Category Archives: RESPIRATIORY

NEONATAL RESPIRATORY DISEASES IMAGING

NEONATAL DISEASES IMAGING is very important

Neonatal Respiratory Distress (NRD):

  • RD in the newborn is usually due to one of 4 disease entities:
1.     Respiratory distress syndrome (RDS; hyaline membrane disease, HMD)

2.     Transient tachypnea of the newborn (TTN)

3.     Meconium aspiration

4.     Neonatal pneumonia

The most common complications of RDS are:

  • Pulmonary interstitial emphysema (PIE)
  • Persistent PDA
  • Bronchopulmonary dysplasia (BPD)

Neonatal Respiratory Distress:

Disease Lung Volume Opacities Time Course Complication
RDS:  Low Granular 4-6 days PIE, BPD, PDA
Transient tachypnea: High or normal Linear, streaky* < 48 hours None
Meconium aspiration:  Hyperinflation Coarse, patchy At birth PFC, ECMO
Neonatal pneumonia:  Anything Granular Variable  

*Ground-glass opacity at birth.

ECMO: extracorporeal membrane oxygenation; PFC : persistent fetal circulation;

RDS/ hyaline membrane disease (HMD):

Evolving Terminology:

  • The term hyaline membrane disease is now less commonly used in clinical practice to describe pulmonary surfactant insufficiency in infants.
  • Hyaline membranes are considered a byproduct, not the cause, of respiratory failure in neonates with immature lungs.
  • The term respiratory distress syndrome is currently used to denote surfactant deficiency and should not be used for other causes of respiratory distress.
  • In recognition of the underlying pathogenesis of the disease process, the alternative term surfactant deficiency disorder has been proposed.

Pathogenesis:

  • RDS is caused by surfactant deficiency. Surfactant diminishes surface tension of expanding alveoli. As a result, acinar atelectasis and interstitial edema occur.
  • Hyaline membranes are formed by proteinaceous exudate.
  • Symptoms occur within 2 hours of life.

The incidence of RDS depends on the gestational age at birth:

Birth at Gestational Age (wk) Incidence (%)
27 50
31 16
34 5
36 1

Radiographic Features:

  • In most cases of RDS, the diagnosis is made clinically but may initially be made radiographically. The role of the radiologist is to assess serial chest films.

CXR signs of premature infants:

  • No subcutaneous fat
  • No humeral ossification center
  • Endotracheal tube present

Any opacity in a premature infant should be regarded as RDS until proven otherwise.

o   Lungs are opaque (ground-glass) or reticulogranular (hallmark).

o   Hypoaeration (atelectasis) leads to low lung volumes à bell-shaped thorax (if not intubated).

o   Bronchograms are often present.

o   Absence of consolidation or pleural effusions

o   In contrast to other causes of RDS in neonates, pleural effusions are uncommon.

o   Treatment with surfactant may result in asymmetric improvement

Treatment complication of RDS:

  • Persistent PDA : signs of congestive heart failure (CHF):
  • The ductus usually closes within 1 to 2 days after birth in response to the high Po2 content.
  • Air-trapping : PIE & acquired lobar emphysema
  • Diffuse opacities (whiteout) may be due to a variety of causes:
  • Atelectasis
  • Progression of RDS
  • Aspiration
  • Pulmonary hemorrhage
  • CHF
  • Superimposed pneumonia

Pulmonary interstitial emphysema (PIE):

  • PIE refers to àaccumulation of interstitial air in peribronchial & perivascular spaces.
  • Most common cause à +ve-pressure ventilation.

Complications:

  • Pneumothorax
  • Pneumomediastinum
  • Pneumopericardium

Radiographic Features:

  • Tortuous linear lucencies radiate outward from the hilar regions.
  • The lucencies extend all the way to the periphery of the lung.
  • Lucencies do not change with respiration.

Bronchopulmonary dysplasia (BPD)

  • Caused by oxygen toxicity & barotrauma of respiratory therapy.
  • BPD is now uncommon in larger & more mature infants (gestational age > 30 weeks or weighing >1200 g at birth).

