Chest Flashcards
What are the RUL pulmonary segments?
Apical
Posterior
Anterior
What are the LUL pulmonary segments?
Apical posterior
Anterior
Superior lingula
Inferior lingula
What are the RML pulmonary segments?
Lateral
Medial
What are the RLL pulmonary segments?
Superior Lateral Basal Medial Basal Anterior Basal Posterior Basal
What are the LLL pulmonary segments?
Superior Lateral Basal Medial Basal Anterior Basal Posterior Basal
What are the mechanisms of atelectasis?
Obstructive Relaxation (passive) Adhesive - surfactant deficiency Cicatrical - volume loss from architectural distortion of lung parenchyma by fibrosis
What happens to atelectasis in ICU patients?
Generally causes volume loss. In critically ill ICU patients, however, there may be rapid transudation of fluid into the obstructed alveoli, causing superimposed consolidation.
What is relaxation atelectasis?
Passive atelectasis - caused by relaxation of lung adjacent to an intrathoracic lesion causing mass effect, such as pleural effusion, pneumothorax, or pulmonary mass.
What is adhesive atelectasis?
Due to surfactant deficiency
MC in neonatal respiratory distress syndrome, but can also be seen in acute respiratory distress syndrome (ARDS)
What is Cicatricial atelectasis?
Volume loss from architectural distortion of lung parenchyma by fibrosis.
Sign associated with LUL atelectasis?
Luftsichel - cresent of air seen on the frontal radiograph - interface between the aorta and the hyperexpanded superior segement of the LLL.
Signs associated with RUL atelectasis?
Reverse S sign of Golden - caused by an obstrucgint mass. The central convex margins of the mass form a reverse S.
Justaphrenic peak sign - peridiaphragmatic triangular opacity caused by diaphragmatic traction from an inferior accessory fissure or an inferior pulmonary ligament.
Collapse of which lobe causes silhouetting of the right heart border?
RML collapse.
What things need to be present to diagnose round atelectasis?
Adjacent pleura must be abnormal
Opacity must be peripheral and in contact with the pleura
Opacity must be round or elliptical
Volume loss must be present in the affected lobe
Pulmonary vessels and bronchi leading to the opacity must be curved - comet tail sign
What is the elemental unit of lung function?
Secondary Pulmonary Lobule
What are the contents of a secondary pulmonary lobule?
Central artery (centrilobular artery) and a central bronchus - each branching many times to ultimately produced acinar arteries and respiratory bronchioles.
On CT, the centrilobular artery is often visible as a faint dot. The centrilobular bronchus is not normally visible.
The acinus is the basic unit of gas exchange, containing several generations of branching respiratory bronchioles, alveolar ducts, and alveoli.
Pulmonary veins and lymphatics collect in the periphery of each SPL.
Connective tissue, called interlobular septa, encases each SPL.
Thickening of the interlobular septa can be seen on CT and suggests pathologic enlargement of either the venous or lymphatic spaces.
Where are the pulmonary veins and lymphatics in the secondary pulmonary lobules?
In the periphery.
Connective tissue, called interlobular septa, encases each SPL.
Thickening of the interlobular septa can be seen on CT and suggests pathologic enlargement of either the venous or lymphatic spaces.
What is the DDx of an acute consolidation?
Pneumonia - MC cause
Pulmonary hemorrhage - primary or aspiration
Acute Respiratory Distress Syndrome (ARDS) - Noncardiogenic pulmonary edema seen in critically ill patients and though to be due to increased capillary permeability.
Pulmonary Edema - May cause consolidation, uncommon manifestation.
DDx of chronic consolidation?
Bronchioalveolar Carcinoma - mucinous subtype, a form of adenocarcinoma.
Organizing pneumonia - nonspecific response to injury characterized by granulation polyps which fill the distal airways, producing peripheral rounded and nodular consolidation.
Chronic eosinophilic pneumonia - an inflammatory process characterized by eosinophils causing alveolar filling in an upper-lobe distribution.
