Case Files Pediatrics, (LANGE Case Files) 4th Ed.

CASE 36

A 15-year-old adolescent female has periumbilical pain that began 8 hours ago; since then she has vomited once and has had one small, loose bowel movement. Her last meal was 12 hours ago, and she is not hungry. She denies dysuria, urinary frequency, and sexual activity; her last menses a week ago was normal. On examination, she is moderately uncomfortable, mildly tachycardic, and has a low-grade fever of 101.5°F (38.6°C). Her abdominal examination reveals few bowel sounds, rectus muscle rigidity, and tenderness to palpation, particularly periumbilically. Breath sounds are clear; she has no rashes. Her pelvic examination shows no vaginal discharge, but there is some abdominal tenderness with gentle bimanual palpation. She has right lower quadrant pain with digital rectal examination.

Image What is the most likely diagnosis?

Image What is the next step in the management of this patient?

ANSWERS TO CASE 36: Appendicitis

Summary: A 15-year-old adolescent female with periumbilical pain of 8-hour duration, followed by anorexia, emesis, and a loose bowel movement. She has no dysuria or sexual activity, and the pain appears unrelated to her menses. Her physical examination shows a quiet, rigid, tender abdomen, and pain with digital rectal examination.

• Most likely diagnosis: Appendicitis

• Next step in management: A surgeon should be consulted once the diagnosis of appendicitis is suspected. Abdominal ultrasound has high sensitivity for diagnosis of appendicitis in experienced pediatric centers, but abdominal computed tomography (CT) is more generally used. Urinalysis is useful to eliminate a urinary tract infection (UTI) as a cause, and a complete blood count (CBC) often shows leukocytosis. Despite this adolescent’s denial of sexual activity, a urine pregnancy test should be obtained.

ANALYSIS

Objectives

1. Recognize the presenting clinical signs for appendicitis.

2. Know the differential diagnosis for appendicitis.

3. Recognize the need to maintain a high index of suspicion for appendicitis to prevent possible complications.

Considerations

The definitive diagnosis of appendicitis may not be made until surgery. For this patient, the initial abdominal pain followed by anorexia and vomitingsuggests appendicitis. The pain of appendicitis classically begins periumbilically and then migrates to the right lower quadrant. The pain can occur laterally (retrocecal appendix), or it can be more diffuse (perforated appendix with resultant generalized peritonitis). The utility of rectal examinations for children with suspected appendicitis is debatable; they can be helpful for localizing the pain source in a female adolescent.

The adolescent female in this case is early in her disease process and arguably might be safely observed for a few hours if the diagnosis remains in question. However, once appendicitis seems likely, surgical management should occur in a timely fashion; perforation rates exceed 65% if diagnosis is delayed beyond 36 to 48 hours from symptom onset. Complications, such as wound infection, abscess formation, intestinal obstruction, or adhesions, are infrequent (5%-10%) following uncomplicated appendectomy but increase (15%-30%) with appendiceal perforation.

APPROACH TO:

Appendicitis

DEFINITIONS

APPENDICITIS: Appendix inflammation occurs after luminal obstruction. If the appendix is not removed, appendiceal wall necrosis results in perforation and peritoneal contamination.

MCBURNEY’S POINT: The junction of the lateral and middle third of the line joining the right anterior superior iliac spine and the umbilicus (Figure 36-1); typically this area is of greatest discomfort in acute appendicitis.

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Figure 36-1. McBurney’s point.

PSOAS SIGN: Irritation of the psoas muscle caused by active right thigh flexion or passive right hip extension in patients with appendicitis.

OBTURATOR SIGN: Irritation of the obturator muscle caused by passive internal rotation of the right thigh in patients with appendicitis.

ROVSING’S SIGN: Palpation of the left lower quadrant causes pain at the right lower quadrant in patients with appendicitis.

CLINICAL APPROACH

A person’s lifetime risk of appendicitis has been estimated at 6% to 20%, with the peak incidence in adolescence. Intrinsic appendiceal obstruction caused by inspissated fecal material (an appendicolith) is found in 30% to 50% of patients at the time of surgery. Extrinsic compression usually is caused by enlarged lymph nodes associated with bacterial or viral infections. The obstruction causes vascular thrombosis, ischemia, and, ultimately, perforation.

The differential diagnosis for acute abdominal pain in childhood is long (Table 36-1). Worsening abdominal pain in the periumbilical area, which then migrates to the right lower quadrant, is characteristic of acute appendicitis. Likewise, anorexia, nausea, and vomiting that begin after the onset of pain is strongly indicative of the diagnosis.

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Table 36-1 • PARTIAL DIFFERENTIAL DIAGNOSIS OF ACUTE ABDOMINAL PAIN IN CHILDREN BEYOND INFANCY

A gentle abdominal examination can provide meaningful data while not frightening the child. Observation of the child getting on and off the examination table can be revealing; children with appendicitis avoid sudden movements (such as jumping off the table). The abdomen is inspected, then auscultated for bowel sounds, followed by gentle palpation for the area of maximal tenderness and rigidity. Gentle finger percussion assesses for peritoneal irritation (“rebound tenderness”). If performed, a rectal examination should occur last.

Although not a specific finding, leukocytosis with a predominance of polymorphonuclear cells (a “left shift”) on a CBC supports an inflammatory process. Hematuria and pyuria raise the possibility of a genitourinary etiology, but they can occur with acute appendicitis if it also causes irritation of the bladder or ureteral wall. Plain abdominal radiographs can be obtained but are infrequently helpful. Psoas shadow obliteration, right lower quadrant intestinal dilatation, scoliosis toward the affected region, and an appendicolith (seen in 10% of cases) support appendicitis. Chest radiographs eliminate pneumonia as an alternate diagnosis. Ultrasonography is more sensitive than plain films for appendicitis and is particularly useful in female adolescents, in whom the differential diagnosis includes ovarian cysts and pregnancy. Its main limitation is that the appendix cannot always be visualized. CT has become the diagnostic test of choice in most centers and is particularly helpful for patients who are neurologically impaired, immunologically suppressed, or obese, or for patients in whom perforation is suspected. Its disadvantages are the amount of radiation exposure generated and increased cost, and that it may give limited information without the use of contrast.