Definition of BPD & Diagnostic Criteria:

Diagnostic Criterion Gestational Age < 32 wk Gestational Age > 32 wk
Time point of assessment o   36 wk PMA* or

o   discharge to home, whichever comes first;

o   treatment with >21% oxygen for at least 28 days plus

o   >28 days but <56 days postnatal age or

o   Discharge to home, whichever comes first;

o   Treatment with >21% oxygen for at least 28 days plus

Mild BPD o   Breathing room air at 36 wk PMA or

o   discharge, whichever comes first

o   Breathing room air by 56 days postnatal age or

o   discharge, whichever comes first

Moderate BPD o   Need* for <30% oxygen at 36 wk PMA or

o   discharge, whichever comes first

o   Need* for <30% oxygen at 56 days postnatal age or

o   discharge, whichever comes first

Severe BPD o   Need* for ≥30% oxygen and/or positive pressure (PPV* or nasal CPAP) at 36 wk PMA or

o   discharge, whichever comes first

o   Need* for ≥30% oxygen and/or positive pressure (PPV or nasal CPAP) at 56 days postnatal age or

o   discharge, whichever comes first

*Using a physiologic test (pulse oximetry saturation range) to confirm the oxygen requirement.

  • BPD : bronchopulmonary dysplasia.
  • CPAP: continuous positive airway pressure.
  • PMA : postmenstrual age (gestational age at birth plus chronologic age).
  • PPV : positive-pressure ventilation.
  • There are 4 stages in the development; the progression of BPD àthrough all 4 stages is now rarely seen because of the awareness of this disease entity.
  • Stages of Bronchopulmonary Dysplasia:
Stage Time Pathology Imaging
1 o   < 4 days o   Mucosal necrosis o   Similar to RDS
2 o   1 week o   Necrosis, edema, exudate o   Diffuse opacities
3 o   2 weeks o   Bronchial metaplasia o   Bubbly lungs*
4 o   1 month o   Fibrosis o   Bubbly lungs*

*Bubbly lungs (honeycombing): rounded lucencies surrounded by linear densities; hyperaeration.

Prognosis of Stage 4:

  • Mortality, 40%
  • Minor handicaps, 30%
  • Abnormal pulmonary function tests in almost all in later life
  • Clinically normal by 3 years, 30%

Meconium aspiration syndrome:

  • Meconium (mucus, epithelial cells, bile, debris) à the 1.st stool that is evacuated within 12 hours after delivery.
  • In fetal distress, evacuation may occur into the amniotic fluid (up to 10% of deliveries).
  • However, in only 1% does this aspiration cause respiratory symptoms.
  • Only meconium aspirated to below the vocal cords is clinically significant.
  • Meconium aspiration sometimes clears in 3 to 5 days.
  • CXR nearly always returns to normal by 1 year of age.

Radiographic Features:

o   Patchy, bilateral opacities, may be “rope-like”

o   Atelectasis

o   Hyperinflated lungs

o   Pneumothorax, pneumomediastinum, 25%

Complication:

  • Mortality (25%) from persistent fetal circulation

Neonatal pneumonia (NP):

  • Pathogenesis:

Trans-placental infection: ·        TORCH:

ü Pulmonary manifestation of TORCH is usually less severe than other manifestations.

Perineal flora: ·        Group B streptococci, enterococci, Escherichia coli:

ü Ascending infection

ü Premature rupture of membranes

ü Infection while passing through birth canal

Radiographic Features:

  • Patchy asymmetrical opacities in a term infant represent neonatal pneumonia until proven otherwise.
  • Hyperinflation

Transient tachypnea of the newborn (TTN):

  • TTN (wet lung syndrome) is a clinical diagnosis.
  • It is caused by a delayed resorption of intrauterine pulmonary liquids.
  • Normally, pulmonary fluids are cleared by:

Bronchial squeezing during delivery, 30%

Absorption, 30%: lymphatics, capillaries

Suction, 30%

Causes:

  • Cesarean section, premature delivery, maternal sedation (no thoracic squeezing)
  • Hypoproteinemia, hypervolemia, erythrocythemia

Radiographic Features:

o   Fluid over-load àsimilar appearance as non-cardiogenic pulmonary edema.

o   Prominent vascular markings

o   Pleural effusion

o   Fluid in fissure

o   Alveolar edema

o   Lungs clear in 24 48 hours.

