e n i c i d e m r a l u c s a v o d r a C i 149 Driving and the heart The rules on driving with heart conditions vary from state to state, and you should become familiar with the laws in your state before discussing driving with y our patients. In general, it is the responsibility of the driver, but you should guide your patients appropriately. Pulmonary medicine L. Dwight Wooster , M.D., F.C.C.P. e n i c i d e m y r a n o m u P Introduction 150 Outline of pulmonary diseases 151 History and physical exam 151 Clinical s tudies in pulmonary medicine 155 Pneumonia 160 Specific pneumonias 164 Complications of pne umonia 165 Cystic fibrosis 166 Bronchiectasis 168 Lung abscess 169 Fungal infection of the lung 169 Neoplasms of the lung 173 Asthma 176 Asthmatic bronchitis/Refractory asthma 177 Ch ronic obstructive pulmonary disease 179 Interstitial lung disease 183 Acute respiratory dis tress syndrome 185 Respiratory failure 186 Pulmonary embolism 188 Pneumothorax 189 Pleural effusion 190 Sarcoidosis 192 Hypersensitivity pneumonitis/Extrinsic allergic alveolitis (EA A) 194 Hypersensitivity pneumonitis with eosinophilia 194 Pulmonary hypertension 195 Indust rial dust diseases 196 Cor pulmonale 198 Obstructive sleep apnea/hypopnea syndrome 200 Lung transplantation 201 l 6 150 Introduction The respiratory system consists of the central nervous system, the periph- era l nervous system, the nose and sinuses, the mouth and upper airways, the lungs, chest wall, and diaphragm and the pulmonary circulation. The functions of the respiratory system inclu de filtering and humidification of air, oxygenating of blood and elimination of carbon diox ide, and the pro- tection of each respiratory system component. Pulmonary disorders or thos e disorders affecting the lungs cause dysfunction of these respiratory functions, resulting in a variety of symptoms, the most common of which is dyspnea, difficulty in breathing. Ot her forms of breathlessness are ortho- pnea (shortness of breath when lying down), dyspnea on exertion, parox- ysmal dyspnea and nocturnal paroxysmal dyspnea (sudden paroxysms of dys pnea), and platypnea, or shortness of breath when standing up. Cough, chest tightness or di scomfort, wheezing, and hemoptysis are other frequent symptoms suggestive of respiratory sy stem disorders. Outline of pulmonary diseases Airway diseases-predominately obstructive \212 \212 \212 \212 \212 \212 Lung parenchyma disease-predominately restrictive \212 Pulmonary fibrosis \212 Sarcoidosis \212 Lung abscess \212 Pneumonia \212 Malignancy: Primary or metastat ic Chest wall diseases-restrictive \212 \212 \212 e n i c i d e m y r a n o m u P Acute bronchitis and upper respiratory tract infections Emphysema Chronic bronchitis/bronch iectasis Asthma Chronic obstructive pulmonary disease Bronchiolitis l Skeletal: Pectus deformities, kyphoscoliosis, ankylosing spondylitis Extraskeletal: Obesity Neurological: Multiple Guillain-Barr syndrome, paralyzed diaphragm sclerosis, amyotrophic lateral sclerosis, Vascular disease-neither obstructive nor restrictive \212 \212 Pulmonary emboli (PE) Pulmonary hypertension History and physical exam Refer to pp. 36 \200\22339; in addition to the clinical points in the chapter of Clinical Skills, a few other points; Smoking history Ask the patient: \200 \234Have you ever smoked? How long? Number of cigarettes per day? Filtered or unfiltered? G eneric versus brand-named cigarettes? Menthol or nonmenthol? \200\235 Did the patient \200 \231s par- ents smoke? If one has stopped smoking, how long? Ask about other tobacco produc ts; question about snuff or chew, fre- quency of use, history of previous dental or mouth e xaminations. Ask about other inhalants, such as THC/cocaine. Ask about occupational history ; nature of the patient \200\231s work; exposure to fumes, chemicals dyes; e.g., if taking a history from a fire-fighter, is there a history of smoke inhalation? Is there a modificat ion of symptoms when away from work environment compared to symptoms at work? Ask about con struction projects at work or at home. Question the patient about exposure to variations in tempera- ture or humidity. Physical exam of the chest In addition to examination of the ch est discussed in Clinical Skills (p. 36): \212 \212 151 Listen to chest sound during quiet breathing and with deep breathing. With the stethoscope over the upper and anterior portion of the chest, have the patient perform a forced expirat ion \200\224listen for wheezes or rhonchus. Chest radiographs The routine chest radiograph (p. 691) is the first radio- graphic step in diagnosing pulmonary disease. Although chest computed tomography (ct) scans have greater l ung and mediastinum resolution and are commonly ordered, the routine chest x-ray (cxr) is l ower in cost and has less radiation exposure. The noncontrast ct has a radiation exposure o f 7.00 millisieverts, whereas