Tag Archives: Pneumonia

WWWTP #23 (What’s Wrong With This Picture?) Answer

March 12, 2015

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Patient presented with cough, fevers.  This Chest Xray was obtained:

WWWTP 21 1

One finding on this Xray is very concerning.  The Xray showed free air under the diaphragm.

A further diagnostic study was obtained (CT abdomen/pelvis):

WWWTP 21 2 WWWTP 21 3

Turns out this patient has pneumatosis cystoides intestinalis.  He has a history of this disorder and has had a prior laparoscopy showing multiple cystic structures in the intestinal walls.

Findings on imaging:

1.  Chest Xray:  Concern for free air underneath the diaphragm.  He also has a tracheostomy, pacemaker, scoliosis, and a right lower lung infiltrate.

2.  CT abdomen/pelvis:  The coronal imaging shows multiple cystic structures full of free air in the cecal area.  The cross-sectional imaging above shows a large amount of pneumoperitoneum.

Luckily this patient has a history of pneumatosis cystoides intestinalis.  He has had multiple abdominal CT’s showing similar findings.  Clinically he had no abdominal tenderness.  Keep this rare diagnosis in mind for the patient presenting with free air in the abdomen!  Information about pneumatosis cystoides intestinalis:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3235639/

Author:  Russell Jones, MD

Image Contributor:  Mary Bing, MD

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Student Corner: A Cavitary Lesion

January 6, 2015

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Cavitary lesions in the lungs are gas or fluid filled compartments in an area of pathology, such as a consolidation or a mass. Interestingly, a specific set of pathologies are known to cause this specific finding. Cavitary lesions can be detected on a chest x-ray, as is shown below.

cavitary-mass with IDCavitary masscavitary mass lateral with IDCavitary mass 2

Legend: Red Ellipse–cavity (with margins), Blue Ellipse–air-fluid level

The lesion practically jumps out of the picture on the AP view, but the colored circles are there just to point out the entire area of pathology (blue) and the cavity within (red). The pathology is a bit harder to see on lateral view, but the cavity has an air-fluid level that is easily identified as a vertical line separating a lighter fluid filled portion from an air filled portion. This air-fluid interface is often called a meniscus. You might remember being in chemistry class and measuring water out of tall beakers where the water stuck to the sides of the glass creating a concave meniscus. The surface tension of water allows it to stick to both itself and surrounding surfaces. If you look close enough, you’ll notice that the air-fluid level in the image above, best visualized in the AP view, has a slightly concave shape because the liquid at the bottom is sticking to the solid sides of the cavity.

The underlying pathophysiology is an interesting concept to understand when discussing cavitary lesions. A cavity can form in lung tissue for various reasons, but infection is the major underlying cause. Abscesses are localized collections of pathogens, fluid and immune system components that are walled off from the surrounding tissue, therefore creating a fluid-filled cavity. Tuberculosis is a disease process that involves caseous necrosis, which results in coagulation of cell proteins and liquefaction of cellular components. Eventually, the liquid portion drains out through the lymph system or through the bronchi, leaving air pockets behind. Necrotizing pneumonia and non-infectious processes such as ischemia and neoplasm can also cause a similar picture. Rheumatologic diseases such as granulomatosis with polyangitis and sarcoidosis also cause cavitary lesions by causing localized inflammation, which in turn leads to an area of increased mass, which then in turn can cavitate once the inflammatory reaction recruits fluid to the area. In other words, most of these processes, even if they aren’t inherently related to one another, all converge on the same mechanism of causing a localized area of inflammation.

With such a wide array of categories to choose from, it is perhaps more important than usual to contextualize the radiographic image with information about the patient.

This particular patient is a 30 year old male who presents with a cough.  He has been traveling around the world to multiple continents including Sub-Saharan Africa.  The extensive travel history, including to continents with rare infectious diseases leaves infection at the top of the differential. Things like Staphylococcal pneumonia, fungal infections and even amebiasis are possible because of the patient’s travel history. For a complete list of the infectious causes of a cavitary lesion, check the first two references at the bottom of the page.