Extracorporeal membrane oxygenation (ECMO):

  • Technique of providing prolonged extracorporeal gas exchange.

Indications:

  • Any severe respiratory failure with predicted mortality rates of > 80%.

Exclusion criteria for ECMO include:

  • < 34 weeks of age
  • >10 days of age
  • Serious intracranial hemorrhage
  • Patients who require epinephrine

Complications:

  • Late neurologic sequelae; developmental delay, 50%
  • Intracranial hemorrhage, 10%
  • Pneumothorax, pneumomediastinum
  • Pulmonary hemorrhage (common)
  • Pleural effusions (common)
  • Catheter complications

IMAGING OF PNEUMONIA IN CHILDREN

IMAGING OF PNEUMONIA IN CHILDREN is very important for very doctor to know .

  • Childhood pneumonias are commonly caused by:

– Mycoplasma, 30% àlower in age group < 3 years.

– Viral, 65% àhigher in age group < 3 years)

– Bacterial, 5%

Viral pneumonia:

Causes

  • respiratory syncytial virus (RSV), parainfluenza

Radiographic Patterns of Viral Pneumonia:

Pattern Frequency Description
Bronchiolitis:

Common o   Normal CXR

o   Overaeration is only diagnostic clue

o   Commonly due to RSV

Bronchiolitis+parahilar, peribronchial opacities:

Most Common o   Dirty parahilar regions caused by:

–         Peribronchial cuffing (inflammation)

–         Hilar adenopathy

Bronchiolitis+atelectasis:

Common o   Disordered pattern with:

–         Atelectasis

–         Areas of hyperaeration

–         Parahilar+peribronchial opacities

Reticulonodular interstitial:

Rare o   Interstitial pattern
Hazy lungs:

Rare o   Diffuse increase in density

Pearls:

  • All types of bronchiolitis & bronchitis cause air trapping (over-aeration) with flattening of hemi-diaphragms.
  • RSV, Mycoplasma, & parainfluenza virus : the most common agents that cause radiographic abnormalities (in 10 30% of infected children).
  • Any virus may result in any of the 5 different radiographic patterns.

Bacterial pneumonia:

  • The following 3 pathogens are the most common:

– Pneumococcus (ages 1 to 3)

– Staphylococcus aureus (infancy)

– Haemophilus influenzae (late infancy)

Radiographic Features:

Consolidation: o   Alveolar exudate

o   Segmental consolidation

o   Lobar consolidation

Other findings: o   Effusions

o   Pneumatocele

Complications: o   Pneumothorax

o   Bronchiectasis (reversible)

o   Swyer-James syndrome:

– Acquired pulmonary hypoplasia.

-Radiographically ch.ch by small, hyperlucent lungs + diminished vessels (focal emphysema).

o   Bronchiolitis obliterans

Round Pneumonia:

  • Usually age < 8 years
  • Pneumococcal pneumonia in early consolidative phase
  • Pneumonia appears round because of poorly developed collateral pathways (pores of Kohn & channels of Lambert).
  • With time the initially round pneumonia develops into a more typical consolidation.

Causes of recurrent Infections:

1-    Cystic fibrosis

2-    Recurrent aspirations

3-    Rare causes of recurrent infection:

o   Hypogammaglobulinemia (Bruton disease):  DDx clue : no adenoids or hilar LNs.

o   Hyperimmunoglobulinemia E (Buckley syndrome)

o   Kartagener syndrome.

o   Other immune-deficiencies

o   Bronchopulmonary foregut malformation

 

Aspiration pneumonia:

  • Results from inhalation of swallowed materials or gastric content.
  • Gastric acid damages capillaries causing acute pulmonary edema.
  • 2ry infection or acute respiratory distress syndrome (ARDS) may ensue.

Causes:

aspiration due to :

Swallowing dysfunction:

(most common cause)

o   Anoxic birth injury (common)

o   Coma,

o   Anesthesia.