What is organizing pneumonia?
Nonspecific response to injury characterized by granulation polyps which fill the distal airways, producing peripheral rounded and nodular consolidation.
Causes chronic consolidation
What is chronic eosinophilic pneumonia?
An inflammatory process characterized by eosinophils causing alveolar filling in an upper-lobe distribution.
Causes chronic consolidation
What is the difference between consolidation and ground glass opacification?
Consolidation - complete filling of affected alveoli with a liquid-like substance (blood, pus, water, or cells). Pulmonary vessels are not visible through the consolidation on an unehanced CT. Air bronchograms are often present if airway is patent.
Ground glass opacification - partial filling of alveoli - pulmonary vessels are still visible.
DDX of acute ground glass opacification?
Similar to acute consolidation.
Pulmonary edema - usually dependent
Pneumonia - more commonly seen in atypical pneumonia such as viral or Pneumocystis jiroveci pneumonia
Pulmonary hemorrhage
Acute respiratory distress syndrome (ARDS)
DDx of chronic ground glass opacification?
Similar but broader DDx compared to chronic consolidation
Bronchioalveolar Carcinoma - tends to be focal or multifocal
Organizing Pneumonia - Rounded, peripheral chronic consolidation
Idiopathic Pneumonias - Inflammatory responses to pulmonary injury.
Hypersensitivity Pneumoitis (HSP), especially in the subacute phase. A type III hypersensitivity reaction to inhaled organic antigens. Subacute there is ground glass, centrilobular nodules, and mosaic attenuation.
Alveolar proteinosis - idiopathic disease characterized by alveolar filling by a proteinaceous substance. Distribution is typically central, with sparing of the periphery.
DDx of ground glass in a central distribution?
Pulmonary edema
Alveolar hemorrhage
Pneumocystis jiroveci pneumonia
Alveolar proteinosis
DDx of peripheral ground glass or consolidation?
Organizing pneumonia
Chronic eosinophilic pneumonia - typically with an upper lobe predominance
Atypical or viral pneumonia
Pulmonary edema - peripheral tends to be noncardiogenic in etiology, such as triggered by drug reaction - peripheral is unusual for cardiogenic pulmonary edema.
DDx of smooth interlobular septal thickening?
Conditions that dilate the pulmonary veins - pulmonary edema is most common. However, the DDx is identical to the differential for central ground glass.
Pulmonary edema
Pulmonary alveolar proteinosis
Pulmonary hemorrhage
Atypical pneumonia - especially Pneumocystis jiroveci pneumonia
DDx of nodular, irregular, or asymmetric septal thickening?
Processes that infiltrate the peripheral lymphatics - MC lymphangitic carcinomatosis and sarcoidosis.
Lymphangitic carcinomatosis - tumor spread through the lymphatics
Sarcoidosis - noncaseating granulomas, which form nodules and masses primarily in a lymphatic distribution.
What is crazy paving?
Interlobular septal thickening with superimposed ground glass opacification.
Nonspecific, but first described for alveolar proteinosis, where the GGO is caused by filling of alveoli by proteinaceous material and the interlobular septal thickening is caused by lymphatics taking up the same material.
DDx of crazy paving?
Alveolar proteinosis
Pneumocystis jiroveci pneumonia
Organizing pneumonia
Bronchioloalveolar carcinoma, mucinous subtype
Lipoid pneumonia - inflammatory pneuonia caused by a reaction to aspirated lipids.
Acute respiratory distress syndrome
Pulmonary hemorrhage
What are centrilobular nodules?
Opacification of the centrilobular bronchiole (or less commonly the centrilobular artery) at the center of each secondary pulmonary lobule
Multiple small nodules seen in the centers of the secondary pulmonary lobule - never extend to the pleural surface.
May be solid or ground glass attenuation - range in size from tiny up to a cm.
May be caused by infectious or inflammatory conditions.
What are the general categories of causes of centrilobular nodules?
Infectious or inflammatory conditions
What are the infectious causes of centrilobular nodules?