References/resources:

Gadkowski LB, Stout JE. Cavitary Pulmonary Disease. Clinical Microbiology Reviews 2008;21(2):305-333. doi:10.1128/CMR.00060-07. (LINK)

Ryu, Jay H. et al. Cystic and Cavitary Lung Diseases: Focal and Diffuse. Mayo Clinic Proceedings , Volume 78 , Issue 6 , 744 – 752. (LINK)

Good pathologic image of caseous necrosis with resulting cavitation

Image Contributor:  James Luz, MD

Author:  Jaymin Patel

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Student Corner: How to Read a Chest X-Ray

August 25, 2014

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In these “Student Corner” pieces, we will go over certain aspects of radiology in EM that are of interest to medical students. Topics will include: common (and interesting) case presentations with accompanying imaging, schematics for how to read different types of imaging in various anatomical locations, discussions on what types of imaging to order and when in the EM setting, and others.

In this inaugural edition of the Student Corner, we’ll take a look at how to tackle reading an anterior-posterior chest x-ray.

For starters, it is important to understand that having a “gameplan” for reading any type of image is key when you first start out trying to decipher radiological images. As a reader and interpreter, you must be systematic in your thought process as you analyze the image in front of you. For chest x-rays, there is a classic schematic: ABCDE. Any medical student will tell you that this is not the only time you will see “ABC…” used as a way to quickly memorize something, but at least it’s easy to remember.

Here’s the image we are going to use and let’s start to dissect it using the mnemonic:

Note: For the purpose of keeping this a short piece, we’ll only focus on the anterior-posterior view only.

CXR UL pna Airway

A-Airway

Legend: Red Arrows–trachea; Blue Arrows–carina; Green arrows–L and R main bronchus

The upper airway, including the trachea, carina and both main bronchi, should all be visible on an AP view. Things to look for include deviation of the trachea away from the midline (there is some deviation to the patient’s right in this image, but this is due to the aortic arch, which passes to the left of the trachea as it passes posteriorly in the mediastinum), obstruction due to aspiration of a foreign object and obscuring of the upper airway due to enlarged mediastinal lymph nodes.

Let’s explore tracheal deviation a bit further. Deviation from the midline is not associated with a defect in the trachea itself, but with a force from either the R or L side of the chest cavity that is pulling or pushing the trachea to one side or the other. For example, introduction of air into one side of the chest cavity will cause that lung to collapse due to the loss of negative intrapleural pressure. The collapsed lung will shrink to the size of a ball and “push” the trachea to the opposite side. You can think of the two lungs like bungee cords that put roughly equal force on the trachea in each direction. If one of the cords snaps or is released from where it is attached to, the cord that is still intact will pull the trachea towards one side, resulting in a deviation that will show up on a CXR.

B-Bones

CXR example Bones

Legend: Numbers–ribs; Red Arrow–clavicle; Blue Arrow–medial border of scapula

A CXR offers a good view to look for rib fractures and clavicle fractures. Clavicular fractures are usually easy to spot, as they usually reveal distinct fracture lines in the middle 3rd of the clavicle. Hairline fractures are less common. Rib fractures are sometimes hard to spot, but each rib should be followed across it’s length to look for fracture lines or step-offs (disruptions in the normal curve of the rib) that could indicate a fracture.

The number of ribs is also important to assess because it is an indirect measurement of the volume of the chest cavity. Hyperinflated lungs are usually the result of obstructive disease where the patient is unable to fully expel the air that is inhaled with every breath they take–this increase in residual volume will build up over time and overinflate the chest cavity. This overinflation will result in a greater-than-normal number of ribs being visible on an AP view. Normally, you should expect to see 8-10 ribs on an upright chest X-ray, depending on whether the patient was instructed to exhale or inhale before the picture was taken.

C-Cardiac

CXR Cardiac

 

Legend: Red Dashed Lines–heart borders

This part of the mnemonic involves the heart and surrounding structures. The silhouette of the heart should be identified and the heart borders should be clear. A general rule of thumb is that the heart base should not be wider than 1/2 the total width of the diaphragm. As with a lot of “general rule of thumb”s in medicine, it’s not quite clear whether this has any diagnostic value–for example, if the heart base is indeed 1/2 the width of the diaphragm on CXR, is that really sensitive for cardiomegaly? In any case, it’s something to keep in mind.

The aortic arch and the L pulmonary artery should be visible as two semi-circles above the left atrium. There is a space called the “AP Window” that has the following borders: ascending aortic arch (anterior), descending aortic arch (posterior), L pulmonary artery (inferior), inferior border of aortic arch (superior). The window should be “concave” in the sense that the lateral border should be caved in medially. If it is not, things like mediastinal lymphadenopathy and aorta/pulmonary artery aneurysms are possible.

