ANA 404 Part 1: Chest Diseases and Conditions

Practice flashcards covering definitions, causative organisms, and radiological signs of chest diseases including pneumonia, atelectasis, oedema, and tuberculosis.

Lobar Pneumonia

An infection characterized by the consolidation of an entire lung lobe, where lung consolidation occurs in a lobar distribution with little or no collapse.

Klebsiella pneumoniae

An aggressive causative organism of pneumonia often associated with a bulging fissure, multifocal distribution, and frequent cavitation.

Pneumatocele

A thin-walled, air-filled cyst in the lung often seen in children (up to 60%) with Staphylococcus aureus pneumonia.

Silhouette Sign

A radiographic principle where two structures in contact lose their borders if they have the same density; used to localize consolidation by observing the blurring of the cardiac margin or hemidiaphragm.

Hilar Overlay Sign

A radiographic finding where the hilum is visible through a mediastinal mass, helping to differentiate the mass from the heart or hilar structures.

Air Bronchogram Sign

The visualization of an air-filled bronchus surrounded by opacified alveoli, indicating airspace disease such as pulmonary consolidation or edema.

Lung Collapse (Atelectasis)

The partial or complete loss of lung volume, resulting in a reduced volume of air in the lung.

Obstructive (Resorptive) Collapse

A mechanism of lung collapse where bronchial obstruction (e.g., from mucus plugs or foreign bodies) leads to the absorption of alveolar gas.

Adhesive Atelectasis

Lung collapse occurring when the central airway is patent but alveoli collapse due to decreased or absent surfactant, seen in respiratory distress syndrome.

Cicatrisation Atelectasis

Lung collapse caused by decreased lung compliance due to parenchymal fibrosis, seen in conditions like tuberculosis or scleroderma.

Direct Signs of Collapse

Radiological indicators including displacement of interlobar fissures (most reliable), loss of aeration/increased density, and vascular or bronchial crowding.

Plate-like Atelectasis

A type of collapse appearing as densities $1$–$3\,\text{mm}$ thick, oriented parallel to the diaphragm.

Compensatory Hyperinflation

An indirect sign of lung collapse where the contralateral lung becomes markedly hyperinflated and appears transradiant.

Pulmonary Oedema

The accumulation of fluid in the alveoli, typically resulting from heart failure when pulmonary capillary wedge pressure exceeds the normal limit of less than $15\,\text{mmHg}$.

Bat's Wing Appearance

A radiological feature of pulmonary oedema characterized by confluent alveolar shadows in the perihilar regions bilaterally.

Kerley B Lines

Short, horizontal septal lines seen on a chest radiograph that indicate the presence of pulmonary edema.

Primary Tuberculosis

TB infection in a person not previously sensitized, often presented as subclinical (>90%) but may show a Ghon focus or hilar lymphadenopathy on imaging.

Ghon Focus

A peripheral lung consolidation representing a healed or active primary tuberculosis lesion.

Miliary Tuberculosis

A form of TB resulting from haematogenous spread, appearing as multiple $1$–$2\,\text{mm}$ pinpoint opacities throughout the lungs.

Destroyed Lung Syndrome

A condition caused by bronchial obstruction and chronic infection leading to fibrosis, cystic changes, and complete lung collapse with the heart shifted to the affected side.

Post-Primary Tuberculosis

The reactivation or reinfection of tuberculosis in a previously sensitized individual, commonly affecting the apical posterior segment of the upper lobe.

Cavitation

A hallmark feature of post-primary TB occurring in approximately 50% of adult cases, characterized by thin or thick-walled necrotic areas in the lung.

Tuberculoma

A solitary, well-defined tuberculous granuloma nodule ($0.5$–$5\,\text{cm}$) that commonly calcifies but rarely cavitates.

Increased Drainage Markings

Significant radiographic sign for TB consisting of multiple minute nodular opacities in linear beaded rows directed toward the ipsilateral hilum.

Empyema Thoracis

A complication of tuberculosis involving the accumulation of pus in the pleural space.