Pulmonary Board Review Lecture 1 Lisa M. Zahn, MD Mount Sinai School of Medicine Department of Emergency Medicine November 14, 2007
Lecture 1 Pneumonia: community acquired, immunocompromised host, aspiration, pediatric Pneumothorax Mycobacterium tuberculosis Miscellaneous: Pleural effusion, lung abscess, ARDS, acute chest syndrome in Sickle Cell Anemia Lecture 2 Asthma COPD Pulmonary Embolism Fat Embolism Cystic Fibrosis Lung Cancer Pediatric topics: Croup, FB
Which of the following statements regarding community-acquired pna is correct? a) Positive blood cx’s reflect the etiologic agent more accurately than do sputum cultures b) Radiographic findings are often predictive of the infectious etiology c) The incidence of positive blood cx’s is higher in pna-specific severity index Class I than in Class V d) The pna-specific severity index has been validated as a triage screening tool e) Typical pna is differentiated from atypical pna by clinical presentation
Positive blood cx’s reflect the etiologic agent more accurately than do sputum cultures. Pneumonia Patient Outcomes Research Team (PORT) determined 20 statistically significant criteria that, when combined, yield a pna-specific severity index (PSI). PSI is further categorized into 5 classes with associated increasing mortalities. This information is further extrapolated for use in determining the need for hospital admission and type of bed (e.g., ICU). PORT findings were validated as a mortality prediction rule, not as a method for triaging pts with CAP.
The clinical utility of blood cx’s in CAP pts with no comorbidities and lower PSI scores (Classes I-III) is low (6-11%). The clinical yield becomes higher (about 30%) in pts with severe pna (PSI Class V). Yield of sputum analysis is variable. Sputum cx and gram stain are best performed in high-risk hospitalized pts (e.g., intubated or ICU pts). In contrast, positive blood cx’s reflect the etiologic agent more accurately than sputum cx’s.
The terms “typical” and “atypical” pna refer to the causative agent. Typical refers to pna caused by pyogenic organisms (e.g, Streptococcus pneumoniae, Haemophilus influenzae) Atypical refers to pna caused by Mycoplasma, Chlamydia, Legionella, viruses or rickettsiae. Although CXR can provide a clue to the causative pathogen, the findings overall are nonspecific for accurately predicting a particular infectious etiology.
An important consideration regarding pna in elderly pts, compared to younger patients is that: a) Elderly pts are less likely to have pneumococcal bacteremia b) Elderly pts are less likely to present in an advanced stage of illness c) Elderly pts are less likely to present with productive cough and fever d) Mycoplasma is the most common atypical causative agent in elderly pts e) Temperature higher than 38.3 c (100.9 f) is more worrisome in younger pts
c) Elderly pts are less likely to present with productive cough and fever Classic signs and symptoms of PNA, such as cough productive of purulent sputum, SOB, fever, are often absent in elderly or debilitated pts. Initial presenting complaints can include acute confusion, weakness, tremulousness, and decline in functional status. Elderly pts are often sicker and in an advanced stage of illness in initial presentation (e.g., septic shock in absence of previous signs and symptoms).
As c/w younger adults, febrile (>38.3 c) elderly pts with PNA are more likely to have serious bacterial infection. Pneumococcal bacteremia is 3x more common in elderly pts than in younger pts with pna. When c/w pts younger than 65, the mortality from pneumococcal pna is 3-5 times greater in the elderly (up to 40%). The most common atypical organism in the elderly is Legionella. Mycoplasma pneumoniae is a common cause of CAP in healthy pts younger than 40.
Poor prognostic indicators for elderly pts with pna include: hypothermia, temperature greater than 38.3 c (100.8 f), low WBC count, immunocompromise, Gram negative or staphylococcal infection, CV disease, bilateral infiltrates, and extrapulmonary disease.