a routine cxr has an exposure of 0.02; concerning cost, nationa l data from commercial insurance and Medicare show a cost range of $620-$386 for chest ct; the cost range for a cxr is $77-$51. Detailed analysis of chest radiographs are reviewed in the Radiology chapter. The replications of chest radiographs in Figure 6.1 show characteri stic changes of infiltrates or lung lesions in all five lobes. Other chest imaging Chest CT is modality of choice for evaluating lung or thoracic abnormalities detected on a routine cxr; excellent for lung parenchyma, mediastinum, and chest wall abnormalities. High-resolut ion CT (HRCT) produces cross-section images of 1 \200\2232 mm, in contrast to usual ct cros s-sections of 7 \200\22310 mm; excellent for delineation of lung parenchyma and small airwa ys, especially in interstitial lung disease. Helical CT produces quicker ct scans with sing le-breath imaging, con- trast images with collection of continuous data, and may develop th ree-dimensional (3-D) images. In 2010, the National Cancer Institute (NCI) reported on a lu ng cancer screening study that included participants who were between 55 and 74 years of ag e and who were smokers of at least 30 pack-years. The participants were randomized to low-d ose helical ct or to screening routine chest radiographs. The findings indicated that scree n- ing with low-dose helical ct was beneficial in reducing mortality from lung cancer. None theless, the nci recommended further lung cancer screening studies and advocated cost-effec tive review of low-dose helical ct for lung cancer screening. Magnetic resonance imaging (M RI) is less sensitive than chest ct in the evaluation of lung parenchyma; effective for stu dy of chest wall, breast, and mediastinum. Nuclear medicine techniques Ventilation and perf usion nuclear scans were previously used to diagnose PE; ct angiography is now the radio- graphic tool of choice to evaluate for PE. Ventilation/perfusion (V ) scans /Q are helpf ul in preoperative analysis of lung resection candidates, for regional blood flow and venti lation functional analysis of the proposed lung to be removed, and in calculating its contr ibution or noncontribution to overall lung function in comparison to the uninvolved lung. P ositron emission tomography (PET) scans utilize a radiolabeled glu- cose compound, fluoro-2 -deoxyglucose, which is absorbed by metabolically active cells. 18-F decays and is detected by the PET camera. PET is useful for evaluation of solitary pulmonary nodules and for the inclusion or exclusion of metastatic lung disease. False negatives occur with neoplastic pr ocesses of low metabolic activity, such as carcinoid tumors and bronchioloalveolar carcinom a. False-positive results are detected in inflammatory processes having a high metabolic ac tivity, such as pneumonias and inflammatory, granulomatous disorders. Pulmonary angiography uses the direct injection of radiographic contrast dye into the pulmonary artery for evalu ation of the pulmonary vasculature; it can be used to rule out PE or evaluate for arteriove nous malformations or congenital abnormalities of the pulmonary circulation. CT angiography is presently the technique of choice for diagnosing PE; used instead of pulmonary angiogra phy. ct angioradiography is ideal for the assessment of aortic aneurysms, aortic dissection , and of posttraumatic aortic arch injury. ct angiography uses less contrast material and i s less risky than pulmonary angiography. Ultrasound (US) of the chest uses echo images diff erentiate among tis- sue, air, and fluid, due to their differing acoustic properties. US is used for the detection and localization of pleural effusions, of an empyema, and for 152 adjunct diagnosis of pneumothoraces. US is additive in percutaneous-guided thoracentesis or for biopsy of pleural/chest wall lesions and for guidance in placement of chest tubes. Por table US is useful in intensive care units for these applications and for evaluation of dia phragmatic movement. Virtual bronchoscopy produces 3-D generated images from the multide- t ector ct (mdct); utilizes multiple sensors along the scanning axis; e.g., the mdct, 64-slic e technique. Computers then generate a compilation of images to form a virtual bronchoscope image; there is high radiation exposure, but extraordinary images with significant airway specificity. e n i c i d e m y r a n o m u P l 153 Figure 6.1 Left upper lobe collapse Left lower lobe collapse Left lower lobe collapse Lingular consolidation Lingular consolidation 154 Right upper lobe collapse Right upper lobe collapse Right middle lobe collapse Right lower lobe collapse Clinical studies in pulmonary medicine Sputum examination Collect a good sample; deep cough expectoration. Observe the appearance: Clear and colorless (chronic bronchitis), yellow/ g reen (pulmonary infection), blood-streaked or grossly