1. Pediatric CXR
Moritz Haager
Nov 20, 2003

2. Not just small adults What’s different about the pediatric CXR? Thymus
Occult FB aspiration
Congenital anomalies
Smaller airways; more subtle disease findings
Infectious etiologies & presentations

3. Normal newborn chest. Note the inferior border of the thymus blends with the cardiac borders

4. prominent right thymic lobe because of rotation.
A prominent right thymic lobe can be misinterpreted as right upper lobe pneumonia because of rotation.
prominent right thymic lobe because of rotation.

5. wavy thymic sign on the left
Note wavy thymic sign on the left and notch sign on the right.. The thymus is usually seen in newborns. It has right and left lobes and is in the anterosuperior mediastinum. The border of the heart and the inferior border of the thymus may blend (Figure 1), or there may be a notch at the junction of the border of the heart with the inferior border of the thymus  (Figures 2 and 3). Sometimes the thymus has an inferior margin with an acute angle which produces a sail sign. If there is rotation in films of patients with a sail sign, the thymus may appear shifted laterally, which may be incorrectly interpreted as upper lobe pneumonia (Figure 4) [2]. Occasionally gentle undulation is seen of the entire lateral edge of the gland, a result of adjacent rib compression. This is termed the wavy thymic sign [2] (Figure 3).
wavy thymic sign on the left

6. Thymus Anterior upper mediastinal structure
Low density – should be able to see pulmonary vasculature behind it
Does not displace trachea posteriorly
Can increase in size after acute illness
Does not decrease in size w/ aging – rather stays roughly same size (~3x3 cm) and so becomes smaller in proportion to chest
The thymus is usually seen in newborns. It has right and left lobes and is in the anterosuperior mediastinum. The border of the heart and the inferior border of the thymus may blend (Figure 1), or there may be a notch at the junction of the border of the heart with the inferior border of the thymus  (Figures 2 and 3). Sometimes the thymus has an inferior margin with an acute angle which produces a sail sign. If there is rotation in films of patients with a sail sign, the thymus may appear shifted laterally, which may be incorrectly interpreted as upper lobe pneumonia (Figure 4) [2]. Occasionally gentle undulation is seen of the entire lateral edge of the gland, a result of adjacent rib compression. This is termed the wavy thymic sign [2] (Figure 3).

7. 2-month old male with fever, noisy breathing, and tachypnea
Interpretation of Case O The PA view demonstrates moderate cardiomegaly and accentuation of the central markings. These findings are most consistent with early congestive heart failure rather than a viral pneumonia. This PA view is slightly rotated making this radiograph more difficult to interpret. The prominent right side of the heart, was initially felt to be due to the rotation. However, it is too large to be due to rotation alone. Impression: Early congestive heart failure. An echocardiogram confirmed the presence of congestive heart failure due to congenital heart disease. This case is discussed in more detail in Case 3 of Volume 4, Tachypnea in a 2-Month Old.
congestive heart failure due to congenital heart disease

8. CHF Findings Cardiothoracic Ratio CHF findings
Infants (less than 1 yo)
May be up to 0.6
Toddlers and older
Maximum is 0.5
CHF findings
Plethora, fluid in fissures, peribronchial cuffing
Don’t see pleural effusions and upper lobe redistribution as much as in adults

9. 2 mo w/ VSD now presents with resp distress and “seizure”
There is cardiomegaly with slightly prominent pulmonary vascularity suggesting a left to right shunt. An unexpected finding was the absence of a thymic shadow that one would expect to see in a 2-month old. A prominent thymus is usually visible in the upper mediastinum on the AP or PA view. On the lateral view, the space anterior and superior to the heart is usually occupied by the thymus in this age group. However, in this child, the thymic space is occupied by lung tissue. His laboratory studies were significant for hypocalcemia. Although his clinical presentation resembled a classic seizure, in retrospect, the hypocalcemia suggests that these episodes were symptomatic tetany. Impression: Cardiomegaly and absence of the thymic shadow. In conjunction with the VSD and hypocalcemia, this is most consistent with DiGeorge syndrome (thymic and hypoparathyroid aplasia or hypoplasia). This case is discussed in more detail in Volume 2, Case 2.
Cardiomegaly and absence of the thymic shadow most consistent with
DiGeorge Syndrome (thymic and hypoparathyroid aplasia or hypoplasia).

10. 11-month old female presents with fever and coughing.
Interpretation of Case H There are small interstitial central pulmonary infiltrates. Impression: Small interstitial central pulmonary infiltrates most consistent with a viral pneumonia viral pneumonia.
viral pneumonia

11. Viral Pneumonia Far more common than bacterial pneumonia in kids
Non-specific X-ray findings:
Overexpansion
Peribronchial thickening
Interstitial infiltrates
Perihilar flaring

12. 6-week old female with fever and cold symptoms. VS T39
6-week old female with fever and cold symptoms. VS T39.1, P125, R45, BP 75/35, O2 sat 98% RA
Interpretation of Case E The lungs are hyperaerated. The diaphragms are flattened (most notably, on the lateral view). There is a density in the right upper lobe seen best on the PA view. The scapula can be visualized distinctly from this density. This is an area of consolidation or atelectasis in the posterior segment of the right upper lobe. This density is also evident on the lateral view in the superior posterior region. Impression: Hyperaeration of the lungs with an area of consolidation or atelectasis in the posterior segment of the right upper lobe.
consolidation or atelectasis in the posterior segment of the right upper lobe

13. 15-month old male with fever and coughing.
Interpretation of Case D There is a density in the right upper lobe. This is not due to the scapula since the other side does not have this appearance. This is a patchy area of consolidation in the posterior portion of the right upper lobe. Impression: Partial right upper lobe consolidation.
right upper lobe consolidation.