Obstruction: o   Esophageal atresia or stenosis.

o   Esophageal obstruction.

o   Gastroesophageal reflux (GER),

o   Hiatus hernia.

o   Gastric or duodenal obstruction.

Fistula: o   Tracheoesophageal fistula (TEF)

Radiographic Features:

o   Recurrent pneumonias : distribution:

– Aspiration in supine position: upper lobes, superior segments of lower lobes.

– Aspiration in upright position : both lower lobes

o   Segmental and subsegmental atelectasis

o   Interstitial fibrosis

o   Inflammatory thickening of bronchial walls

Sickle cell anemia:

  • Pulmonary manifestations : are the leading cause of death:
  • Pneumonia, acute chest syndrome, & pulmonary fibrosis.
  • Children with acute chest syndrome may present with one or multiple foci of consolidation, fever, chest pain, or cough.

Causes:

  • Infection (higher incidence).
  • Fat emboli originating from infracting bone.
  • Pulmonary thrombosis.

Radiographic Findings

  • Consolidation
  • Pleural effusion
  • Fine reticular opacities (pulmonary fibrosis)
  • Large heart in severe anemia
  • H-shaped vertebral bodies
  • Osteonecrosis, bone infarct in visualized humeri

 

Congenital Pulmonary Abnormalities IMAGING

Congenital cystic adenoid malformation IMAGING IS VERY ESSENTIAL

Bronchopulmonary foregut malformation:

  • Arise from a supernumerary lung bud that develops below the normal lung bud.
  • Location and communication with GIT depend on when in embryonic life the bud develops.
  • Most malformations present clinically when they become infected (communication with GIT).

Overview of Bronchopulmonary Malformations:

Malformation Location
Sequestration:

·        Intralobar

Sequestration

 

60% basilar, left

80% left or below diaphragm

Bronchogenic cyst Mediastinum, 85%; lung, 15%
CCAM All lobes
Congenital lobar emphysema LUL, 40%; RML, 35%; RUL, 20%

Pulmonary sequestration:

Clinical Findings:

  • Recurrent infection
  • Lung abscess
  • Bronchiectasis
  • Hemoptysis during childhood.

Pathology:

  • Non-functioning pulmonary tissue ànearly always posteromedial segments of lower lobes.
  • Systemic arterial supply à anomalous arteries from the aorta (less common branch of the celiac artery)
  • No connection to bronchial tree

Types of Pulmonary Sequestration:

                                                          

Feature Intralobar Sequestration Extralobar Sequestration
Age ·        Older children, adults ·        Neonates
Pleura ·        Inside lung (intralobar) ·        Outside lung àextralobar, own pleura)
Forms ·        Airless (consolidation) and air-containing, cystic type ·        Always airless (pleural envelope) unless à communication with GIT
Venous return: ·        Pulmonary vein ·        Systemic: IVC, azygos, portal
Arterial supply: ·        Thoracic aorta > abdominal aorta
Associations: ·        In 10% of patients:

o   Skeletal anomalies, 5%

o   Foregut anomalies, 5%

o   Diaphragmatic anomalies

o   Other rare associations

·        In 65% of patients:

o   Diaphragmatic defect, 20%

o   Pulmonary hypoplasia, 25%

o   Bronchogenic cysts

o   Cardiac anomalies

     

Radiographic Features:

  • Large (>5 cm) mass near diaphragm
  • Air-fluid levels if infected
  • Surrounding pulmonary consolidation
  • Sequestration may communicate with GIT.

Bronchogenic cyst:

  • It Results from the abnormal budding of the tracheobronchial tree. Cysts contain respiratory epithelium.

Location:

  • Mediastinum, 85% àposterior > middle > anterior mediastinum)
  • Lung, 15%

Radiographic Features:

o   Well-defined round mass in subcarinal / parahilar region

o   Pulmonary cysts commonly located in medial 1/3 of lung

o   Initially no communication with tracheobronchial tree

o   Cysts are thin walled.

o   Cysts can be fluid or air filled.

 

 

 

Congenital cystic adenoid malformation (CCAM):

  • CCAM refers to a proliferation of polypoid glandular lung tissue without normal alveolar differentiation.
  • Respiratory distress occurs during first days of life.