bloody (hemopty- sis), black (smoke, coal), or frothy white/pink (pulmonary edema). Send the sample to the laboratory for micros copic examination: Gram stain for bacteria, special stains for fungi and mycobacterium, and for culture or cytology if indicated. Peak expiratory flow (PEF) is measured by a maximal forced expiration through a peak flow meter or during routine pulmonary function studies (F igure 6.2). PEF correlates well with the forced expiratory volume in 1 second (FEV 1 ) and is used as an estimate of airway caliber. PEF may be measured regularly in asthmatics to mo nitor response to therapy, disease control, and in the early detection of acute asthmatic e xacerbations. See Figure 6.3. Pulse oximetry is a noninvasive determination of peripheral O 2 satura- tion. Pulse oximetry is a valuable tool in clinical circumstances for the assess ment of criticality of a patient \200\231s illness. It is also helpful in stable outpatient settings in determining the need and/or effectiveness of home or portable oxygen utilizati on. Normal O 2 saturation is between 96 \200\22398%. Oxygen saturation readings are useful in chronic obstructive pulmonary disease (COPD), as well as in acute or chronic congestive heart failure. Evaluating oxygen saturation during light exercise and during sleep are addi tive in judging severity of a pulmonary illness. Erroneous readings may occur with poor per ipheral perfusion such in Raynaud \200\231s phenomena and in instances of finger motion, pr esence of nail polish or rings, and in carbon monoxide intoxication. If pulse oximetry yiel ds variable results then arterial blood gasses (ABGs) are indicated (p. 177). Arterial bloo d gas (ABG) analysis Heparinized blood is taken from the radial, brachial, or femoral arter y, and pH, P a O 2 , and P a CO 2 are measured using an automated analyzer. Remember to ind icate the FiO 2 (fraction/per- centage of inspired oxygen) on the requisition form. \212Ac id \200\223base balance: Normal pH is 7.35 \200\2237.45. A pH <7.35 indicates acidosis e n i c i d e m y r a n o m u P l 155 and a pH >7.45 indicates alkalosis /Q . \212Oxygenation: Normal P a O 2 is 85 \200\223100 mm Hg. Hypoxia is caused by one or ) mis match, hypoventilation, abnormal mismatch is the most more of ventilation/perfusion (V diffusion, right-to-left cardiac shunts. Of these, V commo n cause. Severe hypoxia is defined as a P a O 2 <60 mm Hg. . /Q . \212Ventilation efficiency: Normal P a CO 2 is 35 \200\22345 mm Hg. P a CO is directly rel ated to alveolar ventilation. A P a CO 2 <35 mm Hg indicates hyperventila- tion and a P a C O 2 >45 mm Hg indicates hypoventilation . Type I respiratory failure, or insufficient oxyge nation, is defined as P a O 2 <60 mm Hg and P a CO 2 <45 mm Hg; Type II respiratory failure , or failure of alveolar venti- lation, is defined as P a O 2 <60 mm Hg and P a CO 2 >45 mm Hg. Alveolar \200\223arterial O 2 concentration gradient may be calculated from the FiO 2 , P a O 2 , and P a CO 2 : See Alveolar-arterial oxygen gradient calcula- tion in Table 6.1. Spi rometry is a measurement of air flow and is used to evaluate the degree of obstruction in a sthma, COPD, and bronchiectasis. FEV 1 and forced vital capacity (FVC) are measured from a full deep inspiration to a forced expiration into spirometer; exhalation continues until no more breath can be exhaled. Both FVC and FEV 1 are effort-dependent, yet FEV 1 is less eff ort-dependent than PEF. The FEV 1 /FVC ratio gives a good estimate of severity of airflow o bstruction; normal FEV 1 /FVC ratio is 75 \200\22380%. See Figure 6.4. Table 6.1 (Aa)po 2 : The alveolar \200\223arterial (Aa) oxygen gradient The Aa oxygen gradient is the difference in the partial pressures of oxy- gen between the a lveolar air and arterial blood. The normal Aa gradient for individuals \211 25 yrs is 2 \200\22312 mm Hg; however, aging influences the Aa gradient as normal for a 75-year-old is 12 \200\22325 mm Hg. The partial pressure of oxygen in arterial blood is determined with AB G analysis. The partial pressure in alveolar air is calculated using the alveolar gas equat ion. This calculation is based on the body \200\231s oxygen consump- tion, which in turn is related to oxygen uptake and metabolic carbon dioxide production; the ratio of O 2 uptake/ CO 2 production is called R , the respiratory quotient ( 0.85); this respiratory quotient depends on diet and on particular foods being metabolized. The partial pressure of alveolar oxygen calculation uses barometric pressure ( P B 760 mm Hg at sea level) and P O 47 mm H Hg, as inspired air is usually fully saturated by the time it gets to the 2 carina). P A O 2 clearly depends on F i O 2 , the fractional concentration of O 2 in inspired air; e .g., F i O 2 is 0.5 if breathing 50% O 2 and 0.21 if breathing room air). So: P A O 2 = ( P B + P H , the water saturation of airway gas ( P H O 2 O ) \227 F i O 2 P a CO 2 /R 2 = (760 + 47) \227 F i O 2 P a CO 2 /0.8 (at sea level) = 713 \227 F i O 2 \200\223 1. 