Thoracic 2 Flashcards
Emphysema
Permanent enlargement of the airspaces distal to the terminal bronchioles accompanied by destruction of the alveolar wall without clear fibrosis
Chest radiograph findings of emphysema
- Flattening of the diaphragm due to hyperinflation
- Increased AP diameter due to hyperinflation
- Large retrosternal clear space
- Paucity/pruning of vessels
Definition of flattening of the diaphragm
Diaphragmatic dome less than 1.5 cm above a ling drawn between the costophrenic and cardiophrenic sulci
Saber sheath trachea
Diffuse narrowing of the trachea from O -> I on axial slices and chest radiograph
Note: This is fairly specific for COPD.
What are the main types of pulmonary emphysema?
- Centrilobular
- Panlobular
- Paraseptal
How does centrilobular emphysema appear?
Upper zone predominant centrilobular lucencies with a central dot (representing the bronchovascular bundle within the secondary pulmonary lobule)
Lower lobe predominant emphysema…
Think pan lobular emphysema in pts with alpha-1 antitrypsin deficiency or prior IV Ritalin use
Subpleural lucencies that look like honeycombing, but is less than 3 bubbles thick…
Think paraseptal emphysema
Note: This can be smoking-related or idiopathic.
Which trip of emphysema is most associated with smoking?
Centrilobular emphysema
What is asbestosis?
A form of pulmonary fibrosis secondary to exposure to asbestos
How can you distinguish asbestosis from usual interstitial pneumonia?
Look for parietal pleural thickening, which suggests asbestosis
How long does it usually take between initial exposure to asbestos and development of lung cancer or pleural mesothelioma?
20 years
Absestos exposure increases the risk of which extra pulmonary cancers?
- Peritoneal mesothelioma
- GI cancer
- Renal cancer
- Laryngeal cancer
- Leukemia
What is the earliest pleural-based finding secondary to asbestos exposure?
Benign pleural effusions
Note: Even these take about 5 years to develop after exposure.
Chest radiograph demonstrating “holly-leaf” scattered pleural thickening bilaterally sparing the apices and costophrenic angles…
Think pleural plaques in the setting of asbestosis
Note: Plaques develop about 20-30 years after exposure and may calcify after about 40 years.
Rounded consolidation with “comet tail” in an adult adjacent to some pleural thickening…
Think round atelectasis
Note: If there is not adjacent pleural thickening, this is suspicious for cancer and should get a PET/CT and/or biopsy.
What is the typical distribution of pneumoconiosis?
Upper lobe predominant and centrilobular (due to pathogenic particles being inhaled)
Note: Perilymphatic nodules are also common, especially in silicosis and coal workers pneumoconiosis.
Risk factors for silicosis
- Mining
- Quarry workers
Multiple nodular opacities with upper lobe predominance and hilar nodes with eggshell calcifications in a pt who used to be a miner…
Silicosis
Large masses in the bilateral upper lobes with radiating strands in a pt who used to be a miner…
Progressive massive fibrosis (complicated form of silicosis/coal workers pneumoconiosis)
Cavitation in the setting of silicosis…
Think tuberculosis
Note: Silicosis triples your risk of TB.
How can you differentiate cancer from progressive massive fibrosis
Get an MRI. Progressive massive fibrosis should be T2 dark, whereas cancer would be T2 bright
Progressive massive fibrosis
A complicated form of silicosis or coal workers pneumoconiosis resulting in large masses in the upper lobes with radiating strands
Multiple nodular opacities with calcifications showing a central nodular dot in a perilymphatic distribution in a pt who used to be a miner…
Think coal workers pneumoconiosis
Generalized granulomatous disease with hilar adenopathy and upper lobe predominant reticular opacities in a pt who used to work in aircraft/space manufacturing…
Think berylliosis
Risk factors for berylliosis
Exposure to metals used in aircraft and space industries
Silo filler’s disease
Pulmonary edema and/or ARDS due to exposure to nitrogen dioxide from silage on farms
Acute respiratory distress in a farm worker with extensive pulmonary edema on CT…
Think silo fillers disease (pulmonary edema secondary to nitrogen dioxide exposure from farm silage)
Hyperdense pulmonary micronodules with coalescent masses and ground glass opacities in a pt with history of IV drug use…
Think talcosis secondary to IV administration of ground tablets
What is at the center of the secondary pulmonary lobule?
Terminal bronchiole and accompanying pulmonary artery
Note: The pulmonary veins and lymphatics are located in the periphery of the secondary lobule.
What distribution pattern is most likely if you see many pulmonary nodules without any abutting the pleural surfaces?