Endobronchial spread of TB or atypical mycobacteria.
Bronchopneumonia - spread of infectious pneumonia via the airways.
Atypical pneumonia, especially mycoplasma pneumonia.
What are the inflammatory causes of centrilobular nodules?
Hypersensitivity Pneumonitis- a type III hypersensitivity reaction to an inhaled organic antigen. The subacute phase is primarily characterized by centrilobular nodules.
Hot tube lung - hypersensitivity reaction to inhaled atypical mycobacteria, with similar imaging to HSP.
Respiratory Bronchiolitis Interstitial Lung Disease (RB-ILD) - inflammatory reaction to inhaled cigarette smoke mediated by pigmented macrophages.
Diffuse panbronchiolitis - Chronic inflammatory disorder characterized by lymphoid hyperplasia in the walls of the respiratory bronchioles resulting in bronchiolectasis. Typically affects patients of Asian descent.
Silicosis - Inhalation lung disease that develops in response to inhaled silica particles - upper lobe predominant centrilobular and perilymphatic nodules.
What is Hypersensitivity Pneumonitis?
A type III hypersensitivity reaction to an inhaled organic antigen. The subacute phase is primarily characterized by centrilobular nodules.
What is Hot Tube Lung?
Hypersensitivity reaction to inhaled atypical mycobacteria, with similar imaging to HSP
What is Respiratory Bronchiolitis Interstitial Lung Disease (RB-ILD)?
Inflammatory reaction to inhaled cigarette smoke mediated by pigmented macrophages
What is Diffuse Panbronchiolitis?
Chronic inflammatory disorder characterized by lymphoid hyperplasia in the walls of the respiratory bronchioles resulting in bronchiolectasis. Typically affects patients of Asian descent.
What is Silicosis?
Inhalation lung disease that develops in response to inhaled silica particles - upper lobe predominant centrilobular and perilymphatic nodules.
Where are perilymphatic nodules located?
Follow the anatomic locations of pulmonary lymphatics - 3 locations.
- Subpleural
- Peribronchovascular
- Septal (within the interlobular septa separating the hexagonal secondary pulmonary lobules).
DDx of perilymphatic nodules?
Sarcoidosis - MC by far, typically with an upper lobe distribution.
Pneumoconioses (silicosis and coal workers pneumoconiosis) are reactions to inorganic dust inhalation. Imaging may look identical to sarcoidosis with perilymphatic nodules, but there is usually a history of exposure (e.g. sandblaster who develops silicosis).
Lymphangitic carcinomatosis
What are Pneumoconioses?
Silicosis and Coal Workers Pneumoconiosis - reactions to inorganic dust inhalation.
Imaging may look identical to sarcoidosis with perilymphatic nodules, but there is usually a history of exposure (e.g. sandblaster who develops silicosis).
DDx of randomly distributed nodules?
Hematogenous metastases
Septic emboli - has a propensity to cavitate, but early emboli may be irregular or solid
Pulmonary Langerhan’s Cell Histiocytosis - a smoking-related lung disease that progresses from airway-associated and random nodules to irregular cysts. Usually distinguishable from other causes of random nodules due to the presence of cysts and non-angiocentric distribution.
What is Pulmonary Langerhan’s Cell Histiocytosis?
A smoking-related lung disease that progresses from airway-associated and random nodules to irregular cysts. Usually distinguishable from other causes of random nodules due to the presence of cysts and non-angiocentric distribution.
DDx of miliary nodules?
Disseminated TB
Disseminated fungal infection
Disseminated hematogenous metastases.
What are tree-in-bud nodules?
Multiple small nodules connecting to linear branching structures, which resembles a budding tree branch in springtime as seen on CT.
Linear branching structures represent impacted terminal bronchioles.
Tree-in-bud nodules are due to mucus, pus, or fluid impacting bronchioles and terminal bronchioles.
DDx of tree-in-bud nodules?
Mycobacteria TB and atypical mycobacteria.
Bacterial pneumonia.