25 \227 P a CO 2 Once alveolar oxygen is determined, the difference between alveolar oxygen and arterial oxy gen represents the Aa gradient. This calculation is especially useful in clinical instances of hypoventilation when the pCO 2 is high and one is determining the degree of hypoxemia r elated to hypoven- tilation; it is also useful in determining the degree/severity of hypoxe mia with normal or low pCO 2 . 156 \212Obstructive defect (e.g., asthma, COPD): FEV 1 is reduced more than the FVC and the FEV 1 /FVC ratio is <70%. \212Restrictive defect (e.g., interstitial fibrosis, or chest wall disorder): FVC is reduc ed and the FEV 1 /FVC ratio is normal or raised. Other causes: Sarcoidosis; pneumoconiosis, interstitial pneumonias; connective tissue diseases; obesity; kyphoscoliosis; neuromuscula r problems. Pulmonary function tests PEF, FEV 1 , FVC (p. 154). Total lung capacity (TLC) and residual volume (RV) are useful in distinguishing obstructive and restrictive diseases. TLC and RV a re \206\221 in obstructive airways disease and \206\223 in restrictive lung diseases and musculoskeletal, chest wall limiting abnor- malities. The diffusing capacity (DLCO) measuri ng gas exchange across the alveolar membrane is calculated by measuring carbon monoxide upt ake from a single inspiration in a standard time (usually 10 sec). The diffusion capacity i s reduced in emphysema and interstitial lung disease; it is high in alveolar hemorrhage. DL CO can be corrected for alveolar volume in appropriate circumstances. 1 Flow volume loop me asures flow at various lung volumes. Characteristic flow-volume patterns are seen with intr a-thoracic airways obstruction (asthma, emphysema) and extrathoracic airways obstruction (v ocal cord paralysis, large goiter). 1 Johnson D. Importance of Adjusting Carbon Monoxide Diffusion Capacity and Carbon Monoxide Transfer Co-Efficient for Alveolar Volume. Respir Med. 2000; 94 : 28 \200\22337. e n i c i d e m y r a n o m u P Figure 6.2 Normal peak expiratory flow (pef) l Figure 6.3 Examples of spirograms Restrictive Normal Obstructive 157 1 sec 1 sec 1 sec s r e t i L s r e t i L s r e t i L FVC FVC FEV1 FVC FEV1 FEV1 4.0 5.0 80 FEV1= FVC = % = FEV1= FVC = % = 2.8 3.1 90 FEV1= FVC = % = 1.3 3.1 42 Radiology For techniques, refer to Radiology chapter. Fiberoptic bronchoscopy is performed under conscious sedation and local anesthetic via the nose or mouth. Diagnostic indications : Suspected lung malignancy, slowly resolving pneumonia, pneumonia in the immu- nosuppresse d, interstitial lung disease. Bronchial lavage fluid may be sent to the lab for microscopy, culture, and cytology. Mucosal abnormalities may be brushed (cytology) and biopsied (histo pathology). Therapeutic indi- cations: Aspiration of mucus plugs causing lobar collapse or removal of foreign bodies. Preprocedure investigations: CBC, CXR, spirometry, pulse oximetr y and ABG (if indicated); coagulation studies, especially in clinical circumstances of rece nt anticoagulation treatment and/or probable use of endobronchial lung biopsy. Complication s: Respiratory depression, bleeding, pneumothorax (X-RAY PLATE 6). Bronchoalveolar lavage ( BAL) is performed at the time of bronchos- copy by instilling and aspirating a known volume of warmed buffered 0.9% saline into the distal airway. Diagnostic indications: Suspected m alignancy, pneumonia in the immunosuppressed (especially HIV), suspected tuber- culosis (TB ; If sputum negative), interstitial lung diseases (e.g., sarcoidosis, extrinsic allergic alveolitis, histiocytosis X). Therapeutic indications: Alveolar proteino sis. Complications: Hypoxia, transient fever, transient CXR shadow, and procedure-related i nfection. Lung biopsy may be performed in several ways. Percutaneous needle biopsy is perfo rmed under radiological guidance and is useful for peripheral lung and pleural lesions. Tra nsbronchial biopsy performed during bronchoscopy may help in diagnosing diffuse lung diseas es (e.g., sarcoidosis or diagnosing lung nodules, masses). If these biopsies are unsuccessf ul, an open lung biopsy may be performed under general anesthesia. Surgical procedures are performed under general anesthesia. Rigid bron- choscopy provides a wider bronchoscope lume n, enables larger mucosal biopsies and control of bleeding, and allows the removal of forei gn bodies. Mediastinoscopy and mediastinotomy enables examination and biopsy of the mediast inum lymph nodes/lesions. Video-assisted-thoracoscopy (VAT) uses video technology and invol ves the insertion of VAT tubing through intercostal incisions. This procedure enables the o perator to visualize the pleural space and to biopsy not only lesions in the pleural space but also lesions in the periphery of the lung. VAT has supplanted