen disease

 

Dr. Jarvis, Dr. Freedman, Dr. Helman and Dr. Heslop have no conflicts of interest to declare.

 

 

 

Key References

1. Steiner MJ, deWalt DA, Byerley JS. Is this child dehydrated. JAMA. 2004; 291 (22): 27-46.

2. Friedman JN, Goldman RD, Srivastava R, Parkin PC. Development of a clinical dehydration scale

for use in children between 1 and 36 months of age. J Pediatr. 2004. 145 (2): 201-207.

3. Gorelick MH, Shaw KN, Murphy KO. Validity and reliability of clinical signs in the diagnosis of

dehydration in children. Pediatrics. 1997; 99 (5): E6.

4. Freedman SB, Adler M, Seshadri R, Powell EC. Oral ondansetron for gastroenteritis in a pediatric

emergency department. NEJM. 2006; 354: 1698-705.

5. Fedorowicz Z, Jagganath VA, Carter B. Antiemetics for reducing vomiting related to acute

gastroenteritis in children and adolescents. Cochrane Database of Systematic Reviews. 2011,

Issue 9.

6. Hymen PE, Milla PJ, Benninga MA, et al. Childhood functional gastrointestinal disorders: neonate/

toddler. Gastroenterology. 2006; 130: 1527-37.

7. Rasquin A, Di Lorenzo C, Forbes D, et al. Childhood functional gastrointestinal disorders: child/

adolescent. Gastroenterology. 2006; 130: 1526-3.

8. Dillon MJ, Ozen S. A new international classification of childhood vasculitis. Pediatr Nephrol.

2006;21(9):1219-1222.

For more EM Cases content on Pediatric Emergencies check out our free interactive eBook,

EM Cases Digest Vol. 2 Pediatric Emergencies here.

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About the Author:

Dr. Anton Helman is an Emergency Physician at North York General in Toronto. He is an Assistant Professor at the University of Toronto, Division of Emergency Medicine and the Education Innovation Lead at the Schwartz-Reisman Emergency Medicine Instititute. He is the founder, editor-in-chief and host of Emergency Medicine Cases.

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