Chab: Chest Exam 1

Chest radiograph: Why can the heart appear enlarged on X-ray?

AP thoracic positioning, 40-inch SID, breathing out/expiration, and an elevated diaphragm can make the heart appear larger and more horizontal.

What is the recommended breathing phase for chest films?

Full inspiration/inhalation.

Why should chest radiographs be performed at full inspiration?

To avoid lung field/density changes and the appearance of an enlarged heart caused by expiration.

What is the SID used for chest radiographs in this material?

40 inches.

What chest radiographic position can falsely increase apparent heart size?

AP thoracic position because the heart is farther from the bucky/image receptor.

What happens to the heart when the diaphragm is elevated?

The heart becomes more horizontal.

Why perform chest radiographs?

Chronic cough, especially nonproductive cough; expectoration/hemoptysis; shortness of breath; cyanosis; clubbing of fingers; or pain/complaints involving the chest, thoracic spine, or upper extremities.

Is a PA chest view alone adequate as a screening procedure for elderly adults?

False according to the course material.

How many anterior ribs should normally be visible on a full-inspiration chest X-ray?

5–7 anterior ribs.

How many posterior ribs should normally be visible on a full-inspiration chest X-ray?

9–10 posterior ribs.

How can you determine whether a patient took a full inspiration?

Count the visible ribs.

What is the normal cardiothoracic ratio?

Heart width should be less than one-half of the thoracic/hemithorax width, approximately 1:2 or less.

What does an increased cardiothoracic ratio indicate?

Possible cardiomegaly.

What conditions can cause an increased cardiothoracic ratio?

Mitral regurgitation, aortic regurgitation, idiopathic dilated heart disease, ischemic cardiomyopathy, tricuspid regurgitation, right ventricular failure, and pericardial effusion.

Why can expiration make the heart look larger?

The lungs contain less air, appear denser, and fewer ribs are visible, making the heart appear larger.

What forms the apex of the heart?

The ventricles.

What is pectus excavatum?

A deformity characterized by decreased AP chest cavity depth.

How does pectus excavatum typically affect the heart position?

It typically shifts the heart farther to the left.

What can pericardial calcification be associated with?

A “machine-like hum” on auscultation and a history of constrictive pericarditis.

What is the most common differential diagnosis for an enlarged cardiac silhouette?

Cardiomegaly.

What is the second most common differential/secondary consequence associated with an enlarged cardiac silhouette?

Effusion, such as fluid where it is not supposed to be.

What is a pleural effusion?

Accumulation of fluid within the pleural space.

Where does pleural fluid accumulate?

Between the parietal and visceral pleura.

Is pleural fluid gravity dependent?

Yes. Pleural fluid is gravity dependent.

Where may fluid typically gather first?

In the dependent portions/distal areas, such as the ankles/distal extremities in systemic fluid overload.

What causes a transudative pleural effusion?

Increased hydrostatic pressure or decreased plasma oncotic pressure.

What conditions are associated with transudative effusions?

CHF, cirrhosis, nephrotic syndrome, pulmonary embolism, and hypoalbuminemia.

What is the protein/LDH content of a transudative effusion?

Low protein and LDH.

What causes an exudative pleural effusion?

Inflammation and increased capillary permeability.

What conditions are associated with exudative effusions?

Pneumonia, cancer, TB, viral infection, pulmonary embolism, and autoimmune disease.

What is the protein/LDH content of an exudative effusion?

High protein and LDH.

What is the “vanishing tumor”?

A lenticular/football-shaped pleural effusion located in a fissure that disappears after treatment with a diuretic.

Why is a fissural pleural effusion called a “vanishing tumor”?

Because it can disappear when excess fluid is treated with a diuretic.

What are Kerley lines associated with?

Interstitial thickening caused by poor fluid-volume control, especially with CHF.

Where are Kerley A lines located?

They radiate away from the center and are closer to the apex.

Where are Kerley B lines located?

At the lung bases.

Where are Kerley C lines located?

Between the lung base and center.

Does seeing pulmonary fissures automatically confirm pathology?

False. Visible fissures increase the likelihood of blood, pus, edema, or other material but do not automatically confirm pathology.

What are the four anatomic roentgenometric divisions listed?

A = anterior, B = middle, C = posterior, D = superior.

Where should normal pulmonary lines generally not extend?

Beyond the mid-clavicular lines.

What is air-space disease?

A fluffy/cloudy radiographic pattern caused by air being displaced by something more solid, such as blood, pus, tumor, or edema.

What structures can air-space disease fill?

Alveoli or bronchi.

What does interstitial lung disease look like radiographically?

A wispy pattern resembling a spiderweb.

What happens to fissures with interstitial disease?

They can become visible and thicken due to blood, pus, tumor, or edema.

What does a normal lung field generally look like regarding lines?

You should not see lines extending beyond the mid-clavicular lines.

What is consolidation?

A radiographic term that can describe air-space filling, interstitial thickening, or both.

