Non traumatic acute abdomen in pediatric patients: US Imaging with clinical and surgical correlation-a case-based approach

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1 Non traumatic acute abdomen in pediatric patients: US Imaging with clinical and surgical correlation-a case-based approach Poster No.: C-0870 Congress: ECR 2013 Type: Educational Exhibit Authors: V. Miele, G. L. Buquicchio, V. Di Giacomo, I. Di Giampietro, S Ianniello, G. Menichini, B. sessa, M. Trinci ; Roma/IT, Rome/ 3 IT, Roma, ITALY/IT Keywords: Acute, Diagnostic procedure, Decision analysis, UltrasoundPower Doppler, Ultrasound-Colour Doppler, Ultrasound, Pediatric, Emergency, Abdomen DOI: /ecr2013/C-0870 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 38

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3 Learning objectives The purpose of this exhibit is to review US appearance of the most common causes of non traumatic acute abdomen in pediatric patients and to give a practical approach, showing different clinical cases. Fig. 1 on page 3 Images for this section: Page 3 of 38

4 Fig. 1: Acute appendicitis. 11-years old patient presenting with right lower quadrant pain. Ultrasound scan of inflammed appendix that appears enlarged and surrounded by fluid. Page 4 of 38

5 Background Abdominal pain is a common cause of presentation in the Pediatric Emergency Department. Ultrasound is the first line imaging method to evaluate abdominal pain. The most fraquent causes of presentation in Pediatric Emergency Department are listed below: Cry Vomiting Intestinal occlusion, sub-occlusion, diarrhea Abdominal pain, pelvic pain Fever Palpable mass Trauma Foreign bodies or substances ingestion Articular pain The aetiology of acute abdomen in pediatric population depends on the age. In newborns: acute gastroenteritis intestinal occlusion (es: congenital megacolon) intussusception incarcerated hinguinal hernia torsion of spermatic funicle acute appendicitis (rare) 2-6 years old children: acute gastroenteritis constipation urinary infections trauma acute appendicitis pneumonia mesenteric adenitis >6 years-old: acute gastroenteritis Page 5 of 38

6 constipation recurrent abdominal pain syndrome trauma acute appendicitis urinary infections mesenteric adenitis. Less frequent causes of acute abdominal pain in children aged 2-6: Meckel's diverticulitis Fig. 2 on page 6 Schonlein Henoch purpura intestinal intussusception Fig. 3 on page 7 nephrolithiasis uremic hemolytic syndrome tumours (Wilm's tumour; neuroblastoma) hepatitis diabetic ketoacidosis In children >6 years-old: pneumonia Chron's disease Fig. 4 on page 8 ulcerative colitis peptic ulcer cholecystitis pancreatic disorders diabetic ketoacidosis torsion of ovarian cysts pregnancy In children the localization of abdominal pain is not indicative of a specific pathology as in the adults. In fact, young patients usually refer the pain in the center of the abdomen. [1,2] Images for this section: Page 6 of 38

7 Fig. 2: Meckel's diverticulitis. Page 7 of 38

8 Fig. 3: Large lymphadenopathy (arrow in a) in a patients with a double intestinal intussusception (arrows in b). Page 8 of 38

9 Fig. 4: Chron's ileitis. Page 9 of 38

10 Imaging findings OR Procedure details GASTROINTESTINAL TRACT PATHOLOGIES Necrotizing enterocolitis (NEC) Necrotizing enterocolitis is a serious abdominal disorder of premature neonates; it usually affects the terminal ileum and ascending colon. Clynical symptoms include abdominal distension, hematochezia, apnea, acidosis, temperature instability, lethargy. Diagnosis is usually made on the basis of abdominal radiographs showing pneumatosis, a thick-walled bowel, free air and portal venous air. Sonography may be useful when perforation and abscess formation are suspected. Mural thickening of the terminal ileum and ascending colon may be shown. Free intrabdominal fluid containing echogenic debris or a loculated right lower quadrant mass suggests perforation and abscess formation. Intramural gas (Fig. 5 on page 16) is an early sign that may precede clinical signs. Although abdominal US can depict intraluminal bowel gas, it does not display the pattern of gaseous distention as well as plain abdominal radiography. The commonest cause of portal venous gas in neonates is the passage of small amounts of gas through an umbilical venous catheter in the absence of NEC. In NEC, portal venous gas is an extension of intramural gas that enters the veins of the bowel wall and passes into the portal venous system. Portal venous gas has been reported on plain abdominal radiographs in up to 30% of neonates with NEC and these are usually, but not always, the more severely affected cases. Portal venous gas is not always associated with a fatal outcome.[3] Congenital intestinal obstruction Congenital intestinal obstruction is the most common condition producing a distended and tender abdomen in an irritable neonate. Diagnosis of obstruction is usually made by plain radiographs and contrast studies. Sonography can show free fluid, bowel distension, thickened bowel wall, iperperistaltism or absence of peristalsis. Fig. 6 on page Hypertrophic pyloric stenosis Premature infants tend to present at 3-6 weeks from birth. Hypertrophic pyloric stenosis is rarely seen in children older than 6 months. Clinical presentation is characterized by nonbilious projectile vomiting and dehydration (with hypochloremic metabolic alkalosis). In hypertrophic pyloric stenosis, the circular muscle layer becomes thickened, which narrows the pyloric channel and elongates the pylorus. Page 10 of 38