Centrilobular
Best way to determine the distribution pattern of pulmonary nodules
Look for nodules abutting pleural surfaces (if there aren’t any, the pattern is likely centrilobular)
If there are pleural-based nodules, look for a subpleural/peribronchovascular predominance (perilymphatic distribution) or no clear distribution (random)
What is the major differential for perilymphatic pulmonary nodules?
- Sarcoidosis (90% of cases)
- Lymphangitic carcinomatosis
- Silicosis
What is the major differential for randomly distributed pulmonary nodules?
- Miliary TB
- Hematogenous spread of metastases
- Fungal infection
What is the major differential for centrilobular pulmonary nodules?
- Infection
- Respiratory bronchiolitis- ILD
- Hypersensitivity pneumonitis (if nodules are ground glass)
What is the major differential for interlobular septal thickening?
- Pulmonary edema (smooth and symmetric)
- Lymphangitic carcinomatosis (nodular and asymmetric)
Honeycombing
Multiple layers of cysts in a subpleural location, a hallmark of UIP
Note: If there is only one row of cysts, its more likely parasepmtal emphysema.
What is the first finding of UIP on chest radiographs?
Reticular opacities in the posterior costophrenic angle
Basilar predominant opacities with traction bronchiectasis and honeycombing…
Definite UIP
Note: Do not biopsy if it’s definite UIP.
Criteria for “definite” UIP
- Honeycombing
- Reticular opacities
- Subpleural and basal predominant
- Absence of inconsistent features (ground glass opacities more pronounced than reticular opacities, air trapping involving 3 or more lobes)
Pulmonary fibrosis with biopsy demonstrating “heterogeneous” histology…
UIP
What are common causes of UIP
- Idiopathic (idiopathic pulmonary fibrosis)
- Collagen-vascular diseases (e.g. Rheumatoid arthritis, scleroderma)
- Sarcoidosis
How can you differentiate UIP from chronic hypersensitivity pneumonitis?
Chronic HP should be mid-upper lobe predominant
Air trapping involving 3 or more lobes also favors chronic HP
Pulmonary fibrosis greatly increases the risk of lung cancer. Where does lung cancer most often arise in these pts?
- Lower lobes
- The interface between the fibrotic cysts and normal lung
In a pt with pulmonary fibrosis, you identify progressive wall thickening of a pulmonary cyst…
Suspicious for cancer
Note: Enlarging pericystic nodules are likewise very suspicious for cancer.
What are the two types of NSIP?
Cellular (ground glass alone) and fibrotic (reticulations and traction bronchiectasis)
What is the most common interstitial lung disease in scleroderma?
NSIP
Pulmonary fibrosis with a lower lobe and peripheral predominance that demonstrates subpleural sparing…
NSIP
Respiratory bronchiolitis-ILD
A smoking-related pulmonary disease that appears as apical centrilobular ground glass nodules
Desquamative interstitial pneumonia
A severe form of smoking-related respiratory bronchiolitis where there are diffuse ground glass opacities with a patchy/subpleural distribution
Peripheral, lower-lobe predominant ground glass opacities with small cystic spaces in a pt with a long extensive history of smoking…
Think desquamative interstitial pneumonia (severe form of respiratory bronchiolitis-ILD)
Why are the ground glass nodules of respiratory bronchiolitis in a centrilobular distribution?
The ground glass nodules are due to macrophages filling up the terminal bronchioles
African American female in her 30s…
Think sarcoidosis
Epidemiology of sarcoidosis
- Usually presents in 20s or 30s
- More common in black females
What laboratory abnormalities are associated with sarcoidosis?
- Elevated angiotensin-converting enzyme (ACE)
- Hypercalcemia
Bilateral hila and right paratracheal lymphadenopathy where the lymph nodes do not abut the cardiac border…
Think sarcoidosis (1-2-3 sign, Garland triad)
Note: This is equivalent to the lambda sign on Gallium scans. If the lymph nodes abut the cardiac border, consider lymphoma.
Bilateral hilar lymph node enlargement, arthritis, and erythema nodosum…
Acute sarcoidosis (AKA Lofgren syndrome)
Perilymphatic nodules with an upper lobe predominance and associated lymphadenopathy…
Think sarcoidosis
Upper lobe conglomerate masses with satellite nodules…
Think sarcoidosis (CT galaxy sign)
Note: Can also be seen with tuberculosis.
What are the stages of sarcoidosis?
- 0 (normal CXR)
- 1 (hilar/mediastinal lymph nodes)
- 2 (nodal and pulmonary parenchymal disease)
- 3 (parenchymal disease only)
- 4 (end stage fibrosis)
What are the two classic signs of sarcoidosis on Gallium scans?
