Transcript Slide 1

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
Pneumonia
Which of the following statements regarding communityacquired 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
a) 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)
b)
c)
d)
e)
Anaerobes have a major role in aspiration pna
Antibiotics should be initiated early regardless of whether he is
symptomatic
Early initiation of corticosteroids will not help prevent lung injury
Expectorated sputum cx’s will have high yield in identifying the
causative organism
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:
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Streptococcus pneumoniae
Staphylococcus aureus
Haemophilus influenzae
Enterobacteriaceae
Hospital-acquired aspiration PNA, in addition to the
above is caused 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 nonHIV 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)
b)
c)
d)
e)
Acute rejection can be differentiated clinically from
infection
Bacterial pna is a common complication during the early
post-op period
EBV is the most common viral infection after lung tx
Prophylaxis against pneumocystis jiroveci should be
initiated only in lung tx pts who have HIV infection
Steroids are contraindicated for the management of acute
rejection
b) Bacterial pna is a common complication during the early postop 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 nonopportunistic 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. Highdose 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 community
acquired pneumonia, which of the following statement
is correct?
a)
b)
c)
d)
e)
Age is the most important factor in selecting
empiric antibiotic therapy
Concurrent presence of watery diarrhea reliably
identifies a viral etiology
Localized chest pain is most commonly
associated with viral pna
Viral and bacterial pneumonia can reliably be
differentiated in infants
Wheezing in preschool-aged children is
pathognomonic for viral pna
a) 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.
Pneumothorax
Which of the following conditions is most likely to be
a precipitating factor for PTX?
a)
b)
c)
d)
e)
COPD
Cigarette smoking
Marfan syndrome
Physical exertion
Pneumocystis carinii pna
b) 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
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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
d) 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.
Mycobacterium tuberculosis
Which of the following conditions places a
patient at higher risk for the progression of TB
from latent infection to active disease?
a)
b)
c)
d)
e)
Asthma
CHF
DM
Influenza
Smoking
Risk factors for developing active TB in a previously infected pt
include:
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•
•
•
•
•
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.
Miscellaneous
Which of the following statements regarding pleural
effusions is correct?
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
d) 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.
• Bloody pleural effusions can be from trauma, malignancy,
pulmonary infarction.
• Hemothorax defined when the hematocrit of the pleural fluid is
more than 50% of the peripheral blood.
• Trauma can cause hemothorax. Other causes include rupture of
tumor or blood vessel (ruptured aortic aneurysm).
• Parapneumonic effusions, malignancies, rheumatoid effusions,
TB and systemic acidosis are associated with a pleural fluid
pH of less than 7.3,
• A pH of less than 7 suggests empyema or esophageal rupture.
Which of the following statements regarding lung
abscess is correct?
a) A cancerous etiology is more likely if the abscess
develops in the posterior portion of the lung
b) Anaerobic bacteria are more commonly found in
immunocompromised pts than in
immunocompetent pts
c) In most cases, the abscess cavity communicates
with a bronchiole
d) Infectious lung abscesses commonly occur in the
superior segments of the lower lobes
e) Surgical intervention is commonly necessary
c)
In most cases, the abscess cavity communicates with a
bronchiole
Etiology of lung abscess includes:
•
•
•
Infectious: i.e., bacterial, fungal, parasitic
Neoplastic
Inflammatory
•
Infectious etiology, most commonly anaerobic bacteria.
However in immunocompromised pts, aerobic bacteria such
as Staphylococcus aureus, Escherichia coli, Klebsiella
pneumoniae and Haemophilus influenzae have been
implicated.
•
Pts who have conditions that predispose to aspiration, such
as stroke or seizure area at higher risk for developing lung
abscess.
• Basal segments of the lower lobes and the posterior segments of the
upper lobes are common locations for infectious lung abscesses.
• Cancerous etiology should be suspected when the abscess is located
in the anterior portion of the lung.
• Frequently, pts with lung abscesses have a prolonged (more than 2
week) course of symptomatology. Clinical features include cough,
fever, chest pain.
• Hemoptysis is seen in up to 25% of cases
• In 75% of cases, the abscess cavity communicates with a bronchiole.
CXR will show a cavitary lesion with an air-fluid level.
• 85 to 90% of pts with bacterial lung abscess can be successfully
treated with broad-spectrum abx alone. Surgical intervention is
rarely required.
Which of the following statements regarding
mediastinal disorders is correct?
a) Barium studies of the GI tract are not useful for
evaluating posterior mediastinal lesions
b) Hamman crunch is best heard with the pt in the left
lateral recumbent position
c) Median sternotomy for cardiac surgery is a
common cause of chronic mediastinitis
d) The phrenic nerve is located within the anterior
mediastinum
e) TB is a common cause of acute mediastinitis
b)
Hamman crunch is best heard with the pt in the left lateral
recumbent position
Mediastinum is divided into 3 compartments:
•
Anterior: from the sternum to the pericardium and
brachiocephalic vessels. It contains the thymus and internal
mammary arteries and veins. Common lesions include
thymomas, lymphomas, teratomatous neoplasms, and
thyroid masses.
•
Middle: contains the heart, ascending and transverse aortic
arches, vena cava, brachiocephalic vessels, phrenic nerves,
trachea and main bronchi, pulmonary arteries and veins.
Common lesions include: vascular masses,
lymphadenopathies from metastases or granulomatous
diseases, and pleuropericardial and bronchogenic cysts.
