Abdominal Pain

Home , Biliary colic

The Approach to the Child with Abdominal Pain

David J. Worhunsky, MD Assistant Professor of Surgery Pediatric Surgery

12 September 2020

@UKPedSurg Disclosures

• None Pediatric Abdominal Pain (AP)

 Incidence

• 5‐10% of all ED visits by pediatric patients (Caperell et al, Pediatrics 2013)

• 9% of childhood visits to primary care

 Cost

• Limited data

• Uruguayan study suggests 3.8% of all health care spending (Saps et al, JPGN 2008) The Problem (i.e., Educational Need)

 Definitive diagnosis can be challenging but life‐altering or even life‐saving

• Why so difficult?

1) All children with abdominal pain (out/inpatient)  only 5‐10% have an underlying organic disease

(Much higher among patients presenting to the emergency department) The Problem

 Definitive diagnosis can be challenging but life‐altering or even life‐saving

• Why so difficult?

2) Some have a limited pathophysiologic explanation (e.g., URI, pneumonia) The Problem

 Definitive diagnosis can be challenging but life‐altering or even life‐saving

• Why so difficult?

3) Most are nonsurgical in nature, some non‐abdominal in origin

 URI with or without otitis or sinusitis (24%)

 AP of unclear etiology (15%)

 Gastroenteritis (15%)

 Constipation (9%)

 UTI (8%) The Problem

 Definitive diagnosis can be challenging but life‐altering or even life‐saving

• Why so difficult?

4) Surgical etiology present in up to 20%  timely identification/management can be life‐ saving/altering The Problem

 Definitive diagnosis can be challenging but life‐altering or even life‐saving

• Why so difficult?

5) Differential diagnosis is broad and can seem overwhelming…

Can we simplify this? Differential Diagnosis Based on Age

Any Age Newborn 2‐12 mo 1‐5 yo 5‐12 yo > 12 yo

UTI UTI UTI Constipation Colic Colic Functional Functional Non‐urgent Group A Strep Group A Strep Group A Strep

Urgent URI HSP HSP DKA Non‐surgical Acute gastro DKA DKA

Duplication cyst Inguinal hernia Duplication cyst Abdominal/RP tumor Biliary colic Biliary colic Referral Abdominal/RP tumor

IRA/volvulus Appendicitis Incarcerated hernia Appendicitis Urgent Neonatal Ovarian torsion Meckel diverticulitis Intussusception Intussusception Ovarian torsion obstruction Ectopic pregnancy Surgical Bowel obstruction Trauma/NAT Appendicitis (comp) Biliary tract (comp) Trauma/NAT Biliary tract (comp) Evaluation Perforated viscus IBD IBD Trauma

Adapted from Smith and Fox. Emerg Med Clin N Am 2016 Differential Diagnosis Based on Age

Any Age Newborn 2‐12 mo 1‐5 yo 5‐12 yo > 12 yo

UTI UTI UTI Constipation Colic Colic Functional Functional Non‐urgent Group A Strep Group A Strep Group A Strep

Urgent URI HSP HSP DKA Non‐surgical Acute gastro DKA DKA

Duplication cyst Inguinal hernia Duplication cyst Abdominal/RP tumor Biliary colic Biliary colic Referral Abdominal/RP tumor

Adapted from Smith and Fox. Emerg Med Clin N Am 2016 Differential Diagnosis Based on Age

Any Age Newborn 2‐12 mo 1‐5 yo 5‐12 yo > 12 yo

UTI UTI UTI Constipation Colic Colic Functional Functional Non‐urgent Group A Strep Group A Strep Group A Strep

Urgent URI HSP HSP DKA Non‐surgical Acute gastro DKA DKA

Duplication cyst Inguinal hernia Duplication cyst Abdominal/RP tumor Biliary colic Biliary colic Referral Abdominal/RP tumor

Adapted from Smith and Fox. Emerg Med Clin N Am 2016 Differential Diagnosis Based on Age

Any Age Newborn 2‐12 mo 1‐5 yo 5‐12 yo > 12 yo

UTI UTI UTI Constipation Colic Colic Functional Functional Non‐urgent Group A Strep Group A Strep Group A Strep

