EM Board Review Pulmonary & Critical Care...Carrie Clark
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Transcript of EM Board Review Pulmonary & Critical Care...Carrie Clark
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Board Review: Pulm and Critical CareCarrie Clark DO
+Respiratory Physiology
A-a gradient =PAO2-PaO2
PAO2 value from alveolar gas equation Alveolar gas equation: PAO2=150-(1.25xPaCO2) (at sea
level and room air) PaO2 obtained from ABG
+Hypoxemia
Defined as PaO2<60mmHg
Etiology V/Q mismatch
Airspace not being perfused OR perfused areas not being ventilated
Etiologies: asthma, COPD, PE, interstitial lung disease Management: oxygen and treat underlying cause
Shunting Decreased diffusion of oxygen Etiologies: alveolar collapseARDS, also from alveolar filling
(pneumonia, pulmonary edema) Management: does NOT respond well to oxygen responds
better to PEEP
+Hypoxemia
Decreased diffusion Etiologies: thickening of alveolar/capillary interface
(commonly interstitial lung disease) Management: responds to O2
Hypoventilation Lack of respiratory effort resulting in low PaO2 and high
PaCO2, commonly from drug overdose Normal A-a gradient
High Altitude Decrease in partial pressure of available O2 Normal A-a gradient
+Critical Care: ARDS
Acute onset of alveoli edema caused by capillary membranes injury and increased permeability Sepsis, acute pulmonary infection, DIC, shock lung,
freebase cocaine smoking
You will see bilateral infiltrates on chest x-ray
Ratio of PaO2/FiO2<200mmHg
Symptoms: respiratory distress, hypoxemia unresponsive to increasing supplemental O2
Onset is often within the first 2 hours of inciting event, but it can be delayed as long as 1-3 days
+Critical Care: ARDS
Management 35-50% mortality Treat underlying disease Mechanical ventilation with PEEP
Use low tidal volumes to prevent barotrauma
Steroids NOT shown to be beneficial
+Disorders of Pleura, Mediastinum and Chest Wall
Mediastinitis
Pneumomediastinum
Pleural Effusion
Pneumothorax
+Mediastinitus
Inflammation of the mediastinum
Etiology Mixed organisms but most commonly Streptococcus and
Bacteroides Esophageal rupture most common cause (foreign body
ingestion or stuck fish bone may accompany history or esophageal inj)
Risk Factors Immunocompromise and diabetes, drug abuse
Symptoms Fever, dyspnea, pleuritic, retrosternal chest pain, sub-q
emphysema of neck and chest
+Mediastinitis
Diagnosis A CXR may show a widened mediastinum Soft tissue x-ray of the neck may show precervical or
retropharyngeal air/edema CT should be performed to further evaluate soft tissue
spaces
Management Broad-spectrum antibiotic therapy ENT and cardiothoracic consult
+Pneumomediastinum Etiology
Spontaneousextremely rare, blunt chest trauma, endoscopy, obstructive lung disease
Considerer Boerhaave syndrom if h/o vomiting Valsalva maneuver (foreceful cough against a closed glottis,
consitpation) Observed in crack cocaine users
Symptoms Chest pain and dyspnea Signs: sub-q emphysema and Hamman sign (crunching,
rasping sound, synchronous with heartbeat) Decreased cardiac output if tension pneumomediastinum is
present
+Pneumomediastinum
Diagnosis CXRreveals free air within the mediastinum, air posterior to
sternum and posterior to the heart on lateral film Esophagogramperform in right lateral decubitus position,
use a water-soluble contrast, if clinical suspicions remain high and the initial study is negative, repeat study with oral barium contrast
Esophagoscopyfor suspected esophageal rupture in acute traumatic rupture
Bronchoscopyfor suspected bronchotracheal tree rupture
Management Should be admitted and observed for signs of serious
complications Broad-spectrum antibiotics for suspected esophageal rupture
+Pleural Effusion Collection of fluid within pleural space
Epidemiology CHF is the most common cause followed by malignancy,
bacterial pneumonia, and PE TB is the most common etiology of pleural effusion in
developing countries
Etiology TransudativeCHF, cirrhosis with ascites, nephrotic
