Bronchiolitis is an inflammation of the bronchioles, often seen in young children with viral respiratory infections. Although the most common radiographic finding of bronchiolitis is a normal chest radiograph, patients may also present with pulmonary hyperinflation, peribronchial thickening, and discoid atelectasis. Care should be made not to mistake an underinflation artifact with peribronchial thickening related to bronchiolitis. Alternatively, when the heart is enlarged, care should be made not to confuse pulmonary vascular congestion related to congenital heart disease with peribronchial thickening related to bronchiolitis. The utility of the chest radiograph in the evaluation of bronchiolitis is to rule out related complicating features, including superimposed pneumonia, atelectasis, and pneumothorax/pneumomediastinum. Chest x-ray may also help to rule out other causes of wheezing such as a foreign body aspiration.
Bronchiolitis patients are often neonates to 2-year-olds and present with tachypnea, wheezing, hypoxia, copious rhinorrhea, and in more severe cases respiratory distress. Common pathogens of bronchiolitis include respiratory syncitial virus (RSV), influenza, parainfluenza, human metapneumovirus, and many other viruses. Patients who are less than one month old, born prematurely and are less than 48 weeks post-conceptual age, and those with co-morbid conditions are at risk of developing apnea. Days 3-5 are usually the most severe of the illness in regards to respiratory distress. Dehydration is a common finding in this time period as younger patients have difficulty swallowing when their respiratory rates get above 60. Treatment of bronchiolitis is ever changing but beta agonist and steroids have generally not been shown to be helpful. Criteria for discharge should include adequate hydration status, oxygenation saturations above 90%, and close follow-up within 24 hours.
The chest radiograph is primarily used in bronchiolitis to rule out complicating factors such as foreign body aspiration and pneumonia.
Consideration should be given to whether the patient could have congenital heart disease when there is an enlarged cardiac silhouette on chest radiograph.
Figure 12.5 ▪ Pneumomediastinum.
AP radiograph of the chest demonstrates complications of bronchiolitis with pneumomediastinum. Note elevation of the thymus (arrowheads) and pneumopericardium (arrow). The presence of subcutaneous air in the soft tissues of the neck (arrow,*) is related to pneumomediastinum.
Fractures specific for child abuse include classic metaphyseal fractures in the extremities and posterior rib fractures. Alternative names for the classic metaphyseal fracture of child abuse include corner fracture and metaphyseal bucket handle fracture. Without a history of major accidental trauma such as an auto accident, child abuse should also be suspected if there are fractures of the sternum, scapula, posterior element fractures of the spine, and fractures of the femur in a child not walking. However, any fracture may be a result of abuse and must be correlated with the history provided.
Where there is a possibility of child abuse, the age of the child and physical exam findings can help drive what radiologic tests should be performed. In the child less than a year of age with any fracture and an unclear or concerning history, a full skeletal survey and head CT should be performed. This allows not only an opportunity to identify acute fractures but also old healing fractures indicative of abuse. Healing fractures can further concerns for child abuse or suggest medical problems simulating abuse. For the younger patient, particular attention should be paid to radiographs of the chest looking for rib fractures and to the long bone metaphyses looking for classic metaphyseal lesions. In addition to radiographic examinations, an ophthalmologist should perform fundoscopic examination looking for retinal hemorrhages. In any case where there is suspected abuse, the local child protection services agency must be notified by law for an investigation to be completed.
Posterior rib fractures and multiple healing fractures are highly concerning for child abuse.
When there is concern for abuse in the young child, a full skeletal survey and noncontrasted head CT should be performed.
Figure 12.9 ▪ Bilateral Subdural Hematomas.
Axial T2-weighted MRI in another patient demonstrates bilateral subdural hematomas. The image shows blood products of differing ages being hyperintense (arrowheads), isointense (*), and hypointense relative to brain tissue with a blood-fluid level seen (arrow), a finding highly suggestive of child abuse. The hyperintense component indicates chronic subdural, with areas of iso and hypointensity indicating acute and subacute hemorrhage into the chronic collections.
