A chest X-ray shows a 'silhouette sign' with opacity obscuring the right heart border. Which lobe of the lung is most likely affected?
Which is NOT a feature of pleural effusion?
PA view of chest X-ray is given here. What is the diagnosis?

A patient presented with complaints of dyspnoea. The shown X-ray is suggestive of:

Mark the false statement regarding testing of COVID-19.
In a child with coarctation of aorta, all the following are seen in plain chest radiograph except:
Snowman appearance on x-ray is seen in which cardiac pathology -

A female patient with clinical symptoms of systemic sclerosis presents with shortness of breath and bilateral basal rales. Her chest X-ray showed reticular opacities in bilateral basal fields. What is the next best step?
A patient of Scleroderma presents with acute respiratory distress. Chest X-ray shows B/L reticular basilar shadows. What is the next line of investigation in this patient?
Chest CT shows bilateral ground-glass opacities with crazy paving pattern and preserved bronchial markings. Likely diagnosis?
Explanation: ***Right middle lobe*** - The **silhouette sign** occurs when two objects of similar radiographic density are in direct contact, obscuring their common border. - The **right middle lobe** is adjacent to the right heart border, so an opacity in this lobe will typically obscure the border. *Right upper lobe* - The right upper lobe is positioned superiorly and medially, meaning opacification would more likely obscure the **right paratracheal stripe** or the superior mediastinal borders. - It does not directly border the right heart, thus it would not produce a silhouette sign with the cardiac outline. *Right lower lobe* - The right lower lobe is primarily associated with obscuring the **right hemidiaphragm** when it collapses or becomes consolidated. - Although it is somewhat posterior to the heart, it usually does not directly obscure the anterior right heart border. *Left lower lobe* - The left lower lobe is on the opposite side of the chest and opacification would not affect the **right heart border**. - Consolidation here would more likely obscure the **left hemidiaphragm** or the medial part of the left cardiac silhouette in certain views.
Explanation: ***Muffled heart sound*** - This is **NOT a feature of pleural effusion** and is the correct answer to this negation question. - Muffled heart sounds are characteristic of **pericardial effusion** or **cardiac tamponade**, where fluid accumulates in the pericardial sac around the heart itself. - Pleural effusion involves fluid in the pleural space surrounding the lungs, not the heart. - While massive pleural effusions can displace mediastinal structures, they do not typically cause muffled heart sounds. *Horizontal fluid level* - This **IS a feature** when air is also present in the pleural space (**hydropneumothorax**). - In **simple pleural effusion** (fluid only), the fluid typically forms a **meniscus-shaped curve** with blunting of the costophrenic angles on upright chest X-ray, not a horizontal level. - However, when both air and fluid are present, a distinct horizontal air-fluid level is visible on upright imaging. - Since the question asks about pleural effusion broadly, and effusions can be associated with air (empyema with gas-forming organisms, post-thoracentesis), this can be considered a radiological feature in certain contexts. *Low lung volume* - This **IS a feature** of pleural effusion. - The accumulating pleural fluid causes **compression atelectasis** of the adjacent lung parenchyma. - This results in **reduced functional lung volume** on the affected side, visible on chest imaging. *Decreased chest movements* - This **IS a feature** of pleural effusion. - Fluid in the pleural space restricts normal lung expansion and chest wall movement. - On physical examination, there are **diminished respiratory excursions** on the affected side. - This is one of the classic clinical signs of pleural effusion.
Explanation: ***Right Pneumothorax with left tracheal shift*** - The image shows a large **radiolucency (black area) on the right side** of the chest, indicative of **air in the pleural space**, consistent with a **right-sided pneumothorax**. - The **trachea is shifted towards the left** (away from the pneumothorax), which is the **expected finding** in pneumothorax due to increased pressure in the right pleural space pushing mediastinal structures to the contralateral side. - In pneumothorax, the trachea and mediastinum shift **away from** the affected side due to the pressure effect of air accumulation in the pleural cavity. - This **contralateral tracheal deviation** is a classic radiological sign of pneumothorax and helps confirm the diagnosis. *Right Pneumothorax with right tracheal shift* - While the **right pneumothorax** is correctly identified, the tracheal shift direction is incorrect. - In pneumothorax, the trachea shifts **away from** the affected side (contralateral), not toward it (ipsilateral). - **Ipsilateral tracheal shift** would suggest volume loss (atelectasis) or lung collapse, not pneumothorax alone. *Left Pneumothorax with right tracheal shift* - The pneumothorax is clearly on the **right side**, not the left. - The radiolucency and absent lung markings are visible on the right hemithorax. - A left pneumothorax would show these findings on the left side. *Left Pneumothorax with left tracheal shift* - There is **no pneumothorax on the left side** of the chest. - The left lung shows normal vascular markings and no evidence of pleural air. - This combination would be medically implausible as it suggests pneumothorax with ipsilateral shift.
