The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay
The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay
In children, one of the most common symptoms is abdominal pain. Many parents attest that their children would always complain of some tummy aches. In many cases, these episodes are known to be insignificant. Many children would have various thresholds of tolerating pain3. On the other hand, the parents would have a variation in their threshold of the appropriate time of bringing their child to the hospital. The paediatric and paediatricians rooms of emergency are always full of parents in need of attention from the doctors. In this case, the physician need to decide the patients who warranty for more work up with imaging and the type of patients who require the referral to the paediatric surgeon.4 The surgeons need to decide the types of patients that warranty the interventions of the surgeon and the patients who need medical observation or management .The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay. Even though the presentation in a child with abdominal pain may be common, all the individual children would give unique challenges to the involved physicians.
The abdominal pain pathophysiology is complex. The abdominal organ stimuli together with the gastrointestinal tract, move through the sympathetic nerves towards the ganglia of the thorax and the spinal cord. The shown stimuli have been reported to be poorly localized. The pain coming from the visceral glands is equally poorly localized, and is always believed to be the midline that is linked with the secondary autonomic effects like vomiting, nausea and pallor. In many cases, the many pain location may characterize the organ that is affected. The Epigastric pain comes from duodenum, stomach, pancreas, biliary system, or liver. Periumblical pain, comes from the small intestine. The infraumblical pain, on the other hand comes from the rectum and colon, ovaries and uterus, kidneys and bladder. The ovarian and renal pain is always located laterally to the side that is affected.
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In children abdominal masses usually arises from the kidney and urinary tract. The reasons for patient’s presentation may be abdominal pain, palpable abdominal mass (usually discovered during the physical exam) and hematuria. Ultrasonography should be the first imaging investigation performed in children with an abdominal mass. It can be performed safely regardless of the clinical status of the patient, it is noninvasive and painless, requires no radiological contrast media and it is a relatively inexpensive. Ultrasonography is usually able to give an accurate localization of the lesion to a specific area or organ of the abdomen and provides good differentiation of solid from fluid or blood-filled masses. The purpose of this pictorial essay is to demonstrate the ultrasonographic features of the most frequently encountered reno-urinary masses in children.The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay.
Acute Appendicitis
Acute appendicitis is the most common cause of a surgical abdomen in children. The evaluation of appendicitis using sonography has been described as early as 1981.1 Graded compression and the use of high‐frequency transducers were introduced in 1986.2 The 6‐mm cutoff size for a normal appendix was suggested soon after.3
Since then, little has changed in the sonographic evaluation of the appendix. Currently, we identify the normal appendix as a blind‐ending, tubular, and nonperistalsing segment of bowel that arises from the cecum and measures at most 6 mm in wall‐to‐wall transverse diameter; it is compressible and should have no surrounding mesenteric edema (Figure 1). A dilated noncompressible appendix is therefore compatible with appendicitis (Figure 2A). Doppler evaluation may be used to detect inflammation of the appendiceal wall. Since hyperemia is a marker of inflammation, the addition of color Doppler imaging can increase the specificity of sonography in diagnosing acute appendicitis
Normal sonogram of an appendix,. The appendix (between calipers) measures less than 6 mm in diameter. The arrow points to the cecum as the origin of the appendix.
Acute appendicitis. A, The appendix is distended and noncompressible, and the surrounding mesentery (arrow) is thickened and echogenic, secondary to edema. The calipers delineate a shadowing and obstructing appendicolith. B, Doppler sonogram showing shows hypervascularity of the appendiceal wall due to inflammation.
More recent studies, however, question whether these time‐honored criteria remain applicable. For instance, lymphoid hyperplasia and fecal impaction of the appendix may increase the size of a normal appendix. The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay.In the absence of secondary signs of inflammation, 7 mm may be a more reasonable maximum diameter of the normal appendix.5 The reliability of graded compression has also been questioned; guarding may preclude adequate compression, and the appendix may slide away from the transducer. Operator technique as well as patient obesity may also limit adequate application of pressure.6 Furthermore, it is essential that the sonographer use the transducer that optimally images the appendix in a given patient. Although curved transducers are useful for obtaining a general overview of the abdomen, high‐frequency linear transducers are usually necessary to image the appendix—and also to apply adequate pressure. As a general rule, higher‐frequency linear transducers are especially useful for imaging the appendix in a thin, young pediatric patient, although lower‐frequency and even curved transducers may be necessary in larger children.
Periappendiceal inflammation may be the most reliable indicator of appendicitis.6This is illustrated in one of our patients with a proximal appendicolith and mildly dilated appendix measuring 6.5 mm (Figure 3). The physical examination performed by the pediatric surgeon was inconclusive, and the patient actually showed substantial improvement of symptoms after several hours of observation. The patient was sent home after 24 hours without surgical intervention. In retrospect, the periappendiceal fat was clean, and there were no secondary signs of inflammation.
Mildly distended appendix and appendicolith without periappendiceal inflammation. An appendicolith (arrow) is evident in the proximal appendix, and the appendix measured 6.5 mm. Notice that the adjacent mesentery is not echogenic, and there is no surrounding fluid. The patient improved without surgical intervention.