Urgent URI HSP HSP DKA Non‐surgical Acute gastro DKA DKA

Duplication cyst Inguinal hernia Duplication cyst Abdominal/RP tumor Biliary colic Biliary colic Referral Abdominal/RP tumor

Adapted from Smith and Fox. Emerg Med Clin N Am 2016 Goals for this talk

 Hernia  Examine and refer

 Trauma/NAT  Refer to center with pediatric trauma/forensic peds

 Obstructions  Refer to center with pediatric GI/surgical expertise

 Neonatal intestinal obstruction  Refer (2+ day conference) Goals/Objectives for this Talk (Outline)

1) Intestinal rotation abnormality (IRA) +/‐ volvulus

2) Appendicitis

3) Intussusception

4) Ovarian torsion

5) Biliary tract disease

6) Constipation Epidemiology of Intestinal Rotation Abnormality

 Incidence varies in the literature

 Autopsy series suggest an incidence of 5/1000 or 0.5%

 Incidence of volvulus only 1/6000 or 0.017%

• Only 1/30 patients with malrotation will develop volvulus Nomenclature

 Old terminology: Malrotation

 Newer terminology: Intestinal rotation abnormality

• More inclusive

 Nonrotation

 Incomplete rotation (malrotation) with or without volvulus

 Reverse rotation

 Paraduodenal and paracolic hernias Clinical Presentation

 Bilious emesis in a neonate is a surgical emergency until proven otherwise

• Must rule out midgut volvulus

Surgical cause of bilious emesis found in 38% of neonates

 Know that 60% of work‐up will be negative! Clinical Presentation

 Bilious emesis in a neonate is a surgical emergency until proven otherwise

• Must rule out midgut volvulus

 What counts as bilious?

• “It looks green to me, how about to you?”

• “I can’t tell if it is more green or yellow.”

• If “bilious” or “green” is mentioned or even questioned 

volvulus until proven otherwise Clinical Presentation

 Bilious emesis due to malrotation/volvulus:

• Due to extrinsic obstruction of duodenum (twisted bowel or Ladd bands)

 Late signs (usually associated with necrotic bowel)

• Abdominal distension

• Hematemesis

• Hematochezia

• Hemodynamic instability Assessment

 Start with clinical exam:

• High suspicion  Operative exploration • Neonate in extremis  Operative exploration • Clinical deterioration  Operative exploration • Inability to obtain upper GI  Operative exploration

 Clinically stable with suspicion  urgent Upper GI contrast study

• Does not wait until morning

• No plain radiograph (XR) findings that can exclude IRA/volvulus Upper Gastrointestinal (GI) Series

 Gold standard

4 Components to a Normal UGI Study

1 Contrast leaves stomach from patient’s left to right (AP view)

2 Contrast moves posteriorly through retroperitoneal 2nd portion (lateral view)

3 Contrast crosses midline from patient’s right to left (AP view)

4 DJ junction located at same height as duodenal bulb/pylorus (AP/lateral views)

Requires technical expertise

Acute Appendicitis

 Incidence

• 1 per 1000 in the U.S., overall lifetime risk around 8% with peak in teen years

• Most common surgical emergency in children

• ~75,000 appendectomies performed annually in children in the U.S.

 Cost

• Mean cost of $9000; higher when complicated/perforated Pathophysiology of Acute Appendicitis

 Mostly thought to be due to obstruction of the appendiceal lumen

• Lymphoid hyperplasia, fecoliths, parasites (e.g., enterobius vermicularis), tumors

 Luminal obstruction may not account for all cases

 Final pathway is common regardless of cause: invasion of appendiceal wall by

intraluminal bacteria Pathophysiology of Acute Appendicitis

Uncomplicated (early) Appendicitis Complicated Appendicitis Pathophysiology of Acute Appendicitis

Uncomplicated (early) Appendicitis Complicated Appendicitis

 Preoperative antibiotics alone  4‐10 days of antibiotics  Home same day or next  7‐10 day hospital stay  <2% complication rate  20% complication rate  Limited activity restrictions  Emesis/diarrhea common  Back to school in 2‐3 days  Out of school for 2‐3 weeks  Phone follow‐up  Close clinic follow‐up Pathophysiology of Acute Appendicitis

Uncomplicated (early) Appendicitis Complicated Appendicitis

Two different diseases with very different clinical course

How do we accurately diagnose appendicitis? How do we not miss early appendicitis? How do we triage complicated appendicitis? Diagnosis of Acute Appendicitis

Appendicitis is a Clinical Diagnosis!

