Acute Dx: What is the Cause of Sudden Illness?

History

An 8-year old previously healthy boy presents to your office with a poor appetite, nausea, vomiting, and intermittent abdominal pain. He has had a poor appetite for about 24 hours, with intermittent nausea and 5 non-bloody, non-bilious emesis in the last 12 hours. He developed right, lower quadrant (RLQ) abdominal pain about 6 hours ago. The pain is sharp, moderate, and worsened by activity—ie, running and playing basketball. 

He denied any fever, diarrhea, constipation, cough, sore throat, dysuria or hematuria. There was no history of trauma. 

The patient was born at 35 weeks with a small atrial septal defect, which closed spontaneously at 12 months of age. He has been healthy and has been on no medications. His vital signs included a temperature of 37.6° C, a heart rate of 120 beats per minute, a respiratory rate of 20 breaths per minute, 02 sats at 100%, blood pressure at 111/65 mm Hg, and a weight of 38 kg.

Physical Examination

On examination, he was alert and well appearing. He ambulated well. He had dry mucous membranes, but no intraoral lesions or posterior pharynx erythema, edema, or exudates. His cheeks were flushed. Lungs and cardiovascular exam were normal. His abdomen was soft and nondistended. 

The patient pointed to his RLQ and stated that it hurts, but there was only minimal RLQ tenderness to palpation. There was no rebound tenderness or guarding. He had a negative Rovsing and obturator sign, but had a positive psoas sign. 

His bowel sounds were normal, as was his genital exam and no costovertebral angle tenderness was elicited. There was no pallor, jaundice, or rash. His neurological and musculoskeletal exams were normal.

What’s Your Diagnosis?

A. Viral gastroenteritis with mesenteric adenitis.

B. Acute appendicitis.

C. Nephrolithiasis.

D. Constipation.

(Answer and discussion on next page)

Answer: Retrocecal appendicitis

The patient’s initial appendix ultrasound found a 3 mm tubular structure in the RLQ, compressible, and consistent with a normal appendix. No free fluid, mass or lymphadenopathy (Figure 1) was present. His urinalysis showed 160 ketones and small blood. The patient had one emesis after an oral dose of ondansetrone and intravenous fluid (IVF) were started. His white blood count was 22,500 with 76% neutrophils and 12 lymphocytes. 

The patient felt better and wanted to go home. However, the patient was admitted to pediatric floor of the local hospital for observation and serial abdominal exams. He did well initially, but 8 hours after admission developed severe RLQ pain. An abdominal CT was done and the findings included acute appendicitis with a 1.4 cm appendicolith. 

Enlarged, dilated fluid collection measuring 1.3 cm in diameter was seen distal to the appendicolith, which contained multiple foci of gas although maintained a curvilinear shape. This may represent inflammatory material contained within the distal appendideal walls; however, early rupture into a small periappendiceal abscess was difficult to exclude (Figure 2). 

Diagnosis

Appendicitis can be difficult to diagnose in young children for several reasons:

• Classic symptoms of appendicitis (ie, anorexia, vague periumbilical pain followed by RLQ pain, fever, and vomiting) are present in less than 60% of patients.

• Lack of migration of pain to RLQ in 50%.

• Absence of anorexia in 40%.

• No rebound tenderness in 52%.

• Vomiting often precedes abdominal pain, unlike adults.

Approximately 44% of patients diagnosed with appendicitis presented with 6 or more of following atypical features:¹

• Absence of maximal pain in RLQ.

• Abrupt onset of pain.

• No migration of pain.

• No guarding.

• No rebound pain.

• No percussive tenderness.

• Negative Rovsing sign.

• No anorexia.

• No fever.

• Normal or increased bowel signs.

An estimated 15% of patients with retrocecal appendicitis do not localize signs and symptoms to the RLQ but to the psoas muscle. They typically have vomiting prior to pain (irritation of nearby duodenum). They may have no pain until the appendicitis is advanced or the appendix perforates. A psoas sign is especially helpful in those patients. 

Patients with the tip of the appendix deep in the pelvis (pelvic appendicitis) may have signs and symptoms localized to rectum or bladder and present with diarrhea or dysuria. The obturator sign is particularly helpful in those patients. Patients with a medially positioned appendix may have suprapubic pain while patients with a laterally positioned appendix may have flank pain. 

The white blood count (WBC) is elevated in 70% to 90% of patients, but is often within normal range in the first 24 hours of symptoms. Elevation occurs when the disease progresses. Elevation of neutrophils or bands with a normal total WBC count may support the diagnosis of appendicitis. A WBC > 15,000 compels evaluation and suggests perforation.

Figure 1. An axial CT of appendicitis.

Ultrasound Imaging

According to a recent observational study of 263 children between the ages of 4-17 years with suspected appendicitis, ultrasound was inaccurate in 101 cases (88 false positives and 13 false negatives). This was particularly true for children with a BMI >85th percentile or those with low pretest clinical suspicion for appendicitis.² Appendix ultrasound visualization rates in children vary from 22% to 98%—sensitivities ranging from 74% to 100% and specificities ranging from 88% to 90%. 

Ultrasound imaging for diagnosis of appendicitis has limitations. Fat absorbs and diffuses the ultrasound beam, making it more difficult to scan overweight children. It can be difficult to identify an appendix that is only focally inflamed (tip appendicitis). In addition, gaseous distention of the intestines overlying the appendix makes it more difficult to visualize. Pain and/or anxiety make ultrasound imaging difficult is some children. 

