Respiratory System PDF

RESPIRATORY SYSTEM Internal Devices  ENDOTRACHEAL TUBE or ETT is a flexible tube that is placed in the trachea (windpipe) through the mouth or nose. It can be used to assist with breathing during surgery or to support breathing in people with lung disease, chest trauma, or airway obstruction...

RESPIRATORY SYSTEM Internal Devices  ENDOTRACHEAL TUBE or ETT is a flexible tube that is placed in the trachea (windpipe) through the mouth or nose. It can be used to assist with breathing during surgery or to support breathing in people with lung disease, chest trauma, or airway obstruction. ENDOTRACHEAL TUBE or ETT AFTER PLACEMENT - ensure proper positioning of the tube because clinical evaluation (bilateral breath sounds, symmetric thoracic expansion, and palpation of the tube in the sternal notch) does not allow detection of the majority of malpositioned tubes DAILY - ensure that the tube has not been inadvertently displaced by the weight of the respiratory apparatus, the patient’s coughing, or other unforeseen events. On the chest radiograph, position of an ETT is determined by the location of its tip in relation to the carina. The position of tip of ETT should be 5-7 cm above the carina in the neutral position of neck. Central Venous Catheter is a device inserted into a large, central vein (most commonly the internal jugular, subclavian, or femoral) and advanced until the terminal lumen resides within the inferior vena cava, superior vena cava, or right atrium. A person may need a CVC for the following reasons: to administer medications, such as antibiotics, chemotherapy, and pain medications to provide nutrition to conduct certain medical tests CVP catheter. Located in the right internal jugular vein. CVP catheter with its tip in the pleural space. A right subclavian catheter, which was introduced for total parenteral nutrition, perforated the superior vena cava and eroded into the right pleural space. Note the tip of the catheter projecting beyond the right border of the mediastinum (arrow). The direct infusion of parenteral fluid into the pleural space has led to a large right hydrothorax Swan-Ganz Catheterization -also called right heart catheterization or pulmonary artery catheterization passing of a thin tube (catheter) into the right side of the heart and the arteries leading to the lungs. It is done to monitor the heart's function and blood flow and pressures in and around the heart. TRANSVENOUS ENDOCARDIAC PACING is the method of choice for maintaining cardiac rhythm in patients with heart block or Brady arrhythmias. Radiographic evaluation plays an important role in the initial placement of a pacemaker and in the detection of any subsequent complications. There are two major types of cardiac conduction devices: pacemakers and automatic implantable cardioverter-defibrillators (AICD/ICD), and these may be co-implanted as an ICD-pacemaker combination. Ideally, the tip of the pacemaker should be positioned at the apex of the right ventricle. Cardiac pacemaker. Fracture of a pacemaker wire (arrow).  Lung Abnormal Appearance Reticular Densities Hazy Densities Lung Abnormal Appearance Consolidation or Solidification CONGENITAL / HERIDITARY DISORDERS CYSTIC FIBROSIS (Mucoviscidosis) is a hereditary disease characterized by the secretion of excessively viscous mucus by all the exocrine glands; it is caused by a defective gene in the middle of chromosome 7 thick mucus secreted by mucosa in the trachea and bronchi blocks the air passages. The thick mucus is the result of an imbalance of sodium and chloride production and reabsorption. These mucous plugs lead to focal areas of lung collapse. Recurrent pulmonary infections are common because bacteria that are normally carried away by mucosal secretions adhere to the sticky mucus produced in this condition. Beca Multiple small cysts superimposed on diffuse, coarse, reticular patten HYALINE MEMBRANE DISEASE idiopathic respiratory distress syndrome (IRDS) one of the most common causes of respiratory distress in the newborn. It occurs primarily in premature infants, especially those who have diabetic mothers or who have been delivered by cesarean section. Hypoxia and increasing respiratory distress may not be immediately evident at birth but almost always appear within 6 hours of delivery  CAUSE: lack of surfactant and immature lungs. Surfactant consists of a mixture of lipids, proteins, and carbohydrates that creates a high surface tension, requiring less force to inflate and maintain the alveoli. Normally, the alveolar cell walls produce lipoprotein, which maintains the surface tension within the alveoli. This tension permits the alveoli to remain inflated so that atelectasis does not occur. The disease process results from surfactant deficiency caused by cell immaturity or birth trauma In addition to pronounced underaeration, the radiographic hallmark of hyaline membrane disease is a finely granular appearance of the pulmonary parenchyma. A peripherally extending air bronchogram develops because the small airways dilate and stand out clearly against the atelectasis in the surrounding lung INFLAMMATORY DISORDERS OF RESPIRATORY SYSTEM CROUP primarily a viral infection of young children that produces inflammatory