A 75 year old NH pt with a PMH significant only for mild dementia choked on water while sitting at a table eating his lunch. He recovered uneventfully but was sent to the ED for evaluation of aspiration pna. He is in no respiratory distress and has nl VS, including pulse oximetry, an unremarkable PE, and a normal CXR. Which of the following considerations regarding his tx is correct? a) Anaerobes have a major role in aspiration pna b) Antibiotics should be initiated early regardless of whether he is symptomatic c) Early initiation of corticosteroids will not help prevent lung injury d) Expectorated sputum cx’s will have high yield in identifying the causative organism e) He is likely to have lung involvement in the superior segments of the lower lobes
c) Early initiation of corticosteroids will not help prevent lung injury. Community-acquired aspiration PNA is caused by: Streptococcus pneumoniae Staphylococcus aureus Haemophilus influenzae Enterobacteriaceae Hospital-acquired aspiration PNA, in addition to the above iscaused by gram-negative organisms (e.g., Pseudomonas aeruginosa)
If patient has a hx of chronic alcoholism, severe periodontal dz, putrid sputum, evidence of necrotizing pna or lung abscess on cxr consider: Anaerobic organisms The posterior segments of the upper lobes and the superior segments of the lower lobes are the most common sites of involvement, if aspiration occurred in a recumbent position. The basal segments of the lower lobes, commonly RLL, are typically affected if the aspiration took place in an upright or semi-recumbent position. Expectorated sputum cx’s in aspiration PNA has low clinical utility secondary to OP colonization. Corticosteroids in aspiration PNA have not been supported. Prophylactic abx are not recommended in pts with an episode of an aspiration who have nl radiographic studies and no signs or symptoms of infection.
Which of the following organisms is the most common cause of pna in a pt with HIV infection and a CD4+ count of 850 cells/microliter? a) Cryptococcus neoformans b) Mycobacterium tuberculosis c) Pneumocystis jiroveci d) Pseudomonas aeruginosa e) Streptococcus pneumoniae
e) Streptococcus pneumoniae • The most common cause of bacterial pneumonia in pts with HIV is Streptococcus pneumoniae. C/w non-HIV positive pts, the incidence of streptococcal pna is 9 to 10 x higher in HIV pts, and is commonly associated with bacteremia. Bacterial infections are more likely to cause pna when the pt’s CD4+ count is above 800 cells/microliter. • Haemophilus influenzae and Pseudomonas aeruginosa are also common causes of bacterial pna in HIV pts. The incidence of Haemophilus influenzae is 100 x higher in HIV pts than in non-HIV pts.
C/w other bacterial pathogens, Pseudomonas aeruginosa pna in HIV pts is more likely to cause lower WBC and CD4+ counts. CD4+ counts between 250 and 500 cells/microliter increase the risk of infection by: Mycobacterium tuberculosis Cryptococcus neoformans Histoplasma capsulatum CD4+ count below 200 cells/microliter increase the risk of infection by Pneumocystis jiroveci (formerly Pneumocystis carinii)
Bacterial pna, TB and opportunistic infections can result in pulmonary nodules in HIV pts. Pleural effusions are also common in HIV pts and are often caused by Streptococcus pneumoniae and Staphylococcus aureus. Common noninfectious etiologies of pleural effusions in HIV pts include NHL, Kaposi sarcoma and adenocarcinoma of the lung.
A 48 year old man presents complaining of SOB, cough, and fever. His pulse oximetry reading is 92% on room air; CXR demonstrates a RLL infiltrate. He underwent right lung transplantation 4 weeks earlier for idiopathic pulmonary fibrosis. Which of the following statements regarding the pt’s condition is correct? a) Acute rejection can be differentiated clinically from infection b) Bacterial pna is a common complication during the early post-op period c) EBV is the most common viral infection after lung tx d) Prophylaxis against pneumocystis jiroveci should be initiated only in lung tx pts who have HIV infection e) Steroids are contraindicated for the management of acute rejection
Bacterial pna is a common complication during the early post-op period. Lung transplantation is most commonly performed for: COPD, idiopathic pulmonary fibrosis, CF, alpha1-antitrypsin deficiency emphysema, primary pulmonary htn, sarcoidosis and bronchiectasis. Absolute exclusion criteria for lung transplantation are: HIV infection, noncurable malignancy, active cigarette smoking, chronic HBV or HCV, and nontreatable infections. Secondary to the use of various immunosuppressive agents, lung tx pts are at a higher risk for both opportunistic and non-opportunistic infections. Prophylaxis against Pneumocystis jiroveci (formerly Pneumocystis carinii) with bactrim is customary after lung tx.