Figure 12.10 ▪ Subdural Hematoma.
An infant with nonaccidental trauma. Axial computed tomographic image at presentation show left-side frontoparietal-convexity high-density small subdural hemorrhage (arrow). There is mass effect on underlying brain parenchyma with associated midline shift to the right. Also seen is bilateral cerebral low density (*) with loss of gray–white matter differentiation indicating diffuse ischemic injury.
Congenital diaphragmatic hernia (CDH) is due to failure of a foramen in the fetal diaphragm to close, causing abdominal viscera to protrude into the thoracic cavity. CDH more commonly occurs in the left hemithorax compared with the right. When imaging is obtained early, CDH may appear as a mass, without gas delineated bowel loops. The diagnosis of CDH is usually obvious based on clinical presentation and the presence of bowel loops located in the lower chest. However, there is a differential when there is a bubbly appearing intrathoracic mass. This includes congenital cystic adenomatoid malformation (CCAM) and congenital lobar emphysema. However, both of these entities tend to occur in the upper, right middle, and lingular lobes, rarely affecting the lower chest with involvement of the diaphragm as would be seen with a CDH.
Neonates with a CDH often present with significant respiratory distress. This is due to the fact that patients with CDH will have hypoplastic lung development on the side of the hernia and therefore oxygenation may be compromised. On physician exam, one might see a scaphoid abdomen, especially if the CDH is left sided. CDHs are also associated with other congenital abnormalities, including renal and congenital heart anomalies. When these patients present, bag valve mask ventilation is contraindicated as this may cause rapid gastric insufflation and possibly further inhibit pulmonary expansion. As soon as a CDH is identified, the patient should be immediately intubated and an orogastric tube inserted for gastric decompression. Many of these patients quickly worsen and require extracorporeal membrane oxygenation (ECMO). Emergent transfer to a tertiary institution with surgical capabilities should occur.
The chest radiograph of a neonate with CDH will show a hypoplastic lung and bowel protruding into the thoracic cavity.
CDH should be treated with immediate intubation and orogastric tube placement. Bag valve mask ventilation should be avoided to prevent worsening respiratory compromise by gastric insufflation.
Figure 12.11 ▪ Congenital Diaphragmatic Hernia.
AP radiograph of the chest shows multiple gas delineated bowel loops occupying the left hemithorax with rightward deviation of the mediastinum consistent with congenital diaphragmatic hernia. Note that the enteric tube tip is present in the stomach located in the left hemiabdomen.
Figure 12.12 ▪ Congenital Diaphragmatic Hernia.
AP radiograph of the chest shows complete opacification of the left hemithorax with rightward deviation of the mediastinum. When radiographs are obtained early in life, bowel loops may not be gas delineated and a congenital diaphragmatic hernia can mimic a space-occupying mass, as in this example.
Congenital heart disease refers to a problem with the heart’s structure and function due to abnormal heart development. The chest radiograph can be helpful to assess for cardiomegaly and pulmonary edema. Care should be made to only diagnose an enlarged cardiac silhouette in a normally or hyperinflated chest radiograph. A hypoinflated chest radiograph may artifactually make the heart appear larger than normal. With a normally inflated chest on AP radiograph, a cardiothoracic ratio of 0.6 or higher should be considered cardiomegaly. On a PA chest radiograph, a ratio of 0.5 or higher should be considered cardiomegaly.
The lungs should be assessed to determine whether there is normal pulmonary vascularity, shunt vascularity, and/or pulmonary edema. The diagnosis of edema or shunt vascularity should be approached with caution when the lungs are hypoinflated, as there may be artifactually increased pulmonary vascular markings.
Patients with newly discovered congenital heart disease are most likely to present with respiratory distress or feeding difficulties, at which time a murmur may be auscultated. For those patients presenting in the first week of life with cyanosis, consideration should be given to whether or not this is due to cyanotic congenital heart disease such as truncus arteriosus, transposition of the great vessels, tricuspid atresia, Tetralogy of Fallot, or total anomalous pulmonary venous return. For these patients, prostaglandins should be initiated immediately to open and maintain the patency of the ductus arteriosus. Patients with a ventricular septal defect may present a few weeks after birth with a murmur, sweating during feeds, and tachypnea and a chest radiograph consistent with pulmonary edema.