11 Normal pylorus. Fig. 7 on page 18 The first and most important step in patient workup of suspected hypertrophic pyloric stenosis is a thorough physical examination. If the clinical suspicion for hypertrophic pyloric stenosis is moderate to high, ultrasonography is also recommended. Ultrasound specific signs of Hypertrophic pyloric stenosis are: 1) elongation of the pyloric channel: DL > 17mm (range 15-20mm) 2) Antero-posterior diameter of the pylorus > 12mm 3) Thickness: >2mm (range 2.5-4mm) Fig. 8 on page 18 Indirect signs of Hypertrophic pyloric stenosis: - gastric distension - gastric hyperperistaltism - alteration of gastric peristalsis + gastroesophageous reflux. - shoulder sign - beak sign - double track sign The shoulder sign is seen during barium examination and refers to the bulging of the hypertrophied pyloric muscle into the lumen of the antrum. The "beak" sign is peak of barium entering the narrowed pyloric channel. Cohen HL et al. performed a fluid aided real-time ultrasound examination of 10 cases of hypertrophic pyloric stenosis, showing the ultrasound equivalent of the "double track" sign. This finding is the result of pyloric fluid compressed into smaller tracks as it is impinged upon circumferentially by the thickened circular muscle. This sign, previously seen in barium studies, although nonspecific, may prove to be a sensitive ultraound diagnostic criterion. Fig. 9 on page 20 Fig. 10 on page 20 A negative ultrasonogram often leads to a upper gastrointestinal study (UGI study) to rule out other diagnoses that a focused ultrasonographic evaluation does not detect. This study more effectively rules out other problems, such as malrotation and gastroesophageous reflux.[4] Page 11 of 38

12 Intestinal intussusception M>F; peak age between 3 and 9 months. Intussusception occurs when a portion of the digestive tract becomes telescoped into the adjacent bowel segment. The traditional diagnostic approach to childhood intussuscption of plain radiography and enema examination is being changed to plain radiography and ultrasonography at some istitutions. The classification of this condition depends on the gastrointestinal tract involved: Colo-colic Ileo-cecal (the most frequent in children) Ileo-ileal Ileo-cecal-colic Intussusception is usually idiopathic in the first year of age; in the olders it recognizes a lot of different causes (appendicitis, lymphoma, Meckel's diverticulum, celiachia, gastronintestinal duplication cyst, etc). On cross section the usual sonographic image is a "target" or "doughtnut" appearance; the longitudinal appearance is that of a pseudokidney characteristic of thickened bowel. Other ultrasound signs suggestive of intussusception are: double ring sign at Dolor doppler US, large adenopathies, free fluid, bowel distention. Fig. 11 on page 21 Fig. 12 on page 22 In some cases, if the onset of intussusception is recent and blood is absent in the fecies, it is possible try to resolve the pathology during the ultrasound examination. Indicators of ischemia and irreducibility are trapped fluid at US and absence of blood flow at Doppler imaging. In our institution we usually perform sonographically-guided hydrostatic reduction by contrast enema. Fig. 13 on page 23 The aim of enema therapy is to reduce the greatest number of intussusceptions without producing perforation. Barium, water-soluble contrast media, water, electrolyte solutions, or air may be used with radiographic or US guidance.[5] Acute appendicitis It represents 80% of surgical pediatric emergencies. Clinical presentation could be unusual, expecially in the youngers. For this reason it could be discovered in the late stage when an abscess or diffuse peritonitis is present. Page 12 of 38