Acute rejection and infection are common complications during the first post-op year. Distinguishing between the two is difficult because of overlap between the signs and symptoms. Dx requires bronchoscopy and transbronchial bx. High- dose steroids is the tx for acute rejection. Bacterial pna is a common complication during the early post-op period, especially the first 3 months. Among viral agents, CMV is the most common pathogen (within the first post-op year). Other viral infections (e.g., EBV, HSV) are less common, but possible as well. Among fungi, Aspergillus species can be associated with invasive disease.
For previously healthy children with communityacquired pneumonia, which of the following statement is correct? a) Age is the most important factor in selecting empiric antibiotic therapy b) Concurrent presence of watery diarrhea reliably identifies a viral etiology c) Localized chest pain is most commonly associated with viral pna d) Viral and bacterial pneumonia can reliably be differentiated in infants e) Wheezing in preschool-aged children is pathognomonic for viral pna
Age is the most important factor in selecting empiric antibiotic therapy The organisms associated with CAP in previously healthy children differ by age. Perinatally acquired organisms (GBS, gram negative enteric bacteria) have been identified as the etiologic agents in the first 3 weeks of life, only. Infants of this age are admitted and administered ampicillin and gentamicin with or without cefotaxime. Other organisms in this age group include CMV, Listeria monocytogenes.
In infants 3 weeks to 3 months organisms include: Chlamydia trachomatis, RSV, Parainfluenza 3, Streptococcus pneumoniae, Bordetella Pertussis (more likely to cause bronchitis), and less commonly Staphylococcus aureus. Afebrile infants between 3 weeks and 3 months old with normal oxygen saturation, an oral macrolide such as erythromycin or azithromycin is recommended. Afebrile infants between 3 weeks and 3 months old with hypoxia, hospital admission for IV erythromycin is recommended. Febrile infants between 3 weeks and 3 months old, admission to the hospital for IV cefotaxime is recommended.
Infants and children between 4 months and 4 years old, the recommended outpt tx is oral amoxicillin. Although, most commonly pna is caused by RSV, parainfluenza virus, influenza virus, adenovirus, rhinovirus. If inpatient tx is indicated, (e.g., signs of sepsis, alveolar infiltrates, or large pleural effusions) IV amp or IV cefotaxime or cefuroxime. Bacterial organisms include Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae (although more common in the older children) and TB (in certain populations).
In children 5 to 15 years old, Mycoplasma pneumoniae is the chief cause of pna. Although Chlamydia pneumoniae is possible. Streptococcus pneumoniae is more likely for a lobar pna, and TB should be considered in certain populations. Children 5 to 15 years old treated as outpts, oral erythromycin, azithromycin, or clarithromycin is recommended. Children 5 to15 years old who do not have lobar or lobular infiltrates or pleural effusions but are ill enough to be admitted, IV erythromycin or IV azithromycin is recommended. For children older than 8 years, oral or IV doxycycline may be substituted for macrolide inpt or outpt therapy. Children 5 to 15 years old who require hospital admission, i.e., with signs of sepsis, an alveolar infiltrate, or a large pleural effusion, IV cefotaxime or cefuroxime is recommended.
Localized chest pain is most commonly associated with bacterial pna. Other factors, such as concurrent OM, rhinorrhea, sick contacts, myalgias, diarrhea, do not reliably differentiate bacterial vs viral pnas. Although wheezing is more commonly seen with viral pna than with bacterial pna, wheezing is not pathognomonic for viral pna. In studies that directly examined this, wheezing was seen in 435 to 56% of viral pna cases and in 16% of bacterial pna cases.