the use of open thoracoto my, yet the latter may be use in specific clinical circumstances. Thoracoscopy allows exami nation and biopsy of pleural lesions, drainage of pleural effusions, and various pleurodesi s. 158 e n i c i d e m y r a n o m u P Figure 6.4 Lung volumes: Physiological and pathological (a) l Flow volume loops (b) 159 In upper airway narrowing PEF, peak expiratory flow; FEF 50 , forced expiratory flow at 50% TLC; FEF 25 , forced expi ratory flow at 25% TLC; PIF, peak inspiratory flow; FIF 50 , forced inspiratory flow at 50% TLC. Pneumonia Pneumonia is an infection of the lung parenchyma and commonly pres- ents with sym ptoms of fever, chest pain, cough and shortness of breath along with other systemic symptom s. Pneumonia may be categorized into three major pathognomonic groups: Community-acquired p neumo- nia (CAP); health care-acquired pneumonia (HCAP); this group includes hospital-acqui red pneumonia (HAP)and ventilator-associated pneumonia (VAP), in addition to pneumonia acqu ired in institutions such as nursing homes and chronic care institutions. The last category of lung infections is pneumonia in immunocompromised individuals . One of the most critica l problems in treating pneumonia is the evolution of multiple drug-resistant bacteria occur ring not only in HCAP but also in CAP. Classification and causes 1 CAP may be primary or se condary to underlying disease: Streptococcus pneumoniae is the most common, followed by Hae mophilus influenza , Mycoplasma pneumonia, Staphylococcus aureus, Legionella species, and C hlamyd ia. Gram-negative bacilli, Coxiella burnetii, and anaerobes are rare. Viruses may ac count for up to 15 \200\22318% of CAP. 2 HCAP(nosocomial and other health care institutions) (>48 h after admis- sion): Most commo n organisms in this group of pneumonia include enterobacteria or Staphylococcus aureus-meth icillin resistant, Streptococcus pneumonia ; Pseudomonas, Klebsiella, Bacteroides, Clostrid ia, Haemophilus influenza, and Acinetobacter. 3 Aspiration pneumonia: These pneumonias commonly occur in persons with impaired upper airw ay defense mechanisms, such as in patients with cerebral vascular events, myasthenia gravis , bulbar palsies, and those with altered level of consciousness (e.g., postseizure, or alco hol intoxication; other clinical instances predisposing to aspiration pneumonia include eso phageal disease (achalasia, reflux) and persons with poor dental hygiene (a risk for aspira ting oropharyngeal anaerobes). 160 Pneumonia in immunocompromised patients is related to the type and loca- tion of the neopla sm and to competency of the patient \200\231s bone marrow; i.e., the presence or absence of neutropenia or of lymphocyte depletion. S. pneumoniae, H. influenza, S. aureus, Enterobact er, other gram-negative bacilli, and Pneumocystis ; fungi, viruses (cytomegalovirus [CMV], herpes simplex virus [HSV]), and mycobacteria. 4 VAP : The occurrence of VAP is related to the duration of artificial ventila- tion and to the colonization of the oropharynx with pathogenic organ- isms. VAP is associated with mul tiple drug-resistant organisms, with excessive sedation, and with aspiration of secretions from above the endotracheal or tracheal cuff; also, these pneumonias are associated with al tered normal defense mechanisms such as in anemia, hyperglycemia, and malnutrition. Clinical features of pneumonia Symptoms : Fever, rigors, malaise, anorexia, dyspnea, cough, and purulent sputum, hemoptysis, and pleuritic chest pain. Signs: Fever, cyanosis, confusi on (may be the only sign in the elderly), tachypnea, tachycardia, hypotension, signs of con solidation (dimin- ished expansion, dull percussion note, ^ tactile vocal fremitus/vocal re so- nance, bronchial breathing), and a pleural rub. Clinical studies are aimed to establish diagnosis, identify pathogen, and assess severity (see below). CXR (X-RAY PLATE S 5 and 8) : Lobar or multi- lobar infiltrates, cavitation, or pleural effusion. Assess oxygensation: Oxygen saturation (ABGs if s a O 2 <92% or severe pneumonia). Blood tests: CBC, electrolyte s, liver function tests (LFT), c-reactive protein (CRP), blood cultures. Sputum : For micro scopy and culture; in severe cases, check for Legionella (sputum culture, urine antigen), a typical organism/viral serology (complement fixation tests acute/chronic-paired serology); may check for pneumococcal, legi onella antigen in urine, sputum, or blood. Pleural fluid may be aspirated for culture. Cons ider bronchoscopy and BAL if patient is immunocompromised or if with multilobar, critical p neumonia. Management (p. 708): Antibiotics (see Table 6.2, p. 162) may be admin- istered or ally if the pneumonia in uncomplicated and if the patient \200\231s oral intake is adequate . Oxygen: Keep P a O 2 >60 and/or saturation \211 92%. IV fluids : Treatment of dehydrati on, shock. In severe