Eur. Radiol. 9, 1672±1674 (1999) Ó Springer-Verlag 1999

European Radiology

Pediatric radiology

Case report CT diagnosis of delayed presentation of congenital diaphragmatic hernia simulating massive pleuropneumonia G. Gayer1, R. Bilik2, A. Vardi3 1

Department of Diagnostic Imaging, Chaim Sheba Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, IL-52621 Tel Hashomer, Israel 2 Department of Pediatric Surgery, Chaim Sheba Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, IL-52621 Tel Hashomer, Israel 3 Pediatric Intensive Care Unit, Chaim Sheba Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, IL-52621 Tel Hashomer, Israel Received: 17 June 1998; Revision received: 8 September 1998; Accepted: 17 November 1998

Abstract. A case of an 11-month-old infant with a delayed presentation of congenital diaphragmatic hernia is reported. Incarceration of the herniated colon caused a misleading appearance on the chest X-ray which was interpreted as massive pleuropneumonia. Computed tomography, performed because of continuing deterioration in the clinical condition, showed fluid-filled bowel loops in the chest and dilated bowel loops with air±fluid levels in the abdomen, suggesting the correct diagnosis. Key words: Congenital diaphragmatic hernia ± Delayed presentation ± CT

Introduction Congenital diaphragmatic hernia (CDH) presents most commonly in the newborn period with severe respiratory distress [1].The classical features on chest X-ray are intrathoracic gas-filled loops of bowel with contralateral shift of the mediastinum. Rarely CDH presents after the neonatal period. It may then show features similar to those seen in the neonatal period, in which case CDH should be included in the differential diagnosis [2, 3, 4, 5, 6]. The diagnosis may be difficult, however, when herniated bowel becomes incarcerated and obstructed. Fluid-filled bowel loops will then appear as an opacity in the lower part of the affected hemithorax, mimicking a lung consolidation. We report on an 11-month-old male infant with delayed presentation of congenital diaphragmatic hernia complicated by incarceration of the left colon. This was not suspected on serial chest X-rays but correctly diagnosed by intravenously contrast-enhanced computed tomography. An emergency laparotomy confirmed the diagnosis. Correspondence to: G. Gayer

Case report An 11-month-old healthy infant was hospitalized for recurrent vomiting and lethargy. Previous medical history was unremarkable, other than several episodes of mild respiratory distress that were diagnosed as wheezy bronchitis and treated with inhalations. Three days prior to the present admission, the infant developed cough and fever and was treated with erythromycin, salbutamol, and betamethasone. A chest X-ray on admission showed a small opacity in the left lower lung base contiguous with the diaphragm and with a convex border and a small pleural effusion (Fig. 1). This was presumed to be pneumonia and treated with IV ceftriaxone. There was no clinical improvement and a chest radiograph the following day showed a completely opacified left hemithorax and a mediastinal shift to the right (Fig. 2). Transthoracic US revealed a large amount of fluid with ªseptations.º A chest tube drained approximately 200 cc of serosanguinous fluid under pressure and an additional 180 cc over the next 12 h. Although the patient was less dyspneic, a repeat chest film showed no improvement. Therefore, a contrast-enhanced CT study of the chest was performed. Scans at the level of the heart showed dilated fluid-filled bowel loops with bowel wall enhancement, containing no air, atelectasis of the left lower lobe, and mediastinal shift to the right (Fig. 3). Scans at the level of the kidneys also showed dilated bowel loops containing air±fluid levels with some enhancement of slightly thickened bowel wall (Fig. 4). These findings suggested the presence of an incarcerated congenital diaphragmatic hernia causing bowel obstruction, but preserved bowel perfusion. A repeat US examination again showed thick ªseptaº surrounded by fluid, but no peristalsis. After consultation with the pediatrician and the pediatric surgeon, it was decided to proceed with gastrointestinal studies because both were in doubt as to the diagnosis of a late-presenting congenital diaphragmatic hernia. A plain abdominal film was not performed. An upper gastrointestinal tract

G. Gayer et al.: CT diagnosis of delayed presentation of congenital diaphragmatic hernia

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Fig. 1. Chest X-ray on admission shows a small opacity with a convex border in the left lung base and obliteration of the left costophrenic angle due to some pleural effusion

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study was normal, but a subsequent barium enema showed complete obstruction at the level of the left colonic flexure. At laparotomy the left colonic flexure was found to be herniated and incarcerated in the left hemithorax. The colon was reduced into the abdominal cavity and the diaphragmatic defect closed. Recovery was uneventful. Discussion This patient presented some of the problems that may be encountered in a late-appearing CDH. Such delayed herniation through a congenital defect has been postulated to occur when there is increased abdominal pressure from causes such as vomiting and bowel distention [3]. The infant described may indeed have had an upper respiratory infection and the cough may have caused the herniation of the bowel through the congenital defect. The radiographic pattern on the chest X-ray in infants with late presentation is variable. If the herniated bowel loops contain air, thin-walled round translucencies in the affected hemithorax will be seen, as well as a contralateral mediastinal shift, as in the neonatal period. If the herniated bowel loops become fluid filled, as when incarceration and obstruction occur, a dense opacification is observed [5]. In such a case lung consolidation would be the main consideration. This may lead to inappropriate therapy, as happened in our patient. There was no suspicion of bowel obstruction and therefore a plain film of the abdomen was not performed. The assumed diagnosis of pleuropneumonia was based

