Acute Abdominal Pain In Children: "Classic" Presentations Vs. Reality

Table of Contents

 

1. Epidemiology, Etiology, And Pathophysiology
2. Differential Diagnosis
3. Emergency Department Evaluation
   1. History
   2. Physical Examination
4. Diagnostic Studies
5. Special Circumstances
   1. Sickle Cell Disease
   2. Immunocompromised Children
   3. Children With Leukemia
   4. Children With Infectious Mononucleosis
   5. Technology-Dependent Children
6. Treatment
7. Disposition
8. Discharge Instructions
9. Common Pitfalls And Medicolegal Issues
10. Summary
11. Key Points In The Management Of Children With Abdominal Pain
12. Cost-Effective Strategies In Children With Abdominal Pain
13. Risk Management
14. High-Yield Historical Questions
15. Clinical Pathway: Abdominal Pain In Previously Healthy Prepubertal Children
16. Clinical Pathway: Abdominal Pain In Previously Healthy Prepubertal Children (continued)
17. Clinical Pathway: Abdominal Pain In Previously Healthy Adolescent Boys
18. Clinical Pathway: Abdominal Pain In Previously Healthy Adolescent Boys (continued)
19. Clinical Pathway: Abdominal Pain In Previously Healthy Adolescent Girls
20. Clinical Pathway: Abdominal Pain In Previously Healthy Adolescent Girls (continued)
21. Tables
    1. The Most Common Clinical Diagnoses In Chilren 2 12 Years of Age Presenting With Acute Abdominal Pain
    2. Important Diagnoses Not To Be Missed
    3. Features Indicative Of Appendicitis In Children
    4. Common Signs And Symptoms In Children 2 Years Of Age Or Younger With Appendicitis
    5. Findings On Plain Radiographs Of The Abdomen And Suggested Diagnoses
    6. Treatment Approaches To Common And Serious Causes Of Abdominal Pain In Children
22. References

Epidemiology, Etiology, And Pathophysiology

Differential Diagnosis

A comprehensive differential diagnosis of abdominal pain in children of all ages⁴ can be soporific even for the insomniac. In this section we discuss a short list of critical diagnoses that should be considered. A comprehensive list is so ponderous as to be practically useless for an ED evaluation.

The diagnoses of most concern are those that require operative intervention. The three most common surgical conditions are appendicitis, incarcerated inguinal hernia, and intussusception.⁷

When developing a differential diagnosis, consider the child's age. For example, intussusception is most commonly seen in children between 4 and 10 months of age^5,6 but almost never in adolescents. (See Table 2.)

Although appendicitis occurs in nearly all age groups, the incidence peaks in older school-age children.⁸ The classic presentation consists of constant, vague periumbilical pain followed by vomiting, migration of the pain to the right lower quadrant, and low-grade fever.⁹ Table 3 presents features that Wagner suggests best identify appendicitis.

Unfortunately, young children are poor historians and localize abdominal pain poorly. This may be responsible for the fact that as many as 60%-100% of toddlers will perforate by the time they are diagnosed. ^10,11 In one study of 120 children 5 years of age or younger, more than 40% of the patients had a delayed diagnosis while nonsurgical diagnoses were explored.¹¹ Children 2 years of age or younger with appendicitis commonly have symptoms or signs, including cough, rhinitis, grunting respirations, and walking with a limp, that lead the emergency physician or pediatrician away from the correct diagnosis.¹² (See Table 4.)