Labs History  WBC  Acute onset  Neutrophils  Will not improve Exam Imaging  CRP  Periumbilical  RLQ  Focal RLQ tenderness  Ultrasound  Procalcitonin  Emesis, anorexia (early)  Avoid CT  Calprotectin  Diarrhea  Diffuse tenderness (late)  Plain radiograph Diagnosis of Acute Appendicitis

Appendicitis is a Clinical Diagnosis!

Why is the diagnosis so tricky? Diagnosis of Acute Appendicitis

Why is the diagnosis so tricky?

 Children (especially 4‐8 yo) are unreliable historians • Will to play, have fun, be a kid > Pain from appendicitis • Less “in tune” with the body • More likely to present with perforated appendicitis Diagnosis of Acute Appendicitis

Why is the diagnosis so tricky?

 Other diagnoses much more common • Acute gastroenteritis • Constipation • Group A strep • Viral lymphadenitis Diagnosis of Acute Appendicitis

Why is the diagnosis so tricky?

 Our patients do not follow the textbook! • Presentations vary (10 yo chows down a burger prior to arrival) • Appendix not always in the abdomen Diagnosis of Acute Appendicitis

 Appendicitis risk scores can help (but are not perfect) Comparison of AIR, Avarado and PAS

747 consecutive children

AIR Score had the highest discriminating power Low AIR – 14% missed appendicitis High AIR –6% negative appendectomy

Not great Lacks imaging correlate (US) Better scoring systems?

Macco et al, Surgery 2016 Characteristic  Improved prediction model (vs PAS)  Sex

 Duration of pain  Near perfect calibration (AUC 0.85)  WBC  Neutrophil %  Half of patients can be classified as very low (<15%)  Pain with walking or very high (>85%) risk  Maximal tenderness in RLQ  Abdominal guarding  Validated pARC in community‐based health care systems (not Children’s Hospital ED)

 More accurate than PAS

 374 children (4‐16 yo) with suspected appendicitis from largest children’s hospital in Singapore

 Children Appendicitis Score (CAS) –two components

1) Combination of WBC, Neutrophil %, and CRP

2) Clinical/Lab criteria for Raw Score Children Appendicitis Score:

Start with 3 labs: If normal, not appendicitis

1) WBC • < 10,000 2) Neutrophil % • < 75% 3) CRP • < 5 mg/L Children Appendicitis Score:

If any one is elevated, calculate a CAS raw score

< 1.5 > 5.0 Low Probability 1.5 –4.5 High Probability Intermediate Probability Discharge Surgery Ultrasound Imaging in Appendicitis (i.e., Ultrasound)

 Ultrasound has become the imaging modality of choice for pediatric appendicitis

• 60‐80% appendiceal identification rate at higher volume centers

Advantages Disadvantages

Rapid, bedside modality Operator dependent No IV required Learning curve Best for small children Availability Avoids ionizing radiation Limited in obese patients No IV contrast required Imaging in Appendicitis (i.e., Ultrasound)

 Ultrasound has become the imaging modality of choice for pediatric appendicitis

US Findings of Appendicitis

Blind‐ending, tubular structure Noncompressible Dilated (> 6mm) Appendicolith Periappendiceal fluid Increased periappendiceal echogenicity Hyperemia Imaging in Appendicitis (not CT Scan)

 Computed tomography (CT) scans are the mostly widely used/accepted modality in adults

 The same does NOT apply in children

 Exposes children to ionized radiation, often unnecessarily

 Limited in younger children with little intraabdominal fat

 Examples from the last month at KCH… 14yoF pARC = 66% (intermed) CAS = 7.5 (high) 3yoF pARC = 77% (intermed) 14yoM CAS = 7.5 (high) pARC = 59% (intermed) CAS = 4.5 (intermed) Imaging in Appendicitis (not CT Scan)

 Computed tomography (CT) scans are the mostly widely used/accepted modality in adults

 The same should NOT apply in children

 Exposes children to ionized radiation, often unnecessarily

 Limited in younger children with little intraabdominal fat

My recommendations:

If considering CT scan, rethink that decision If still considering CT scan, discuss the case with KCH EM or Ped Surg If still considering CT scan, must be with IV contrast (no enteral) Appendicitis Summary (Pearls)

1) Start with history and physical –don’t skip to the technology!