obstructive swelling localized to the subglottic portion of the trachea. The edema causes inspiratory stridor or a barking cough, depending on the degree of laryngeal obstruction IMAGING APPEARANCE: Frontal radiographs of the lower neck show a characteristic smooth, fusiform, tapered narrowing (hourglass shape) of the subglottic airway caused by the edema, which is unlike the broad shouldering normally seen EPIGLOTTITIS Acute infections of the epiglottis, most commonly caused by Haemophilus influenzae in children, cause thickening of epiglottic tissue and the surrounding pharyngeal structures. The incidence of epiglottitis has decreased dramatically since the inception of the Haemophilus influenzae type B (HiB) vaccine as a routine childhood immunization Imaging Appearance On lateral projections of the neck using soft tissue techniques, a rounded thickening of the epiglottic shadow gives it the configuration and approximate size of an adult’s thumb , in contrast to the normal, narrow epiglottic shadow resembling an adult’s little finger. THUMB SIGN ALVEOLAR PNEUMONIA Alveolar, or air-space, pneumonia, exemplified by pneumococcal pneumonia, is produced by an organism that causes an inflammatory exudate that replaces air in the alveoli so that the affected part of the lung is no longer air containing but rather appears solid, or radiopaque. The inflammation spreads from one alveolus to the next by way of communicating channels, and it may involve pulmonary segments or an entire lobe (lobar pneumonia). Imaging Appearance: Consolidation or Solidification of the lung parenchyma with little or no involvement of the airways produces the characteristic air bronchogram sign. The sharp contrast between air within the bronchial tree and the surrounding airless lung parenchyma permits the normally invisible bronchial air column to be seen radiographically. The appearance of an air bronchogram requires the presence of air within the bronchial tree, which suggests that the bronchus is not completely occluded at its origin. The presence of an air bronchogram excludes the diagnosis of a pleural or mediastinal lesion because there are no bronchi in these regions. Because air in the alveoli is replaced by an equal or almost equal quantity of inflammatory exudate and because the airways leading to the affected portions of the lung remain open, there is no evidence of volume loss in alveolar pneumonia. Air bronchogram: air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white) BRONCHOPNEUMONIA typified by staphylococcal infection, is primarily an inflammation that originates in the bronchi or the bronchiolar mucosa and spreads to adjacent alveoli. Because alveolar spread of the infection in the peripheral air spaces is minimal, the inflammation tends to produce small patches of consolidation. Bronchial inflammation causing airway obstruction leads to atelectasis with loss of lung volume IMAGING APPEARANCE Imaging appearance. The small patches of consolidation may be seen radiographically as opacifications that are scattered throughout the lungs but are separated by an abundance of air-containing lung tissue ; air bronchogram is absent. If consolidation causes obstructed airways, atelectasis is evident. Ill-defined consolidation at right base INTERSTITIAL PNEUMONIA most commonly produced by viral and mycoplasmal infections. In this type of pneumonia, the inflammatory process predominantly involves the walls and lining of the alveoli and the interstitial supporting structures of the lung, the alveoli septa. IMAGING APPEARANCE. The interstitial dispersal of the infection produces a linear or reticular pattern. When seen on end, the thickened interstitium may appear as multiple small nodular densities. Left untreated, interstitial pneumonia may cause “honeycomb lung,” which is demonstrated on CT as cystlike spaces and dense fibrotic walls ASPIRATION PNEUMONIA The aspiration of esophageal or gastric contents into the lung can lead to the development of pneumonia. Aspiration of esophageal material can occur in patients with esophageal obstruction (e.g., tumor, stricture, and achalasia), diverticula (Zenker’s), or neuromuscular swallowing disturbance Imaging appearance. Both types of aspiration cause multiple alveolar densities, which may be distributed widely and diffusely throughout both lungs. Because the anatomic distribution of pulmonary changes is affected by gravity, the posterior segments of the upper and lower lobes are most commonly affected, especially in debilitated or bedridden patients. Bilateral inhomogeneous patchy airspace opacities mainly in the lower zones. Effacement of the costophrenic recesses consistent with aspiration. ANTHRAX serious infectious disease caused by gram-positive, rod- shaped bacteria known as Bacillus anthracis. It occurs naturally in soil and commonly affects domestic and wild animals around the world. People can get sick with anthrax if they come in contact with infected animals or contaminated animal products. Imaging Appearance Inhalation anthrax causes mediastinal widening and often pleural effusion without infiltrates on a chest image. Rarely, infiltrates may develop. Gastrointestinal involvement manifests as mesenteric adenopathy on CT. Treatment. Although high-dose