Aspiration pneumonia
Airway-invasive aspergillus - opportunistic fungus with several patterns of disease. Seen in immunocompromised patients and may present either as bronchopneumonia or small airways infection.
What is airway-invasive Aspergillus?
Opportunistic fungus with several patterns of disease. Seen in immunocompromised patients and may present either as bronchopneumonia or small airways infection.
What is a solitary cavitary nodule/mass?
Thick, irregular wall, often with a solid mural component.
Overlap between benign and malignant nodules.
Maximum wall thickness <4 mm is usually benign
Wall thickness >15 mm is usually malignant.
Spiculated margins also suggest malignancy.
DDx of solitary cavitary lesion?
Primary bronchogenic carcinoma - SCC and adenocarcinoma can cavitate - SCC more frequently. Small cell never cavitates.
Tuberculosis - classically produces an upper-lobe cavitation.
DDx of multiple cavitary lesions?
Septic emboli
Vasculitis - including Wegener granulomatosis, which is especially prone to cavitate
Metastases - SCC and uterine carcinoma are known to cavitate.
DDx of multiple lung cysts?
Lymphangioleiomyomatosis (LAM) - diffuse cystic lung disease caused by smooth muscle proliferation of the distal airways. LAM causes uniformly distributed, thin-walled cysts in a diffuse distribution. Classically associated with a chylous effusion.
Emphysema - tends to be upper lobe predominant in a smoker.
Pulmonary Langerhans Cell Histiocytosis - irregular cysts and nodules predominately in the upper lungs.
Diffuse Cystic Bronchiectasis - Congenital or post-infectious causes can have a diffuse or lower-lobe distribution. CF is the MC cause of bronchiectasis has an upper lobe predominance.
Pneumocystis Jiroveci Pneumonia - features cysts in late-stage disease.
Lymphoid Interstitial Pneumonia (LIP) - Rare disease usually associated with Sjogren syndrome and characterized by alveolar distortion from lymphotic infiltrate and multiple cysts.
What is Lymphangioleiomyomatosis (LAM)?
Diffuse cystic lung disease caused by smooth muscle proliferation of the distal airways. LAM causes uniformly distributed, thin-walled cysts in a diffuse distribution. Classically associated with a chylous effusion.
What is Pulmonary Langerhans Cell Histiocytosis?
Irregular cysts and nodules predominately in the upper lungs.
What is Lymphoid Interstitial Pneumonia (LIP)?
Rare disease usually associated with Sjogren syndrome and characterized by alveolar distortion from lymphotic infiltrate and multiple cysts
DDx for a single cyst?
Bulla - Air filled cyst >1 cm
Bleb - Air-filled cystic structure continguous with the pleura measuring <1 cm. Rupture of a bleb is the MC cause of spontaneous pneumothorax.
Pneumatocele - Air-filled space caused by prior lung trauma or infection.
DDx of basal-predominant fibrotic change?
Idiopathic Pulmonary Fibrosis (IPF)- clinical syndrome of progresive pulmonary fibrosis of unknown etiology and is MC cause of basilar fibrosis. Almost always features honeycombing.
End-stage asbestosis - Asbestosis is an asbestos-induced inflammatory process ultimately producing pulmonary fibrosis. Usually other signs of asbestos exposure are present, such as pleural plaques.
Nonspecific Interstitial Pneumonia (NSIP), fibrotic form - Idiopathic pneumonia. Lung response to injury commonly associated with collagen vascular disease and drug reaction. Two histiologic subtypes- cellular and fibrotic forms - the latter may produce basal-predominant fibrosis. In contrast to IPF, honeycombing is usually absent.
What is Idiopathic Pulmonary Fibrosis (IPF)?
Clinical syndrome of progresive pulmonary fibrosis of unknown etiology and is MC cause of basilar fibrosis. Almost always features honeycombing.
What is Nonspecific Interstitial Pneumonia (NSIP)- fibrotic form?