syndrome, PE ExudativeCancer, infectious (pneumonia, empyema,
abscess, TB), inflammatory (SLE, pancreatitis, RA, and PE
+Pleural Effusion Symptoms
Dyspnea and pleuritic chest pain, decreased breath sounds on auscultation, dullness to percussion
Diagnosis CXR: AP XR demonstrates effusion when pleural fluid volume
approaches 150cc CT or US most sensitive Thoracentesis necessary when etiology is unclear
Light criteriaa single positive criterion is enough to classify the fluid as an exudate
Glucoselow pleural fluid levels (<25)=RA, TB, empyema, and malignancies
pHlow pH=inflammatory and infiltrative processes (empyema, malignancies, TB, esophageal rupture)
Amylasehigh amylase (>200) pancreatitis, malignancy, rupture
+Pleural Effusion
Light Criteria
Transudate Exudate
Pleural and serum Protein
<0.5 >0.5
Pleural and serum LDH
<0.6 >0.6
Pleural LDH <200 >200
+Pleural Effusion Management
Treat underlying cause Therapeutic thoracentesis for patients dyspneic at rest Thoracotomy tube placement for empyema
+Pneumothorax Etiology
Spontaneousno underlying lung disease Male:female 6:1 Young, tall, thin Smoking 20:1 Valsalva Ruptured bleb Many recur (20-50%)
Secondary-caused by underlying lung disease Asthma, COPD, neoplasm Marfan, Ehlers Danlos, Cystic fibrosis Penumonia, especially with abscess or cavitation HIV-PCP
Tension pneumo
+Pneumothorax Symptoms
Dyspnea and pleuritic chest pain Decreased breath sounds and hyperresonace to percussion JVD and hypotension Tracheal deviation away from affected side
Diagnosis Pneumothorax
CXR for simple pneumothorax (end expiratory for highest sensitivity)
CT test of choice for supine trauma patient Tension pneumo
Clinical diagnosis Tracheal deviation away from affected lung Hypotension Do NOT wait for x-rays before treating
+Pneumothorax Management
Small, stable ptx (<10%) 100% O2 Reabsorb 5-7% per day Stable patient with a small ptx can be discharged with
next day follow up after 6 hours observation and stable x-ray
Large ptx 100% O2 Tube thoracostomy
Tension ptx Immediate decompression followed by chest tube
+Noncardiogenic Pulm Edema
Definition: radiographic evidence of alveolar fluid accumulation without hemodynamic evidence of a cardiogenic etiology (ie pulmonary capillary wedge pressure <18mmHg)
Etiology ARDS High-altitude pulmonary edema Reexpansion pulmonary edema
Large volume thoracentesis (>1L) Rapid lung re-expansion of ptx, especially when it has
been collapsed for >3 days Drug induced (meprobamate, opiates, naloxone, PCP,
Salicylate)
+Obstructive Lung Disease
Asthma and reactive airway disease
COPD
Cystic Fibrosis
+Asthma and reactive airway disease Chronic inflammatory disorder of the small airways
characterized by reversible obstruction
Etiology and patho Airway inflammation/bronchial wall edema leading to decreased
airway diameter Airway hyperreactivity, smooth muscle contraction Secretions forming mucous plugs Chronic inflammation leads to lung remodeling
Symptoms Dyspnea with or without cough Prolonged expiratory phase with predominantly exp wheezing Severe exacerbations may present with absence of wheezing,
inability to speak, pulses paradoxus and hypoxia
+Asthma and reactive airway disease
History associated with higher mortality >2 hospitalizations during past year >3 ED visits during past year Prior intubation or ICU admission Use of 2 or more adrenergic canisters per month Current use of systemic steroids or recent withdrawal Low socioeconomic class
+Asthma and reactive airway disease
Diagnosis Bedside spirometrypeak flow to monitor response to beta-
agonist treatment Peak flow <50% indicates severe exacerbation
Treatment Oxygen to keep O2>88% Beta agonistsrelaxation of bronchial smooth muscle Epinephrine (1:1000)reserved for severe exacerbations, is
administered sub-q 0.3 q20-30 minutes up to three doses Terbutaline reserved for severe exacerbations given SC
0.25mg every 20-30 min up to three doses Longer duration of action than epinephrine
+Treatment cont.