14. 15-month old male with fever, coughing, and tachypnea.
Interpretation of Case A Bilateral central pulmonary infiltrates, but most marked in the right middle and left lower lobes. The left lower lobe infiltrate is best seen on the lateral view inferiorly over the spine. The lungs are hyperaerated. Impression: Right middle and left lower lobe infiltrates.
Right middle and left lower lobe infiltrates

15. 9 year old male with a history of fever, headache, nausea, and coughing
Interpretation of Case N There is a circular density in the right lung. This is the superior segment of the right lower lobe. Although this has the appearance of a mass, it is most likely an infectious process. Impression: Spherical consolidation in the right lower lobe (round pneumonia).
round pneumonia

16. Round Pneumonia Often present w/ pleuritic chest pain
See spherical opacity with poorly defined margins (compared to tumors which have clear margins)
Usually located posteriorly adjacent to pleura
Uncommon to see air bronchograms

17. 10 year old male with a history of coughing and fever.
Interpretation of Case G The left lung is consolidated. This atelectasis results in a mediastinal shift to the left. There are air bronchograms evident over the left lung. On the original film, there is a suggestion of a 1.5cm cylindrical foreign body in the left mainstem bronchus. Further history revealed that he had "swallowed" a plastic bullet several days ago. Impression: Consolidation of the entire left lung with the suggestion of a foreign body in the left mainstem bronchus.
Left-sided pneumonia and foreign body in the left mainstem bronchus

18. 4-month old with respiratory distress and diminished breath sounds on the right
PA inspiratory and expiratory views are shown here. The inspiratory view demonstrates hyperexpansion of the right hemithorax. The right hemithorax is blacker than the left. The right hemithorax is also bigger than it should be. Lung markings are evident throughout both lungs making this incompatible with a pneumothorax. The expiratory view shows satisfactory emptying of the left lung, but persistent hyperexpansion of the right lung. The diagnosis of foreign body is considered, but the typical age group for a bronchial foreign body is 2 years and above. This child's past history is significant for complaints of abnormal breathing in the past. Closer examination of the radiographs on the right show a density in the upper medial hemithorax (small density compressed against the upper mediastinum). This is probably a compressed right upper lobe. Impression: Hyperexpansion of the right middle and right lower lobes raising the possibility of an obstruction in the intermediate right bronchus. This child is ultimately found to have a congenital lobar emphysema of the right middle lobe. The topic of lobar emphysema is discussed in more detail in Case 9 of Volume 1, Respiratory Distress - That's a Tension Pneumothorax Isn't It?
Congenital RML lobar emphysema

19. Foreign Body Aspiration
Many FB’s are radiolucent
CXR less than perfect in detecting FB’s
Difficult histories often but if clear history of object in mouth + choking then need bronchoscopy regardless of radiographic results (especially with nuts)
If unclear and child asymptomatic then reasonable to d/c after informing parents of signs + Sx to be vigilant for

20. 7 mo native child w/ cough & fever
There are two types of pulmonary TB: primary and postprimary.. Postprimary TB involves the reactivation of dormant bacilli which occurs with episodes of immunosuppression, malnutrition, or debilitation, typically within two years following exposure. It occurs in 5% to 15% of cases of TB. Primary and postprimary TB differ clinically, pathologically, and radiologically. There are five distinct radiographic presentations of primary TB: 1. Parenchymal disease 2. Atelectasis 3. Lymphadenopathy 4. Pleural effusion 5. Miliary disease. During the hematogenous stage of primary TB, between 1% and 7% of patients will have radiographic evidence of miliary disease. Children under two years of age are most commonly affected, usually within six months of infection. When symptoms begin, the chest radiograph is typically normal. Hyperinflation may occur during the first two weeks. This can be followed by diffuse, small nodular opacities about six weeks after the onset of symptoms. Left untreated, the nodules may enlarge to about five millimeters or may coalesce and cavitate. With proper therapy, the nodules resolve within two to six months. Miliary calcification is uncommon. These PA and lateral chest radiograph views are taken in a 7-month old with miliary TB. There are multiple small nodules throughout the lungs bilaterally. There is a focal consolidation in the right upper lobe.
Miliary TB

21. 11-month old female w/ near-drowning episode
This is an 11-month old female who experienced a near-drowning episode in a bathtub. She had been placed in a bathtub approximately one-fourth full of water by her mother. Her mother then left the child unattended and went to the restroom herself. The child was behind the shower curtain. The mother was gone approximately five minutes, and upon returning she found the child floating in the water face up without any respiratory effort. She immediately grabbed the infant out of the bathtub, took her to the closest bed and attempted mouth-to-mouth resuscitation and some chest compressions. She called 911 at that time. Immediately prior to the arrival of the ambulance, the mother noted spontaneous respirations. Paramedics initiated positive pressure ventilation with a bag and mask apparatus. Five minutes later, they arrived at the E.D. at which time the infant was noted to be crying. Exam: VS T 36.5, P 120, R 45, BP 130/50, oxygen saturation while on supplemental oxygen (exact FiO2 not known) and continuous positive airway pressure was 98%. She was crying and active. Head without signs of trauma. Eyes normal. Pupils equal and reactive. Neck supple. Heart regular. Lungs spontaneous respirations with bilateral wheezing and rales. Good air exchange. Abdomen benign. Extremities with good pulses and perfusion. No evidence of trauma. Neuro: active, crying, recognizes mother, interactive with mother. Muscle tone good ABG: pH 7.11, pCO2 27, pO2 140, bicarb 9. Electrolytes Na 125, K 4.0, Cl 92, bicarb 11. Glucose 245. WBC 29,500 with 5% segs, 1% bands, 92% lymphs. Hgb 12.3, Hct 35.8, platelets 394,000. A chest radiograph was obtained.
Pulmonary
edema