Idiopathic pneumonia. Lung response to injury commonly associated with collagen vascular disease and drug reaction. Two histiologic subtypes- cellular and fibrotic forms - the latter may produce basal-predominant fibrosis. In contrast to IPF, honeycombing is usually absent.
MC cause of pulmonary fibrosis?
Idiopathic Pulmonary Fibrosis
DDx of upper lobe fibrotic changes?
End-stage sarcoidosis
Chronic hypersensitivity pneumonitis
End-stage silicosis
MC cause of community-acquired pneumonia?
S. pneumoniae
Pneumonia cause in young and otherwise healthy patients?
Atypical pneumonia, including Mycoplasma, viral, and Chlamydia.
Mycoplasma has a varied appearance and can produce consolidation, areas of ground glass attenuation, centrilobular nodules, and tree-in-bud nodules.
MC cause of pneumonia in elderly smokers?
Legionella - infection tends to be severe.
Peripheral consolidation often progresses to lobar and multifocal pneumonia.
Cause of pneumonia in alcoholics and aspirators?
Klebsiella and other gram-negatives.
Klebsiella classically leads to voluminous inflammatory exudates causing the bulging fissure sign.
What is the Bulging Fissure Sign?
Secondary to voluminous inflammatory exudates due to Klebsiella
What causes Hospital Acquired Pneumonia?
Aspiration of colonized secretions due to aspiration of colonized secretions.
Wide variety of organisms- most important pathogens include MRSA and resistant gram-negatives including Pseudomonas.
What is Health Care Associated Pneumonia (HCAP)?
Pneumonia in a nursing home resident or a patient with a >2 day hospitalization over the past 90 days.
Pathogens are similar to Hospital Acquired Pneumonia- MRSA and gram-negatives including Pseudomonas.
What is Ventilator Associated Pneumonia (VAP)?
Caused by infectious agents not present at the time mechanical ventilation was started.
Most are polymicrobial and primarily involve gram-negative rods such as Pseudomonas and Acinetobacter.
What causes pneumonia in immunocompromised patients?
Any pathogens plus opportunistic infections including Pneumocystis, fungi such as Aspergillus, Nocardia, CMV, etc.
What is Lobar Pneumonia?
Consolidation of a single lobe.
Usually bacterial in origin and is MC presentation of community acquired pneumonia.
What is lobular pneumonia (bronchopneumonia)?
Patchy consolidation with poorly defined airspace opacities, usually involving several lobes, and most commonly due to S. aureus.
Difference between Lobar and Lobular Pneumonia?
Lobular pneumonia = bronchopneumonia
Patchy consolidation with poorly defined airspace opacities, usually involving several lobes, and most commonly due to S. aureus.
Lobar = Consolidation of a single lobe.
What is interstitial pneumonia?
Inflammatory cells located predominantly in the interstitial tissue of the alveolar septa causing diffuse or patchy ground glass opacification.
Can be viral pneumonia, Mycoplasma, Chlamydia, or Pneumocystis.
What is Round Pneumonia?
Infectious mass-like opacification seen only in children, MC due to Streptococcus pneumoniae.
Infection remains somewhat confined due to incomplete formation of pores of Kohn.
Causes of lung abscesses?
Staphylococcus aureus, Pseudomonas, or anaerobic bacteria.
Air-fluid level is almost always present.
An abscess is usually spherical, with equal dimensions on frontal and lateral views.
What is pulmonary gangrene?
Very rare complication of pneumonia - extensive necrosis or sloughing of a pulmonary segment or lobe.
Severe manifestation of pulmonary abscess.
What are the three stages of development of an empyema?
- Free-flowing exudative effusion- can be treated with needle aspiration or simple drain.
- Development of fibrous strands- requires large-bore chest tube and fibrinolytic therapy.
- Fluid becomes solid and jelly-like- usually requires surgery.
What is a pneumatocele?
Thin-walled, gas-filled cyst that may be post-traumatic or develop as a sequela of pneumonia- typically from Staphylococcus aureus or Pneumocystis.
Pneumatoceles almost always resolve.