- Lambda sign (gallium uptake resembling lambda symbol due to bilateral hilar and right paratracheal lymphadenopathy)
- Panda sign (gallium uptake in the lacrimal glands, nasopharynx, and parotid glands giving the appearance of a panda face)
Immediate complications of lung transplant (<24 hours)
- Donor-recipient size mismatch
- Hyperacute rejection
Donor-recipient size mismatch complication following lung transplant
When there is a mismatch between the size of the donor lung and the recipients thoracic cavity (a mismatch of up to 25% is considered fine)
Pathophysiology of hyper acute rejection following lung transplant
HLA or ABO antigen incompatibility
Note: This is rapid and often fatal.
Pt dies within hours of receiving a lung transplant and imaging showed massive homogenous pulmonary infiltration…
Hyperacute rejection secondary to HLA/ABO antigen incompatability
What are the early complications status post lung transplant (24 hours to 1 week)
- Repercussion injury
- Air leak/persistent pneumothorax
Pulmonary edema on POD 4 s/p lung transplant that improves by POD 7…
Reperfusion injury (noncardiogenic pulmonary edema secondary to reperfusion ischemia)
Postoperative pneumothorax s/p lung transplant that persists for > 7 days…
Air leak
What are the intermediate (8 days - 2 months) complications s/p lung transplant?
- Acute rejection (+/- cryptogenic organizing pneumonia)
- Bronchial anastomotic complications (leaks in first month, stenoses later in months 2-4)
Ground glass opacities and interlobular septal thickening on POD 14 s/p lung transplant…
Acute rejection
Note: Should improve with steroids.
What bronchial anastomotic complications should you look for and when s/p lung transplant?
- Bronchial anastomotic leak (usually occurs in the first month)
- Bronchial anastomotic stenosis (usually develops 2-4 months s/p transplant)
Ground glass and tree-in-bud opacities 3 months following a lung transplant…
Think cytomegalovirus infection
What is the most common opportunistic infection following lung transplant?
Cytomegalovirus infection
Note: This is rare in the first 2 weeks s/p transplant.
Late complications of lung transplant (>4 months)
- Chronic rejection
- Cryptogenic organizing pneumonia
- Post-transplant lymphoproliferative disorder (PTLD)
- Upper lobe fibrosis
Bronchiectasis, bronchial wall thickening, and air trapping with remote history of lung transplant…
Chronic rejection (bronchiolitis obliterans)
Post transplant lymphoproliferative disorder is associated with…
Epstein Barr virus infection (90% of cases)
What percentage of lung transplant pts develop chronic rejection?
50% at 5 years s/p transplant
Air trapping on expiratory imaging 6 months following lung transplant…
Think chronic rejection/bronchiolitis obliterans
What is the most common recurrent primary disease following lung transplant for that disease?
Sarcoidosis (approximately 35% of cases recur following transplant)
Pulmonary alveolar proteinosis
Pulmonary disease caused by surfactant accumulation in the alveoli and terminal bronchioles leading to a crazy paving appearance
Note: Associated with smoking.
Crazy paving
Interlobular septal thickening with ground glass opacities, classically seen with pulmonary alveolar proteinosis on multiple choice tests
Note: In real life, crazy paving is also seen with pulmonary edema/hemorrhage, bronchoalveolar carcinoma, acute interstitial pneumonia, and COVID.
Pts with pulmonary alveolar proteinosis are at an increased risk for…
Nocardia infections (including Nocardia brain abscesses)
Pulmonary alveolar proteinosis presenting in a child <1 y/o is associated with…
Alymphoplasia
Pulmonary alveolar proteinosis can progress to…
Pulmonary fibrosis
Treatment for pulmonary alveolar proteinosis
Bronchoalveolar lavage
What is the classic appearance of pulmonary alveolar proteinosis?
Central, symmetric crazy paving that spares the apices and costophrenic angles
What are the two types of lipoid pneumonia?