Explanation: ***Pleural effusion*** - The X-ray shows a significant **right-sided pleural effusion** with blunting of the costophrenic angle and a meniscus sign characteristic of fluid accumulation in the pleural space. - Key radiological features include: **homogeneous opacity** in the lower zone, **obliteration of the costophrenic angle**, and the typical **concave upper border (meniscus sign)** of fluid layering. - The presence of dyspnea with these radiological findings is consistent with pleural effusion. **Note:** While the X-ray confirms pleural effusion, **differentiating between exudative and transudative effusion requires pleural fluid analysis** (Light's criteria), not imaging alone. *Pneumothorax* - A pneumothorax would appear as a **dark, air-filled space** with a visible **visceral pleural line** where the lung has collapsed away from the chest wall. - The image clearly shows **fluid opacity** (white/grey) in the right hemithorax, not air (black). *Hydropneumothorax* - This condition involves both **fluid and air** in the pleural space, typically presenting with a **straight horizontal air-fluid level** on an erect chest X-ray. - The X-ray here shows a **curved meniscus** rather than a straight air-fluid level, indicating pure fluid without air. *Consolidation* - Consolidation (as seen in pneumonia) appears as a **homogenous opacity within the lung parenchyma**, often with **air bronchograms**. - The image shows fluid in the **pleural space** (outside the lung), **displacing the lung medially**, rather than an opacity within the lung tissue itself.
Explanation: ***First line screening assay: N gene assay.*** * While the **nucleocapsid (N) gene** is a common target for COVID-19 PCR assays, the statement that it is the *first-line screening assay* is often a simplification or outdated, as many assays target multiple genes (e.g., N, E, RdRp) for increased sensitivity and specificity from the outset. * Different health organizations and diagnostic kits have varied recommendations for initial screening targets, but there isn't a universal consensus that the N gene alone is the specific 'first-line screening assay' in all contexts when considering the breadth of available PCR tests. *Confirmatory assay: RdRp gene assay.* * The **RdRp (RNA-dependent RNA polymerase) gene** is a highly specific and conserved target for SARS-CoV-2 detection and is often used in **confirmatory PCR assays**. * Detection of the RdRp gene, sometimes alongside other targets like the E (envelope) gene, helps in confirming the presence of the virus. *Peripheral ground glass opacities on CT is the hallmark feature.* * **Peripheral ground glass opacities (GGOs)** are indeed a **hallmark radiological finding** in COVID-19 pneumonia, seen on CT scans. * These opacities reflect alveolar inflammation and fluid accumulation, especially in the early and moderate stages of the disease. *Most predominant method of diagnosis of COVID-19 is PCR.* * **Reverse transcription-polymerase chain reaction (RT-PCR)** remains the **gold standard and most predominant method** for diagnosing active COVID-19 infection. * PCR tests directly detect viral genetic material, offering high sensitivity and specificity in symptomatic and asymptomatic individuals.
Explanation: ***'E' Sign or 'Reverse Three sign' (Reverse ε sign)*** - The **'E' sign** or **'reverse three sign'** is seen on **barium esophagram** (lateral view), NOT on a plain chest X-ray - On barium swallow, the esophagus shows indentation creating a reverse '3' or 'ε' shape due to impression from the dilated pre-stenotic aorta, the coarctation site, and the dilated post-stenotic aorta - **This is the correct answer** as the question asks specifically about plain chest radiograph findings - This sign requires contrast study and cannot be visualized on plain radiography *Three sign ('3' sign)* - The **'three sign'** is a **classic finding** in coarctation on plain chest X-ray (PA view) - Seen on the **left heart border** representing: (1) dilated left subclavian artery, (2) indentation at coarctation site, (3) post-stenotic dilation of descending aorta - Creates the shape of the numeral '3' along the aortic knuckle region - This is directly visible on plain radiograph *Prominent ascending aorta* - **Commonly seen** in coarctation due to increased afterload on the left ventricle - Results in **left ventricular hypertrophy** and dilation of the ascending aorta - Part of the cardiovascular remodeling in response to chronic pressure overload - Visible as widening of the superior mediastinum on plain chest X-ray *Rib notching* - **Classic finding** in long-standing coarctation of the aorta (usually after 5-6 years of age) - Due to **collateral circulation** through dilated intercostal arteries that erode the inferior rib margins - Typically affects **ribs 3-9** bilaterally - Represents chronic compensatory mechanism to bypass the obstruction
Explanation: ***TAPVC*** - The **snowman sign**, or **figure-of-8 heart**, on a chest X-ray is characteristic of supracardiac **Total Anomalous Pulmonary Venous Connection (TAPVC)**, where pulmonary veins drain into the superior vena cava via a vertical vein and an innominate vein, causing the dilated superior vena cava and innominate vein to form the "head" of the snowman and the cardiac silhouette the "body". - This appearance is due to the **dilated superior vena cava** and the **vertical vein**, which return all pulmonary venous blood to the systemic circulation, leading to right heart enlargement and increased pulmonary vascularity. *TGA* - **Transposition of the Great Arteries (TGA)** typically presents with an **egg-on-a-string** appearance on chest X-ray, characterized by a narrow vascular pedicle and an enlarged cardiac silhouette. - This is due to the transposed great arteries, where the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. *Ebstein's anomaly* - **Ebstein's anomaly** usually shows a **massive cardiomegaly**, often described as a **box-shaped heart**, due to severe right atrial and right ventricular enlargement. - The characteristic finding is the apical displacement of the tricuspid valve leaflets into the right ventricle. *Fallots tetralogy* - **Tetralogy of Fallot** classic X-ray finding is a **boot-shaped heart** (coeur en sabot), caused by right ventricular hypertrophy and a concave pulmonary artery segment. - Pulmonary oligaemia is also common due to the right ventricular outflow tract obstruction.