2) Labs  WBC, neutrophil, CRP

3) Use a risk calculator  pARC

4) Triage into low, intermediate, high risk Appendicitis Summary (Pearls)

Low Risk Intermediate Risk High Risk

Consider discharge Ultrasound Refer to center with PO trial No CT Pediatric Surgery Close follow‐up (24 hrs) Intussusception

 Epidemiology

• 50‐75 per 100,000 children

• Most common cause of bowel obstruction in infancy

• 2nd most common cause of abdominal pain in childhood

• Age important: 60% before the age of 1, 80% before the age of 2 (peak is 5‐9 months)

• Slight male predominance (3:2)

• No seasonal variation Pathophysiology

 Pathogenesis of ileocolic intussusception is unclear

 Association with recent viral or bacterial gastrointestinal illness

• Proliferation of lymphoid tissue within bowel wall may serve as lead point

 Pathologic lead point Consider exploration • More common in older children (> 5 yo) rather than radiographic reduction • Meckel, polyp, lymphoma Presentation

Actual Clinical Scenario “Classic” Clinical Triad Abdominal pain (98%) Severe, crampy, intermittent Colicky abdominal pain Lasts 2‐10 minutes Emesis Legs pulled up to abdomen Bloody stool Emesis (70%) Currant jelly stool (<30%) Presentation ‐ Most are well (in US)

Perforation Shock

Lethargic Dehydrated Well‐ appearing Patient Assessment

 Ensure the child has not progressed toward shock/perforation

 Intravenous access

• Can await diagnostic imaging if well‐hydrated, but low threshold for rehydration

with 10‐20 cc/kg bolus of NS

 Imaging (i.e., ultrasound) Ultrasound for Intussusception

 Imaging modality of choice  most sensitive test (98%)

 Start in right hemiabdomen

 Findings include target sign, donut crescent sign, pseudo‐kidney sign Management of Intussusception

 Start with resuscitation (10‐20 cc/kg bolus of normal saline)

• Necessary before any attempt at reduction

 Two options:

1) Peritonitis  Operative exploration

2) Stable exam  Air contrast/pneumatic reduction Intussusception Pearls

 Air contrast reduction requires 60  120 mm Hg of pressure

• Perforation can lead to tension pneumoperitoneum with immediate cardiovascular collapse

 Partial reductions can be reattempted in 4‐6 hours (if child remains stable)

 Recurrent intussusception occurs in 10‐15% of cases Reason for ED • 1/3 in the first 24‐48 hrs, 1/3 in the second 48 hrs, 1/3 as late as one week discharge after 6 hours of observation

 Operative management much less common (<10%)…

Ovarian Torsion

 Epidemiology

• Infrequent cause of abdominal pain in children  5 cases per 100,000 females

• Major pediatric hospitals see only 0.3‐3.5 cases of torsion per year

• Mean age is 10‐14

• Most are postmenarchal (>80%) Presentation of Ovarian Torsion

Abdominal pain (all) Sudden onset Severe Visible from across the ED/room Nausea and emesis (60%) Dysuria Patient Assessment – Ultrasound

 Transabdominal US is the imaging modality of choice

• But there are significant limitations! Presence of blood flow does not exclude Imaging Findings Suggestive of Torsion torsion!!! Enlarged, heterogenous ovary (2‐3x larger) (normal flow in > 50%)

Adnexal mass

Sonographic whirlpool sign with twisted vessels

Lack of blood flow Diagnosing Ovarian Torsion is Challenging

 Ultrasound can help, but torsion is mostly a clinical diagnosis

 Differentiating from appendicitis can be difficult

• Significant overlap in presentation

 The severity of the pain is distinct from appendicitis

 Low threshold for laparoscopy 11yoF Intermittent, severe abdominal pain x 1 week CT w/ IV contrast  enlarged R ovary; pain improved; discharged Severe pain returned the next day  KCH ED CT reviewed  no concern for torsion/appendicitis Pain worsened on HD2  Pediatric Surgery called… Severe RLQ abdominal pain/tenderness US with 7 cm R ovary with free fluid (2 cm L ovary)

Diagnosing Ovarian Torsion is Challenging!