D-Diaphragm

CXR Diaphragm

 

Legend: Blue Arrow–gastric air bubble; Red Arrow–costophrenic angle

The diaphragm has 3 major characteristics which you look for on CXR. One is the gastric air bubble, which allows you to identify that the stomach is on the left (as opposed to the right, as in situs inversus). Another is the contour of the diaphragm, which should be a “dome” shape. The right side should be a little higher than the left, thanks to the liver. The third is perhaps the most important: the costophrenic angle. It is the lateral point of attachment for the diaphragm and it should be a sharp, triangle-shaped region at either end. The angle should be acute. If the angle is closer to 90 degrees, then one possible explanation is that the lungs are hyperexpanded (perhaps because of COPD) and pushing the diaphragm down into the abdomen. “blunting” of the angle refers to a radio-opaque marking of the angle that usually is indicative of pleural effusion.

E-Everything Else

Everything else is…everything else. Mostly this means the lung parenchyma itself. For this, asymmetry is key. Compare left and right and see whether there is a difference. More on this particular section of the read later.

—–

Now you should try to read the above x-ray for yourself and type your own version of the read in the comments if you’d like. If not the entire read, then try to identify the pathology in the x-ray and post your answer in the comments. Any questions/comments would also be appreciated.

I’ll post the answer with the “correct” read a bit later on the site.

Author: Jaymin Patel

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Multifocal opacities…

May 12, 2014

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A patient presented to the ED with flu-like symptoms in the height of flu season:

multifocal opacities

Chest CT:

Multifocal opacities CT 2 Multifocal opacities CT

The CT demonstrates multifocal opacities with some cavitation on the larger lesions.  There seems to be a peripheral and lower-lobe predominence.  This could represent atypical pneumonia (legionella, mycoplasma, chlamydia), fungal pneumonia (cocciodomycosis, histoplasmosis, aspergillosis), miliary tuberculosis, metastatic lesions or carcinomatosis, septic emboli, or viral pneumonia.

After a significant inpatient workup the final diagnosis was Human Metapneumovirus.  All others were ruled out and viral testing revealed this culprit.

Image contributors:  David Barnes, MD and Julie Phan, MD

Author:  Russell Jones, MD

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19 month old with pneumonia…

November 3, 2013

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Peds PNA

This is an interesting pediatric chest Xray.  Immediately you notice that the right lung is diffusely more dense than the left.  This is because the patient is supine and a pleural effusion is layering behind the right lung in a dependent fashion.  Also notice the hyperinflation of the left side compared to the right.  This patient ended up having a post-obstructive pneumonia due to aspiration!

Author:  Russell Jones, MD

Image Contributor:  Kendra Grether-Jones, MD

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Answer AIDS PNA…

October 22, 2013

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On a previous post I posed a question on the differential diagnosis of pneumonia in an AIDS patient with this chest Xray:

AIDS CXR PNA

This is a multilobar pneumonia vs. ARDS (Acute Respiratory Distress Syndrome).  AIDS patients can have the same bacterial causes of multilobar pneumonia that is present in other patient populations (Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus Influenza, Moraxella catarrhalis, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumoniae, etc.).  If they are healthcare associated or hospital-acquired further drug-resistant bugs such as Pseudomonas aeruginosa and MRSA could be implicated.  Infectious organisms specifically involved in immunocompromised hosts could include (among others):

  • Pneumocystis Jiroveci (PCP pneumonia)
  • Coccidioides species
  • Cytomegalovirus (CMV)
  • Tuberculosis (TB)
  • Histoplasma species
  • Aspergillus species
  • Mycobacterium avium complex (MAC)
  • Influenza
  • Herpes simplex virus (HSV)
  • Varicella-zoster virus (VZV)
  • Legionella species
  • Nocardia species
  • Cryptococcus neoformans
  • Mucoraceae species
  • Strongyloides species
  • Toxoplasma species
  • Capnocytophaga species

Non-infectious causes of multilobar infiltrates such as this could include diffuse alveolar hemorrhage, cardiogenic pulmonary edema, ARDS, among others. The multilobar involvement of the Xray above could implicate certain pathogens in favor of others (for example, Pneumocystis Jiroveci is usually multilobar as opposed to Streptococcus pneumonia which usually will cause a dense, lobar pneumonia).  The other interesting feature of the Xray is that it appears multi-nodular.  This can implicate entities such as CMV rather than a bat-wing ground-glass appearance of Pneumocystis Jiroveci.  For further discussion on pneumonia radiographic findings in AIDS, please see radiopaedia.org discussion below:

http://radiopaedia.org/articles/pulmonary-manifestations-of-hiv-aids

Incidentally, the endotracheal tube should be pulled back about 2 cm.