The bottom line: A negative ultrasound study in the presence of persistent signs and symptoms suggestive of appendicitis is not sufficient to reliably exclude appendicitis. 

Gastroenteritis

Children with acute gastroenteritis typically develop fever, cramping, abdominal pain, and diffuse abdominal tenderness before diarrhea begins. While the severity of the pain can mimic other more serious conditions (ie, appendicitis), the onset of diarrhea generally clarifies the etiology. Many patients have nausea and vomiting. 

Gastroenteritis can be caused by viruses, bacteria, or parasites; clinical manifestations depend on the organism. The majority of cases are caused by viruses. Yersinia enterocolitica gastroenteritis can cause focal RLQ abdominal pain and peritoneal signs that are clinically indistinguishable from appendicitis. Most cases of gastroenteritis in children are self-limited and do not require laboratory evaluation. All patients require fluid and electrolyte therapy to prevent dehydration. 

Figure 2. Coronal appendicitis.

Mesenteric lymphadenitis

Mesenteric lymphadenitis is an inflammatory condition of the mesenteric lymph nodes that can present with acute or chronic abdominal pain. Because the nodes are usually in the RLQ, mesenteric lymphadenitis sometimes mimics appendicitis. Mesenteric lymphadenitis is diagnosed by an ultrasound that shows abdominal lymph nodes greater than 10 mm. 

The presence of enlarged lymph nodes on diagnostic imaging does not, by itself, exclude a diagnosis of appendicitis; it is necessary to demonstrate a normal appendix as well.³ Etiologies of mesenteric lymphadenitis include viral and bacterial gastroenteritis (eg, Yersinia enterocolitica), group A Streptococcal pharyngitis, inflammatory bowel disease, and lymphoma. Viral infection is most common.

Constipation

Constipation is common in children and can present with fecal impaction and severe colicky lower abdominal pain. In a series of 83 children presenting to primary care providers or an emergency department with acute abdominal pain, acute or chronic constipation was the most common underlying cause, occurring in 48% of subjects.⁴ In many cases, rectal examination was a key step in establishing the diagnosis. 

Constipation is likely in children with at least 2 of the following characteristics: fewer than 3 stools weekly, fecal incontinence (usually related to encopresis), large stools palpable in the rectum or through the abdominal wall, retentive posturing, or painful defecation.⁴ Parents may not recognize the relationship of constipation to the child's abdominal pain. 

Nephrolithiasis

Most children with nephrolithiasis present symptomatically, usually with flank or abdominal pain, and/or gross hematuria. Approximately 20% of children are asymptomatic and primarily young children under 6 years of age are diagnosed because of stone detection when abdominal imaging is performed for other purposes.⁵ 

Pain can be located either as abdominal or flank pain, and varies with age. The age-related difference in pain may be related to stone location at presentation. Younger children (>5 years of age) are less likely to have ureteral stones than school-aged children and adolescents. Ureteral stones are generally painful, since they cause ureteral obstruction, whereas kidney stones are often asymptomatic and may be diagnosed as an incidental finding on abdominal imaging.

The intensity of pain can vary from a mild ache to severe debilitating pain. In children younger than 5 years of age, the pain, if present, appears to be milder and is non-specific. In addition, young children often are unable to articulate the location and severity of the pain. As a result, young children are frequently evaluated for other causes of abdominal pain before the diagnosis of nephrolithiasis is made. Roughly 30% to 55% of children present with gross hematuria. Approximately 10% of children with nephrolithiasis present with symptoms of dysuria and urgency suggestive of a urinary tract infection.⁶ In addition to these symptoms, nausea and vomiting has been described as a presenting symptom in 10% of patients. 

In our case, the patient underwent laparoscopic appendectomy. The surgeons noted that “the appendix was a curled up and partially retrocecal appendix, with severely inflamed tip that was adherent to the lateral abdominal wall.” The patient was hospitalized for 48 hours, treated with an IV of Zosyn (piperacillin and tazobactam injection), and then completed a 10-day course of augmentin at home. He did well with no complications afterwards. ■

Maya Myslenski, MD, is an assistant professor of Pediatrics at Case Western Reserve University and attending physician in the department of Emergency Medicine at the MetroHealth Medical Center in Cleveland, Ohio.

David Effron, MD, is an assistant professor of emergency medicine at Case Western Reserve University, attending physician in the department of emergency medicine at the MetroHealth Medical Center, and consultant emergency physician at the Cleveland Clinic Foundation, all in Cleveland.

References:

1.Becker T, Kharbanda A, Bachur R. Atypical clinical features pf pediatric appendicitis. Acad Emerg Med. 2007;14:124-129.

2.Schuh S, Man C, Cheng A, et al. Predictors of non-diagnostic ultrasound scanning in children with suspected appendicitis. J Pediatr. 2011;158:112-118.

3. Simanovsky N, Hiller N. Importance of sonographic detection of enlarged lymph nodes in children. J Ultrasound Med. 2007;26:581-584.

4.Loening-Baucke V, Swidsinski A. Constipation as a cause of acute abdominal pain in children. J Pediat. 2007;151:666-669.

5.Van Dervoort K, Wiesen J, Frank R, et al. Urolithiasis in pediatric patients: a single center study of incidence, clinical presentation and utcome. J Urol. 2007;177:2300-2305.

6.Sternberg K, Greenfield SP, Williot P, Wan J. Pediatric stone disease: an evolving experience. J Urol. 2005;174:1711-1714.

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