 Ultrasound can help, but torsion is mostly a clinical diagnosis

 Differentiating from appendicitis can be difficult

• Significant overlap in presentation

 The severity of the pain is distinct from appendicitis

 Low threshold for laparoscopy Biliary Tract Disease

Cholelithiasis

Biliary Colic Cholecystitis

US with Tokyo Criteria: gallstones 1.) Pain or RUQ TTP 2.) Fever or ↑ WBC and US with gallstones Biliary Tract Disease Choledocholithiasis Cholelithiasis Obstructive Jaundice

Biliary Colic Cholecystitis Elevated TB Elevated DB US with gallstones US with Tokyo Criteria: Dilated CBD gallstones 1.) Pain or RUQ TTP No fevers 2.) Fever or ↑ WBC Normal WBC and US with gallstones Biliary Tract Disease Choledocholithiasis Cholelithiasis Cholangitis

Biliary Colic Cholecystitis Tokyo Criteria: 1.) Fever or ↑ WBC 2.) Jaundice or ↑ TB and US with Tokyo Criteria: US with gallstones/dilated CBD gallstones 1.) Pain or RUQ TTP 2.) Fever or ↑ WBC and US with gallstones Biliary Tract Disease Choledocholithiasis Cholelithiasis Gallstone Pancreatitis

Biliary Colic Cholecystitis Elevated lipase US with gallstones

US with Tokyo Criteria: gallstones 1.) Pain or RUQ TTP 2.) Fever or ↑ WBC and US with gallstones Biliary Tract Disease Summary

 Simplify the work‐up:

1) History and exam

2) US of RUQ to confirm there are gallstones

3) Labs (WBC, TB, DB, Lipase)

• Consider evaluation for hepatitis as the primary cause (AST, ALT, viral serologies) One Slide on Functional Constipation

 Functional constipation common  up to 20% of all ED visits in the U.S.

 Should be a diagnosis of exclusion

 Should not cause changes in hemodynamics (e.g., tachycardia) or signs of

inflammation (e.g., fevers, leukocytosis, neutrophilia)

 Constipation is a predictor of missed appendicitis (Mahajan et al, JAMA 2020) Summary/Thoughts from a Pediatric Surgeon

 Pediatric abdominal pain is a challenging entity!

 Can you simplify the differential diagnosis by ruling in/out:

• Truly sinister causes (e.g., midgut volvulus)

• Common surgical etiologies (e.g,. appendicitis, intussusception, etc.)? Summary/Thoughts from a Pediatric Surgeon

1) Bilious emesis in a newborn/normal child is midgut volvulus until proven otherwise

 Upper GI to rule out IRA/volvulus and to avoid the catastrophic consequences

2) Simplify your work‐up of appendicitis

 Unless US readily available and reliable  use WBC/neutrophil/CRP + pARC to risk stratify

 Trust your clinical judgment

 Avoid CT scans! Summary/Thoughts from a Pediatric Surgeon

3) Intussusception is diagnosed and treated by radiology

 Unless septic or peritoneal signs  Exploration

4) Biliary tract disease (gallstones)

 Labs and US are your friend

• Cholelithiasis  Cholecystitis (Tokyo criteria)

• Choledocholithiasis  Cholangitis or Gallstone pancreatitis Summary/Thoughts from a Pediatric Surgeon

5) Ovarian torsion is a very tricky, clinical diagnosis

 Do not be fooled by blood flow on Color Doppler US (>50% of torsion cases have blood flow!)

6) Functional Constipation

 Diagnosis of exclusion

 Should not cause signs of inflammation or systemic unwellness Questions? Extra Slides Pathophysiology of IRA

 Intestinal rotation anomalies alone are

not problematic

 True risk/danger comes from volvulus

 Risk of volvulus due to the narrow

mesenteric base associated with A B incomplete rotation! C