22. 13 month old male with wheezing, coughing, and rhinorrhea for the past month. T 37.5, P 138, RR 52, BP 95/40, O2 95% RA
13 month old male brought to the ED with wheezing, coughing, and rhinorrhea x 1 mo. Reason they bring him in is b/c now he has fever. Had left lower lobe consolidation on CXR 3 wks ago . treated with albuterol syrup and a ten day course of clarithromycin with some improvement. He was noted to have a poor appetite and lost approximately one kilogram over the course of the month. Past medical history. He was born at 39 weeks gestation without complications. In the nursery, he was noted to be tachypneic with subcostal retractions. A chest radiograph in the nursery revealed a left lower lobe infiltrate. He was treated with oxygen and intravenous antibiotics. He was then discharged home after one week. Over the first year of his life, he was seen by his pediatrician on seven occasions for upper respiratory tract infections. Exam in the E.D.: T 37.5 degrees rectally, P 138, RR 52, BP 95/40, oxygen saturation in room air 95%. General appearance: Responsive with diminished activity in mild respiratory distress. HEENT: Normal except for white rhinorrhea. Neck without adenopathy. Lungs clear to auscultation bilaterally. Breath sounds were diminished at the left base. There were no wheezes, rhonchi, or rales. He has mild subcostal retractions and a paroxsymal cough. Heart regular without murmurs. Abdomen benign. Color and perfusion are good Labs in the E.D.: Hgb 9.6, hct 30.0, WBC 30,600 with a differential of 48% segs, 13% bands, 33% lymphs and 6% monos. Platelet count 518,000. A blood culture is drawn. A chest radiograph is obtained.
The PA view demonstrates a left sided triangular density of the medial left lung base. On the lateral view, the triangular density is seen posteriorly over the left lung base. Usually, the right diaphragm is higher than the left diaphragm. In this case, the left diaphragm, which is higher than the right diaphragm, can be identified as the diaphragm with the underlying gastric bubble. In this lateral view, the density can be determined to be on the left side.
The patient is hospitalized and treated with intravenous antibiotics. The history of recurrent pulmonary infections suggests the possibility of a pulmonary anomaly. An aortogram is performed.

23. This is a 13 month old male brought to the emergency department with wheezing, coughing, and rhinorrhea. He has had these symptoms for the past month. Tonight, he developed fever which prompted his parents to bring him to the E.D. He was seen by his primary care physician three weeks ago. A chest radiograph was obtained on that day, revealing a left lower lobe consolidation. He was treated with albuterol syrup and a ten day course of clarithromycin with some improvement. He was noted to have a poor appetite and lost approximately one kilogram over the course of the month. Past medical history. He was born at 39 weeks gestation without complications. In the nursery, he was noted to be tachypneic with subcostal retractions. A chest radiograph in the nursery revealed a left lower lobe infiltrate. He was treated with oxygen and intravenous antibiotics. He was then discharged home after one week. Over the first year of his life, he was seen by his pediatrician on seven occasions for upper respiratory tract infections. Exam in the E.D.: T 37.5 degrees rectally, P 138, RR 52, BP 95/40, oxygen saturation in room air 95%. General appearance: Responsive with diminished activity in mild respiratory distress. HEENT: Normal except for white rhinorrhea. Neck without adenopathy. Lungs clear to auscultation bilaterally. Breath sounds were diminished at the left base. There were no wheezes, rhonchi, or rales. He has mild subcostal retractions and a paroxsymal cough. Heart regular without murmurs. Abdomen benign. Color and perfusion are good Labs in the E.D.: Hgb 9.6, hct 30.0, WBC 30,600 with a differential of 48% segs, 13% bands, 33% lymphs and 6% monos. Platelet count 518,000. A blood culture is drawn. A chest radiograph is obtained.
The PA view demonstrates a left sided triangular density of the medial left lung base. On the lateral view, the triangular density is seen posteriorly over the left lung base. Usually, the right diaphragm is higher than the left diaphragm. In this case, the left diaphragm, which is higher than the right diaphragm, can be identified as the diaphragm with the underlying gastric bubble. In this lateral view, the density can be determined to be on the left side.
The patient is hospitalized and treated with intravenous antibiotics. The history of recurrent pulmonary infections suggests the possibility of a pulmonary anomaly. An aortogram is performed.