Corticosteriodsused in both acute and chronic setting to prevent late phase inflammatory response Oral dosing as effective as IV administration
Magnesiumbenefit in severe exacerbation
Mechanical ventilation Avoid air-trapping or auto-peep Smaller tidal volumes Keep rate low Consider increasing peak inspiratory flowlonger expiratory
time
+Treatment cont
When treating pregnant asthmatics… Fetus more susceptible to hypoxia than mother No contraindications to use of beta agonists, corticosteroids
and anticholinergics Chronic steroids may result in lower birth weights Epinephrine is teratogenic during first trimester and
associated with preterm delivery
+COPD
Progressive partially reversible limitation of airflow
Caused by two processeschronic bronchitis and emphysema, which occur together in most patients
Epidemiology The single most important risk factor for COPD is smoking
Etiology 80% of acute COPD exacerbations are of infectious origin
Streptococcus pneumoniae, Haemophilus influenzae, or moraxella catarrhalis
+COPD
Signs and symptoms Dyspnea on exertion, tachypnea, cyanosis, agitation,
apprehension, and hypertension are indicative of hypoxia Wheezing, rales, rhonci, prolonged expiratory phase, pursed-lip
breathing and clubbing of digits
Diagnosis Elevated hematocrit 2/2 chronic hypoxia ABG: mild to moderate hypoxemia without hypercapnea in
early stages CXRhyperinflation, flattened diaphragm, long narrow heart
shadow EKGa-fib, multifocal atrial tachycardia, cor-pulmonale (tall p-
waves), right axis deviation and right ventricle hypertrophy
+COPD
Management Supplemental oxygen reduces mortality in patients with
advanced COPD with room air O2 saturaion <88% Nebulized anticholinergics Bronchodilators Antibiotics
First line choices include amoxicillin, cefaclor, fluoroquinolones, or bactrim
Gram-negative infections more likely in those with frequent exacerbation and need a third-generaltion cephalosporin
corticosteroid
+Cystic Fibrosis
Most common in Europeans and Ashkenazi Jews
Autosomal recessive mutation Abnormalities in chloride transport in exocrine tissues leads
to multiorgan involvement Thick, viscous secretions in lungs, intestine, pancreas, and
reproductive tract
Symptoms and signs Respiratory manifestationsmost common, exacerbations
characterized by increased cough, sputum production, decreased lung function
+CF symptoms and signs cont.
