pediatric chest infection imaging considerations

Pediatric chest infections..that never resolve….imaging considerations .

Dr/Ahmed BahnassyConsultant radiologist

PSMMC

Case 1…

Case 2

Case 3

Case 4

Lines of thinking of unresolved pneumonia

o Virulent or atypical organism.o Low immunity (congenital conditions:Di

gerorge syndrome,Nezelof syndrome,hypogammaglobulinaemia,Chronic granulomatous disease of childhood.

o Recurrent aspirations (severe GERD,mild malrotation.)

o Structural lung abnormality (ELS,CPAM).o Not infection.

Role of imaging

• CT chest (conventional ,with special protocols)• HRCT chest for lung parenchyma evaluation.• Upper GI.• Ultrasound.

What to request ?.

• Prioritize the information you need .• Discuss with radiologist or enter FULL clinical

data in the request form .• Begin with ultrasound-if possible.• Correlate radiological findings with laboratory

results.

Case 1

Bronchiectasis

Another finding

Tree-in bud

thymus

Lymph nodes

Which organ is missing ?!

SV

pan

Diagnosis ?

• Chronic process.• Main feature is bronchiectasis.• The latter involving central and upper lobes.• Severe fatty infiltration of pancreas.

Cystic fibrosis

Historical perspective

• The term CF of the pancreas was first used in 1938 by Dr. Dorothy Anderson, [whose work on clinicopathologic correlation in infants and children led her to the first comprehensive description of the destruction of the pancreas and frequent infection and damage to lung airways. The name was coined because of the macroscopic appearance of the pancreas.

• By the 1940s, physicians understood that the ductal systems and other passages in the organs affected by CF were clogged with thick tenacious secretions.

• By 1946, the autosomal recessive character of the inheritance of a single gene mutation was appreciated.

Radiographic changes• Hyperinflation and peribronchial cuffing may be confused with

asthma or bronchiolitis.• Linear streaking and scattered nodules, which are seen in

moderate CF, may be present in granulomatous or fungal disease or sarcoid.

• CT scan, done with high-resolution technique because it achieves better spatial resolution than is obtainable by conventional imaging, may be useful in the evaluation of minimally affected individuals.

• The earliest radiographic sign of CF in infants and children is hyperinflation due to mucus plugging .

• Atelectasis, especially of the right upper lobe, is common in infancy.

• Obstruction of small airways may result in a nodular or reticulonodular appearance on radiographs and centrilobular nodules on HRCT scan

• On HRCT scan, the centilobular nodule is characterized by a cluster of ill-defined nodules .

• As the disease progresses the classic findings of CF, representing progressive bronchiectasis involving the large airways, become more apparent…Thick parallel bronchial walls are seen as linear shadows or tram-line tracts.

• Ring shadows represent dilated thick-walled bronchi seen on-end and multiple nodular densities represent mucus plugging .

• Bronchiectasis is defined as bronchial dilatation relative to the adjacent pulmonary artery. The normal ratio is 1:1.

• Bronchi adjacent to a pulmonary artery branch demonstrate a signet ring appearance.

• Mucoid impaction of the bronchi with the thick tenacious mucus of CF appears as areas of increased density that follow the course of dilated bronchi .

• Large cystic airspaces may be identified.• Lung abscesses may develop late in the course of the

disease. • Spontaneous pneumothorax is believed to be due to a

rupture of subpleural blebs. It is observed in 5% to 20% of patients and it is associated with a worse prognosis, generally being seen in more severe disease.

Scoring systems

• The most commonly used is the Birmingham system .• 5 elements are assessed by the Brasfield method including (1) air-trapping;

(2) linear markings; (3) nodular, cystic lesions; (4) general severity; and (5) large lesions, such as atelectasis or consolidation.

• The first four elements are scored from zero to four.the last 0,3 or 5. • The points are added together and then subtracted from 25. A normal chest

radiograph scores 25. The minimum score is three.• Newer scoring systems, including those utilizing HRCT scan have been

developed to assess less severe disease and in an attempt to correlate better with minimal progression of disease. The most popular scoring system utilizing HRCT scan is the Bhalla system.