antibiotics in the early stages attack the bacteria, the anthrax toxins are still produced and sometimes cause death. Vaccines are highly effective and available for limited use. They are not employed routinely in the United States because the last known reported incidence was 1976 (until the previously mentioned 2001 attacks). LUNG ABSCESS a necrotic area of pulmonary parenchyma containing purulent (puslike) material. A lung abscess may be a complication of bacterial pneumonia, bronchial obstruction, aspiration, a foreign body, or the hematogenous spread of organisms to the lungs either in a patient with diffuse bacteremia or as a result of septic emboli. Aspiration, which is the most common cause of lung abscesses, frequently occurs in the right lung because the right main bronchus is more vertical and larger in diameter than the left. Imaging appearance The earliest radiographic finding in lung abscess is a spherical density that characteristically has a dense center with a hazy, poorly defined periphery. If there is communication with the bronchial tree, the fluid contents of the cavity are partly replaced by air, producing a typical air–fluid level within the abscess. A cavitary lung abscess usually has a thickened wall with a shaggy, irregular inner margin. CT can assist in the diagnostic process to demonstrate an ill-defined outer wall and rule out empyema. TUBERCULOSIS caused by Mycobacterium tuberculosis, a rod-shaped bacterium with a protective waxy coat that permits it to live outside the body for a long time. Tuberculosis spreads mainly by droplets in the air, which are produced in huge numbers by the coughing of an infected patient. Therefore, it is essential that respiratory precautions be followed by radiographers imaging patients with active disease to prevent spreading of the infection. The organisms may be inhaled from sputum that has dried and turned into dust. They are rapidly killed by direct sunlight but may survive a long time in the dark. Tuberculosis may also be acquired by drinking the milk of infected cows. However, routine pasteurization of milk has virtually eliminated this route of infection PRIMARY TUBERCULOSIS Considered a disease of children and young adults. However, with the dramatic decrease in the prevalence of tuberculosis (especially in children and young adults), primary pulmonary disease can develop at any age. The current decline is the result of wider screening and prevention programs Self limited disease Combination of a focal parenchymal lesion and enlarged hilar or mediastinal lymph nodes produces the classic primary complex (the Ghon lesion), an appearance strongly suggestive of primary tuberculosis. Imaging Appearance The infiltrate may be seen as a lobar or segmental air-space consolidation that is usually homogeneous, dense, and well-defined. The apical lordotic projection best demonstrates the apices without superimposition of bony structures Associated enlargement of hilar or mediastinal lymph nodes is very common. Pleural effusion is common, especially in adults. Most primary tuberculous pleural effusions are unilateral and clear rapidly with treatment Primary tuberculosis. Consolidation of right upper lobe Primary tuberculosis. Enlargement of right hilar lymph nodes without discrete parenchymal infiltrate.  A “Ghon Lesion” or focus is a granuloma in the lung from a previous tuberculous infection It is a abnormality of primary tuberculosis Primary tuberculosis. Unilateral right tuberculous pleural effusion without parenchymal or lymph node involvement. Miliary tuberculosis refers to dissemination of the disease by way of the bloodstream. Radiographically, this development produces innumerable fine discrete nodules (granulomas) distributed uniformly throughout both lungs. Miliary tuberculosis. Fine discrete nodules uniformly throughout both lungs Miliary tuberculosis TUBERCULOUS PNEUMONIA May resolve completely and leave a normal lung. However, if necrosis and caseation develop, some fibrous scarring occurs. Calcification may develop within both the parenchymal and the nodal lesions, and it may be the only residue of primary tuberculous infection on subsequent images. If the disease responds poorly to therapy and continues to progress (especially in patients with immunodeficiency or diabetes and in those receiving steroid therapy), the pneumonia may break down into multiple necrotic cavities or a single large abscess filled with caseous material Multiple large cavities with air– fluid levels in both upper lobes. Note chronic fibrotic changes and upward retraction of hila.  