13 Clinical signs of acute appendicitis are: abdominal pain, fever, elevated WBC, nausea, leg pain, lower right thoracic pain, etc. At ultrasonography the appendix appears enlarged, thickned, with endoluminal fluid and/ or appendicolith; other US findings are hyperechoic mesentery, lymphadenopathies, free fluid, abscess. Fig. 14 on page 23 Fig. 15 on page 24 Fig. 16 on page 25 Doppler examination can show an increase of vascularity of the appendiceal wall in the first stage and loss of vascularity in the late stage. Failure to identify the appendix by ultrasound or identification of a normal appendix less than 6 mm in diameter, makes the diagnosis of appendicitis very unlikely. Differential diagnoses in patients with suspected appendicitis are Chron's disease Fig. 4 on page 34, ovarian pathologies, mesenteric adenitis, nephrolitiasis and Meckel's diverticulitis Fig. 2 on page 35.[3,6,7] Mesenteric adenitis It can mimick appendicitis because it causes abdominal pain, fever and elevated WBC. Mesenteric adenitis is classified as primary or secondary depending on wether an identifiable inflammatory process can be found (secondary) or not (primary).[7] Ultrasound examination shows several enlarged nodes in the mesentery. Fig. 17 on page 25 Omental torsion Omental torsion is a rare cause of acute abdominal pain, and clinically mimics acute appendicitis. Torsion of the omentum is a condition wherein the organ twists along its long axis to such an extent that its vascularity is compromised. Although omental torsion is rarely diagnosed preoperatively, knowledge of the entity is important to the surgeon because it mimics the common causes of acute surgical abdomen.[8,9] Fig. 18 on page 26 Other causes of gastrointestinal pain Fig. 19 on page 27 Small intestine duplication Page 13 of 38

14 In 1937, Ladd introduced the term duplication of the alimentary tract. This condition consists of a group of congenital anomalies with the following 3 characteristics: A well-developed coat of smooth muscle is present. The epithelial lining represents some portion of the alimentary tract. Duplications are frequently intimately attached to some portion of the gastrointestinal tract. Clinical presentation depends on the type, size, location, and mucosal lining of the duplication. Cystic duplications of the small intestine can be anchor points for intussusception or can result in volvulus, whereas long tubular duplications with proximal communication drain poorly, and retention of intestinal contents can obstruct adjacent intestine. Distal communication is more common and is more difficult to diagnose than proximal communication. The diagnosis is often not established before surgery. Fig. 20 on page 27 URINARY TRACT PATHOLOGIES Acute dilatation of the renal pelvis can produce abdominal pain, particularly in younger children; in some of these the pain may be appreciated as midline in the abdomen. Obstruction is usually at the ureteropelvic junction. Pyelonephritis with distension of the renal capsule can produce similar pain. In most children, pain is localized at the groin or flank. Clinical signs of urinary tract disorders are: dysuria, fever, abdominal pain, haematuria, pyuria, etc. Ultrasound can show hydronephrosis and its degree, stones, thickened bladder walls, alteration of urine echogenicity. Fig. 21 on page 28 Pyourachus Infected urachal remnant can represent a cause of right lower quadrant pain. The urachus is an embryonic remnant resulting from the involution of the allantoic duct and the ventral cloaca. An urachal cyst develops if the urachus remains patent between the umbilicus and the bladder. Infection of such cysts occur more commonly in adults and only occasionally in children. Infected urachal cysts usually present with lower abdominal pain, fever, midline hypogastric tenderness, palpable mass and evidence of urinary infection. Page 14 of 38