Undiagnosed patients may present with failure to thrive chronic cough, repeated pulmonary or sinus infections, chronic diarrhea from pancreatic insufficiency
Alternative presentations Increased salt content in sweat gland secretion Meconium ileus in neonates Steatorrhea from pancreatic enzyme insufficiency Intestinal obstruction Spontaneous pneumo Chronic pancreatitis Hepatobiliary disease
+CF diagnosis
Electrolytes Hyponatremia and alkalosis
CXR Bronchiolar thickening, hyperinflation, and patchy, diffuse
infiltrates
Newborn screening
Chloride sweat testing or genetic testing
+CF Management Broad-spectrum antibiotics
Cover Staph aureus, H. flu, and double cover Pseudomonas Chronic colonization with pathologic bacteria and chronic
antibiotic use leads to resistant organisms requiring intravenous vanco, tobramycin, meropenem, cipro, and piperacillin
Mucolytics
Bronchodilators
Aggressive chest physiotherapy
Provide O2
Consult Pulm
+Restrictive Lung disease
Loss of lung compliance resulting in volumes loss Interstitial Lung Disease
Idiopathic pulmonary fibrosis Sarcoidosis
+ILD ILD
Restrictive pulmonary dysfunctions with the common end-point of interstitial collagen deposits and scarring
Idiopathic pulmonary fibrosis 50% of ILDs Likely autoimmune Symptoms and signsdyspnea, cough, fine dry crackles,
clubbing of fingers DiagnosisCXR has honeycombed lungs, CTground glass
opacity Management corticosteroids, immune modulators, lung
transplant
+Sarcoidosis
Epidemiology African americans>caucasians females>males
Etiologytypical finding includes non-caseating granuloma, which is composed of T-helper cells and other inflammatory cells
+Sarcoidosis Symptoms and Signs
Most patients are asymptomatic Disease is fatal in 10% of patients because of extensive
organ involvement Constitutional symptomsfever, fatigue, weight loss,
polyarthritis, myositis Pulm symptomscough, hemoptysis, shortness of breath
with exertion Neurobells palsy, seizures Skin lesionsplaques, subcutaneous nodules, erythema
nodosum Cardiacarrhythmias, CHF Lympthadenopathy Ophthalmologicuveitis, or conjunctivitis
+Sarcoidosis Diagnosis
CXR Stage 0no findings Stage 1hilar adenopathy Stage 2Hilar adenopathy and parenchymal involvement Stage 3parenchymal involvement without adenopathy Stage 4pulmonary fibrosis
Lab studies Leukocytosis, elevated ESR or serum ACE, hypercalcemia
or hyperphosphatemia, elevated CK and CK-MB with cardiac involvement
Gallium 67used to detect extrapulmonary sarcoidosis Biopsy of involved organ is most useful for diagnosis
+Sarcoidosis
Management Cardiac monitoring Consider steroids or cytotoxic medications Lung transplantation for patients with severe refractory
disease
+Thromboembolic Disease
DVT
PE
+DVT Risk factors
Previous thrombosis Vascular endothelial damage
Trauma, sugery (especially ortho), smoking Hypercoagulability
Protein C or S deficiency Factor V Leiden (most common hereditary
hypercoagulability Antithrombin III deficiency Oral contraceptives or 3rd trimester pregnancy
Immobilization or low cardiac output Long periods of sitting, CHF
+DVT
Signs and Symptoms Pain, warmth and edema Discoloration of affected extremity Palpable cord of a thrombosed vein
+DVT Diagnosis
CT angiography Doppler ultrasonography
Limitationsoperator dependent, cannot distinguish between old and new clot, not accurate in detecting DVT in the pelvis or the small vessels of the calf
Management Anticoagulationunfractionated low-molecular weight
heparin or warfarin therapy Filter placement for patients with failure of anticoagulation
or contraindication to anticoagulation
+Pulmonary Embolus
Risk factor are the same as for DVT 60% of patients with a DVT have a PE
Symptoms and signs Sudden-onset dyspnea, tachypnea, tachycardia, pleuritic
pain, hemoptysis, syncope, cough, and wheeze
+PE diagnosis ECG
Nonspecific ST-T wave changes and/or sinus tach are most common, S1Q3T3, precordial flipped T waves
CXR Findings are abnormal but nonspecific, pleural effusion, elevated
hemidiaphragm secondary to atelectasis and noninfectious infiltrates Westermark signabrupt cut-off of vascular markings Hamptom humppleural based wedge-shaped infarct
CT pulm angiography
VQ scanuseful in severe contrast allergies A normal scan is sufficient to exclude PE in patient with low pretest