What is a Bronchopleural Fistula?
Abnormal communication between the airway and the pleural space - caused by rupture of the visceral pleura.
MC cause is surgery, but can get with lung abscess, empyema, and trauma.
What is Empyema Necessitans?
Extension of an empyema to the chest wall - MC secondary to TB.
Other causative organisms include Nocardia and Actinomyces.
What can initial exposure to TB lead to?
- Contained disease (90%)- results in classified granulomas and/or calcified hilar lymph nodes. With normal immunity, the tuberculous bacilli are sequestered with a caseating granulomatous response.
- Primary Tuberculosis - host cannot contain the organism. More common in children and immunocompromised patients.
What is Primary TB?
Infection from the first exposure to TB. May involve the pulmonary parenchyma, airways, and the pleura. Often causes adenopathy.
Up to 15% may have no radiographic changes and the imaging appearance of primary TB is nonspecific.
Four imaging manifestations: ill-defined consolidation, pleural effusion, lymphadenopathy, and miliary disease.
Primary may occur in any lobe, but most typical locations are the lower lobes or RML. Can be difficult to distinguish between primary and post-primary TB - treatment is the same.
Gohn Focus: Initial focus of parenchymal infection, usually located in the upper part of the lower lobe or lower part of the upper lobe.
Ranke Complex: Ghon focus and LAD.
Cavitation is rare in primary TB, in contrast to reactivation TB.
What are the four imaging manifestations of primary TB?
Ill-defined consolidation, pleural effusion, lymphadenopathy, and miliary disease.
Most typical locations of primary TB?
Primary may occur in any lobe, but most typical locations are the lower lobes or RML.
What is a Gohn Focus?
Initial focus of parenchymal infection, usually located in the upper part of the lower lobe or lower part of the upper lobe.
What is a Ranke Complex?
Ghon focus and LAD.
What is reactivation TB?
Post-primary TB
Adolescents and adults- reactivation of dormant infection acquired earlier in life.
Chronic cough, low-grade fever, hemoptysis, and night sweats.
MC occurs in the upper lobe apical and posterior segments.
Immunocompetent- upper-lobe predominant disease with cavitation and lack of adenopathy. Focal upper lobe consolidation and endobronchial spread are common. Tree-in-bud nodules suggest active endobronchial spread.
Immunosuppressed patient (such as HIV), low-attenuation adenopathy is typical additional finding, similar to adenopathy seen in primary TB. Low density lymph nodes may mimic immune reconstitution syndrome in HIV patients.
Tuberculoma is a well-defined rounded opacity usually in the upper lobes.
What does reactivation TB look like in immunocompetent patients?
Upper-lobe predominant disease with cavitation and lack of adenopathy. Focal upper lobe consolidation and endobronchial spread are common. Tree-in-bud nodules suggest active endobronchial spread.
What does reactivation TB look like in immunocuppressed patients?
Low-attenuation adenopathy is typical additional finding, similar to adenopathy seen in primary TB. Low density lymph nodes may mimic immune reconstitution syndrome in HIV patients.
What is a Tuberculoma?
Tuberculoma is a well-defined rounded opacity usually in the upper lobes.
Signs of healed tuberculosis?
Apical scarring, usually with upper lobe volume loss and superior hilar retraction.
Calcified granulomas may be present as well, which indicate containment of the initial infection by a delayed hypersensitivity response.
What form of TB can miliary TB seen?
Primary or reactivation TB.
What is the classic presentation of atypical mycobacteria?
Elderly woman with cough, low-grade fever, and weight loss - Lady Windermere syndrome.
What are the atypical mycobacterial infections?
Mycobacterium avium intracellulare and M. kanasii.
Findings of atypical mycobacteria infection?
Bronchiectasis and tree-in-bud nodules - MC in RML or lingula.
What is Lady Windermere Syndrome?
Elderly woman with cough, low-grade fever, and weight loss - Atypical mycobacteria infection.
What is hot tube lung?