24. Pulmonary sequestration
This aortogram shows contrast injected into the aortic arch. There is a large anomalous vessel from the infradiaphragmatic portion of the aorta that supplies the abnormal density at the left lung base. The venous phase (not shown) revealed drainage into the hemiazygous vein (a systemic vein). This abnormal vascular supply is indicative of a pulmonary sequestration.
Pulmonary sequestration (PS) as first described by Rektorzik in 1861 is a mass of accessory lung tissue with an anomalous arterial supply. The pulmonary tissue is dysplastic and nonfunctioning without any connection to the tracheobronchial tree (1). The etiology of this defect is thought to be congenital (2). There are two types of pulmonary sequestration: intralobar and extralobar. Intralobar PS is three to six times more common than the extralobar type (3). In intralobar PS, the pulmonary tissue is isolated from the normal lung tissue; however, the pleural covering remains contiguous with that of the lung. The left lung is involved in 65% of the cases (4). Typically, the mass is confined to the posterior basilar segments of the lower lobe of the lung. There are rarely associated anomalies or foregut communications. The symptoms typically occur during early childhood with the patient presenting with recurrent pneumonia. The diagnosis is made after the age of 20 years in fifty percent of this type of PS (5). The incidence of intralobar PS is equal in males and females (6). The arterial supply is via a systemic artery and the venous drainage is through the pulmonary veins. The accessory lung tissue of extralobar PS is contained within its own pleural sac and is separated from the rest of the lung. It may be located between the inferior surface of the lower lobe and diaphragm, below the diaphragm, within the diaphragm, or in the mediastinum. It occurs on the left in greater than 90% of the cases (5). There may be an occasional foregut communication and associated anomalies are quite common. These may consist of a diaphragmatic hernia, cardiovascular malformation, bronchogenic cyst, pectus excavatum, or other lung anomalies (4). In contrast to intralobar PS, extralobar PS is usually diagnosed in infancy secondary to respiratory distress or feeding difficulties. Since the accessory tissue is sequestered within its own pleura, the chances of presentation with an infection are less than that of intralobar PS, unless there is a foregut communication. The arterial supply is from a systemic artery and the venous drainage is typically via the systemic veins, rather than the pulmonary veins as seen in intralobar PS. Most radiographically visible sequestrations occur in children over one year of age. The appearance of the chest radiograph depends on several factors: 1) whether the lesion is a site of infection, 2) if there is a communication with the airway or contiguous lung tissue, and 3) if there are other associated lung anomalies (7). Intralobar sequestration typically appears as a mass, cystic lesion, or infiltrative shadow with ill-defined borders. The majority of extralobar sequestrations are small lesions and are not visible on chest radiographs. However, they may present as an infiltrate or mass in the region between the lower lobes and the diaphragm (but can also be found in the superior or anterior mediastinum, pericardium, or infradiaphragmatic region). In the diagnosis of pulmonary sequestration, a CT, MRI, or ultrasound may be diagnostic. However, a normal study does not exclude the diagnosis. The gold standard for identifying a sequestration is angiography (7). Angiography confirms the anatomy, identifies the systemic supply, and shows the venous drainage. It is now thought that there are many "variants" to the pulmonary sequestration spectrum (8,9) which include: scimitar syndrome, horseshoe lung, cystic adenomatoid malformation, and pulmonary arteriovenous fistula/malformation. In the scimitar syndrome, the anomalous vein drains into the inferior vena cava or at its junction at the right atrium. This vein has the appearance of a scimitar. This may or may not be accompanied by hypoplasia of the right lung and dextrocardia, anomalies of the lobes of the right lung, hypoplasia of the right pulmonary artery, and an anomalous systemic vascular supply to the lung (10). The horseshoe lung is a rare congenital anomaly. It is associated with some of the findings of the scimitar syndrome. There is an isthmus of pulmonary tissue which extends from the right lung base across the midline behind the pericardium and then fuses with the left lung base. Likewise, there may be an anomalous systemic supply (1). The cystic adenomatoid malformation is an abnormality of the pulmonary parenchyma due to an overgrowth of bronchioles (1). There is usually a normal vascular supply, however there may be an aberrant systemic artery. Lastly, the pulmonary arteriovenous fistula/malformation consists of an abnormal pulmonary artery and venous connection (1). In this condition, there is normal pulmonary parenchyma (1) . Regardless of which variant is present, a diagnosis is suggested clinically and confirmed with angiography.
Pulmonary sequestration

25. Pulmonary Sequestration
Congenital non-functional (not connected to tracheobronchial tree) accessory lung tissue w/ anomalous arterial supply
Intralobar
More common, shares pleural lining w/ lung
Present w/ recurrent pneumonia
Extralobar
Contained in its own pleural sac
Present w/ resp distress or feeding difficulty in infancy
Angiography is gold standard for Dx
Multiple variants
Scimitar syndrome, horseshoe lung, cystic adenomatoid malformation, pulmonary AVM
Pulmonary sequestration (PS) as first described by Rektorzik in 1861 is a mass of accessory lung tissue with an anomalous arterial supply. The pulmonary tissue is dysplastic and nonfunctioning without any connection to the tracheobronchial tree (1). The etiology of this defect is thought to be congenital (2). There are two types of pulmonary sequestration: intralobar and extralobar. Intralobar PS is three to six times more common than the extralobar type (3). In intralobar PS, the pulmonary tissue is isolated from the normal lung tissue; however, the pleural covering remains contiguous with that of the lung. The left lung is involved in 65% of the cases (4). Typically, the mass is confined to the posterior basilar segments of the lower lobe of the lung. There are rarely associated anomalies or foregut communications. The symptoms typically occur during early childhood with the patient presenting with recurrent pneumonia. The diagnosis is made after the age of 20 years in fifty percent of this type of PS (5). The incidence of intralobar PS is equal in males and females (6). The arterial supply is via a systemic artery and the venous drainage is through the pulmonary veins. The accessory lung tissue of extralobar PS is contained within its own pleural sac and is separated from the rest of the lung. It may be located between the inferior surface of the lower lobe and diaphragm, below the diaphragm, within the diaphragm, or in the mediastinum. It occurs on the left in greater than 90% of the cases (5). There may be an occasional foregut communication and associated anomalies are quite common. These may consist of a diaphragmatic hernia, cardiovascular malformation, bronchogenic cyst, pectus excavatum, or other lung anomalies (4). In contrast to intralobar PS, extralobar PS is usually diagnosed in infancy secondary to respiratory distress or feeding difficulties. Since the accessory tissue is sequestered within its own pleura, the chances of presentation with an infection are less than that of intralobar PS, unless there is a foregut communication. The arterial supply is from a systemic artery and the venous drainage is typically via the systemic veins, rather than the pulmonary veins as seen in intralobar PS. Most radiographically visible sequestrations occur in children over one year of age. The appearance of the chest radiograph depends on several factors: 1) whether the lesion is a site of infection, 2) if there is a communication with the airway or contiguous lung tissue, and 3) if there are other associated lung anomalies (7). Intralobar sequestration typically appears as a mass, cystic lesion, or infiltrative shadow with ill-defined borders. The majority of extralobar sequestrations are small lesions and are not visible on chest radiographs. However, they may present as an infiltrate or mass in the region between the lower lobes and the diaphragm (but can also be found in the superior or anterior mediastinum, pericardium, or infradiaphragmatic region). In the diagnosis of pulmonary sequestration, a CT, MRI, or ultrasound may be diagnostic. However, a normal study does not exclude the diagnosis. The gold standard for identifying a sequestration is angiography (7). Angiography confirms the anatomy, identifies the systemic supply, and shows the venous drainage. It is now thought that there are many "variants" to the pulmonary sequestration spectrum (8,9) which include: scimitar syndrome, horseshoe lung, cystic adenomatoid malformation, and pulmonary arteriovenous fistula/malformation. In the scimitar syndrome, the anomalous vein drains into the inferior vena cava or at its junction at the right atrium. This vein has the appearance of a scimitar. This may or may not be accompanied by hypoplasia of the right lung and dextrocardia, anomalies of the lobes of the right lung, hypoplasia of the right pulmonary artery, and an anomalous systemic vascular supply to the lung (10). The horseshoe lung is a rare congenital anomaly. It is associated with some of the findings of the scimitar syndrome. There is an isthmus of pulmonary tissue which extends from the right lung base across the midline behind the pericardium and then fuses with the left lung base. Likewise, there may be an anomalous systemic supply (1). The cystic adenomatoid malformation is an abnormality of the pulmonary parenchyma due to an overgrowth of bronchioles (1). There is usually a normal vascular supply, however there may be an aberrant systemic artery. Lastly, the pulmonary arteriovenous fistula/malformation consists of an abnormal pulmonary artery and venous connection (1). In this condition, there is normal pulmonary parenchyma (1) . Regardless of which variant is present, a diagnosis is suggested clinically and confirmed with angiography.

