Chest Radiology - The Silhouette Sign

By Dr Deepu

Silhouette sign/loss of silhouette sign/ loss of outline sign.

I was always confused with the silhouette sign for its hidden meaning and failure to decode it by many medical students. So, I thought it would be apt to unravel it so that it could be handy for many medical students.

One of the most useful signs in chest radiology is the silhouette sign. This sign was described by Dr. Ben Felson. The silhouette sign is in nothing but  elimination of the silhouette or loss of lung/soft tissue interface caused by a mass or fluid in the normally air filled lung. For instance, if an intrathoracic opacity is in anatomic contact with, for example, the heart border, then the opacity will obscure that border. The sign is commonly applied to the heart, aorta, chest wall, and diaphragm. The location of this abnormality can help to determine the location anatomically. 

Just go through the X Ray to know the  various structures seen in the chest x ray.

Let me explain this with this image.

What do we see???

There is plastic bottle which is surrounded by air, the margins of the shadow is very  well demarcated from the surrounding air.

First scenario: There are two bottles, made of same material, placed apart from each other. The shadows appears separate from each other. Let us consider the right bottle to be the heart and the air surrounding the bottle as lung. The left bottle as a mass, since they are far from each other, the border of both  is visible clearly.

Second scenario: Here we see the bottles are touching each other at two points and there is no gap in between and if we look at the shadow, we cannot differentiate between the two shadows, they appear like a single opacity at the upper and lower ends.

For the heart, the silhouette sign can be caused by an opacity in the RML, lingula, anterior segment of the upper lobe, lower aspect of the oblique fissure, anterior mediastinum, and anterior portion of the pleural cavity.

This contrasts with an opacity in the posterior pleural cavity, posterior mediastinum, of lower lobes which cause an overlap and not an obliteration of the heart border. Therefore both the presence and absence of this sign is useful in the localization of pathology.

want to read more in chest radiology??? Have a look at the following pages
Chest Radiology
Signs in Chest Radiology

Chest Radiology _ A Case Of Azygous Lobe

By Dr Deepu
The lungs are normally divided into five lobes by three main fissures .
 Occasionally, invaginations of the visceral pleura create accessory fissures that separate individual bronchopulmonary segments into accessory lobes .
 An azygos lobe is found in approximately 0.4% of patients . In contrast to other accessory lobes, the azygos lobe does not correspond to a distinct anatomical bronchopulmonary segment .

It forms during embryogenesis when the precursor of the azygos vein fails to migrate to its medial position in the mediastinum, where it normally arches over the origin of the right upper lobe bronchus.
 This gives rise to the following characteristics, which are visible on a standard chest x-ray

: the laterally displaced azygos vein lies between folds of parietal pleura, also referred to as the mesoazygos, where it assumes a characteristic teardrop shape ; the mesoazygos indents the right upper lobe, thereby creating the accessory (azygos) fissure, which is similar in shape to an inverted comma; the fissure delineates the azygos lobe, located superomedially ; laterally, the pleural folds of the mesoazygos separate before reaching the chest wall, resulting in a radiopaque triangular area ; and medially, the tracheobronchial angle appears empty .

 An azygos lobe may be confused with a pathological air space such as a bulla or abscess . In addition, the abnormally located azygos vein may be mistaken for a pulmonary nodule, while a consolidated azygos lobe may be confused with a mass . An understanding of the pathogenesis and characteristic x-ray features of the azygos lobe will enable an accurate diagnosis in most cases .
 If the x-ray findings are equivocal, computed tomography will be diagnostic .

Sleep-Disordered Breathing In Kids May Be Linked To Academic Problems

By Dr Deepu

HealthDay (9/9) reports that research suggests that “when children have sleep troubles due to breathing problems – such as sleep apnea – they may struggle in school.” Investigators “reviewed the results of 16 studies dealing with sleep apnea or related disorders in children and academic achievement.” The data indicated that kids “with sleep-disordered breathing did worse in language arts, math and science tests compared to those without such conditions.” The findings were published online in Pediatrics.

The researchers reviewed the results of 16 studies dealing with sleep apnea or related disorders in children and academic achievement. The investigators found that children with sleep-disordered breathing did worse in language arts, math and science tests compared to those without such conditions.

Medical students with mental health problems do not feel adequately supported

Survey provides a snapshot of mental health problems among medical students in the UK

Over 80% of medical students with mental health issues feel they receive poor or only moderately adequate support from their medical schools, finds a small online survey published in Student BMJ today.

Of the 1,122 UK respondents, 30% (343) said they had experienced or received treatment for a mental health condition, and almost 15% (167) revealed that they had considered committing suicide while studying at medical school.