Fig. 2. Chest X-ray 1 day later: There is now a massive opacity of the left hemithorax and a mediastinal shift to the right Fig. 3. Intravenously contrast-enhanced CT scan at the level of the heart shows tubular fluid-filled structures, with slight enhancement of their walls representing incarcerated bowel loops. There is secondary total atelectasis of the left lower lobe and a marked mediastinal shift to the right Fig. 4. Contrast-enhanced CT scan of the upper abdomen shows similar tubular structures with slightly enhanced walls, some of which contain air±fluid levels, representing obstructed bowel loops

on the combination of clinical symptoms and misinterpretation of the serial chest X-rays, the thoracic US, and the significance of the serosanguineous pleural effusion. The most common causes for the latter in children are pneumonia and inflammatory conditions of the abdomen or mediastinum. Less commonly it is found in association with mesenchymal diseases such as lupus erythematosus, periarteritis, and rheumatic fever [7]. Gaisie et al. reported a case of CDH in which strangulation and necrosis of the herniated bowel occurred with subsequent serosanguineous pleural effusion [5]. Although the value of US in diagnosing delayed presentation of CDH has been described [8], in our case US did not contribute to the diagnosis, possibly due to inexperience of the performing radiologist or because pleuropneumonia with empyema was the working diagnosis at the time. Computed tomography, however, showed clearly that the lung ªopacityº consisted of grossly dilated fluid-filled bowel loops. The presence of dilated intra-abdominal bowel loops with air±fluid levels further supported the diagnosis of entrapped and fluid-filled bowel loops in the incarcerated diaphragmatic hernia with mechanical bowel obstruction. As small bowel hernias occur more frequently than colonic hernias [5, 8], an upper gastrointestinal tract study was performed first and, because it was normal, a barium enema was added. This proved the evidence of obstructed colon in an incarcerated diaphragmatic hernia. We found only two case reports in which CT of the chest was performed during the investigation of an infant with a late-presenting CDH [8, 9]. In both infants rounded structures were seen in the left hemithorax in

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addition to a left pleural effusion. In one of them the importance of a curvilinear fat stripe, probably representing mesenteric fat between dilated loops of bowel in a fluid-filled hemithorax, was stressed as an important diagnostic point [9]. In that case the correct diagnosis was reached only upon review of the chest X-ray and the CT scans when the child's condition further deteriorated. There is often a dangerous delay in the clinical diagnosis because the presence of a previously normal chest radiograph leads to confusion. In a large series of 26 patients with CDH presenting over the age of 8 weeks, in 5 patients a previous chest X-ray was available and normal. In 15 of the 26 patients the radiological assessment on presentation was incorrect and two previously healthy children died due to cardiorespiratory arrest [2]. In our case the diagnosis was also delayed for 3 days during which he was unsuccessfully treated for suspected pleuropneumonia. We conclude that although rare, delayed presentation of CDH is a considerable diagnostic challenge with a potentially fatal outcome. In all children with a lung opacity on chest X-ray, which does not resolve with therapy, the diagnosis of CDH with incarcerated bowel, stomach, herniated spleen, or omentum should be included in the differential diagnosis. Computed tomography allows identification of the opacification as a diaphragmatic hernia and helps to characterize hernial content and to assess bowel perfusion; therefore, CT is

the modality of choice in all cases that cannot be solved by plain film and/or US. References 1. Carty H, Donoghue V (1994) The gastrointestinal tract. In: Carty H, Brunelle F, Shaw D, Kendall B (eds) Imaging children. Churchill Livingstone, Edinburgh, pp 250±485 2. Berman L, Stringer DA, Ein S, Shandling B (1988) Childhood diaphragmatic hernias presenting after the neonatal period. Clin Radiol 39: 237±244 3. Fotter R, Schimpl G, Sorantin E, Fritz K, Landler U (1992) Delayed presentation of congenital diaphragmatic hernia. Pediatr Radiol 22: 187±191 4. Saifuddin A, Arthur RJ (1993) Congenital diaphragmatic hernia: a review of pre- and postoperative chest radiology. Clin Radiol 47: 104±110 5. Gaisie G, Young LW, Oh KS (1983) Late-onset Bochdalek's hernia with obstruction: radiographic spectrum of presentation. Clin Radiol 34: 267±270 6. Schimpl G, Fotter R, Sauer H (1993) Congenital diaphragmatic hernia presenting after the newborn period. Eur J Pediatr 152: 765±768 7. Stern RC (1992) The respiratory system. In: Behrman (ed) Nelson textbook of pediatrics. Saunders, Philadelphia, pp 1035±1123 8. Betremieux P, Debadie A, Chapuis M, Pladys P, Treguier C, Fremond B, Lefrancois C (1995) Late presenting Bochdalek hernia containing colon: Misdiagnosis risk. Eur J Pediatr Surg 5: 113±115 9. Buxi TBS, Pruthi PK, Dutta T (1991) CT diagnosis of strangulated diaphragmatic hernia. Pediatr Radiol 21: 527±528