Treatment:

surgical resection (sarcomatous degeneration has been described).

Types:

Macrocystic:

(Stocker types 1 & 2)

o   single cyst or multiple cysts > 5 mm confined to one hemi-thorax.

o    Better prognosis.

o    Common.

Microcystic:

(Stocker type 3)

o   Homogeneous echogenic mass without discernible individual cysts.

o   Closely resembles pulmonary sequestration or intrathoracic bowel from a diaphragmatic hernia.

o   Less common.

Radiographic Features:

o   Multiple cystic pulmonary lesions of variable size

o   Air-fluid levels in cysts

o   Variable thickness of cyst wall

 

 

Congenital lobar emphysema:

  • Progressive overdistention of one or more pulmonary lobes but usually not the entire lung.
  • 10% of patients have congenital heart disease àpatent ductus arteriosus [PDA] & ventricular septal defect [VSD].

Causes:

  • Idiopathicà 50%
  • Obstruction of airway with valve mechanismà 50%:
  • Bronchial cartilage deficiency or immaturity
  • Mucus
  • Web, stenosis
  • Extrinsic compression

 

Radiographic Features:

o   Hyperlucent lobe (hallmark)

o   1.st few days of life à alveolar opacification because there is no clearance of lung fluid through bronchi

o   May be asymptomatic in neonate but becomes symptomatic later in life

o   Use CT to àdifferentiate from bronchial obstruction

o   Distribution

§  LUL, 40%

§  RML, 35%

§  RUL, 20%

§  2 lobes affected, 5%

 

Pulmonary hypoplasia:

Types of Pulmonary Underdevelopment:

  • Agenesis: Complete absence of one or both lungs (airways, alveoli, & vessels).
  • Aplasia: Absence of lung except for a rudimentary bronchus that ends in a blind pouch.
  • Hypoplasia: decrease in number and size of airways and alveoli; hypoplastic PA.
  • Scimitar Syndrome (Hypogenetic Lung Syndrome, Pulmonary Venolobar Syndrome)

– A special form of a hypoplastic lung.

– The hypoplastic lung is àperfused from the aorta & drained by the IVC or portal vein.

– The anomalous vein has a resemblance to a Turkish scimitar (sword).

– Associations include:

   1) Accessory diaphragm, diaphragmatic hernia

   2) Bony abnormalitiesà hemivertebrae, rib notching, rib hypoplasia

   3) CHD: atrial septal defect (ASD), VSD, PDA, tetralogy of Fallot

 

 

  • Radiographic Features:
o   Small lung àmost commonly the right lung.

o   Retrosternal soft tissue density à hypoplastic collapsed lung.

o   Anomalous vein resembles a scimitar

o   Systemic arterial supply from aorta

o   Dextroposition of the heart àshift because of hypoplastic lung)

 

Congenital diaphragmatic hernia (CDH):

Incidence:

  • 1 in 2000 to 3000 births.
  • The mortality rate of isolated hernias is 60% (with postnatal surgery) and higher when other abnormalities are present.
  • Respiratory distress occurs in the neonatal period.
  • Associated abnormalities include:

Pulmonary hypoplasia (common)

CNS abnormalities:

Neural tube defects : spina bifida, encephalocele Anencephaly

Types:

Bochdalek’s hernias: Ø 90% of CDH à posterior:

o   75% are on the left, 25% on right

o   Right-sided hernias are more difficult to detect because of similar echogenicity of liver & lung.

o   Contents of hernia:

ü Stomach, 60%.

ü Colon, 55%.

ü Small intestine, 90%.

ü Spleen, 45%.

ü Liver, 50%.

ü Pancreas, 25%.

ü Kidney, 20%.

o   Malrotation of herniated bowel is very common.

Morgagni hernias: Ø 10% of CDH à anterior:

o   Most occur on right (heart prevents development on the left).

o   Most common hernia contents: omentum, colon

o   Accompanying anomalies common

Eventration: o   Due to relative absence of muscle in dome of diaphragm

o   Associated with:

ü Trisomies 13, 18, congenital CMV, rubella arthrogryposis multiplex, pulmonary hypoplasia

  • Radiographic Features:
o   Hemi-diaphragm not visualized

o   Multi-cystic mass in chest

o   Mass effect

 

Kartagener syndrome (immotile cilia syndrome):

  • Due to the deficiency of the dynein arms of cilia causing immotility of respiratory, auditory, & sperm cilia.