"The number of students reporting mental illness or considering suicide is shocking," says Twishaa Sheth, chair of the BMA’s student’s welfare committee, adding that "what is more concerning is the lack of independent support available for students."

Student BMJ invited its readers to take part in a survey on the health of medical students. The number of respondents represents around 2% of medical students.

The survey also asked questions about smoking, drinking and alcohol use. In total, 15.8% (177) of respondents claimed they smoked, one quarter reported binge drinking each week, and 10.9% (123) said they had taken illegal drugs more than once.

Furthermore, 8.3% (94) claimed to have tried a legal high, and the same number had used cognitive enhancing drugs to help with revision.

Reasons behind the high rates of mental health problems among medical students are "complex", writes Matthew Billingsley, Editor of the Student BMJ.

"Students often have a relentless timetable of exams as well as having to balance the emotional strain of seeing sick patients and uphold high professional standards," he says, adding that "the demands of the course can cause an over competitive environment that can have a detrimental effect on the health of students."

Deborah Cohen, senior medical research fellow at the University of Cardiff, describes Student BMJ’s results as "concerning," but that they are in line with previous research.

A study she carried out found that 15% of 557 respondents from two large UK medical schools had substantial levels of depression and 52% reported substantial levels of anxiety.

Earlier this year, Student BMJ reported that there was not a clear separation between medical school staff with pastoral roles and those who rule on fitness to practice disciplinary issues. This raised concerns about students being able to report a problem without it affecting their final result.

In July, the General Medical Council and the Medical Schools Council issued new guidelines to clarify that teaching and pastoral roles should be separate.

Iain Cameron, chair of the MSC, says "Medical schools take the mental wellbeing of their students seriously. The Student BMJ survey highlights key issues and similar concerns have been raised previously."

"It is crucial that students who have concerns about their health are able to make this known so that they can be provided with the necessary advice and support."

He adds that the MSC would like to work with Student BMJ and colleagues across the sector to promote the new guidelines and other initiatives on student mental health.

Link to research

COPD Patients With Comorbid Mental Issue Have Higher Readmission Risk

According to Lung Disease News (8/18, Semedo), a recent study in the journal CHEST found that psychological conditions such as depression anxiety, or psychosis were associated with a higher risk of hospital readmission for COPD complications. “These psychological disorders are more likely to predict early readmission than other significant factors,” said Gurinder Singh of the University of Texas Medical Branch at Galveston. “This is likely related to the limited ability of these patients to handle the COPD, poor social support or community resources and non-adherence with treatment,” Singh added.

Helicobacter Pylori May Be Common In Patients With COPD

The Daily Mail (UK) (8/16) reported that “the bacteria helicobacter pylori” may “be common in patients with chronic obstructive pulmonary disease (COPD).” Research has “found that levels of the bacteria are up to three times higher in people with COPD, and one theory is that infection in childhood may affect the growth of the lungs, making them more vulnerable to disease.”

PULMONARY MEDICINE POWERPOINT 3 (TUBERCULOSIS)

1)Self-Study Modules

Module 1: Transmission and Pathogenesis of TB (text only version)
Download complete Power Point Presentation   (2M)
Download Participant Guide   (832K)

·         Introduction (5 slides)

·         History of TB (10 slides)

·         TB Transmission (9 slides)

·         Drug-Resistant TB (6 slides)

·         TB Pathogenesis (16 slides)

·         Progression from LTBI to TB Disease (9 slides)

·         Sites of TB Disease (4 slides)

·         TB Classification System (4 slides)

·         Case Studies (5 slides)

Module 2: Epidemiology of TB (text only version)
Download complete Power Point Presentation   (1M)
Download Participant Guide   (326K)

·         Introduction (3 slides)

·         Epidemiology of TB (16 slides)

·         TB Case Rate (6 slides)

·         People at High Risk for Becoming Infected with Mycobacterium tuberculosis (28 slides)

·         People at High Risk for Developing TB Disease after Infection with Mycobacterium tuberculosis(11 slides)

·         Case Studies (3 slides)

Module 3: Targeted Testing and the Diagnosis of Latent TB Infection and TB Disease (text only version)
Download complete Power Point Presentation   (2M)
Download Participant Guide   (430K)

·         Introduction (3 slides)

·         Targeted Testing (8 slides)

·         Diagnosis of LTBI (60 slides)

·         Diagnosis of TB Disease (50 slides)

·         Reporting TB Cases (5 slides)

·         Case Studies (16 slides)

Module 4: Treatment of Latent TB Infection and TB Disease (text only version)
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Download Participant Guide   (358K)

·         Introduction (4 slides)