26. 10 month old male with wheezing and coughing
A 10 month old male comes to the ED with a chief complaint of wheezing and coughing for one day. He has just flown in from the Marshall Islands with his parents and an interpreter, who are not available at this time. He has no fever, vomiting or diarrhea. Despite the language barrier you are able to elicit that the patient has had similar coughing and wheezing episodes in the past. Exam: VS T37.1 (tympanic), P120, R58, oxygen saturation 100% (room air). He is noted to be in mild respiratory distress with audible wheezes, mild-moderate retractions, moist expiratory rhonchi and crackles diffusely. He is given an albuterol nebulizer treatment with marked improvement in symptoms. His respiratory rate decreases, his retractions resolve, his aeration improves and his breath sounds clear except for a slight decrease in aeration on the left. His mother communicates that he is to see a doctor the following day, and you decide to discharge the patient on albuterol syrup with instructions to follow-up with this physician in the morning. The next day he comes to the clinic with his interpreter, who has a copy of his medical records from the Marshall Islands. He has had a history of recurrent episodes of wheezing and cough with respiratory distress for which he has been hospitalized at 1, 3 and 4 months of age. His mother indicates that he is doing much better since his ED visit last night. A chest radiograph is ordered.
The PA view demonstrates decreased pulmonary vascularity and hyperlucency of the left lung. His right lung demonstrates increased pulmonary vascularity. The lateral view demonstrates a mass effect posterior to the lower portion of the trachea, which compresses and bows the trachea anteriorly with considerable narrowing of the inferior portion of the trachea and left main bronchus. These findings are suspicious for a large mediastinal mass which is compressing the lower trachea and mainstem bronchus causing obstructive emphysema of the left lung and decreased perfusion of this lung. A barium esophagram is ordered.

27. cystic mass posterior to the trachea and the mainstem bronchi
Barium is hand injected into the proximal esophagus through a nasogastric tube. The esophagus is displaced laterally as seen on the AP view. The lateral view demonstrates the mass located between the trachea (the tracheal air column is compressed and displaced anteriorly) and the barium filled esophagus (which is displaced posteriorly). A CT scan of the chest is ordered.
There is a 4.5 x 4.5 x 2.5 cm cystic mass posterior to the trachea and the mainstem bronchi. The mass causes marked narrowing of the left main bronchus. The esophagus is displaced to the patient's right by the mass with flattening of the esophageal lumen. This mass is most likely a mediastinal bronchogenic cyst. An esophageal duplication cyst could have a similar appearance. The patient underwent surgical excision of the mediastinal mass via thoracotomy without complications. Pathology confirmed the mass to be a bronchogenic cyst. Discussion Bronchogenic cysts represent 10-20% of congenital cystic diseases of the lung, and account for approximately 10% of mediastinal masses. These cysts are the result of ectopic budding of the tracheobronchial tree during embryologic development from the primitive foregut. Histologically, these cysts are composed of tissue normally found in the trachea and bronchi (mucous glands, smooth muscle, elastic tissue and usually cartilage). Fluid found within is mucoid and clear or white, unless hemorrhage has occurred, in which case the contents are thick and brown. Calcium crystals may also be seen. Because these cysts form before the development of alveoli, there is no gas exchange potential, even if communication exists. Bronchogenic cysts can be classified by location: paratracheal, carinal, paraesophageal, hilar and miscellaneous. The majority of bronchogenic cysts are either attached to the tracheobronchial tree by a stalk of fibrous tissue or are embedded in the wall of the trachea or bronchus. Less frequently, there may be communication with the respiratory tract, resulting in progressive dilatation with air, resulting in atelectasis, recurrent infection and mediastinal shift. Clinically, the majority of bronchogenic cysts are symptomatic and occur in infancy or early childhood. Respiratory distress is the most common presentation in pediatric patients, manifested by recurring episodes of cough, stridor, wheezing and retractions. In later childhood or adulthood, bronchogenic cysts are more commonly asymptomatic, with symptoms eventually developing due to increasing size of the cyst. Chest pain, cough and dyspnea are the most common complaints in adults. Persistent or recurrent pneumonia, abscess or empyema can occur at any age as a result of impaired clearance of secretions past the cyst, or infection, or rupture of the cyst itself. Diagnostically, bronchogenic cysts can be identified on plain chest radiographs in up to two thirds of cases in any age group. The radiographic appearance depends on whether the cyst is air filled, fluid filled, or air and fluid filled. An air filled cyst has the appearance of a pneumatocele. Completely fluid filled cysts cannot be discriminated from solid masses on plain film. The presence of air-fluid levels on erect or decubitus films imply tracheobronchial communication and active infection, which can be difficult to distinguish from a lung abscess. Bronchogenic cysts may not be visible on chest radiographs due to surrounding mediastinal structures and inflammation. Hyperinflation, pneumonitis, atelectasis, mediastinal deviation, or abnormal separation of the trachea and esophagus may impede the radiographic visibility of a bronchogenic cyst. Computed tomography helps to better define the cyst in terms of fluid content, wall thickness, solitary or multiple nature, location and other findings. Treatment options for bronchogenic cysts include observation, resection and aspiration. All symptomatic or enlarging cysts should be resected. Infected cysts should be removed once tissue levels of broad-spectrum antibiotics have been established. In poor surgical candidates, aspiration of a cyst can be done to confirm a benign diagnosis. Instillation of a sclerosing agent is another therapeutic option. Asymptomatic simple cysts, if observed, have the potential to grow and can result in higher rates of perioperative complications once becoming symptomatic. There is also a rare association of bronchogenic cysts with rhabdomyosarcoma.
cystic mass posterior to the trachea and the mainstem bronchi