Hypersensitivity pneumonitis in response to atypical mycobacteria which are found in hot tubs.
No active infection and the typical patient is otherwise healthy.
Imaging is similar to other causes of hypersensitivity pneumonitis, featuring centrilobular nodules.
What is Histoplasma Capsulatum found?
Localized to the Ohio and Mississippi river valleys - in soil contaminated with bat or bird guano.
Chronic infection can mimic reactivation TB with upper lobe fibrocavitary consolidation.
What is a rare complication of Histoplasma capsulatum infection?
Fibrosing medastinitis - infection of mediastinal lymph nodes leading to pulmonary venous obstruction, bronchial stenosis, and pulmonary artery stenosis. Affected lymph nodes tend to calcify.
What is Fibrosing Mediastinitis?
Rare complication of Histoplasma capsulatum infection
infection of mediastinal lymph nodes leading to pulmonary venous obstruction, bronchial stenosis, and pulmonary artery stenosis. Affected lymph nodes tend to calcify.
Where is Coccidioides Immitus found and what does it look like on imaging?
SW US and has a variety of radiologic appearances, including multifocal consolidation, multiple pulmonary nodules, and miliary nodules.
Where is Blastomyces Dermatitidis and what does it look like?
Central and SE US.
Infection is usually asymptomatic, but may present with flu-like illness that can progress to multifocal consolidation, ARDS, or miliary disease.
Immunocompromised patient with a focal air space opacity?
Most likely to have a bacterial pneumonia (MC pneumococcus), but TB should also be considered if CD count is low.
Multifocal opacities have a wider DDx including Pneumocystis pneumonia and opportunistic lung fungal infection such as Cryptococcus or Aspergillus.
Immunocompromised patient with mulfifocal opacities?
Multifocal opacities have a wider DDx including Pneumocystis pneumonia and opportunistic lung fungal infection such as Cryptococcus or Aspergillus.
Most likely to have a bacterial pneumonia (MC pneumococcus), but TB should also be considered if CD count is low.
What is Pneumocystis jiroveci pneumonia?
Opportunistic fungus that may cause pneumonia in individuals with CD4 counts <200 cells/cc.
CXR can be normal, but classic finding is bilateral perihilar (central) airspace opacities with peripheral sparing.
CT: geometric perihilar ground glass opacification, sometimes with crazy paving.
Normal CT rules out Pneucystis pneumonia, but can hide in a normal CXR.
Propencity to cause upper lobe pneumatoceles, which may predispose to pneumothorax or pneumomediastinum.
CXR findings of Pneumocystis jiroveci pneumonia?
CXR can be normal, but classic finding is bilateral perihilar (central) airspace opacities with peripheral sparing.
Normal CT rules out Pneucystis pneumonia, but can hide in a normal CXR.
CT findings of Pneumocystis jiroveci pneumonia?
CT: geometric perihilar ground glass opacification, sometimes with crazy paving.
Normal CT rules out Pneucystis pneumonia, but can hide in a normal CXR.
What does Pneumocystis jiroveci pneumonia have a propensity to cause?
Propencity to cause upper lobe pneumatoceles, which may predispose to pneumothorax or pneumomediastinum.
What is Cryptococcus Neoformans pneumonia?
Opportunistic organism and is the MC fungal infection in AIDS patients. Pulmonary infection usually coexists with cryptococcal meningitis. CD4 is usually less than 100 in affected individuals.
Can have a wide range of appearances ranging from GG attenuation to focal consolidation to cavitating nodules.
Can also present as milliary disease, often with LAD or effusions.
Spectrum of pulmonary Aspergillus with Asthma?
Increased/inappropriate immune response
Allergic bronchopulmonary aspergillus
Finger-in-glove sign: mucoid impaction of bronchiectasis.
Spectrum of pulmonary Aspergillus with preexisting cavity (e.g. sarcoid, TB)?
Abnormal lungs or abnormal host
Aspergilloma/Mycetoma
Mobile mycetoma
Monad Sign: Air surrounding mycetoma
