Staph Aureus

Bronchopneumonia, Fig. 1 Poorly marginated large nodular areas of consolidation are seen in the periphery of both lungs. These findings are typical of bronchopneumonia. Air bronchograms are usually absent; pleural fluid may or may not be present. This patient had a staphylococcal infection.

pneumatocele a localized collection of air in the interstitium of the lung, usually following bacterial pneumonia or trauma, Langerhans cell histiocytosis, barotrauma or aspiration of hydrocarbon (see aspiration hydrocarbon). An abscess tends to appear earlier in the course of the illness, and have irregular, thicker walls. Most pneumatocoeles, even larger ones with airfluid levels, will disappear spontaneously within a few days

Pneumatocele, Fig. 1 Chest X-ray with two thin-walled cysts in the right lower zone. The child was recovering from staphylococcal pneumonia.

Aspiration pneumonia a common cause of pneumonia in young children and in those with an impaired cough reflex or swallowing mechanism (Fig.1). There is direct injury to the mucosa of the airways and acinar epithelial cells.

Aspiration pneumonia, Fig. 1 Acute aspiration pneumonia following a recent anaesthetic. There is patchy airspace opacification in the right upper lobe, volume loss and elevation of the horizontal fissure.

Viaral pneumonia

Pneumonia, viral, Fig. 1 Chest radiograph of a 4-year- old child, who presented with an acute chest infection. There is widespread increase in the bronchovascular markings, peribronchial cuffing and slight hilar enlargement on the right. These are typical features of a widespread viral chest infection.

Pneumocystis carinii pneumonia In most patients with PCP, chest films are abnormal and reveal diffuse bilateral and usually fairly symmetrical, fine reticular opacities. Variations in this pattern occur frequently and include unilateral or focal lung opacities of the same quality or, rarely, focal alveolar consolidation. Occasionally, the interstitial pattern is medium to coarse (Fig.1), and on rare occasions a miliary pattern is observed. Focal nodules, measuring 12 cm in diameter, with or without cavitation, have also been attributed to P. carinii infection

Pneumocystis carinii pneumonia, Fig. 1 Diffuse bilateral fine to medium reticulonodular opacities are identified throughout the lungs. This is a typical pattern of PCP seen in patients with AIDS.

Pneumocystis carinii pneumonia, Fig. 2 A PA chest film demonstrates heterogeneous bibasilar opacities and multiple thin-walled air-containing cysts. Pneumatocoeles are seen in approximately 10% of AIDS patients with PCP

A PA chest film demonstrates a large left pneumothorax which spontaneously occurred in a patient with underlying Pneumocystis carinii pneumonia. Pneumothorax occurs in approximately 5% of patients with PCP and AIDS

histoplasmosis Chest radiographs have a variable appearance. In the "epidemic" type of the disease multiple poorly marginated nodules up to 1 cm in diameter are seen throughout the lungs often with bilateral hilar and occasionally mediastinal mediastinal lymphadenopathy (Fig.1). In time these nodules may calcify producing the well marginated 34 mm in diameter uniform calcified nodules of "old" histoplasmosis. Hilar and mediastinal lymph nodes may also calcify and occasionally multiple splenic calcifications can be identified on chest film as well (Fig.2). Less commonly a primary pneumonia simulating bacterial disease may be identified. Histoplasmomas are usually solitary, well marginated nodules approximately 12 cm in diameter which may simulate neoplasm. A calcified central "target" calcification with a small surrounding soft tissue opacity is very typical of histoplasmoma (Fig.3).

Histoplasmosis, Fig. 1 Multiple poorly marginated nodular opacities are seen in both lungs. These are typical of endemic histoplasmosis. In addition, right and perhaps left hilar adenopathy are also appreciated.

Histoplasmosis, Fig. 2 Multiple well marginated calcified nodules are seen throughout the lungs. In addition multiple calcified lymph nodes, some with eggshell calcification, are noted in the mediastinum and hila. These findings are typical of chronic endemic histoplasmosis

Histoplasmosis, Fig. 3 A PA chest film demonstrates a rounded nodule in the right upper lobe. This nodule measures approximately 1 1/2 cm in diameter, is fairly well marginated, and possesses a dense central area of calcification. This so-called target calcification within a nodule is very typical of histoplasmomas