28. 6-month old male with difficulty breathing
Volume 6, Case 19 This is a 6-month old male who presents to the pediatric clinic with difficulty breathing. He has had similar episodes in the past. He has been diagnosed with asthma and has been treated with albuterol with only modest improvement. He has some nasal congestion, but no fever, vomiting or diarrhea. He feeds well and he has been gaining weight well. His past history is remarkable for multiple upper respiratory infections and wheezing during the past several months. He was born at term. His family history is significant for asthma in several relatives and his older siblings. He has three siblings who currently have colds. Exam: VS T 37, P 114, R 39, BP 100/75, oxygen saturation 99% in room air. He is alert, active, and in no distress. He is not toxic. HEENT significant for clear nasal mucus, normal TM's and a clear pharynx with normal oral mucosa. Heart regular without murmurs, but his breath sounds are noisy so it is difficult to be sure. He has mild inspiratory and expiratory "wheezing". His lung fields demonstrate good aeration. He has no retractions. His abdomen is soft, non-tender and without organomegaly. His neurologic exam is unremarkable. An albuterol aerosol is administered and following this, his lung exam is unchanged. A chest radiograph is ordered. An airway anomaly is also suspected so a lateral neck is also ordered.
This is a 6-month old child with a history of several episodes of dyspnea, noisy breathing and/or wheezing. A chest or airway anomaly of some sort is suspected. Take a minute to review these carefully. The PA view of the chest is unremarkable although a right sided aorta can be suspected here. The lateral view of the chest demonstrates a very narrow tracheal air column which is also bent suggesting extrinsic compression of the trachea. The lateral neck is unremarkable.
This esophagram demonstrates extrinsic compression of the esophagus consistent with a vascular ring. Discussion A vascular ring is a malformation of the aortic arch that results in vascular branches or major blood vessels encircling the trachea and esophagus. In nearly all instances, a right-sided aortic arch is present. In a double aortic arch (one of the most common vascular ring malformation patterns), the two arches encircle the trachea and esophagus.
In other vascular ring malformations, vascular remnants such as the ligamentum arteriosum (formerly the ductus arteriosus) may be part of the ring encircling the trachea and esophagus. In our patient's case here, further studies delineate a right sided aortic arch with an anomalous left subclavian artery, in which the ring is completed with a left sided ductus arteriosus which closes to become the ligamentum arteriosum.
Note that the normal aortic arch crosses over the left mainstem bronchus. This is the normal left sided aortic arch. In the vascular ring malformations diagrammed in figures 1 and 2, note that the aortic arch passes over the right mainstem bronchus instead. This is an abnormal right sided aortic arch. In figure 1 (the double aortic arch), the aortic arch bifurcates such that one half of the aorta crosses over the left mainstem bronchus, while the other half of the aorta crosses over the right mainstem bronchus. In figure 2 (the right sided aorta with anomalous left subclavian), the aortic arch crosses only over the right mainstem bronchus.
Recognition of the right sided aortic arch is often a valuable clinical clue in suspecting a vascular ring. A vascular sling (as opposed to a vascular ring) is said to be present when the vessels form an incomplete circle around the trachea and esophagus. Children with vascular rings are often diagnosed during infancy, but presentations later in life my occur in more mild cases and many cases are totally asymptomatic. Presenting symptoms are usually due to tracheal or esophageal compression such as stridor, noisy breathing, frequent respiratory infections, wheezing, dysphagia, choking, apnea, wheezing, croupy cough, hoarse cry, etc. A typical presenting history is that of noisy breathing since birth. It is common for these infants to have more severe symptoms during a respiratory infection. A young infant with a history of "asthma" is another typical way that these patients present. Sometimes these children are diagnosed with cardiac disease, but the vascular ring may be occult until an appropriate imaging study is performed. The key in making the diagnosis is to suspect an airway problem based on symptoms described by the parents. Clinical findings may or may not be present during an examination. Two view chest radiographs are useful in identifying many pulmonary and cardiac anomalies, but the findings are often subtle. Since a right sided aortic arch is almost always present in a vascular ring, identifying this on a chest radiograph is critical. A right sided aortic arch is defined as an aortic arch that crosses over the right mainstem bronchus instead of the usual left mainstem bronchus. Thus, the arch itself may not necessarily occupy the right hemithorax. The normal left sided aortic arch normally pushes the carina to the right as it courses over the left mainstem bronchus. This slight deviation in the normal tracheal air shadow can often be appreciated on the AP or PA view of the chest radiograph. In a right sided aortic arch, the carina deviates to the left instead as the aorta courses over the right mainstem bronchus.
The diagram on the left illustrates the rightward deviation of the distal trachea which occurs when the normal left sided aorta crosses over the left mainstem bronchus. The diagram on the right illustrates the left sided deviation of the distal trachea which occurs when the right sided aorta crosses over the right mainstem bronchus. In a double aortic arch, leftward deviation of the carina may not be visible on the chest radiograph because both left and right aortic arches are present. However, since a double aortic arch often forms a large caliber ring, tracheal compression is often visible on the lateral view of the chest radiograph. In cases where no carina deviation is present and the side of the aorta cannot be determined, a double aortic arch should be suspected. The lateral view of the chest radiograph may reveal a narrowed or constricted tracheal air column (as was seen in the patient in this case). Once an airway anomaly or right sided aortic arch is suspected on plain chest radiographs, a more advanced imaging study should be performed to delineate the anatomy definitively. Occasionally, bronchial compression is severe and unilateral hyperinflation can be seen on the AP or PA view of the chest radiograph. This usually suggests a pulmonary artery sling, a bronchial anomaly or compression of the bronchus by some other structure. An esophagram (barium swallow) is helpful in making the diagnosis and historically, the esophagram was heavily relied upon to delineate the malformation until angiography was performed. Currently, advanced imaging methods such as echocardiography, CT scanning, magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) may eliminate the need for esophagrams, since they are non-invasive and they define the anatomy of the malformation well. Treatment focuses on the surgical correction of the malformation with the goal of relieving the patient's symptoms.

