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.

Chest Medicine Made Easy -By Dr Deepu : BASICS OF CHEST X RAY- PART 2 , EASY WAY TO INTERP...

Chest Medicine Made Easy -By Dr Deepu : BASICS OF CHEST X RAY- PART 2 , EASY WAY TO INTERP...: Welcome to basics of CXR, this is part two of this series, read my previous post part 1, in the next post we will be exploring about the s...

By Dr Deepu

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

Concern over inappropriate use of psychotropic drugs in people with intellectual disability

Over 70% of prescriptions are given to those without a record of mental illness

The proportion of people with intellectual disability in the UK who have been treated with psychotropic drugs far exceeds the proportion with recorded mental illness, finds a study published by The BMJ today.

This suggests that, in some cases, these drugs are being used to manage challenging behaviour rather than for mental illness, say the researchers. They call for changes in the prescribing of psychotropic drugs for people with intellectual disability as well as more evidence on their safety in this group.

People with intellectual disability develop severe mental illness at higher rates than do the general population and may show challenging behaviour.

Concern has existed for many years that psychotropic drugs in general - and antipsychotics in particular (mainly used to treat schizophrenia and bipolar disorder) - are overused in people with intellectual disability, but accurate estimates have been difficult to obtain.

So a team of researchers based at University College London set out to describe rates of recorded mental illness, challenging behaviour, and use of psychotropic drugs in people with intellectual disability in UK primary care.

They analysed data from 571 UK general practices using the The Health Improvement Network (THIN), a large database of electronic health records, and identified 33,016 people with a record of intellectual disability. Average age at study entry was 36 years and average follow-up was five and a half years.

Of 9,135 participants treated with antipsychotic drugs by the end of the study period, 6,503 (71%) did not have a record of severe mental illness.

Of the 11,915 with a record of challenging behaviour, 5,562 (47%) had received antipsychotic drugs, whereas only 1,421 (12%) had a record of severe mental illness.

And of those with a record of prescription of antipsychotics, 26% did not have a record of severe mental illness or challenging behaviour.

New prescriptions for antipsychotics were significantly more common in older people and in those with a record of challenging behaviour, severe mental illness, depression, anxiety, autism, dementia, and epilepsy.

People with a record of challenging behaviour were more than twice as likely to receive a prescription for antipsychotics compared with those without a record of challenging behaviour, say the authors.

Prescription of antipsychotic drugs is disproportionate to the level of recorded severe mental illness and is associated with the presence of challenging behaviour, older age, and diagnoses of autism and dementia, they add.

"Inappropriate use of drug treatment has implications for the individual and for healthcare systems," they warn. "These findings highlight the need for an improved evidence base for use of drugs and optimisation of drug treatment in people with intellectual disability."

Link to article

SPOTTER: GIVE YOUR DIAGNOSIS

Give your Diagnosis?? and comment on X ray, microbiology  and Treatment.