Which of the following conditions is most likely to be a precipitating factor for PTX? a) COPD b) Cigarette smoking c) Marfan syndrome d) Physical exertion e) Pneumocystis carinii pna
Cigarette smoking PTX occurs when air enters the intrapleural space (i.e., space between the visceral and parietal pleura). Tension PTX is caused by positive pressure in the pleural space leading to decreased venous return, hypotension, hypoxia. PTX is classified into: iatrogenic/traumatic spontaneous: primary or secondary
Iatrogenic/traumatic PTX: secondary to invasive procedures such as needle bx of the lung (50%) subclavian line placement (25%) NGT placement positive pressure ventilation other trauma Primary spontaneous PTX accounts for the majority of pneumothoraces no underlying lung disease male smokers of taller than average height relative risk is 6x higher in men than women cigarette smoking confers a greater than 20:1 relative risk c/w non-smokers other risk factors: changes in ambient atmospheric pressure, MVP, Marfan syndrome physical exertion is not a factor
Secondary spontaneous PTX 1/3 of spontaneous PTX underlying pulmonary disease COPD is the most common associated condition other associated lung disease: asthma, CF, necrotizing bacterial PNA, lung abscess, PCP PNA, TB, sarcoidosis, primary lung cancers, pulmonary/pleural mets. Catamenial PTX rare cause of recurrent spontaneous PTX occurs in association with menses develops within 72 hours of onset of menses
Clinical features of PTX: symptoms are directly related to the size, rate of development and underlying lung disease acute onset of pleuritic pain is found in 95% dyspnea occurs in 80% and predicts a large PTX decreased breath sounds on the affected side are present 85% of the time only 5% have tachypnea over 24 breaths per minute EKG changes, including ST changes and T-wave inversion may be seen with PTX Diagnosis: CXR upright PA is 83% sensitive expiratory films may slightly enhance visualization CT scan may be more sensitive recent studies have shown the sensitivity of US to be near 100%
A 22 year-old college basketball player presents with sudden-onset SOB. Chest radiography reveals a 10% ptx. The pt has not had a prior episode of ptx. He is not in acute distress, and VS and oxygen saturation are wnl. w/o any intervention, approximately how long will it take for the ptx to resolve on its own? a) 12 hours b) 24 hours c) 36 hours d) 1 week e) 3 weeks
1 week Management of PTX: If unstable (e.g., suspected tension ptx) place chest tube prior to CXR. Observation is acceptable approach for a healthy, young pt, with a small (i.e., <20% of hemithorax) primary spontaneous PTX. Observe x 6 hours, may repeat cxr and d/c with surgical f/u if no enlargement on cxr. However, 23 to 40% of patients will eventually require tube thoracostomy. Aspiration is another option for small asymptomatic pneumothoraces. Intrinsic reabsorption rate in intrapleural air is approximately 1 to 2% of lung volume qd.
Administration of 100% O2 increases the reabsorption rate by 3 to 4 fold. Mechanism is by lowering the alveolar partial pressure of nitrogen. As a result, the rate at which air diffuses across the pleural-alveolar barrier is accelerated. When dischargeable, pts should be instructed to avoid air travel or underwater diving until the PTX has completely resolved. Management of secondary spontaneous PTX is usually managed by tube thoracostomy, because less invasive approaches such as observation or aspiration has a much lower success rate.
Which of the following conditions places a patient at higher risk for the progression of TB from latent infection to active disease? a) Asthma b) CHF c) DM d) Influenza e) Smoking
Risk factors for developing active TB in a previously infected pt include: HIV Other immunosuppressive conditions (i.e., steroids, s/p organ tx) TB infection within the last 2 years CXR suggestive of prior TB in an untreated person IVDA DM Silicosis Head and neck CA Hematologic and reticuloendothelial disease CRF Low body weight (<10% of ideal body weight)
Risk factors for acquiring TB: Close contact with a person known to have active TB HIV infection Homelessness Incarceration Alcoholism Occupational exposure (e.g., in hospitals, nursing homes) Advanced age IVDA Immigration from areas with higher rates of TB: Asia, Africa, Latin America
General Information TB is a major global problem. More than 30% of the world’s population has latent or active TB. TB causes 2 million deaths yearly. TB rates remain disproportionately high in foreign-born persons, accounting for ½ of all US cases. Pathophysiology: TB is caused by Mycobacterium tuberculosis, a slowing growing aerobic rod, multilayered cell wall which account for its acid-fast property. Transmission occurs through inhalation of droplet nuclei in to the lungs. Hematogenous dissemination may occur. Organism survives in areas of high oxygen content or blood flow: apical and posterior segments of the upper lobe, superior segments of lower lobe, renal cortex, meninges, epiphyses of long bones, vertebrae. Latent TB infections are asymptomatic with positive PPD. Latent TB will progress to active disease in 5% of cases, within the first 2 years of infection. An additional 5% will reactivate over their lifetime. Reactivation rates are higher at extremes of age, pts with recent primary infection, immune deficiency (most notably HIV), and pts with chronic diseases (e.g., DM, renal failure)
Clinical Features: Primary TB infection is usually asymptomatic. (Usually noted with a positive PPD.) Some pts may present with active pneumonitis or extrapulmonary disease. Immunocompromised pts are more likely to develop rapidly progressive primary infections. Reactivation of latent TB accounts for most active cases. Active TB presents subacutely with: fever, cough, weight loss, fatigue, night sweats. Hemopytsis, pleuritic chest pain and dyspnea may develop. The pulmonary physical exam is usually non-diagnostic, but rales or rhonchi may be present.