29. Vascular Ring
Aortic arch malformation causing trachea & esophagus to be encircled by major blood vessels or branches thereof
See a right-sided aortic arch in nearly all cases
passes over the R mainstem bronchus rather than the L
Pushes carina to L rather than the usal R
May see only compression in double arch
In other vascular ring malformations, vascular remnants such as the ligamentum arteriosum (formerly the ductus arteriosus) may be part of the ring encircling the trachea and esophagus. In our patient's case here, further studies delineate a right sided aortic arch with an anomalous left subclavian artery, in which the ring is completed with a left sided ductus arteriosus which closes to become the ligamentum arteriosum.
normal aortic arch crosses over the left mainstem bronchus (left sided aortic arch) In the vascular ring malformations the aortic arch passes over the right mainstem bronchus instead. This is an abnormal right sided aortic arch. Recognition of the right sided aortic arch is often a valuable clinical clue in suspecting a vascular ring. A vascular sling (as opposed to a vascular ring) is said to be present when the vessels form an incomplete circle around the trachea and esophagus. Children with vascular rings are often diagnosed during infancy, but presentations later in life my occur in more mild cases and many cases are totally asymptomatic. Presenting symptoms are usually due to tracheal or esophageal compression such as stridor, noisy breathing, frequent respiratory infections, wheezing, dysphagia, choking, apnea, wheezing, croupy cough, hoarse cry, etc. A typical presenting history is that of noisy breathing since birth. It is common for these infants to have more severe symptoms during a respiratory infection. A young infant with a history of "asthma" is another typical way that these patients present. Sometimes these children are diagnosed with cardiac disease, but the vascular ring may be occult until an appropriate imaging study is performed. The key in making the diagnosis is to suspect an airway problem based on symptoms described by the parents. Clinical findings may or may not be present during an examination. Two view chest radiographs are useful in identifying many pulmonary and cardiac anomalies, but the findings are often subtle. Since a right sided aortic arch is almost always present in a vascular ring, identifying this on a chest radiograph is critical. A right sided aortic arch is defined as an aortic arch that crosses over the right mainstem bronchus instead of the usual left mainstem bronchus. Thus, the arch itself may not necessarily occupy the right hemithorax. The normal left sided aortic arch normally pushes the carina to the right as it courses over the left mainstem bronchus. This slight deviation in the normal tracheal air shadow can often be appreciated on the AP or PA view of the chest radiograph. In a right sided aortic arch, the carina deviates to the left instead as the aorta courses over the right mainstem bronchus.
. In a double aortic arch, leftward deviation of the carina may not be visible on the chest radiograph because both left and right aortic arches are present. However, since a double aortic arch often forms a large caliber ring, tracheal compression is often visible on the lateral view of the chest radiograph. In cases where no carina deviation is present and the side of the aorta cannot be determined, a double aortic arch should be suspected. The lateral view of the chest radiograph may reveal a narrowed or constricted tracheal air column (as was seen in the patient in this case). Once an airway anomaly or right sided aortic arch is suspected on plain chest radiographs, a more advanced imaging study should be performed to delineate the anatomy definitively. Occasionally, bronchial compression is severe and unilateral hyperinflation can be seen on the AP or PA view of the chest radiograph. This usually suggests a pulmonary artery sling, a bronchial anomaly or compression of the bronchus by some other structure. An esophagram (barium swallow) is helpful in making the diagnosis and. Currently, advanced imaging methods such as echocardiography, CT scanning, magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) may eliminate the need for esophagrams, since they are non-invasive and they define the anatomy of the malformation well. Treatment focuses on the surgical correction of the malformation with the goal of relieving the patient's symptoms.

30. Vascular Ring
In figure 1 (the double aortic arch), the aortic arch bifurcates such that one half of the aorta crosses over the left mainstem bronchus, while the other half of the aorta crosses over the right mainstem bronchus. In figure 2 (the right sided aorta with anomalous left subclavian), the aortic arch crosses only over the right mainstem bronchus.