• Posterior: lies between the pericardium anteriorly and
the vertebral column posteriorly. It contains the
descending thoracic aorta, esophagus, thoracic duct,
azygous and hemiazygous veins. Common lesions
include: neurogenic tumors, meningoceles,
meningomyeloceles, gastroenteric cysts, and
esophageal diverticula.
• CT scanning is the dx imaging test of choice. But, for some
conditions found in the posterior mediastinal compartment
(e.g., hernias, esophageal diverticula) barium studies of the GI
tract may be better.
• Acute mediastinitis may be caused by esophageal perforation
or after median sternotomy after cardiac surgery.
• Chronic mediastinits is often due to TB or histoplasmosis.
Sarcoidosis and silicosis are possibilities as well.
• The Hamman sign, or crunch, is a physical finding associated
with pneumomediastinum and or pneumopericardium. It is a
crunching noise synchronous with the heartbeat, and it is best
hear when the patient is in the left lateral recumbent position.
Which of the following statements regarding
acute respiratory distress syndrome is correct?
a)
b)
c)
d)
e)
Advanced age is not a risk factor
CXR often reveals a unilateral focal infiltrate
Early use of corticosteroids reduces mortality
It is a cardiogenic pulmonary syndrome
It might be associated with the use of
amiodarone
e) It might be associated with the use of amiodarone
ARDS is a form of noncardiogenic pulmonary edema.
The most common causes include:
• Sepsis
• Trauma
• Burns
• Multiple transfusions
• Aspiration of gastric contents
• Drug overdose (e.g., salicylates, opiates)
• Other drugs that have been reported to be associated with
ARDS include: TCA’s, cyclosporine, amiodarone, HCTZ,
chemotherapeutic agents (e.g., bleomycin).
• Among infections, bacterial PNA is a common cause.
• Other conditions associated with ARDS include: toxic gas or
smoke inhalation, near-drowning, radiation injury, pancreatitis,
embolism, eclampsia, SAH, DIC, high-altitude exposure,
oxygen toxicity, and cardiopulmonary bypass.
• The ratio of arterial partial pressure of oxygen (Pao2) over
inspiratory oxygen fraction (FIo2) less than 200 mm Hg is a
feature of ARDS.
• Age greater than 75 years, chronic alcohol abuse, metabolic
acidosis, and presence of more than on predisposing condition
(e.g., head trauma and sepsis) increase the risk of developing
ARDS.
• Pts. who develop ARDS from direct lung injury (e.g., pna, pulmonary
contusion) have a lower mortality rate than those who develop ARDS from
indirect lung injury (e.g., drug overdose, pancreatitis).
• CXR show bilateral, diffuse, patchy or homogeneous alveolar or interstitial
infiltrates involving at least ¾ of the lung fields.
• Unlike cardiogenic pulmonary edema, cardiomegaly and pleural effusions
are not commonly seen with ARDS.
• Mechanical ventilation should be initiated with low tidal volumes (6 ml/kg
predicted body weight).
• To date, there is no evidence that corticosteroids reduce mortality when
used in early ARDS.
• Reducing left atrial filling pressures, with fluid restriction and diuretics, is
an important part of ARDS management.
A 26 year old man with sickle cell disease presents with atypical
vaso-occlusive type arm and leg pain. He also reports dull right-side
chest pain, a nonproductive cough and fever to 39 c (102.2 f).
Diagnostic testing reveals an acute RLL infiltrate on CXR, WBC
count of 15.2, Hgb 8.6, platelet count of 112, 000. The next most
appropriate management step is:
a)
b)
c)
d)
e)
Admit the pt, begin broad-spectrum abx and bronchodilators,
ensure oxygenation, address pain control, consider transfusion
Admit the pt for IV hydration and pain control, and await the
results of blood and sputum cx’s to guide appropriate abx
therapy
D/c the pt on a macrolide abx and oral pain medication with
24-hour follow-up
Initiate bronchodilators if the pt has audible wheezing or a peak
expiratory flow rate less than 50% of predicted, and base
disposition decision on the response to bronchodilatory therapy
Order a spiral CT scan of the chest to evaluate for the presence
of PE
a)
Admit the pt, begin broad-spectrum abx and bronchodilators,
ensure oxygenation, address pain control, consider
transfusion
•
Acute chest syndrome is the leading cause of death and
hospitalization in SCA pts.
Acute chest syndrome is defined by: chest pain, fever
greater than 38.5 c, tachypnea.
Wheeze or cough along with a new pulmonary infiltrate
involving at least one complete lung segment.
Half of the pts in Vichinsky’s study were admitted with a
diagnosis other than acute chest syndrome, typically vasoocclusive crisis.
Consider vaso-occlusive symptoms as a prodrome of acute
chest syndrome.
Pts older than 20 were more likely to experience neurologic
complications and death from respiratory failure.
A platelet count less than 200, 000 was an independent
predictor of neurologic complications.
•
•
•
•
•
•
The leading causes of acute chest syndrome were:
• Pulmonary infections 29% (e.g., Chlamydia pneumoniae and
Mycoplasma pneumoniae)
• Pulmonary infarctions 16%
• Fat emboli 9% (diagnosed by bronchoscopic bx)
• Treatment is supportive, and include admission, supplemental
O2, aggressive airway management, hydration, pain control,
broad spectrum abx (including a macrolide), empiric
bronchodilators, and transfusions.
Thank you for your attention.
Questions?