pneumonia, treatment should consist of IV antibiotics; critical care u tilization may be necessary if the patient does not improve quickly or if hypotension, hype rcapnia, or uncor- rected hypoxia evolve. Complications of pneumonia (p. 161): Pleural effu sion, empyema, lung abscess, respiratory failure, septicemia, brain abscess, pericarditis, myo- carditis, cholestatic jaundice. Repeat CRP and CXR in patients not pro- gressing satis factorily. Preventing pneumococcal infection Pneumococcal vaccine (23-valent Pneumovax II , 0.5 mL SC) indicated in: \212 Chronic heart or lung conditions \212 Cirrhosis \212 Nep hrosis \212 Diabetes mellitus (DM) \212 Immunosuppression (e.g., splenectomy, AIDS, or on chemotherapy). CI : Pregnancy, lactation, fever. If high risk of fatal pneumococcal infect ion (asplenia, sickle-cell disease, nephrosis, post-transplant), revaccinate after 5 yrs. I nfluenza prevention : Both inactivated and live attenuated vaccines are avail- able for inf luenza A and B; inactivated vaccines are effective in 50 \200\22380% of persons in offering protection with a low incidence of adverse effects. Live attenuated vaccines may be admini stered in children with a 90% incidence of protection. Usually given by intranasal method; approved for use in non- pregnant healthy individuals 2 \200\22349 yrs. For inactivated vac cinations, the U.S. Public Health Service recommends vaccination of all persons >6 months. Antiviral chemoprophylaxis is effective yet the evolution of viral resistance has limited t he use of antiviral medications. Recommended : Zanamivir and oseltamivir have been >80% eff ective, yet amantadine and rimantadine are no longer recommended due to viral resistance to these drugs. e n i c i d e m y r a n o m u P l 161 1 6 2 Table 6.2 Antibiotic treatment of pneumonia Clinical setting Community acquired Healthy w/o antibiotics in past 3 months Organisms Antibiotic Streptococcus pneumoniae, Haemophilus influenzae Azithromycin 500 mg PO once, then 250 mg/d for 4 days or clarithromycin 500 mg PO bid for 10 days Doxycycline 100 mg PO bid for 10 days Amoxicillin 1 g PO tid; or Augmentin 2 g bid or Cephi traxone 1 \200\2232 g IV qd or Antibiotics In past 3 months with comorbid diseases Multilobar pneumonia Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae Similar plus Staph , possible anaerobes As above, plus gram-negative immunosuppressed patie nt Cefuroxime 500 mg PO bid along with a macrolide Moxifloxacin 400 mg PO qd or Levofloxacin 7 50 mg PO qd Moxifloxacin 400 mg PO/IV qd or levofloxacin 750 mg PO/IV qd Cefotaxime 1 \200 \2232 g IV q8h Ceftriaxone 1 \200\2232 g IV q8h Ertapenem 1 g IV qd Plus: Macrolide IV-clar ithromycin, azithromycin Cefotaxime 1 \200\2232 g IV q8h Ceftriaxone 2 g IV qd Plus: Azithr omycin IV or fluoroquinolone IV w/o ICU care-hospitalized patient Multilobar pneumonia- severe- ICU care Atypical Legionella pneumophila Chlamydia sp. Pneumocystis jiroveci Gram-negative bacilli, Clarithromycin 500 mg/12 h PO/IV rifampin Tetracycline High-dose co-trimoxazole (p. 570) Aminoglycoside IV + antipseudomonal penicillin IV or third-generation cepha- Health care-associated pneumonias Aspiration Pseudomonas , Anaerobes losporin IV (p. 530) Streptococcus pneumoniae, Anaerobe Gram-positive Gram-negative bacilli Fungi (p. 169) Third-generation cephalosporin IV + clindamycin 600 mg/6 h IV Immunocompromised patients cocci, Aminoglycoside IV + antipseudomonal penicillin IV or third-generation cephalosporin IV Cons ider antifungals after 48 h Third-generation, e.g., cefotaxime (p. 530); gentamicin is an example of an aminoglycoside (p. 532). 1 6 3 Pulmonary medicine Specific pneumonias Pneumococcal pneumonia is the most common bacterial pneumonia, affect- ing all ages, yet is more common in the elderly, alcoholics, post-splenectomy patients, imm unosuppressed patients, and patients with chronic heart fail- ure or pre-existing lung dise ase. Clinical features : Fever, pleurisy, malaise, shortness of breath. CXR shows lobar con solidation. Treatment : Refer to Antibiotic Treatment Chart/Infectious disease chapter. Sta phylococcal pneumonia may complicate an influenza infection and may occur in the young, eld erly, or in IV drug users, or in patients with under- lying lung disease, such as cystic fi brosis (CF), or in immunosuppressed patients; frequently isolated in intubated patients in ICU, and a frequently causative agent in HAP. CAP secondary to Staph is usually associated with previous viral, influenza infection. Treatment : Refer to Antibiotic Treatment Chart/I nfectious disease chapter. Klebsiella pneumonia commonly occurs in individuals with comorbi d dis- eases, COPD, DM, or alcoholism; frequent pathogen in HAP, with high incidence in hos pitals and long-term care facilities; usually related to coloni- zation of oropharynx; also seen in VAP; associated with pneumonia-related complications