Chest radiographs should be obtained in pediatric patients presenting with the new onset of wheezing, chest pain, syncope, or unexplained tachycardia. In these patients, a chest radiograph may show cardiomegaly or pulmonary edema. Consideration should then be given to whether this could be myocarditis, anomalous left coronary artery arising from the left pulmonary artery, or whether an intracardiac shunt is present. These patients require an expedited workup with labs and an echocardiogram.
Hypoinflated chest radiographs may give the false impression that cardiomegaly is present.
Congenital heart disease may present similar to a patient with bronchiolitis, with respiratory distress, and pulmonary edema on chest radiograph.
Figure 12.14 ▪ Enlarged Cardiac Silhouette from VSD.
A, B: AP and lateral radiograph in a 3-month-old female with a VSD shows mild cardiomegaly and prominent bilateral pulmonary vascularity consistent with shunt vascularity without frank pulmonary edema. Note pulmonary hyperinflation with flattened diaphragms, best appreciated on the lateral projection. Note left aortic arch (arrow).
Croup is an infection and inflammation of the larynx and trachea in children. It is a clinical diagnosis based on the age of the child and characteristic presentation. The role of imaging is to exclude other entities that may mimic croup. The classic imaging finding of croup is the “steeple sign”. The steeple sign is seen on the AP view and is a reverse V-shaped tapered appearance to the subglottic trachea. The normal trachea on AP view should have a normal lateral convexity. The lateral view will show diffuse subglottic tracheal narrowing in the setting of croup. The radiologic differential for croup includes subglottic stenosis (from prior intubation, trauma, or infection), subglottic hemangioma (the steeple sign has an asymmetric shape), epiglottitis, tracheitis, and foreign body.
Croup is a clinical diagnosis described as a sudden onset of a barky cough, fever, and upper airway obstruction. Stridor is a common finding but is not necessary for the diagnosis. Stridor is often found when the patient is agitated and crying. If the patient has stridor at rest, nebulized racemic epinephrine aerosol should be considered. All patients with a history of stridor either at home or in the emergency department should be given corticosteroids, with dexamethasone 0.6 mg/kg either po, IV, or IM preferred. Sometimes croup may present in a clinically similar fashion to epiglottitis. Epiglottitis was more common twenty years ago as the most common pathogen was Haemophilus influenza B. Since the advent of the HiB vaccine, this condition is rarely seen; however, it should be considered in an unvaccinated child or in patients not responding to racemic epinephrine aerosols. Neck radiographs can help differentiate epiglottitis from croup.
Ingested foreign bodies tend to lodge in four locations in the esophagus: thoracic inlet, aortic arch, left atrium, and GE junctions. These mediastinal structures cause extrinsic compressions upon the esophagus and cause relative stasis of ingested materials at these levels. Ingested foreign bodies should be distinguished from aspirated foreign bodies located within the airway. The majority of food products are radiolucent. Therefore, radiolucent aspirated foreign bodies may demonstrate a normal chest radiograph or may show evidence of airway obstruction.
The AP radiograph should include the lower neck so that the thoracic inlet is well visualized as this is a common location for larger objects to lodge. If there is hyperinflation or asymmetry present on chest x-ray or if an aspirated foreign body is suspected clinically, consideration should be given to obtaining bilateral AP decubitus views of the chest. With the decubitus views, the lung that is hyperinflated in the dependent (down) position is likely to have a foreign body present due to the obstructive limitation of exhalation and resulting hyperexpansion.
Coins are a commonly ingested foreign body in children. When obtaining the chest radiograph, it is important that the AP chest radiograph include the lower neck so the thoracic inlet is well visualized. If the coin is lodged in the esophagus, the face of the coin will be visualized on the AP view. If it is lodged in the trachea, the face of the coin will be visualized on the lateral view. If the object looks wider than a coin on the lateral view, consideration should be made to ensure that the object is not a button battery. If a button battery is ingested, its radiographic hallmark is a beveled appearance.
