Fig. 30.1
Pneumonia masquerading as abdominal pain in a 7-year-old girl. (a) US of the left upper quadrant, above the diaphragm; hypoventilation of the left lung basis with pleural effusion suggesting pneumonia. (b) Chest radiograph confirms a massive pleuro-pneumopathy
On the other hand, a diaphragmatic paralysis and lower lobes hypoventilation (Fig. 30.2a) may be induced by sub-diaphragmatic abscesses following perforation of a retro-hepatic appendicitis (Fig. 30.2) or as a sub-diaphragmatic complication of a pancreatitis. Therefore, in ambiguous cases, an US of the diaphragm or CT in ambiguous cases (Fig. 30.2b) should be performed to search for sub-diaphragmatic collections and establish their origin [2].
Fig. 30.2
Sub-diaphragmatic abscess masquerading as right pleuro-pneumopathy in a 2-year-old boy. (a) Chest radiograph demonstrates hypoventilation and pleural effusion of the right basis. A small air bubble is superimposed to the liver. (b) CE-CT—Reformatted frontal view (US had shown a perihepatic heterogeneous mass suggesting an abscess) confirms the perihepatic abscess and shows the perforated appendix with an air bubble below the liver (arrows)
Furthermore, intrathoracic hernia of abdominal organs may determine thoracic and/or abdominal symptoms (see below).
30.3 The Relation Between Abdominal and Musculoskeletal Diseases
A psoas abscess is a typical disease where symptoms may mimic abdominal disease; clearly, a right psoas abscess may mimic an appendicitis. Psoas abscesses are rare in children and therefore rarely considered. They are mainly encountered in two age groups. A first peak is observed in neonates or infants where it can be isolated or combined with a septic arthritis (entity beyond the scope of this chapter) [3, 4]. A second peak is observed in adolescents (and adults) where it usually develops by contiguous spread from a diseased gastrointestinal tract most frequently involved by Crohn disease (see also Chap. 12). In case of isolated ilio-psoas abscess, US will demonstrate a collection (Fig. 30.3a) and raise the suspicion of an abscess but the technique will not be able to define the exact location and extent. In some cases, the technique will be able to demonstrate the close relation (and fistula) between the psoas and the diseased small bowel segment. The abscess as well as the surrounding digestive anomalies will be better evaluated by musculoskeletal MR imaging (Fig. 30.3b) and MR-enterography sequences. Whenever MR imaging is not available, a CT with and without contrast enhancement is also able to accurately define the anomalies and demonstrate the musculoskeletal involvement, the abscess as well as the associated digestive tract anomalies [5, 6].
Fig. 30.3
Psoas-iliac abscess in a 2-year-old girl with acute abdominal symptoms (its origin could not be defined). (a) US—Sagittal scan of the left flank demonstrates a large oblong hypoechoic mass. The technique was not able to define its exact location. (b) MR imaging T2-weighted sequence—Frontal view—Inverted pyramidal collection below the left kidney with inflammatory reaction in the right hip area. The mass displaces the bladder to the right. (c) MR imaging T2-weighted sequence—parasagittal view. The collection is clearly located within the psoas-iliac muscle. There is an inflammatory reaction extending to the abdominal wall anteriorly and to the left hip muscles
Finally, psoas abscesses may also develop as a result from spondylodiscitis (especially from tuberculous infection) that may present with abdominal symptoms probably due to secondary peritoneal inflammation [7].
The treatment of the psoas abscess will depend upon its size, its nature (bacteria vs mycobacteria), and symptoms induced. Antibiotherapy and abscess drainage under imaging guidance can first be attempted. Surgery will be reserved to recurrence or to cases with unfavorable evolution.
Finally, spinal surgery can induce a postoperative ileus. This ileus may rarely reveal related acute pancreatitis [8].
30.4 Hernias
Hernias may develop in various parts within and at the limits of the peritoneal cavity, their origin may be congenital or acquired (see also Chap. 14). Some will be silent while others will present with acute symptoms. The use of imaging will be adapted to the type of hernia and its complications.
30.4.1 Hernias Through the Diaphragmatic Openings
There are variable openings through the diaphragm that may lead to intrathoracic hernia of abdominal viscera with potential acute abdominal symptoms.
30.4.1.1 Diaphragmatic Hernia
Congenital diaphragmatic hernia through the posterior Bochdalek orifice is the commonest type. This particular hernia is amenable to antenatal diagnosis and postnatal management. Postnatally, symptoms are mainly related to lung hypoplasia and pulmonary hypertension. This malformation is beyond the scope of the present book [9].
30.4.1.2 Hiatal Hernia (See Also Chaps. 5 and 7)
A hiatal hernia corresponds to the herniation through the esophageal orifice into the mediastinum of the esophagogastric junction including a part or with the entire stomach. Very rarely other organs (liver, colon, etc.) may be included in the hernia.
There are three types of hernias: sliding hernia, paraesophageal hernia, or hernia associated with a congenital short esophagus. Hiatal hernias may be congenital or acquired. They most often determine mild to moderate symptoms related to gastroesophageal reflux and potentially failure to thrive. More dramatic symptoms such as acute vomiting may occur following an organo-axial volvulus of the herniated stomach with obstruction of the upper digestive tract. Cautious upper GI opacification with diluted barium can be performed to define the precise anatomy and the site of obstruction [9–11].
The treatment is surgical.
30.4.1.3 Hernia through the Foramen of Morgagni (Also Named Larey)
The foramens of Morgagni (or Larey) are located anteriorly. They extend from the sternum medially towards the 8th rib laterally. The hernia is right sided in 90% of cases. It can be bilateral. The colon is the commonest organ herniated (Fig. 30.4); small bowel loops, the spleen, the liver, and the omentum can be herniated as well. The hernia can cause chronic respiratory symptoms and in rare cases abdominal acute symptoms due to intestinal (sub)obstruction [12, 13].