Definitive treatment is surgical removal of the appendix (appendectomy), accomplished as soon as the diagnosis is strongly suspected to prevent perforation (if it has not already occurred). For perforated appendicitis, initial management consists of intravenous antibiotics and fluid replacement; its course may be complicated by sepsis, abscess formation, or prolonged (4-5 days) paralytic ileus. Percutaneous drainage catheters can be used to drain the abscess and then appendectomy is performed at a later time.

COMPREHENSION QUESTIONS

36.1 A 7-year-old has right-sided abdominal pain and fever to 102°F (38.9°C). His mother says that he has had 2 days of poor appetite and cough; he had two loose stools earlier in the day. On examination, his temperature is 101.7°F (38.7°C), his heart rate is 120 bpm, and his respiratory rate is 50 breaths/min. Breath sounds are diminished, and the abdomen is diffusely tense with hypoactive bowel sounds. Which of the following would likely lead to the diagnosis?

A. Abdominal computed tomography

B. Chest radiograph

C. Liver function tests

D. Stool leukocytes

E. Stool for culture, ova, and parasites

36.2 A 14-year-old adolescent female with a 3-day history of abdominal pain, anorexia, and vomiting and a 1-day history of fever underwent laparoscopic surgery for suspected appendicitis, which was perforated at the time of surgery. Intravenous ampicillin, gentamicin, and clindamycin were initiated prior to surgery and continued postoperatively. On the seventh postoperative day, she continues to have fevers to 102°F (38.9°C). Which of the following is the next most appropriate step in management?

A. Add metronidazole to the antibiotic regimen.

B. Change the antibiotics to amikacin and a cephalosporin.

C. Order a computed tomography scan immediately.

D. Send a urinalysis and urine culture.

E. Perform a pelvic examination.

36.3 A previously healthy 8-year-old boy presents to your clinic with abdominal pain, anorexia, and vomiting that have worsened over the previous 24 hours. The pain is located in the umbilical region. Despite the emesis, he appears well hydrated. A CBC reveals a white blood count of 17,000 cells/mm3 with 50% polymorphonuclear cells. A urine dipstick on a clean-catch specimen shows 2+ leukocytes and 1+ protein but no nitrites. Which of the following is the most appropriate management at this point?

A. Obtain a complete chemistry panel and continue to observe him in the office.

B. Send the patient immediately to the hospital for an abdominal ultrasound.

C. Give him a prescription for trimethoprim-sulfamethoxazole; schedule a follow-up visit in 2 days to reevaluate the urine.

D. Admit him to the hospital for intravenous antibiotics to treat presumed pyelonephritis.

E. Schedule a computed tomography scan of the abdomen for the next morning.

36.4 A 4-year-old girl has a fever of 102.4°F (39.1°C), difficulty swallowing, vomiting, and abdominal pain. Which of the following diagnostic tests is most likely to yield the appropriate diagnosis?

A. Streptococcal antigen test (“rapid strep test”)

B. Antigen test for Epstein-Barr virus (“Monospot”)

C. Lateral neck radiograph

D. Abdominal ultrasound

E. Complete blood count

ANSWERS

36.1 B. Lower lobe pneumonias can cause abdominal pain, which may be the most distressing symptom in a young patient. Inflammation of the diaphragm can result in an abnormal abdominal examination, which may be mistaken for the source of the child’s illness. This child has cough, fever, tachypnea, and diminished breath sounds, which together make pneumonia the most likely diagnosis.

36.2 C. This adolescent female is at risk for an intra-abdominal abscess despite her appendectomy and intravenous antibiotics. It would be unusual for a urinary tract infection or pelvic inflammatory disease to cause persistent fever despite broad-spectrum intravenous antibiotics.

36.3 B. This boy’s symptoms and signs are most consistent with a diagnosis of acute appendicitis. A urinary tract infection in an otherwise healthy boy would be unusual. His pyuria is most likely the result of bladder wall or ureter irritation caused by an inflamed appendix.

36.4 A. Her symptoms are most consistent with streptococcal pharyngitis. In addition to throat pain and fever, group A Streptococcusinfections commonly cause abdominal pain and emesis.


CLINICAL PEARLS

Image Acute appendicitis typically causes periumbilical abdominal pain that eventually migrates to the right lower quadrant. Emesis usually follows, rather than precedes, the onset of pain.

Image Surgical management of appendicitis occurs as soon as the diagnosis is suspected in order to minimize the potential risks of perforation and intra-abdominal abscess formation.

Image Appendicitis often is not confirmed until surgery. A history and physical examination, urinalysis, CBC, and abdominal ultrasound or computed tomography scan are the most useful tools for eliminating other preoperative considerations.


REFERENCES

Aiken JJ, Oldham KT. Acute appendicitis. In: Kliegman RM, Stanton BF, St. Geme III J, Schor N, Behrman R, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: WB Saunders; 2011: 1349-1355.

Egan JC, Aiken JJ. Acute appendicitis, typhlitis, and chronic appendicitis. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:1473-1474.

Pegoli W. Appendicitis. In: McMillan JA, Feigin RD, DeAngelis CD, Jones MD, eds. Oski’s Pediatrics: Principles and Practice. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:2000-2002.