Secondary (Reactivation) Tuberculosis Reactivation of organisms from previously dormant tubercles is termed a secondary lesion or reinfection tuberculosis. At times, the tuberculosis bacillus may remain inactive for many years before a secondary lesion develops, often because of a decrease in the body’s immune defense Imaging appearance. Secondary tuberculosis most commonly affects the upper lobes, especially the apical and posterior segments. It is initially seen as a nonspecific, hazy, poorly marginated alveolar infiltrate that often radiates outward from the hilum Secondary tuberculosis. Bilateral fibrocalcific changes at apices. TUBERCULOMA sharply circumscribed parenchymal nodule, often containing viable tuberculosis bacilli, that can develop in either primary or secondary disease. Although the residual localized caseation may remain unchanged for a long period or permanently, it is potentially dangerous because it may break down at any time and lead to dissemination of the disease. Imaging Appearance Radiographically, tuberculomas appear as single or multiple pulmonary nodules, usually 1–3 cm in diameter. They can occur in any part of the lung but are most common in the periphery and in the upper lobes. A central nidus of calcification (which may be detectable only on tomograms) is strongly suggestive of the lesion representing a tuberculoma However, the lack of calcification is of no diagnostic value. Calcified tuberculoma. Large soft tissue mass in left lung (arrows) that contains dense central calcification.  PULMONARY MYCOSIS means fungal infection of the lung. MOST COMMON: histoplasmosis and coccidioidomycosis Histoplasmosis, caused by the fungus Histoplasma capsulatum, is a common disease that often produces a radiographic appearance simulating that of tuberculosis. The primary form of histoplasmosis is usually relatively benign and often passes unnoticed Coccidioidomycosis is caused by a fungus, Coccidioides immitis, which is found in the desert soil of the southwestern United States. Imaging Appearance Pulmonary histoplasmosis frequently manifests as a solitary, sharply circumscribed, granulomatous nodule (histoplasmoma), which is usually less than 3 cm in diameter and found most often in a lower lobe. Central, rounded calcification within the mass (the target lesion) is virtually pathognomonic (characteristic) of this disease. Multiple soft tissue nodules scattered throughout both lungs may simulate miliary tuberculosis. These shadows may clear completely or may fibrose and persist, often appearing on subsequent chest radiographs as widespread punctate calcifications Imaging Appearance coccidioidomycosis typically produces small pulmonary consolidations in the periphery of the parenchyma that resemble those in extensive pneumonia. Histoplasmosis. Diffuse calcifications in lungs produce snowball pattern. Coccidioidomycosis. Posteroanterior and lateral views demonstrate consolidation caused by fungus in the left lung. Chronic Obstructive Pulmonary Disease Bronchitis Emphysema Asthma Bronchiectasis Advanced bronchiectasis Chronic bronchitis is characterized by excessive tracheobronchial mucus production, leading to the obstruction of small airways. Imaging appearance. Approximately half of patients with chronic bronchial disease demonstrate no changes on chest radiographs. The most common radiographic abnormality in chronic bronchitis is a generalized increase in bronchovascular markings (“dirty chest”), especially in the lower lung Thickening of bronchial walls and peribronchial inflammation can cause parallel or slightly tapered tubular line shadows (“tram lines”) or may appear as thickening of bronchial shadows when viewed end on Emphysema refers to the distention of distal air spaces as a result of the destruction of alveolar walls and the obstruction of small airways. Imaging appearance. The major radiographic signs of emphysema are related to pulmonary overinflation, alterations in the pulmonary vasculature, and bullae formation. The hallmark of pulmonary overinflation is flattening of the domes of the diaphragm. Another important sign seen on lateral chest radiographs is an increase in the size and lucency of the retrosternal air space, the distance between the posterior side of the sternum and the anterior wall of the ascending aorta. Giant emphysematous bulla. Air-containing mass fills most of the left hemithorax ASTHMA occurs when the bronchioles go into spasm, causing decreased airflow and sometimes obstruction of the airway. Early in the course of the disease, chest radiographs obtained between acute episodes demonstrate no abnormalities. During an acute asthmatic attack, bronchial narrowing and difficulty in expiration lead to an increased volume of the hyperlucent lungs with flattening of the hemidiaphragms and an increase in the retrosternal air space. In asthma, unlike in emphysema, the pulmonary vascular markings remain normal. In patients with chronic asthma, especially those with a history of repeated episodes of superinfection, thickening of bronchial walls can produce prominence of interstitial markings and the “dirty chest” appearance. Recurrent pulmonary infections have led to the development of diffuse pulmonary fibrosis and prominence of interstitial markings in lungs Bronchiectasis refers to permanent abnormal dilation of one or more large bronchi as a result of destruction of the elastic and muscular components of the bronchial wall. Imaging appearance. Plain chest radiographs may show coarseness and loss of definition of interstitial markings caused by peribronchial fibrosis and retained secretions In more advanced disease, oval or circular cystic spaces can develop. These cystic dilations can be up to 2 cm in diameter and often contain air–fluid levels. In very severe cases, coarse interstitial fibrosis surrounding local areas of dilation can produce a honeycomb pattern. Chronic bronchiectasis. Severe