Sonography may also suggest appendiceal perforation, with overall sensitivity of 86%.7 Disruption of the echogenic submucosal layer of the appendix is the most sensitive finding that suggests perforation7 (Figure 4). Periappendiceal fluid may be seen with or without perforation, but the presence of complex rather than simple fluid may increase the likelihood of perforation. Furthermore, an abscess may be identified as a collection(s) of fluid either adjacent to the appendix or elsewhere in the abdomen (Figure 5). This sign too is another indicator of perforation.The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay. Sometimes the appendix perforates and then disintegrates to such an extent that sonography fails to identify an abnormal appendix, but the presence of complex fluid and perhaps an appendicolith may then suggest the diagnosis. Some centers manage appendiceal perforation and abscess formation with percutaneous drainage and delayed appendectomy, so it is important to establish the presence of perforation.
Two cases of acute appendicitis showing the appearance of the submucosa without and with perforation. A, Intact submucosa (arrow) in a distended and inflamed but nonperforated appendix. B, Submucosal discontinuity (arrows) in a surgically proven perforated appendicitis. The surrounding echogenicity is consistent with phlegmonous changes.
Perforated appendicitis. A, Distended appendix with appendicoliths (arrows). B, Adjacent irregular fluid collection representing an abscess. C and D, Coronal reformations from computed tomography performed to evaluate the extent of the abscess confirm the sonographic findings (arrow in C, appendicolith; arrow in D, adjacent abscess).
The skilled sonographer should succeed in identifying a pathologic appendix in greater than 95% of cases, but the sensitivity of sonographic diagnosis may be as low as 22%.8 However, sonography should still be the initial modality for attempted diagnosis, since it is quick, inexpensive, readily available, and—in capable hands—highly reliable. The lack of ionizing radiation makes this modality ideal for the pediatric age group. Furthermore, if appendicitis is excluded, the sonographic examination can be extended to evaluate common mimics. In addition, sonography has a high negative predictive value even if the appendix is not identified.9
Mesenteric Lymphadenitis and Enteritis
The clinical symptoms of appendicitis, including abdominal pain, anorexia, nausea, vomiting, and fever, are difficult to differentiate from those of mesenteric lymphadenitis. The latter condition results from inflammatory lymphadenopathy, which in children is often secondary to viral gastroenteritis. In patients undergoing computed tomography for suspected appendicitis, the most common mimic is mesenteric lymphadenitis.10 Sonography is often able to differentiate between these conditions.11 Mesenteric or right lower quadrant lymphadenopathy is of course often seen in the setting of appendicitis. The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay. However, if a normal appendix is visualized, or if there are no secondary signs of appendicitis in a technically adequate study, mesenteric lymphadenitis is likely.
The definition of pathologic lymphadenopathy does vary. Some authors suggest using a longest diameter greater than 10 mm as pathologic,12 whereas some use the term mesenteric lymphadenitis only when the short‐axis diameter of the enlarged lymph node exceeds 10 mm.13 However, even small lymph nodes less than 5 mm in short‐axis diameter may be symptomatic.14 In our experience, multiple mildly enlarged lymph nodes (ranging from 10–15 mmin the long axis) at the root of the mesentery and especially in the right lower quadrant are most often encountered with this condition. Doppler imaging is also useful in showing the hypervascularity of these inflamed lymph nodes (Figure 6A). However, even asymptomatic children can have mildly enlarged abdominal lymph nodes, probably due to a prior inflammatory process. During the sonographic examination, it is also useful to establish whether these nodes are tender, which can be helpful in diagnosing mesenteric adenitis. Enlarged mesenteric lymph nodes can also be seen in giardiasis, Crohn disease, and AIDS. It is also important to remember that lymph nodes that are matted, lack a normal hilum, or are massively enlarged, may be signals of other conditions such as tuberculosis, other myco bacterium infections, or lymphoma. Since viral gastroenteritis may clinically resemble appendicitis or mesenteric adenitis, when we routinely evaluate the proximal jejunum and terminal ileum for the presence of wall thickening, that would suggest enteritis
A, Sonogram from a 3‐year‐old patient with enlarged and tender mesenteric lymph nodes in the right lower quadrant with a long‐axis diameter of 1.5 cm. Doppler imaging also shows hypervascularity of these lymph nodes. B, Transverse scan of the right lower quadrant in a 9‐month‐old girl who presented with vomiting and diarrhea. There is diffuse bowel wall thickening consistent with enteritis. The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay.
Intussusception
Intussusception is the most common cause of bowel obstruction in children younger than 5 years. The classic triad of colicky abdominal pain, a palpable mass, and bloody stools is present in less than 40% of patients, making imaging diagnosis essential. Radiographs, especially a left lateral decubitus film that can aid in the assessment of the cecum and ascending colon, may show a soft tissue mass or bowel obstruction, but the appearance is usually nonspecific, especially in children presenting early in the course of the disease.
Sonography is currently the imaging modality of choice, with sensitivity and specificity of about 98%.15 Classic features include a “target or pseudokidney sign,” which is composed of alternating layers of echogenic mucosa, hypoechoic muscularis, and echogenic serosa. On longitudinal images, a “sandwich sign” can be observed, which represents the outer intussuscipiens and the inner telescoping intussusceptum. If a soft tissue mass with these features is identified, it is important to consider its size to differentiate ileocolic from ileoileal (small‐bowel) intussusception. Small‐bowel intussusception typically measures 1.5 cm or less in transverse diameter (outer wall to outer wall), whereas ileocolic intussusception often will have a transverse diameter greater than 2.5 cm16(Figure 7).The Role of Radiological Imaging in the Diagnosis of a Child with Abdominal Pain Essay. In addition, the presence of a substantial fatty core and lymph nodes along with the intussusceptum suggests ileocolic intussusception.16 (Figure 8). This differentiation is critical, since ileocolic intussusception requires emergent reduction, whereas most small‐bowel intussusceptions resolve spontaneously without intervention.
