Respiratory System- Part III
Lower Respiratory Infection
Bacterial
Viral bronchiolitis
Mycobacterial tuberculosis
Fungal
Mycoplasma
Chlamydia
Immunocompromized host
Bacterial Pneumonia Common Organisms
Pneumococcus
Staphylococcus
Hemophilus influenzae
Klebsiella
Pseudomonas
Bacterial Pneumonia
Cough
Fever
Chest pain
Abdominal pain
Abnormal physical exam
Bacterial Pneumonia Imaging
Lobar or segmental infiltrate
ÒRound pneumoniaÓ usually < 8 years old
Bacterial Pneumonia Complications
Pleural effusion
Empyema
Lung abscess
Pneumatocele
Pleural Effusion
Decubitus films do them both ways
DonÕt do decubitus films with complete whiteout
Ultrasound makes fluid look more complex than it is
CT makes it look less complex than it is
Empyema
CT gives best panoramic view
Enhancing rind
ÒSplit pleuraÓ sign
Volume loss
Lung Abscess
Occurs with central necrosis in lung involved with pneumonia
Communication with airway leads to contents expelled during coughing
Thick, irregular wall
CT best to distinguish from empyema
If multiple, consider endocarditis
Pneumatocele
Thinwalled cyst which may occur following pneumonia
Characteristic of Staph and gram negatives
Also seen in hydrocarbon aspiration and trauma
Viral Lower Respiratory Infection Organisms
RSV
Parainfluenza
Adenovirus
Influenza
Viral Lower Respiratory Infection
Children < 5 years
Primarily involves airways ÒwheezerÓ
Bronchial wall thickening
Air trapping
Mucous plugging
Multifocal atalectasis
Tuberculosis
Granulomatous infection
Usually primary in children
Urban areas, immigrants
Increasing in USA
Tuberculosis Imaging
Lung infiltrate
Unilateral hilar/paratracheal adenopathy
Pleural effusion
Miliary hematogenous spread
Endobronchial sprea
d
Reactivation disease cavitary TB
Fungal Infection
Granulomatous infection
Pulmonary infiltrate
Pulmonary nodules
Mediastinal adenopathy
Calcification common
Fungal Infection
Regional areas of predilection
Ohio River valley histoplasmosis
Western USA coccidiomycosis
Mycoplasma Pneumonia
Common in older children
Variable clinical/radiographic picture
May have lobar/segmental infiltrate
May have reticulonodular pattern
Xray often looks worse than patient
Chlamydia Pneumonia
Chlamydia trachomatis
Average age 6 weeks
Contracted during delivery
Diffuse illdefined opacity
Slow resolution
Lower Respiratory Infection in the Immunocompromised Host
There are no rules
Many patterns, much overlap
Radiology is a poor substitute for microbiology
SwyerJames Syndrome
Idiopathic unilateral hyperlucent lung
Probably secondary to repeated infection, usually adenovirus
Necrotizing bronchiolitis leads to obliterative bronchiolitis
SwyerJames Syndrome
Unilateral hyperlucency with decreased volume
Decreased pulmonary vascularity
Central mild bronchiectasis with small bronchiolar obstruction
Air trapping on expiration
Usually entire lung, may be lobar or segmental