such as abscess formation, pu lmonary necrosis, empyema. Treatment : Refer to Antibiotic Treatment Chart/Infectious disea se chapter. Pseudomonas is a common pathogen in bronchiectasis and CF. In CF, Pseudomonas i nfections are usually chronic and may never be completely eradicated; treatment in CF invol ves IV as well as inhalational therapy with aminoglycosides. Pseudomonas is commonly found in HAP most specifically in VAP; also causes hospital acquired infections, particularly in the ICU or postoperative surgery units. Treatment : Refer to Antibiotic Treatment Chart/ID chapter. Mycoplasma pneumoniae occurs in sporadic epidemics about every 4 \200\2237 yrs. A frequent cause of community acquired respiratory illnesses in children and adults. Common p resentations are flu-like symptoms, headache, myal- gias, and, most commonly, a dry cough. Wheezes and crackles are detected in a large percentage of patients with Mycoplasma pneumon ia. Treatment with penicillin and cephalosporins are ineffectual, whereas treatment with ma crolides and others definitely shorten the duration of illness. Diagnosis : Polymerase chai n reaction detection of Mycoplasma in upper respiratory secretions, tracheal secretions; Ig M and IgG antibodies; enzyme-linked immune assay (primarily recommended). Cold agglutinins may cause an autoimmune hemolytic anemia; extrapulmonary complications include sep- tic art hritis, Guillain-Barr syndrome, erythema multiforme, aseptic men- ingitis. Treatment : A zithromycin, clarithromycin, doxycycline, moxifloxacin and levofloxacin. Legionella pneumop hila colonizes water containers kept at <60 C (hotel air-conditioning and hot water system s); inhalation or aspiration of con- taminated water results in outbreaks of Legionnaire \200\231s disease. Incubation period is usually 2 \200\22310 d; flu-like symptoms with espe cially high fever, mal- aise, precede a dry cough and dyspnea. Chest discomfort and shortne ss of breath occur in 30 \200\22350% of patients. Extrapulmonary features include anorexia, diarrhea, vomiting, hepati- tis, renal failure, confusion, and coma. CXR shows bibasal con solidation. Laboratory studies may show lymphopenia, hyponatremia. Diagnosis : Legionella s erology/urine antigen. Treatment : Macrolides rifampin, or fluoroquinolone. 10% mortalit y. Chlamydia pneumoniae is the most common chlamydial infection and may account for about 1 0% of CAP; person-to-person spread occurs, causing pharyngitis, hoarseness, otitis, followe d by pneumonia. Diagnosis : Serology 164 polymerase chain reaction (PCR) and culture. Treatment : Erythromycin, azithromycin, tetrac ycline, clarithromycin, fluoroquinolones. Chlamydia psittaci causes psittacosis, an ornitho sis acquired from infected birds, parrots, parakeets, turkeys, and ducks; greatest exposure to bird owners and poultry workers. Symptoms include headache, fever, dry cough, lethargy, arthralgia, anorexia, and diarrhea. CXR shows patchy consolida- tion. Diagnosis: Chlamydia serology. Treatment : Tetracycline 250 mg qid for at least 3 wks to avoid relapse; also er ythromycin 500 mg qid. Viral pneumonia: The development of viral diagnostic studies, PCR, t issue cultures, and immunofluorescence, have improved the detection of viruses; viral analy zes have discovered viruses as a more frequent causative agent in both CAP and in HAP, with an incidence of 15 \200\22318%. In CAP, the most common viruses are influenza A/B and resp iratory syncytial virus, as well as adenovirus, parainfluenza virus, rhinovirus, coronaviru s, and the SARS virus; in HAP, the causative viruses are herpes simplex and cytomegalovirus . Pneumocystis pneumonia : Pneumocystis is a world -wide distributed fungus that commonly c olonizes immunosuppressed patients and persons with COPD. This opportunistic organism is a frequent cause of pneumonia in immunocompromised patients. Combination of cellular and humo ral deficiencies predispose to Pneumocystis infection. Clinical presentation is relatively nonspecific; CXR may be normal or show bilateral perihilar interstitial infiltrates. Diagno sis: Visualization of the organism in induced sputum, BAL, or in lung biopsy specimens. Tre atment : First choice is trimethoprim-sulfamethoxazole, 14 d treatment for non-HIV; 21 d th erapy for HIV patients. Alternative treatments include trimethoprim with dapsone, clindamyc in plus primaquine, pentamidine. Prophylaxis for Pneumocystis: First choice is trimethoprim -sulfamethoxazole, in patients with and without HIV, recovering from Pneumocystis pneumonia . e n i c i d e m y r a n o m u P l 165 Complications of pneumonia Respiratory failure (p. 176): Hypoxemia, respiratory failure ( P a O 2 <60 mm Hg) is relatively common. Treatment is with high-flow (60%) oxygen. Transfer the patient to icu if hypoxia does not improve with O 2 therapy or P a CO 2 rises to >45 mm Hg. Careful O 2 administration