Radiographic Features:

o   Complete thoracic & abdominal situs inversus

o   Bronchiectasis

o   Sinus hypoplasia & mucosal thickening

YOU CAN SEE REAL CASE IMAGES AT THIS LINK:

https://radiopaedia.org/articles/congenital-pulmonary-airway-malformation

PEDIATRIC RESPIRATORY TRACT IMAGING

PEDIATRIC RESPIRATORY TRACT IMAGING IS VERY ESSENTIAL AND VERY EASY, IN THE FOLLOWING, WE WILL EXPLAIN IT IN VERY SIMPLE WORDS:

Upper Airway:

Approach:

  • Inspiratory stridor : is the most common indication for radiographic upper airway evaluation.
  • The main role of imaging is to identify conditions that need to be treated emergently & /or surgically (e.g., epiglottitis, foreign bodies).
  • Technique:
  1. Physician capable of emergency airway intervention should accompany child
  2. Obtain 3 films:

– Lateral neck: full inspiration, neck extended

– Anteroposterior (AP) and lateral chest: full inspiration, include upper airway.

 

  1. Fluoroscope the neck if radiographs are suboptimal or equivocal
  2. Primary diagnostic considerations:
  • Infection : epiglottitis, croup, abscess.
  • Foreign body : airway or pharyngo-esophageal.
  • Masses : lymphadenopathy, neoplasms.
  • Congenital abnormalities : webs, malacia
  1. If upper airway is normal, consider:
  • Pulmonary causes : foreign body, bronchiolitis.
  • Mediastinal causes: vascular rings, slings.
  • Congenital heart disease (CHD)

 

Normal appearance:

  • 3 anatomic regions:

– Supra-glottic region

– Glottic region : ventricle & true cords

– Sub-glottic region

  • Epiglottis & aryepiglottic folds are thin structures.
  • Glottic shoulders are seen on AP view.
  • Adenoids are visible at 3 to 6 months after birth.
  • Normal retropharyngeal soft tissue thickness (C1 C4) = three-fourths vertebral body width.

Laryngomalacia:

  • A common cause of stridor in the 1st year of life.
  • Immature laryngeal cartilage leads to supra-glottic collapse during inspiration.
  • Stridor improves with activity & is relieved by prone positioning or neck extension.
  • Self-limited course.
  • Diagnosis is established by fluoroscopy àlaryngeal collapse with inspiration.

Tracheomalacia:

  • Collapse of trachea with expiration.
  • May be focal or diffuse.
  • Focal type is usually Secondary to congenital anomalies that impress on the trachea, such as a vascular ring.

 

Webs:

  • Most common in the larynx.

Tracheal stenosis:

  • Diffuse hypoplasia, 30%
  • Focal ring-like stenosis, 50%
  • Funnel-like stenosis, 20%

Subglottic stenosis:

  • Fixed narrowing at level of cricoid. Failure of laryngeal recanalization in utero.

Epiglottitis:

  • Life-threatening bacterial infection of the upper airway.
  • Most commonly caused by Haemophilus influenzae.
  • Age: 3 to 6 years (older age group than with croup).
  • ttt is with àprophylactic intubation for 24 48 hours & antibiotics.
  • Clinical Findings

Fever

Dysphagia

Drooling

Sore throat

  • Radiographic Features:

Thickened aryepiglottic folds (hallmark)

Key radiographic view: lateral neck

Thickened epiglottis

Subglottic narrowing due to edema, 25%: indistinguishable from croup on AP view

Distention of hypopharynx

  

  • Pearls:
  • Other causes of enlarged epiglottis or aryepiglottic folds:

o   Caustic ingestion

o   Hereditary angioneurotic edema

o   Omega-shaped epiglottis : normal variant with normal aryepiglottic folds.

o   Stevens-Johnson syndrome

Croup:

  • Sub-glottic laryngotracheobronchitis.
  • Most commonly caused by parainfluenza virus.
  • Age: 6 months to 3 years (younger age group than epiglottitis).
  • Clinical Findings:

Barking cough

Upper respiratory tract infection

Self-limited

  • Radiographic Features:

Subglottic narrowing: inverted “V” or “steeple sign”.