Author:  Russell Jones, MD

References

1.  Jones J, Stanislavski A, et al.  Pulmonary Manifestations of HIV/AIDS.  http://radiopaedia.org/articles/pulmonary-manifestations-of-hiv-aids.  Accessed 10/2013.

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Pneumonia in AIDS patient…

October 14, 2013

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This patient has a history of AIDS with very low CD4 count and came in with respiratory distress:

AIDS CXR PNA

This Xray shows a diffuse pulmonary infiltrates, bilateral pleural effusions.  There is an endotracheal tube near the carina, it could come back a couple centimeters.  He also has a nasogastric tube coursing below the diaphragm. 

What is the differential diagnosis of a multilobar pneumonia such as this in an AIDS patient?  Comments appreciated!

Author:  Russell Jones, M.D.

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Answer to chest Xray…

June 2, 2013

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The other day I posted this Chest Xray on an individual with cough, fevers:

PJP PNA

The xray shows diffuse interstitial infiltrates concerning for an atypical pneumonia.  The patient had several weeks of weight loss, fatigue, fevers and he had profound hypoxia into the 40s on room air.  The differential diagnosis in this situation is broad and can include common atypical bacterial pneumonia organisms (Mycoplasma, chlamydia sp, legionella, etc).  ARDS can present like this with diffuse infiltrates and hypoxia.  Influenza is also on the list of pathology.  However, the significant hypoxia also brought up Pneumocystis Jiroveci pneumonia.  An LDH was added and came back at 439 U/L (normally <200).  The patient was empirically covered with common community-acquired antibiotics plus TMP/SMX, steroids for PJP and admitted to the hospital.  His CD4 count came back 10 and a broncheoalveolar was positive on immunofluroescence testing for Pneumocystis Jiroveci.

Author:  Russell Jones, MD

Image Contributor:  James Chenoweth, MD

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WWWTP #6 Answer…

March 21, 2013

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This chest xray was posted several days ago:

RML PNA, high ETT 1

What’s wrong with this picture?

1.  There is an endotracheal tube in the upper trachea, it needs to be advanced!

The other finding on this xray is a right middle lobe pneumonia.  At first this may appear to be a pleural effusion due to the relatively linear appearance to the upper edge of the infiltrate.  However this is a supine film and the diaphragm can be easily seen on the right side.  Effusions, unless loculated, will layer posteriorly in a supine film and the entire lung space will look more radio opaque than the opposing lung.  The fact that the diaphragm can be seen indicates the infiltrate doesn’t come into contact with the diaphragm (see prior post describing “silhouette” phenomena).  Thus, this is a right middle lobe infiltrate.

Author:  Russell Jones, M.D.

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Left Lower Lobe Pneumonia…

February 27, 2013

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Just a quick image of left lower lobe pneumonia today:

LLL pneumonia

In this image the left heart border is obscured and there is an infiltrate taking up airspace in the left lower lung.  That’s it, nothin’ fancy about it.

The symptoms of pneumonia described by Hippocrates (c. 460 BC – 370 BC) (1):

Peripneumonia, and pleuritic affections, are to be thus observed: If the fever be acute, and if there be pains on either side, or in both, and if expiration be if cough be present, and the sputa expectorated be of a blond or livid color, or likewise thin, frothy, and florid, or having any other character different from the common… When pneumonia is at its height, the case is beyond remedy if he is not purged, and it is bad if he has dyspnoea, and urine that is thin and acrid, and if sweats come out about the neck and head, for such sweats are bad, as proceeding from the suffocation, rales, and the violence of the disease which is obtaining the upper hand.

Begs the question:  what does “purged” mean?

Author:  Russell Jones, MD

References

1.  Pneumonia History. http://www.news-medical.net/health/Pneumonia-History.aspx

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