Explanation: ***Do HRCT*** - **High-resolution computed tomography (HRCT)** is the gold standard for evaluating **interstitial lung disease (ILD)**, a common and serious complication of systemic sclerosis, characterized by **reticular opacities** seen on chest X-ray. - HRCT provides detailed images of the lung parenchyma, allowing for accurate characterization of ILD patterns (e.g., usual interstitial pneumonia and non-specific interstitial pneumonia) and assessment of disease extent and severity, which is crucial for determining prognosis and guiding treatment. *2D echocardiography* - This test is primarily used to assess **cardiac function** and evaluate for conditions like **pulmonary hypertension** or **congestive heart failure**, which can cause shortness of breath. - While pulmonary hypertension can be associated with systemic sclerosis, the **reticular opacities** and **basal rales** on chest X-ray strongly point towards a primary lung parenchymal pathology, making HRCT a more direct and immediate diagnostic step for the observed lung findings. *Do Pulmonary Function Test* - **Pulmonary function tests (PFTs)** measure lung volumes, airflow, and gas exchange and are essential for quantifying the extent of lung impairment in conditions like ILD. - While PFTs are crucial for monitoring disease progression and response to therapy, they do not provide the detailed anatomical information needed for the initial diagnosis and characterization of the **interstitial lung changes** suggested by the chest X-ray, which is better served by HRCT. *Do CECT* - **Contrast-enhanced computed tomography (CECT)** is primarily used to evaluate for **vascular abnormalities**, **masses**, or **lymphadenopathy** within the chest. - While it can provide some information about lung parenchyma, **contrast** is not typically necessary or beneficial for the initial assessment of **interstitial lung disease (ILD)** and may even pose risks if the patient has renal impairment, making HRCT a more appropriate choice for this specific clinical presentation.
Explanation: ***High resolution CT*** - A **high-resolution CT (HRCT) scan** is the gold standard for evaluating **interstitial lung disease (ILD)**, which is commonly seen in **scleroderma** and presents with basilar reticular shadows on chest X-ray. - HRCT provides detailed images of the lung parenchyma, allowing for accurate characterization of the **fibrotic changes** and extent of ILD. *Pulmonary function tests to assess lung function.* - **Pulmonary function tests (PFTs)** provide functional information about lung capacity and gas exchange but do not offer detailed anatomical imaging of the lung parenchyma. - While essential for monitoring disease progression and severity, PFTs are not the primary diagnostic tool to further characterize the **reticular basilar shadows** seen on X-ray in an acute setting. *Contrast-enhanced CT scan for vascular assessment.* - A **contrast-enhanced CT scan** is primarily used to assess **vascular structures** or rule out conditions like **pulmonary embolism**, which is not directly indicated by the description of bilateral reticular basilar shadows. - The primary concern here is **interstitial lung disease**, which is best evaluated by **HRCT** without contrast. *Echocardiography to evaluate cardiac complications.* - **Echocardiography** is used to assess cardiac function and look for complications like **pulmonary hypertension** or **myocardial fibrosis**, which can occur in scleroderma. - However, it does not directly evaluate the **lung parenchyma** or the cause of the reticular basilar shadows.
Explanation: ***Pulmonary alveolar proteinosis*** - **Bilateral ground-glass opacities** with a **"crazy paving" pattern** (interlobular septal thickening superimposed on ground-glass opacities) are highly characteristic imaging findings for pulmonary alveolar proteinosis. - The **preserved bronchial markings** further support this diagnosis, as it indicates that the airspaces are filled with proteinaceous material without significant destruction of the bronchial tree. *Edema* - While pulmonary edema can cause **ground-glass opacities**, it typically presents with additional features such as **peribronchial cuffing**, **interlobular septal thickening** uniformly without "crazy paving," and often **cardiomegaly** or **pleural effusions**. - The "crazy paving" pattern is uncommon in pure pulmonary edema. *ARDS* - **Acute Respiratory Distress Syndrome (ARDS)** is characterized by widespread **ground-glass opacities** and **consolidation**, but it usually involves significant **loss of lung volume**, **air bronchograms**, and often **bronchial distortion**, rather than perfectly preserved bronchial markings. - The "crazy paving" pattern is not a primary or characteristic finding in ARDS. *Pneumonia* - **Pneumonia** often presents with **focal consolidation**, **ground-glass opacities**, or **lobar infiltrates**. - While some forms of atypical pneumonia might have ground-glass opacities, the distinct **"crazy paving" pattern** and **preserved bronchial markings** are not typical features.
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