Foreign body ingestions can happen with children of all ages, but most commonly occur in those younger than 5 years of age. Food is the most commonly aspirated object and will therefore generally not be radiopaque. Clinically, the provider must keep a high index of suspicion for any toddler with the acute onset of respiratory distress or choking as there is often not a history of a witnessed ingestion. Even with negative radiographs, if a child is symptomatic with respiratory distress, persistent cough, or inability to handle secretions then they should be taken to the OR for direct laryngoscopy and bronchoscopy for removal of the foreign body.
Button batteries that are lodged in the esophagus should be considered a surgical emergency and taken out expeditiously because of the risk of erosion of the esophagus. For button batteries that make it past the esophagus in the asymptomatic patient, x-rays should be repeated weekly to ensure the battery passes. Any symptomatic patient should have the foreign body removed by endoscopy.
For other objects that pass out of the esophagus, expectant management is the norm as objects have a 90% chance of successful passage. There are a few special considerations to help guide when surgical removal should be considered. The ingestion of more than one magnet carries the risk of attachment between two parts of the small bowel, potentially leading to ischemia. The ingestion of objects longer than 5 cm or wider than 2 cm can also be problematic because of the inability to pass the duodenal sweep or through the pylorus. For most foreign bodies, the caregivers can monitor the child’s bowel movements for the object. If it is not visualized, weekly x-rays are appropriate until the object passes.
Patients with a high likelihood of aspiration but negative x-rays and who are symptomatic should go to the OR for direct laryngoscopy and bronchoscopy.
Foreign bodies that pass out of the esophagus have a 90% chance of successful passage.
The majority of aspirated food foreign bodies are radiolucent. Only indirect signs of aspirated foreign body may be seen, such as air trapping.
If a circular foreign body has a beveled appearance on the radiograph, a button battery is presumed until proven otherwise.
Figure 12.22 ▪ Esophageal Foreign Body.
A, B: Frontal and lateral chest radiographs demonstrate a coin in the upper mediastinum above the aortic arch. The coin is seen en face on the AP view, and on edge on the lateral view, typical for the esophageal location. Note the tracheal air column anterior to the coin.
Hirschsprung’s disease is a congenital abnormality of the bowel in which there is absence of parasympathetic ganglion cells in the wall of the colon. The radiologic differential for a low-lying obstruction on x-ray includes imperforate anus, Hirschsprung’s disease, colonic atresia, ileal atresia, small left colon syndrome, and meconium ileus. Contrast enema is the next step in the work-up of Hirschsprung’s disease. Prior to contrast enema, there should be no rectal stimulation for at least 24 hours. Rectal stimulation may alter the rectal caliber, leading to a false negative exam. The classic radiologic finding on contrast enema is reversal of the rectosigmoid ratio with the rectal caliber smaller than the sigmoid caliber. In the normal child, the rectal:sigmoid ratio should be approximately 1:1 or larger. If small left colon syndrome is encountered, repeat enema in the future may be performed since a small percentage of Hirschsprung’s disease may present radiologically as small left colon syndrome.
Patients with Hirschsprung’s disease can present anywhere from early in life to late childhood with difficulty in having normal bowel movements. A history of a lack of a meconium stool in the first 24 hours of life or for the need to give either a suppository or enema for the patient to have a bowel movement may often be elicited. Because the rectosigmoid colon is devoid of intramural ganglion cells, it is not able to relax and facilitate the movement of stool. This is more commonly seen in males than females (4:1) and older patients may present with failure to thrive, decreased appetite, and intermittent bouts of diarrhea. Patients with Hirschsprung’s disease are at an increased risk for rectal prolapse and enterocolitis. In severe cases of enterocolitis, the patient is at risk for perforation and peritonitis. Diagnosis can be achieved through radiographic tests in addition to rectal manometry and biopsy of the affected tissue.
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