- Endogenous (due to a post obstructive process leading to a buildup of lipid-laden macrophages)
- Exogenous (aspiration of oils/hydrocarbons)
Common causes of exogenous lipoid pneumonia
Aspiration of oils/hydrocarbons:
- Mineral oil laxative use
- Vegetable/animal oil aspirations
- Hydrocarbon exposure
- Fire eating/blowing oils
Pulmonary consolidation with low attenuation/fat density in the consolidation in an elderly pt taking laxatives…
Think lipoid pneumonia due to mineral oil (laxative) aspiration
Pulmonary opacity being shown on a soft tissue window…
Soft tissue windows are usually used to demonstrate fat within a pulmonary opacity, so think hamartoma or lipoid pneumonia
Pathophysiology of organizing pneumonia
Fibroblast proliferation leading to deposition of granulation tissue within the alveolar spaces
Treatment for organizing pneumonia
Steroids
Etiologies of organizing pneumonia
- Idiopathic (cryptogenic OP)
- Post-infectious
- Certain drugs (e.g. Amiodarone)
- Collagen vascular diseases
- Fumes
Persistent cough and low-grade fever lasting several months after being treated for pneumonia with associated patchy consolidate and ground glass opacities…
Think post-infectious organizing pneumonia
Note: Treatment is with steroids.
Reverse halo (atoll) sign
A crescent of consolidation surrounding a ground glass opacity, classically seen in organizing pneumonia
Peripheral patchy consolidations in a pt with a history of asthma
Think chronic eosinophilic pneumonia
Note: Organizing pneumonia looks the same, but labwork should show eosinophilia.
Chronic eosinophilic pneumonia is associated with…
Asthma (50% of cases)
Differential for reverse halo (atoll) sign
- Organizing pneumonia (classic)
- Tuberculosis
- Pulmonary infarction
- Invasive fungal disease
- Granulomatosis with polyangiitis
- COVID
Differential for halo sign (nodule with ground glass surrounding it)
- Invasive aspergillosis (classic)
- Other invasive fungal infections
- Hemorrhagic metastases
- Adenocarcinoma in situ (bronchoalveolar carcinoma)
- Granulomatosis with polyangiitis
Classic appearance of subacute hypersensitivity pneumonitis
Ill-defined centrilobular ground glass opacities with mosaic perfusion and air trapping
Headcheese sign
Ground glass opacities, air trapping, and normal lung parenchyma mixed together, classically seen in chronic hypersensitivity pneumonitis
Pulmonary fibrosis and air trapping…
Think chronic hypersensitivity pneumonitis
Classic appearance of chronic hypersensitivity pneumonitis
- UIP with air trapping
- Headcheese sign (ground glass, air trapping, and normal lung)
Saber sheath trachea
Narrowed trachea (TV diameter < 2/3 the AP diameter), seen in COPD
What is the upper limit of normal for tracheal width?
2.5 cm (no more than the transverse diameter of an adjacent vertebral body)
Thickening of the anterior and lateral tracheal cartilage, sparing the posterior membrane, without associated calcifications in a pt with recurrent pneumonia…
Relapsing polychondritis
Circumferential thickening of the trachea (focal or long segment) with subglottic involvement without associated calcifications…
Granulomatosis with polyangiitis
Cartilaginous and osseous nodules within the submucosa of the tracheal and bronchial walls, sparing the posterior membrane…
Tracheobronchopathia osteochondroplastica (TBO)
Irregular focal or short segment thickening of the trachea with calcifications (+/- posterior membrane involvement)…
Amyloidosis
Differential for tracheal thickening that spares the posterior membrane
- Relapsing polychondritis (diffuse tracheal thickening)
- Tracheobronchopathia osteochondroplastica (nodular thickening)
Differential for tracheal thickening that does not spare the posterior membrane
- Amyloidosis (calcifications common)
- Post intubation (focal in the subglottic region)
- Granulomatosis with polyangiitis (sub glottic location is the most commonly involved)
Pt is C-ANCA positive
Granulomatosis with polyangiitis
Do bronchal carcinoid and GI carcinoid metastasize to the orbit?
Yes, bronchial carcinoid tumors tend to metastasize to the uveal tract (inside eyeball) and GI carcinoid tumors tend to metastasize to the extraoccular muscles (outside eyeball)
Pulmonary nodule that lights up on an octreotide scan and is associated with mitral valve degradation…
Think bronchial carcinoid tumor with carcinoid syndrome leading to left-sided valve degradation
Note: In GI carcinoid, valvular degradation tends to be right-sided (tricuspid, pulmonic valves)
Classic appearance of a typical bronchial carcinoid tumor
Soft tissue nodule (<3 cm) located centrally (e.g. tracheal bifurcation) within the airway lumen +/- calcifications
Note: These are low-grade malignant and NOT associated with smoking.
Classic appearance of an atypical bronchial carcinoid tumor
Soft tissue mass (>3 cm) in a peripheral pulmonary location that may be partially endobronchial or not appear to be associated with a bronchiole at all without calcifications
Note: These are intermediate-grade malignant.
What is the most common tracheal malignancy?
Squamous cell carcinoma (followed by adenoid cystic carcinoma)