·         Treatment of LTBI (59 slides)

·         Treatment of TB Disease (73 slides)

·         Case Studies (17 slides)

Module 5: Infectiousness and Infection Control (text only version)
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·         Introduction (3 slides)

·         Infectiousness (9 slides)

·         TB Infection Control (18 slides)

·         Administrative Controls (5 slides)

·         Environmental Controls (10 slides)

·         Respiratory-Protection Controls (15 slides)

·         TB Risk Assessment (5 slides)

·         Infection Control in Nontraditional Facility-Based Settings (7 slides)

·         TB Infection Control in the Home (9 slides)

·         Case Studies (12 slides)

2)Core Curriculum on Tuberculosis: What the Clinician Should Know

Download complete Power Point Presentation (194 slides)   – (20M)
Text only version

Table of Contents

·         Chapter 1: Overview of TB Epidemiology in the United States (21 slides)

·         Chapter 2: Transmission and Pathogenesis of TB (20 slides)

·         Chapter 3: Testing for TB Infection and Disease (26 slides)

·         Chapter 4: Diagnosis of TB Disease (26 slides)

·         Chapter 5: Treatment for Latent Tuberculosis Infection (20 slides)

·         Chapter 6: Treatment of TB Disease (36 slides)

·         Chapter 7: TB Infection Control (23 slides)

·         Chapter 8: Community TB Control (22 slides)

3)Prevention and Control of Tuberculosis in Correctional and Detention Facilities

Table of Contents

Download complete Power Point Presentation (181 slides)   – (2M) Text-Only Version

·         Introduction (3 slides)

·         Summary of Changes from 1996 Recommendations from CDC (6 slides)

·         Background (10 slides)

·         Screening (42 slides)

·         Case Reporting (3 slides)

·         Airborne Infection Isolation (4 slides)

·         Environmental Controls (5 slides)

·         Respiratory Protection (8 slides)

·         Diagnosis and Treatment of Latent Tuberculosis Infection (LTBI) and Tuberculosis (TB) Disease(35 slides)

·         Discharge Planning (12 slides)

·         Contact Investigation (22 slides)

·         TB Training and Education of Correctional Workers and Inmates (11 slides)

·         Program Evaluation (13 slides)

·         Collaboration and Responsibilities (4 slides)

·         References and Additional Resources (3 slides

4)Guidelines for Preventing the Transmission of M. tuberculosisin Health-Care Settings

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Text Only Version

·         Introduction 
(7 slides)

·         Transmission and Pathogenesis 
(14 slides)

·         Fundamentals of Infection Control 
(7 slides)

·         Recommendations for Preventing M. tuberculosis Transmission in Health-Care Settings (30 slides)

·         Infection Control Program (5 slides)

·         TB Risk Assessment (17 slides)

·         TB Testing Frequency (3 slides)

·         Evaluation (4 slides)

·         Training and Education (1 slide)

·         Managing TB Patients: General Recommendations (51 slides)

·         Airborne Infection Isolation (AII) Policies and Practices (8 slides)

·         Diagnosis (2 slides)

·         AII Precautions for Specific Settings (16 slides)

·         Training and Education (1 slide)

·         Infection Control Surveillance (1 slide)

·         Evaluation (3 slides)

·         Collaborate with Health Departments (1 slide)

·         Environmental Controls (7 slides)

·         Respiratory Protection (12 slides)

·         Estimating Infectiousness of Patients (5 slides)

·         Diagnostic Procedures for Latent TB Infection and TB Disease (23 slides)

·         Treatment Procedures for LTBI and TB Disease(8 slides)

5)Investigation of Contacts of Persons with Infectious Tuberculosis

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·         Introduction(8 slides)

·         Decisions to Initiate a Contact Investigation (10 slides)

·         Investigating the Index Patient and Sites of Transmission (18 slides)

·         Assigning Priorities to Contacts (7 slides)

·         Diagnostic and Public Health Evaluation of Contacts (12 slides)

·         Medical Treatment for Contacts with LTBI (6 slides)

·         When to Expand a Contact Investigation (3 slides)

·         Communicating Through the News Media (6 slides)

·         Data Management and Evaluation of Contact Investigations(3 slides)

·         Confidentiality and Consent in Contact Investigations(3 slides)

·         Staff Training for Contact Investigations (2 slides)

·         Contact Investigations in Special Circumstances(13 Slides)

·         Source-Case Investigations(6 slides)

·         Cultural Competency and Social Network Analysis(8 Slides)

6) Targeted Tuberculosis (TB) Testing and Treatment of Latent TB Infection

7) Treatment of Tuberculosis 

    source:  http://www.cdc.gov