31. 5 year old, male w/ fever x 10 d, coughing, sore throat and mild back pain
Volume 7, Case 3 This is a 5 year old, male who initially developed fever (coughing, a sore throat and mild back pain X 10d. throat culture negative). decreased appetite, increased fatigue and shallow breathing. no ill contacts, trauma, aspiration/choking episodes or foreign travel. His past medical history is negative. He has not had his 5 year old immunizations, but he was up to date prior to this. He presented to his primary care physician earlier today at which time his vital signs were recorded as: T 37.5, P 120, RR 48, BP 100/56 and oxygen saturation 95-98% RA. does not appear to be toxic or in obvious distress, shallow respirations with diminished breath sounds bilaterally.
Other lab studies done as an outpatient: CBC WBC 23,000, 73% segs, 10% bands, 11% lymphocytes and 6% monocytes, Hgb 10.6, Hct ESR 56. His chemistry panel is normal. The chest radiograph demonstrates a large well circumscribed consolidated lesion of the right middle lobe with an air fluid level.. A CT scan of the patient's chest confirms the presence of a 8 x 6 x 8 cm thick walled mass in the RML and RLL consistent with an abscess.. Cultures of the abscess fluid isolate non-typable Hemophilus influenzae (beta lactamase negative) Discussion A lung abscess is defined as an area of necrotic material within a thick walled cavity.. Overall, lung abscess remains a relatively uncommon disease in the pediatric population. Pathogenesis Risk factors for the development of a lung abscess are aspiration, immunodeficiency and hematogenous spread. Aspiration is the most important factor predisposing a child to lung abscess (1). In children, a lung abscess may also be a complication of a necrotizing pneumonia. Aspiration occurs in children with neurologic disorders, altered mental status, impaired cough mechanisms, swallowing dysfunction or even foreign body aspiration. Most lung abscesses related to aspiration are polymicrobial and include anaerobes. Hematogenous spread occurs with emboli, right sided endocarditis and bacteremia. Immunodeficiency in children occurs secondary to myeloproliferative disorders, chemotherapy, chronic granulomatous disease, hyper IgE syndrome, etc. Among pediatric patients, HIV-1 infection has not been reported as a risk factor (2). Additionally, immotile cilia disorders and cystic fibrosis can increase the risk for a lung abscess. A lung abscess can have a well defined fibrotic wall that may converge on adjacent structures causing compression or dissection of the borders. Dissection into a bronchus results in an air fluid level. Dissection into the plural space forms a purulent effusion and if an abscess dissects into the mediastinum, compression of large vessels and the heart may occur. Microbiology The organisms associated with lung abscesses have evolved as antibiotic therapy and our ability to isolate organisms have improved. In normal children with no known underlying disease, the most common organisms are anaerobic bacteria, Staph aureus, Strep pneumoniae and Strep pyogenes (group A strep). Gram negative organisms include non-typable H. influenza, Klebsiella and Pseudomonas. Anaerobic organisms are the predominate organism isolated from children with neurologic disorders (often due to aspiration) and include Bacteroides and Peptostreptococcus. Mycobacterium tuberculosis should also be considered. Signs and Symptoms The most common clinical finding is fever. Additional symptoms include cough (productive if the abscess has ruptured and foul smelling sputum if the organism is anaerobic), dyspnea, chest pain, shoulder pain, anorexia and malaise. Acute onset of symptoms is associated with bacterial organisms while subacute presentations are typical in patients with tuberculosis and fungal abscesses (2). The course of a lung abscess before medical intervention may be surprisingly indolent and may last several weeks (1). On physical examination, findings are not always consistent or specific, especially in children, but include tachypnea, decreased breath sounds and rales. Diagnosis Chest radiographs usually reveal a well circumscribed radiodense cavity with an air fluid level that is confirmed with a lateral decubitus views. The width of the air fluid level is usually of equal length on both frontal and lateral chest radiographs, and its walls are thick with an uneven shaggy appearance (3). Atelectasis may be seen if the abscess compresses nearby lung parenchyma. Initially the lung abscess appears as a solid lesion within the parenchyma (5). Computed tomography is useful in the diagnosis of a lung abscess especially in cases where there may be multiple or small abscesses, to differentiate an abscess from a tumor, and to pinpoint the location of an abscess in proximity to other structures. Classic findings on CT include a thick ragged wall, central fluid and surrounding parenchymal consolidation. Distinctive features of a lung abscess are well marginated edges, greater density of the abscess compared to water and contrast enhancement in adjacent tissue (1). Ultrasound examination shows a thick irregular wall with a blurred outer margin and an oval or round shape that forms an acute angle with the chest wall. However, with ultrasound, a peripheral lung abscess may contain low level echoes and thus can mimic a pleural effusion. Voluntary hyperventilation causes symmetric movement of the anterior and posterior walls of an abscess cavity, while a pleural effusion causes asymmetric movement (3). The location of a lung abscess may be dependent on the patient's position especially if aspiration is involved. Supine position at time of aspiration commonly results in an abscess located in the upper lobes and apical aspects of the lower lobes, while the erect position causes basilar portions of the upper lobes to be affected. The right lung is usually affected twice as often as the left because of the anatomic position of the bronchus (4). Blood cultures are positive in less than 10% of cases (2). Leukocytosis and elevated ESR are nonspecific. A PPD should be placed in all patients suspected of lung abscess.
Lung abscess

32. Congenital lobar emphysema.
Two week old male infant w/ a history of noisy breathing and worsening respiratory distress. VS T36.7, P160, R60, O2 sat 86% RA
There is hyperlucency of the left chest with a mediastinal and cardiac shift to the right. Although this may look like a tension pneumothorax, realize that such a large tension pneumothorax would generally be associated with hypotension, bradycardia, and persistent hypoxia (despite supplemental oxygen). Since this infant appears to have good cardiovascular function and his oxygenation improved with supplemental oxygen, one should not immediately jump to evacuating the left chest since he is currently stable. After carefully reassessing the situation and reexamining the CXR, it is evident that lung markings are present in the left chest. This represents a hyperexpanded lobe. The hyperexpansion is so severe that it compresses the remaining left lung and pushes the heart and mediastinum to the right, compressing the right lung as well. Impression: Left upper lobe hyperexpansion with mediastinal shift. Congenital lobar emphysema.
Congenital lobar emphysema.

33. References Cases courtesy of:
Loren G. Yamamoto, MD, MPH Alson S. Inaba, MD Robert M. DiMauro, MD Kapiolani Medical Center For Women And Children Dept. Pediatrics, University of Hawaii John A. Burns School of Medicine 1319 Punahou Street, Honolulu, HI