15 The preferred imaging method for the diagnosis of urachal cyst is ultrasound, which will show a midline cyst between the umbilicus and the bladder; in cases of sovrainfection (pyourachus) ultrasound will demonstrate wall thickening, internal debris and complex echogenicity.[10] Fig. 22 on page 29 Fig. 23 on page 30 GYNECOLOGIC DISORDERS Common gynecologic diseases in the pediatric population that can present with lower quadrant pain include surgical emergencies such as ovarian torsion, ovarian tumors and hemorrhagic ovarian cysts. Imperforate hymen is a rare congenital anomaly which emergency physicians often forget to include in the differential diagnosis of lower abdominal pain in a pubescent girl. These patients often remain asymptomatic until puberty and present in early adolescence with cyclic abdominal pain and ultrasonographic evidence of a pelvic mass (haematometrocolpos, haematocolpos). Neonatal hydrometrocolpos is a rare condition that follows congenital vaginal obstruction. Association with urinary obstruction and upper tract dilatation has been reported in some cases. Obstruction of the gastrointestinal tract without a coexisting bowel anomaly can also occur, but this is very rare. In some cases, preoperative diagnosis may be difficult. Ovarian torsion Ovarian torsion results from rotation of the ovary on its pedicle, producing vascular congestion and ultimately hemorrhagic infarction. In may occur in the presence of a cyst Fig. 24 on page 31 or tumor or in a normal adnexum. The twisted ovary appears sonographically enlarged and hypoechoic. Color doppler US demonstrates the absence of blood flow in the ovary. Ovarian cysts Ovarian cysts may produce pain seconday to pressure on adjacent structures, hemorrhage or torsion. Hemorrhagic cysts usually are complex masses with internal echoes, septations or fluid-debris levels. Fig. 25 on page 31 [7] Neonatal Hydrometrocolpos It is characterised by an expanded fluid filled vaginal cavity with associated distention of the uterine cavity. It may present in infancy with a lower abdominal mass, or be delayed till menarche. Page 15 of 38

16 It is caused by the influence of the mother's hormone stimulation. It occurs in presence of imperforated hymen (most common), vaginal stenosis, lower vaginal atresia, cervical stenosis. Fig. 26 on page 31 The clinical features of hydrometrocolpos in the newborn are dominated by the abdominal mass with regional compression. Compression of the lower urinary tract has been reported to cause hydronephrosis, but compression of the gastrointestinal tract with obstruction to the passage of meconium is rare.[11] Haematometrocolpos/haematocolpos It refers to a blood filled distended uterus and vagina. It occurs in presence of an imperforated hymen, vaginal stenosis or vaginal atresia. The 5 estimated incidence in teenagers is at ~ 1 in If large enough it can cause obstruction of regional lymph drainage or obstructive hydronephrosis. Fig. 27 on page 32 Fig. 28 on page 32 REFERRED PAIN Some extra-abdominal pathologies, including diseases of the spine and chest, and metabolic disorders such as sickle cell anemia may appear as an acute abdomen. This conditions should be suspected if abdominal imaging findings are negative. Pneumonia of the lower lobes may occasionally be diagnosed during the abdominal ultrasound examination. Fig. 29 on page 33 Images for this section: Page 16 of 38

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18 Fig. 5: Necrotizing enterocolitis (NEC). Note the presence of intraluminal bowel gas. Although abdominal US can depict intraluminal bowel gas, it does not display the pattern of gaseous distention as well as plain abdominal radiography. Fig. 7: Normal pylorus. Page 18 of 38

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20 Fig. 8: Hypertrophic pyloric stenosis. Longitudinal ultrasonogram of the pylorus in a patient with surgically proven hypertrophic pyloric stenosis shows the thickened, circular muscle, the elongated pylorus and narrowed pyloric channel. Transverse ultrasonographic image demonstrates the target sign and heterogeneous echo texture of the muscular layer. Fig. 9: Direct and indirect signs of hypetrophic pyloric stenosis. Page 20 of 38

21 Fig. 10: Gastroesophageal reflux in a patient with hypertrophic pyloric stenosis. Page 21 of 38

22 Fig. 11: An ultrasound showing target sign which is a characteristic finding for intussusception on ultrasound. Page 22 of 38

23 Fig. 12: Intussusception associated to the presence of large lymphadenopathies. Fig. 13: Intussusception: Sonographically-guided hydrostatic reduction by contrast enema. Page 23 of 38

24 Fig. 14: Acute appendicitis; different cases. Note the presence of an appendicolith (a "stone" made of feces within the lumen of appendix) in the first case on the left. Page 24 of 38

25 Fig. 15: A 9-years-old boy presented with symptoms and signs suggestive of appendicitis. The ultrasound examination of abdomen showed a large, inhomogeneous fluid collection (arrows) in the right lower abdominal quadrant. Note the fluid imbibition of the surrounding visceral fat (asterisks). An appendicular abscess was found at surgery. Fig. 16: Transverse (a) and longitudinal (b) ultrasonographic pelvic scans showing a large hyperechoic collection in the Douglas pouch: an appendicular abscess was found at surgery. Page 25 of 38