• The presence, extent, and severity of bronchiectasis, peribronchial thickening, mucus plugging, atelectasis or consolidation, and emphysema are recorded.

Case 2

Diagnosis

• It is severe infection (empyema necessitantes).• Large pneumatoceles which can…• Narrow differential diagnosis .

– AFB– Staph aureus.– Strept.– HI– G-ve organism (Klebsiella-pneumonia)– PCP .

Necrotizing pneumonia

• Necrotising pneumonia has increasingly been identified as a complication of paediatric

• pneumonia. Streptococcus pneumoniae remains the predominant organism, but since 2002, different bacteria have been isolated and the age range of cases has broadened.

• Necrotising pneumonia (NP) is a severe complication of community-acquired pneumonia characterised by liquefaction and cavitation of lung tissue.

Radiological diagnosis

• Radiological diagnosis for NP include the loss of normal pulmonary parenchymal architecture and the presence of areas of decreased attenuation and enhancement,representing liquefaction, that are progressively replaced by multiple small air or fluid filled cavities .

• The pathophysiology of NP is thought to be one of massive pulmonary gangrene, tissue liquefaction and necrosis .

• Prior reports have focused on NP caused by Streptococcus pneumoniae although other bacterial organisms, including

• Staphylococcus aureus and Mycoplasma pneumoniae,• have reportedly led to NP .

Case 3

Case 3 CT

Diagnosis

• It is congenital .• Mass like (not consolidation)• Has aortic (systemic) blood supply .• Venous drainage not clear .

Pulmonary Sequestration

• Pulmonary sequestration is an embryonic mass of lung tissue that has no identifiable bronchial communication and that receives its blood supply from 1 or more anomalous systemic arteries. Multiple feeding vessels may be present. This congenital anomaly can be classified as extralobar sequestration (ELS) or intralobar sequestration (ILS).

• ELSs are masses composed of nonfunctioning primitive pulmonary parenchymal tissue that have no connection to the tracheobronchial tree.

• This sequestration is called extralobar because the mass lies outside of the normal investment of visceral pleura; it also may lie outside of the thorax in a subdiaphragmatic position in 10% of patients.

• The arterial supply is predominantly via systemic arteries (95%) rather than pulmonary arteries (5%); the systemic arteries are commonly branches of the thoracic aorta or the abdominal aorta (80%).

• Venous drainage also occurs most commonly via the systemic veins (75%), for example, the inferior vena cava (IVC) or azygos or portal veins rather than pulmonary veins (25%).

Role of imaging

• CT scans have a 90% accuracy in the diagnosis of pulmonary sequestration.

• Arteriography (conventional or CT angiography [CTA]) is helpful in differentiating the lesion from other abnormalities of the lung, such as pulmonary arteriovenous fistulae.

• MRI and magnetic resonance angiography (MRA) can provide information similar to that on CT scans.

• Ultrasonography is noninvasive and safe, making its use ideal in prenatal and postnatal settings.

• Color flow and duplex Doppler ultrasound can elegantly depict the ectopic blood supply

Differential diagnosis

• Solid mass in the differential diagnosis for ILS

Metastatic lung neoplasmsLung abscessBochdalek herniaNeurogenic tumorMeningocelePleural tumorExtramedullary hematopoiesis

Cystic masses DD for ILS

Congenital lobar emphysemaCystic adenomatoid malformationIntrapulmonary bronchogenic cystArteriovenous malformationLung abscessNecrotizing pneumoniaCavitating infarctFungal , orTB pneumoniaBronchogenic foregut cystPericardial cystEmpyema

DD for ELS

NeuroblastomaTeratomaForegut duplicationMesoblastic nephromaAdrenal hemorrhage

Case 4

Diagnosis

• Bilateral symmetrical involvement.• Mainly intersitial.• Alveoli not aerated.• Cystic changes.• Bronchiolectasis.

Interstitial lung disease

DD

Preferred Diagnosis for last case

• Pulmonary interstitial glycogenosis.• Lymphocytic interstitial pneumonia.• Early pulmonary LCH.

• Recommendation:

• Lung biopsy.

Thank you