The most common misdiagnoses in cases of appendicitis in children include gastroenteritis (42%) and a variety of upper respiratory tract infections (18%).¹³ The presence of diarrhea can be particularly misleading; diarrhea occurs in up to one-third of children under the age of 3 years with appendicitis.¹⁴

The incidence of inguinal hernia is greatest during early infancy; boys are affected six times more often than girls.¹⁵ Unlike umbilical hernias, inguinal hernias generally do not resolve but instead become incarcerated or strangulated 12-20% of the time.^16,17 Infants with incarcerated hernias typically have crampy abdominal pain, vomiting, and irritability. The emesis may become bilious as the obstruction persists.⁷ While the overlying skin is usually normal, it may become erythematous or purple as the condition progresses.⁸

Intussusception is another condition that typically strikes infants. Affected children are usually between the ages of 2 months and 5 years (with a peak incidence between 4 and 10 months of age).^5,6 The classic triad consists of colicky intermittent abdominal pain, vomiting, and bloody stool. However, this constellation is seen in only 10%-20% of documented cases.¹⁸ Currant jelly stools occur even less frequently.¹⁹ More commonly, infants have periods of crying and drawing up their legs followed by periods of appearing playful and normal. A right upper-quadrant mass may be palpable. This is because the site of the telescoping bowel is usually at the ileocecal junction.^5,6 The diagnosis of intussusception may be obscured if the patient presents with nonspecific symptoms, including lethargy, pallor, or shock.⁶ A subset of infants with intussusception present with suspected sepsis or central nervous system dysfunction, including generalized weakness, lethargy, and even seizures.²⁰ The connection between intussusception and neurologic symptoms is not well-understood but is thought to be due to neurochemical mediators.²⁰ When this is the case, coming to the correct diagnosis can be extremely difficult, particularly if bloody stool is not found on rectal exam or if a rectal exam is not performed. In one study, 75% of children with intussusception tested positive for occult blood in the stool.²¹

Although testicular torsion typically presents with scrotal discomfort, some children localize the pain to their abdomen.^5,22 While testicular torsion can be seen at any age, there is a bimodal age distribution. A small peak occurs in the neonatal period, but cases predominate in older school-age children and young adolescents. ^23-26 Many of the neonatal cases involve torsion that occurs before birth. The swollen, discolored scrotum is identified in the nursery, and the testis is not viable by that time.

Malrotation with midgut volvulus is a true surgical emergency. Although symptomatic malrotation may occur in children older than 1 year of age, the vast majority of cases occur in the neonate. In older children, the time course of the symptoms is usually measured in months.

Malrotation is characterized by intermittent vomiting and abdominal pain.²⁷ In neonates, bilious vomiting is considered a hallmark of the condition. In one series, bilious vomiting was present in all infants with midgut volvulus.²⁷

Unfortunately, child abuse or non-accidental trauma (NAT) is always a possible cause of abdominal pain. Clues to abuse include bruises of varying ages, ecchymoses in unusual locations, untreated burns, and fractures in varying stages of healing. Parents may give inconsistent stories for these findings. In addition to solid organ injury, NAT may involve the gut. A sharp blow to the upper abdomen can produce a duodenal hematoma. This results in obstruction and relentless vomiting, absent any external signs of trauma.

Although not typically considered a disease of childhood, ectopic pregnancy must be considered in preteen and teenage girls. Their denials of sexual contact may be unreliable, particularly when a parent is present during the history taking. A significant percentage of females who deny sexual activity may be pregnant.²⁸ A pregnancy test should be performed on menstruating females with abdominal pain, regardless of age.

Other gynecologic conditions occur in school-age and adolescent girls. Ovarian torsion typically presents as moderately severe lower abdominal pain, localized to one side. When the right ovary is torsed, differentiating this diagnosis from appendicitis may require laparoscopy, laparotomy, or computerized tomography. ²⁹ The rupture of a hemorrhagic cyst can present in a dramatic fashion, with hypotension, abdominal tenderness, and referred shoulder pain (from blood irritating the diaphragm). A negative pregnancy test in this case does not preclude emergent laparotomy. In addition, pelvic inflammatory disease with or without peritonitis may present in sexually active teens. It also occurs in preadolescent victims of sexual abuse.