26 Fig. 17: Mesenteric adenitis. Transverse sonogram shows several hypoechoic lymph nodes in mesentery. Page 26 of 38

27 Fig. 18: A 10-years-old boy presented with symptoms and signs suggestive of appendicitis. The ultrasound examination of abdomen showed hyperechoic intraabdominal fat (arrows in a) associated to the presence of intraperitoneal fluid (arrow in b). The appendix could not be visualized. Surgery revealed torsion of a segment of the greater omentum. A segmental omentectomy was done. Fig. 19: Other causes of acute abdomen of gastrointestinal origin. Page 27 of 38

28 Fig. 20: Intestinal duplication. Page 28 of 38

29 Fig. 21: Abdominal pain of genito-urinary origin. Different aetiologies. Page 29 of 38

30 Fig. 22: Pyourachus. Note a focal, ill defined, hypoechoic collection along the anterosuperior aspect of the bladder. Page 30 of 38

31 Fig. 23: Pyourachus. Transverse pelvic scans showing a well defined hypoechoic collection (red arrow in a; calipers in b) indenting the bladder (yellow arrow in a) dome. Fig. 24: Ovaric torsion. Fig. 25: Complex ovarian cystic mass (yellow calipers) in a 12 years old girl with acute lower abdominal pain. The laparoscopic diagnosis was hemorrhagic cyst. Page 31 of 38

32 Fig. 26: Neonatal hydrometrocolpos. Fig. 27: Haematocolpos. Note a distended midline echogenic tubular stucture between the bladder and the rectum. It is a vaginal distension with uterine dislocation. Page 32 of 38

33 Fig. 28: Two cases of haematocolpos. Page 33 of 38

34 Fig. 29: Pneumonia (red arrows) and pleural effusion (yellow arrow) in a 8-year old patient with flank pain. Page 34 of 38

35 Fig. 4: Chron's ileitis. Page 35 of 38

36 Fig. 2: Meckel's diverticulitis. Page 36 of 38

37 Conclusion In the different age groups of children admitted to the pediatric ED, acute abdomen recognizes various etiologies. The most common causes of acute abdominal pain in the newborn babies are hypertrophic pyloric stenosis and intussusception. In the younger children intussusception, appendicitis and mesenteric adenitis. In the older children inflammatory bowel disease and ovarian pathology are also included. Ultrasound is an optimal diagnostic tool in the evaluation of children with acute abdomen allowing, in most cases, the visualization of the direct cause. Even when the underlying pathology is not identified, Ultrasound will show indirect signs that indicate the need of a surgical exploration or of further investigations. References 1. Il dolore addominale acuto Gestione al Pronto Soccorso Rivista di Emergenza ed urgenza pediatrica Anno 3 - n. 1 - december january Il dolore addominale acuto Gestione al Pronto Soccorso Rivista di Emergenza ed urgenza pediatrica Anno 3 - n. 1 - december january Imaging of the acute abdomen in infants and children. E.A. Franken Jr, Simon C.S., et al. AJR: 153, November Ultrasonic "double track" sign in hypertrophic pyloric stenosis. Cohen HL et al. J Ultrasound Med 1987 Mar;6(3): Intussusception in children: current concepts in diagnosos and enema reduction. del Pozo G. et al Radiographics 1999; 19: Clinical and Imaging mimickers of acute appendicitis in the Pediatric Population. Sung T. et al. AJR: 186, January Color doppler US of children with acute lower abdominal pain. Quillin S.P., Siegel M.J.. Radiographics 1993; 13: A case report of idiopathic omental infarction in an obese child. Tsunoda T. et al. Case Reports in pediatrics Omental torsion. Paresh J. et al. J Indian Assoc Pediatr Surg Oct-Dec; 13(4): Pyourachus: study of two cases. R.B. Thapar et al. The British Journal of Radiology, 79 (2006), e1-e Hydrometrocolpos from a low vaginal atresia: An uncommon cause of neonatal intestinal and urinary obstruction. Ezenke S et al. African journal of pediatric surgery. 2008; 5(1): Page 37 of 38

38 Personal Information V. Miele, G. L. Buquicchio, V. Di Giacomo, I. Di Giampietro, S. Ianniello, G Menichini, B. Sessa, M. Trinci ; Roma/IT, Rome/IT, Roma, ITALY/IT Mail to: Dr.ssa Vincenza Di Giacomo (enzadigiacomo1983@hotmail.it) Page 38 of 38