What can cause alveolar consolidation from blood?

Alveolar hemorrhage and Goodpasture disease.

What can cause consolidation from edema?

CHF and pneumonitis.

What can cause consolidation from pus?

Pneumonia.

What can cause consolidation from tumor?

Lymphoma and alveolar cell carcinoma.

What is the airspace of the lung?

The primary lobule, or acinus.

Where is the primary lobule located?

Distal to a respiratory bronchiole.

How does the primary lobule communicate with neighboring airspaces?

Through pores of Kohn and canals of Lambert.

What is the smallest structural segment of the lung enclosed by a connective tissue septum?

The secondary lobule.

What do Type I pneumocytes do?

They cover approximately 90% of the alveolar surface and function as lining cells.

What do Type II pneumocytes do?

They produce surfactant.

Why is the thin interface between capillaries and Type I pneumocytes important?

It facilitates gas exchange.

What is the pulmonary interstitium?

The connective-tissue support network of the lung.

Where are capillaries, venules, and lymph vessels found in the pulmonary interstitium?

In axial, parenchymal, and peripheral spaces.

What is the axial interstitium?

The peribronchovascular space surrounding the primary bronchi.

What is the parenchymal interstitium?

The space between the air-exchanging portions of the lung.

What is the peripheral interstitium?

The outermost space between the visceral pleura and lung parenchyma.

What is a URI?

An upper respiratory tract infection occurring above the clavicles.

What structures are involved in a URI?

The sinuses, pharynx, and larynx.

What are examples of URIs?

Common cold, tonsillitis, sinusitis, and laryngitis.

What is an LRI?

A lower respiratory tract infection occurring below the clavicles.

What structures are involved in an LRI?

The bronchi and lungs.

What are examples of LRIs?

Bronchitis and pneumonia.

What is pneumonia?

Inflammation of the functional portion of the lung, also called the alveolar parenchyma.

Why is pneumonia clinically important?

It is described in the material as the most life-threatening infectious disease.

How long do most cases of pneumonia take to resolve?

Approximately 4 weeks.

What is usually the last symptom of pneumonia to resolve?

Cough.

How does pneumonia affect gas exchange?

It compromises oxygen/CO2 exchange.

What are the stages of pneumonia listed?

Invasion by pathogen, multiplication of pathogen, opsonization by the immune system, and resolution.

Can pneumonia have no radiographic findings?

Yes.

What are radiographic features that may be seen with pneumonia?

Partial or complete air-space consolidation, silhouette sign, air-bronchogram sign, pleural effusion, lung cavitation, and empyema.

What is lung cavitation?

A space created within the lung parenchyma.

What is empyema?

Pus located between the pleural layers.

What are the methods of pneumonia acquisition listed?

Community-acquired, nosocomial, immunosuppressed, and aspiration.

What is aspiration pneumonia associated with?

Alcoholism or inability to swallow.

What are the four radiographic patterns of pneumonia?

Broncho/lobular pneumonia, lobar pneumonia, interstitial pneumonia, and aspiration pneumonia.

What is broncho/lobular pneumonia?

Involvement of segmental bronchi and surrounding alveoli with a central-to-peripheral pattern of consolidation.

What is lobar pneumonia?

Involvement of distal bronchioles and surrounding alveoli with a peripheral-to-central pattern of consolidation.

What is interstitial pneumonia?

Thickening of the interstitium involving alveolar septa, producing a “fishing net” appearance and linear radiodense shadows.

What is aspiration pneumonia radiographically?

Gravity-dependent consolidation, especially in posterior lung segments, with a mixed pattern of consolidation.

What is the most common causative agent of pneumonia in this material?

Streptococcus pneumoniae (pneumococcus).

What is the typical X-ray distribution of Streptococcus pneumoniae pneumonia?

Usually lobar distribution.

What settings can Streptococcus pneumoniae pneumonia occur in?

Bacterial community-acquired and nosocomial pneumonia.

What is the second most common causative agent listed for pneumonia?

Haemophilus influenzae.

Who is at increased risk for Haemophilus influenzae pneumonia?

People with alcoholism, diabetes, chronic disease, and those over 50.

Which lung contains the lingula?

The left lung.

What is the lingula equivalent to?

The right middle lobe, anatomically.

Which lung lobes touch the heart?

The left upper lobe and right middle lobe.

What is the silhouette sign?

Loss of the margin between two opposing structures of the same radiographic density.

Why does the silhouette sign occur?

When structures of the same radiographic density are touching, their borders blend together.

What radiographic density are muscles and organs considered?

Water density.

What happens when fluid, blood, pus, tumor, or edema fills an airspace adjacent to a water-density structure?

The border may become shaggy or disappear, producing a silhouette sign.

If the heart is silhouetted, where is consolidation likely located according to the material?

Left upper lobe.

If the left heart border is normal/well defined, where is consolidation likely located?

Left lower lobe.

If the right heart border is not well defined, where is consolidation likely located?

Right middle lobe.