The presentation of urinary tract infections (UTIs) often depends on the age of the child. Neonates with UTIs may be febrile and appear septic. In addition to fever, infants with UTI can have vomiting and diarrhea. ³⁰ Also, consider UTI if a previously toilet-trained child begins wetting her pants. UTIs in preschool and school-age girls are usually associated with gastrointestinal complaints, including abdominal pain and vomiting without diarrhea. In adolescent girls, urinary tract infections mimic the adult pattern of dysuria, urinary frequency, and urinary urgency.

A simple clean-catch urinalysis is essential in toilet-trained young girls with abdominal pain. However, the finding of white cells in the urine does not clinch the diagnosis, as some cases of appendicitis also present with low-grade pyuria (and even bacteruria).^31,32

Nonsurgical causes of abdominal pain range from the pathologically inert (e.g., school anxiety) to the lifethreatening. Strep pharyngitis is a common cause of abdominal pain in school-age children and is responsible for up to 16% of cases.² Diabetic ketoacidosis causes dramatic abdominal pain and vomiting. Absent a history of diabetes, the fruity odor of ketones and a recent history of polyuria and polydipsia will suggest the diagnosis. Lobar pneumonia is another important cause of abdominal pain. While cough and fever are typically present, these may be overshadowed by the abdominal complaints. Other unusual "extra-abdominal" causes of abdominal pain include the bites of scorpions and black widow spiders, poisoning from lead or other heavy metals, porphyria, and Rocky Mountain spotted fever.³³

Constipation can cause abdominal pain. While some physicians obtain an x-ray to evaluate a child for constipation, this is not supported by the literature.^34,35 The presence of stool on plain radiographs does not exclude alternative diagnoses. Infants, particularly some breast-fed infants, may stool only once in several days. When parents ask to have their child evaluated for "constipation," ascertain good weight gain, a wellappearing infant, and a history of soft stools. Reassurance and follow-up with their primary doctor may be all that are required.

Gastroenteritis is one of the most common causes of abdominal pain in children. The crampy pain may result from the increased intestinal motility, or children may interpret their nausea and malaise as "abdominal pain." These children typically have both vomiting and diarrhea, often accompanied by fever. Their abdomens are typically soft and nontender and demonstrate increased bowel sounds. Vomiting and diarrhea are also commonly seen in appendicitis (see Table 4), and failure to perform an adequate initial or repeat examination risks missed pathology.^10-14,36,37 Serial examinations in the ED can help distinguish gastroenteritis from other, more serious etiologies. The moderately dehydrated child with gastroenteritis will often dramatically improve after oral or intravenous hydration.

Infant colic is a controversial diagnosis.^38-40 Concerned parents may present with a child who has cried for the greater part of an evening, apparently from abdominal pain. Typically, these infants are younger than 4 months of age. (A full discussion of the inconsolable infant is beyond the scope of this article; a good source is: Pawel BB, Henretig FM: Crying and colic in early infancy. In: Fleisher GR, Ludwig S, Henretig FM, eds. Textbook of Pediatric Emergency Medicine. Philadelphia: Williams & Wilkins; 2000:193-195.)

Emergency Department Evaluation

History

Physical Examination

The physical examination of the child with abdominal pain must not be restricted to the abdomen. Early during the examination, decide whether the child appears ill or dehydrated. Are the mucous membranes moist, the eyes bright and shiny? Is the skin turgor normal? Examine the throat for exudates, as strep pharyngitis may be the culprit. Also look also for oral thrush. Thrush in the older child suggests immunosuppression, diabetes, or recent antibiotic use. Examine the child for respiratory findings such as tachypnea, grunting, rales, or egophony, as pneumonia is an important cause of pediatric abdominal pain. Rashes, too, may provide important clues to the etiology of abdominal pain. The petechial rash of Henoch- Schönlein purpura (HSP) may be seen in some children with intussusception.⁴² The rash of HSP is usually petechial; can be discrete or confluent; and is usually concentrated on the buttocks and lower extremities. HSP predisposes to a variety of intra-abdominal pathology, usually intussusception. Rocky Mountain spotted fever, generally characterized by a petechial rash that begins in the extremities, is frequently associated with abdominal pain.^43,44