is required in COPD patients; check ABG frequently and cons ider elective mechanical ventilation if rising P a CO 2 or worsening acidosis and hypoxemia . Hypotension may be due to a combination of dehydration and vasodilata- tion due to bacter emia/ sepsis. If systolic blood pressure (BP) is <90 mm Hg, give an IV fluid challenge of 2 50 mL colloid/crystalloid over 15 min. If BP does not rise, insert a central line and infus e IV fluids to maintain the systolic BP >90 mm Hg. If systolic BP remains <90 mm Hg despite fluid therapy, asses for vasopressive support. Atrial fibrillation (p. 120) is a quite com mon arrhythmia, particularly in the elderly; usually resolves with treatment of the pneumon ia. Digoxin, calcium-channel blockers, or \222 -blockers may be required to slow the ven- tricular response rate. Pleural effusion Inflammation of the pleura by adjacent pneumonia m ay cause fluid exudation into the pleural space. If fluid accumulates in the pleu- ral spac e faster than reabsorption, a pleural effusion develops. If the effusion is small, <10% of the hemithorax area, then it may be of little consequence. If it becomes larger and symptom atic, or infected (empyema), drainage is required (pp. 180, 661). Empyema is pus within the pleural space; clinically suspected if a patient with pneumonia and a pleural effusion doe s not respond to antibiotic therapy or if a patient with a resolving pneumonia develops a r ecurrent fever. Diagnosed by clinical features and a CXR indicating a pleural effu- sion. The aspira ted pleural fluid is typically yellow and turbid, or with frank pus, with a pH <7.1, glucos e \206\223 , and lactate dehydrogenase(LDH) \206\221 . The empyema should be drained usin g a chest drain, preferably inserted under sonographic guidance. Lung abscess is a cavitati ng area of localized, suppurative infection within the lung. Causes: \212 \212 \212 \212 \212 \212 Clinical features: Cyclical fever; cough; purulent, foul-smelling sputum; pleu- ritic chest pain; hemoptysis; malaise; weight loss. Look for finger clubbing, anemia. Empyema develops in 20 \200\22330% of lung abscesses. Tests: Blood: CBC (anemia, neutrophi lia), erythrocyte sedimentation rate (ESR), CRP, blood cultures. Sputum: Microscopy, cultur e, and cytology. CXR : Walled cavity, often with a fluid level. Consider CT scan to exclude obstruction, and bronchoscopy to obtain diagnostic specimens. Treatment: Antibiotics as in dicated by sensitivities; continue until healed (4 \200\2236 wks). Postural drainage. Repea ted aspiration, antibiotic instillation, or surgical excision may be required. Septicemia m ay occur as a result of bacterial spread from the lung paren- chyma into the bloodstream. B acteremia may cause physiologic changes of hypotension, tachycardia, renal insufficiency, a nd metastatic infection (e.g., infective endocarditis, meningitis). Treatment is with IV an tibiotic according to sensitivities. Pericarditis and myocarditis may also complicate pneum onia. Jaundice This is usually cholestatic, and may be due to sepsis or secondary to antibi otic therapy (particularly penicillin or erythromycin derivatives). Inadequately treated pneumonia Aspiration (e.g., alcoholism, esophageal obstruction, bulbar palsy) Bronchial obstruction (tumor, foreign body) Pulmonary infarction Septic emboli (sep ticemia, right-heart endocarditis, IV drug use) Subphrenic or hepatic abscess. 166 Cystic fibrosis Cystic fibrosis (CF) is an autosomal recessive disease that is classically detected in childhood, yet 5% of patients are diagnosed with CF as adults. The primary muta tions occur in CFTR gene found on chromosome 7; at least, 1,400 mutations have been documen ted. CF manifests ethnic variabil- ity with 1 in 3,000 Caucasian births 1 in 17,000 births in African Americans and 1 in 90,000 in Asian populations. Although in previous decades the life expectancy of a CF patient was short, today \200\231s median survival is >40 yrs. The genetic defect in the CFTR gene causes abnormalities in sodium absorp- tion and in chlorid e secretion; this dysfunction of electrolyte movement affects normal hydration of the pulmo nary airways, pancreatic ducts, sweat glands, and sex glands. This genetically induced dehy dration within the air- ways impairs ciliary movement and airway clearance, both primary de fense mechanisms, thus leading to susceptibility to infections. See Table 6.3. Clinical man ifestations Neonates and early childhood: Common presentation in neonates; one-fifth of neo nates present within 24 hours of birth with GI obstruction, meco- nium ileus, emesis, inabi lity to pass stool; within the first 2 yrs of life, respi- ratory tract infections are prom inent, along with recurrent sinusitis. Children and young adults: As with early childhood, respiratory manifestation are major; however, with older ages the evolution of pancreatic i nsufficiency