coarsening of interstitial markings involves the bases and right upper lobe. Oval and circular cystic spaces, which produce a honeycomb-like pattern, are best seen in the right upper lobe. SILICOSIS the most common and best known work-related lung disease. The inhalation of high concentrations of silicon dioxide (crystalline silica) primarily affects workers engaged in mining, foundry work, and sandblasting. Quartz dust, the most frequent cause of inhalation silicosis, is the second most common element in the earth’s crust. The lung reacts to the silica by producing a fibroblast-stimulating factor that results in extensive fibrosis. Imaging appearance. The classic radiographic pattern in silicosis consists of multiple nodular shadows scattered throughout the lungs. These nodules, usually fairly well circumscribed and of uniform density, may become calcified Silicosis. Calcification in miliary nodules is scattered throughout both lungs. Silicosis ASBESTOSIS may develop in improperly protected workers engaged in manufacturing asbestos products, in handling building materials, or in working with insulation composed of asbestos. In the 1980s, many public buildings with fireproof plasterboard and ceiling panels containing asbestos, such as schools, were reconstructed, and the asbestos was removed to prevent excessive public exposure to this particulate. Asbestos particles occur as long, thin fibers that cause little dust but produce major fibrosis in the lung. Imaging Appearance The radiographic hallmark of asbestosis is involvement of the pleura. Initially, pleural thickening appears as linear plaques of opacification, which are most often along the lower chest wall and diaphragm. Calcification of the pleural plaques is virtually pathognomonic of asbestosis, especially when the calcified plaques appear in the form of thin, curvilinear densities conforming to the upper surfaces of the diaphragm bilaterally In the lungs, round or irregular opacities produce a combined linear and nodular pattern that may obscure the heart border, producing the so-called shaggy heart Shaggy Heart Figure 1. Comparison of chest X-ray obtained 12 years prior and on admission. Chest X-ray imaging revealed pleural thickening 12 years prior (A). Current chest X-ray showed a few nodular opacities with lung nodules and pleural thickening (B). The red arrows indicate lung nodules. Solitary Pulmonary Nodule The asymptomatic solitary pulmonary nodule seen as an incidental finding on a screening chest radiograph poses a diagnostic dilemma because it could represent a benign granuloma or neoplastic process, a primary bronchogenic carcinoma, or a solitary metastasis. In persons younger than 30 years, a small, round, sharply defined solitary pulmonary nodule is associated with a minimal risk of cancer Imaging appearance. The presence of central dense or popcorn calcification is diagnostic of a benign process, and a low-kVp technique may be required to demonstrate the calcification to best advantage Benign solitary pulmonary nodule (tuberculoma). Note central calcification characteristic of this benign lesion (smooth surface) Bronchial Adenoma Neoplasms of low-grade malignancy that constitute approximately 1% of all bronchial neoplasms. They are equally common in men and women. Bronchial adenomas appear in a younger age group than bronchogenic carcinoma. Hemoptysis and recurring pneumonia are the most common symptoms. They arise in the same glandular structures in the bronchi in which malignant neoplasms develop Approximately 80% of bronchial adenomas occur centrally in major or segmental bronchi and cause obstruction. The most common radiographic findings are peripheral atelectasis and pneumonitis due to bronchial obstruction. This obstruction characteristically produces a homogeneous increase in density corresponding exactly to a lobe or one or more segments, usually with a substantial loss of volume. If large enough, a central bronchial adenoma causing peripheral atelectasis and pneumonia may be identifiable as a discrete, lobulated, soft tissue mass. A tumor too small to obstruct the lumen may not be detectable on the chest radiograph. Peripheral bronchial adenoma. Nonspecific solitary pulmonary nodule at the left base. BROCHOGENIC CARCINOMA closely linked to smoking and to the inhalation of cancer-causing agents (carcinogens), such as air pollution, exhaust gases, and industrial fumes. major form -solitary pulmonary nodule within the lung parenchyma The most common type of lung cancer is squamous carcinoma, which typically arises in the major central bronchi and causes gradual narrowing of the bronchial lumen. Adenocarcinomas usually arise in the periphery of the lung rather than in the larger central bronchi. The least common type of lung tumor is bronchiolar (alveolar cell) carcinoma. Non–small cell lung cancers (i.e., the three types of lung cancer just listed) make up 80% of all lung cancers. Small cell (oat cell) carcinomas characteristically cause bulky enlargement of hilar lymph nodes, often bilaterally, and are responsible for the remaining 20% of primary pulmonary malignancies. PULMONARY METASTASES Hematogenous metastases. Multiple, well- circumscribed nodules scattered diffusely throughout both THE END!!