The abdominal examination in the young child requires artistry. While palpating the abdomen of a preschooler, asking "Does this hurt?" always gets an affirmative nod to every location touched. Frustrated parents frequently say, "Tell the doctor where it hurts"—to little avail. Likewise, forcing a kicking and screaming young child onto the gurney and then trying to palpate his or her abdomen is similarly fruitless.

Several approaches to the examination of the pediatric belly have been described; unfortunately, there is essentially no data available to validate them. That said, here are some of our favorite techniques.

When examining neonates and young infants, flex their knees to their abdomen, as this will soften their abdominal muscles. Allow the fearful child to remain seated in the parent's lap during abdominal palpation. Watch their facial expressions instead of asking for verbal affirmations of pain.

Another strategy is making the examination a game. A child with a tender abdomen will play until a sensitive area is examined. Tell them that you are going to feel their belly to guess what they ate; having them participate can promote a better exam. Palpating for gummy worms and toast is sure to reassure the child of your professionalism. Some physicians pretend to blow out imaginary candles on the child's abdomen.

If the abdomen is tender, assess for peritoneal signs. An alternative to rebound testing is to have the child jump up and down. Children with appendicitis typically jump only once, as the painful landing abruptly terminates the game.

A hurried physical exam without complete exposure will miss an inguinal hernia or testicular torsion. In the young child, "dropping the diaper" is an essential maneuver. Simply undressing the child may yield a prompt diagnosis. Feel for an incarcerated inguinal hernia and look for the scrotal discoloration while palpating for an abnormal testicular lie. A grossly bloody stool in the diaper of a lethargic child points to intussusception.

The value of a rectal examination in children with abdominal pain is controversial. On the one hand, localized tenderness, fecal impaction, or heme-positive stools can be important findings. On the other hand, a review of its clinical utility shows that it is rarelyhelpful.⁴⁵ In one study of 1140 children 2-12 years old with acute abdominal pain, the authors noted that of eight patients with appendicitis in whom a rectal examination was performed, findings were noncontributory in six.⁴⁶ Overall, they believed that the rectal examination was clinically useful in 12 of 56 patients (21%): five with constipation, three with gastroenteritis, two with appendicitis, and one patient each with abdominal adhesions and abdominal pain of uncertain etiology.

Although there is no literature directly supporting this practice, per se, we recommend a pelvic examination be performed on all sexually active teen females with abdominal pain. Prominent cervical motion tenderness or an adnexal mass may lead the emergency physician to the correct diagnosis. In the virginal preteen or teenage female with abdominal pain, the preferred approach is the bimanual rectal examination. In this exam, the examiner does not place anything in the vagina. Instead, the examiner palpates the uterus and adnexa via a finger in the rectum. In this manner large masses or prominent tenderness may be appreciated.

Risk Management

1. "The patient had diarrhea, so I just thought that it was gastroenteritis."

2. "I didn't think that a repeat exam was warranted. He looked so good the first time."

3. "There was no complaint related to the diaper area, so I didn't examine there."

4. "They seemed like such a nice family that I didn't even consider abuse."

5. "I just left it up to the family to take the patient to the pediatrician as needed."

6. "She said she had never had sex, so I didn't order a pregnancy test."

7. "He was so lethargic that I thought for sure he was septic."

8. "The child didn't say that it hurt when she urinated, so I didn't check the urine."

9. "It couldn't have been appendicitis. The white count was normal."

10. "He never said that he had had mononucleosis."

Tables

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study, will be included in bold type following the reference, where available. In addition, the most informative references cited in the paper, as determined by the authors, will be noted by an asterisk (*) next to the number of the reference.

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