Key view: AP view

Lateral view should be obtained to exclude à

Steeple sign : loss of subglottic shoulders.

  • Pearls:

Membranous croup:

Uncommon infection of bacterial origin Staphylococcus aureus.

Purulent membranes in subglottic trachea.

Epiglottitis may mimic croup on AP view.

 

Retropharyngeal abscess:

  • Typically due to the extension of a suppurative bacterial lymphadenitis, most commonly S. aureus, group B streptococci, oral flora.
  • Age  < 1 year.
  • Other causes include foreign body perforation and trauma.
  • Clinical Findings

Fever

Stiff neck

Dysphagia

Stridor (uncommon)

Most cases present as àcellulitis rather than a true abscess.

  • Radiographic Features:
o   Plain film findings : usually nonspecific.

o   Widened retropharyngeal space : most common finding

o   Air in soft tissues is specific for abscess.

o   Straightened cervical lordosis

o   CT is helpful to define superior & inferior mediastinal extent.

  • Main DDs:

Retropharyngeal hematoma

Neoplasm àe., rhabdomyosarcoma.

Lymphadenopathy

Tonsillar hypertrophy:

  • The tonsils consist of lymphoid tissue that encircles the pharynx.
  • 3 groups:

Pharyngeal tonsil (adenoids).

Palatine tonsil.

Lingual tonsil.

  • Tonsils enlarge secondary to infection and may obstruct nasopharynx & /or eustachian tubes.
  • Rarely, bacterial pharyngitis can lead to àa tonsillar abscess (quinsy abscess), which requires drainage.
  • Specific causes include:

                                      

o   Mononucleosis (Epstein-Barr virus)

o   Coxsackievirus (herpangina, hand-foot-mouth disease)

o   Adenovirus (pharyngoconjunctival fever)

o   Measles prodrome (rubeola)

o   Beta-Hemolytic Streptococcus (quinsy abscess)

  • Radiographic Features:
o   Mass in posterior nasopharynx (enlarged adenoids)

o   Mass near end of uvula (palatine tonsils)

o   CT is useful to determine the presence of a tonsillar abscess.

 

Airway foreign body (FB):

  • Common cause of respiratory distress.
  • Age à 6 months to 4 years.
  • Acute aspiration results in cough, stridor, wheezing; chronic FB causes à hemoptysis or recurrent pneumonia.
  • Location à right bronchi > left bronchi > larynx, trachea.
  • Radiographic Features:
Bronchial FB: o   Unilateral air tapping causing hyperlucent lung à 90%

o   Expiratory film or lateral decubitus àmakes air trapping more apparent.

o   Atelectasis is uncommon, 10%

o   Only 10% of FBs are radio-opaque.

o   Chest fluoroscopy or CT should be performed if plain film findings are equivocal.

Tracheal FB:

 

o   FB usually àlodges in sagittal plane

o   CXR is usually ànormal.

     

Mediastinum:

Thymus:

  • The ratio of thymus to body weight â with age.
  • Thymus is routinely identified on CXR from birth to 2 years of age.
  • Size & shape of the thymus are highly variable from person to person.

Common mediastinal tumors:

Anterior: o   Thymic hyperplasia & thymic variations in shape & size (most common)

o   Teratoma

o   T-cell lymphoma

o   Cystic hygroma

o   Thymomas are extremely rare.

Middle: o   Adenopathy (leukemia, lymphoma, TB)

o   Bronchopulmonary foregut malformation

Posterior: o   Neuroblastoma

o   Ganglioneuroma

o   Neurofibromatosis

o   Neurenteric cysts

o   Meningoceles

Pearls:

  • Any pediatric anterior mediastinal mass is considered thymus until proven otherwise.
  • Posterior mediastinal masses are the most common abnormal chest masses in infants

If you want to view Real Case Imaging of each disease , this link will be very helpful :

https://radiopaedia.org/playlists/6642