Extrapulmonary TB develops in 15% of cases. The most common form is lymphadenitis. Also, pleural effusion or pericarditis may occur. TB peritonitis presents insidiously after extension from local lymph nodes. TB meningitis can occur from hematogenous spread. With symptoms of fever, HA, meningeal signs, and/or CN deficits. Miliary TB is a multisystem disease caused by massive hematogenous spread. Most common in immunocompromised pts and children. P/w fever, cough, weight loss, adenopathy, HSM, cytopenias. Prior partially treated TB is a rf for drug-resistant TB. Multi-drug resistant TB is more common in HIV pts than in the general population, and has a higher fatality rate.
Diagnosis: CXR are the most useful diagnostic tool for active TB in the ED. Active primary TB presents with parenchymal infiltrates in any lung area. Hilar and/or mediastinal adenopathy may occur with or without infiltrates. Lesions may calcify. Reactivation TB presents with lesions in the upper lobes or superior segments of the lower lobes. Cavitation, calcification, scarring, atelectasis and effusions may be seen. Cavitation is associated with increased infectivity.
Miliary TB may cause diffuse small (1 to 3 mm) nodular infiltrates. Pts coinfected with HIV and TB are particularly likely to have atypical or nl cxr Acid fast staining of sputum can detect mycobacteria in 60% of pts with pulmonary TB (lower yield in HIV pts). Therefore a single sample may yield a false negative. Atypical mycobacteria can yield false positives. PPD tests identifies latent, prior, or active TB infection. Results read within 48 to 72 hours. Pts with positive PPD and no active TB disease should be evaluated for prophylactic treatment with INH to prevent reactivation TB. Immunosuppresed pts may yield false-negative results to PPD even if not fully anergic.
Emergency department care and disposition: Initial therapy includes a 4 drug regimen, until susceptibilities are available. (e.g., INH, rifampin, pyrazinamide, and streptomycin or ethambutol x 2 months). Then at least 2 drugs are continued for four more months. Admission for clinical instability, dx uncertainty, unreliable outpt f/u or compliance, and active known MDR TB. Admit to respiratory/droplet isolation. ED staff should receive regular PPD skin testing.
a) A common cause of atraumatic hemothorax is SLE b) A pH of less than 7.3 strongly suggests pleural empyema or esophageal rupture c) Effusions associated with PE are transudative d) Management of complicated parapnuemonic effusions includes tube thoracostomy e) The most common cause in developing countries is CHF Which of the following statements regarding pleural effusions is correct?
Management of complicated parapnuemonic effusions includes tube thoracostomy. • Parapneumonic effusion is a pleural effusion associated with bacterial pna, bronchiectasis or lung abscess. • A complicated parapneumonic effusion requires a tube thoracostomy, in addition to abx. • Most common cause of pleural effusions in developed countries is CHF. • Other causes of pleural effusions: malignancy, bacterial PNA,PE • In developing countries, TB is the leading cause of pleural effusion.
Pleural effusions: exudative or transudative. Exudative: inflammatory or neoplastic conditions, high protein content Transudative: CHF, Nephrotic syndrome: low protein content. Form from imbalance in hydrostatic or oncotic pressures across the pleural membrane. PE or sarcoidosis can cause either exudative or transudative effusions.