probability
Echomay reveal evidence of right heart strain
Pulmonary angiographythe gold standard for diagnosing PE (used infrequently because of noninvasive CT scans
+PE management
Supplemental O2
Hemodynamic support
Anticoagulation
Thrombolytic Indicated in patients with associated hemodynamic
instability
Surgical Embolectomy
IVC filter for anticoagulation failure or contraindication
+Pulmonary Infections
Pneumonia Bacterial viral
Tuberculosis
+Bacterial Pneumonia
Etiology Typical Pneumonia
S. pneumoniae, H. influenzae, and Staph (S. Pneumo most common)
Atypical Pneumonia Influenza virus, mycoplasma, chlamydia, legionella, and
adenovirus IV drug usersS. aureus Alcoholism, diabetes, and COPDK, Pneumoniae AsthmaticsH. Flu Hospital acquired pneumoniapseudomonas aeruginosa
+Bacterial Pneumonia Symptoms and signs
Chest pain Productive cough
Klebsiellacurrant jelly S. Pneumoniaebloody or rusty colored Aspirationfoul-smelling sputum Chlamydiastaccato cough
Rigorsparticularly associated with S. Pneumonia Diarrhea and GI upset with Legionella Bullous myringitis with Mycoplasma pneumoniae Pleural rubs
+Bacterial Pneumonia
DiagnosisChest radiography Bilateral diffuse infiltrates consistent with atypical
infections (M. Pneumoniae, P. Carinii, C. Psittaci) Abscess and bulging lung fissures are indicative of
infections caused by Klebsiella and S. aureus Pleural effusions and empyema associated with cavitary
lesions are seen with s. aureus and M. tuberculosis Upper lung fieldsK. Pneumoniae Lower lung fieldsL. Pneumoniae Miliary patternM. Tuberculosis
+Bacterial Pneumonia Laboratory studies
Hyponatremia and hypophosphatemia associated with L. Pneumophila
Sputum samples for gram stain and culture are accurate about 50% of the time Adequate sputum contains <10 epithelial cells, >25 WBC
per low power field and remain uncontaminated from oral flora
Mycoplasma and Chlamydia immunoglobulin M antibodies a rise in antibody titer of 1:128 confirms the diagnosis
+Bacterial Pneumonia Management
Community-acquired pneumonia Pneumonia severity index score helps determine risk Admit if total score >90 points and consider ICU for >130
Hospital-acquired pneumonia Double-drug coverage for Pseudomonas Optimal combinations include cefipime plus levofloxacin,
aztreonam, meropenem, or aminoglycoside Aspiration pneumonia
Intubation should be considered in any patient who is unable to protect airway, add anaerobic coverage
+Types of Bacterial Pneumonia Bordetella Pertussis (whopping cough)
Summer and fall months, neither active disease nor vaccination provides lifelong immunity
Symptoms and signs3 stages, each lasting about 2 weeks Catarrhal
Most infectious during this time, symptoms indistinguishable from a URI
Paroxysmal Coughing episodes followed by an inspiratory “whoop” ,
post-tussive exhaustion and emesis Convalescent
Chronic cough that can last several months Complications include mucous plug, secondary bacterial
infection, ruptured diaphragm, hernia, and rectal prolapse
+Pertussis
Diagnosis Degree of lymphocytosis correlates with severity of disease Definitive diagnosis is made via nasopharyngeal culture
Treatment Erythromycin x14 days Consider prophylaxis with erythromycin for close contacs Consider hospitalization for infants <6 months, premature
infants, and those with significant comorbitites
+Mycoplasma Pneumonia
Most common atypical
14-day incubation period
More common in young adults
CXR may show interstitial pattern or patchy infiltrate
Treat with macrolide antibiotic
Associations Bullous myringitis Meningitis and encephalitis Erythema multiforme Guillain-Barre
+Chlamydia Pneumonia
Obligate intracellular parasite
Infants Acquired at birth 50% conjunctivitis Tachypnea May be afebrile CXR shows hyperinflation and diffuse infiltrates
Common in young adults complaining of hoarseness, cough, and persistent malaise
Staccato cough
Treat with macrolide
+Legionella Pneumonia Airborne and associated with water sources
Classically associated with recent air travel
No person to person transmission
Symtpoms and signs Pleuritic chest pain, relative bradycardia, GI symtpoms
Diagnosis Labs may reveal hyponatremia and hypophosphatemia Chest x-ray may show alveloar infiltrates or consolidation
that my progress to hilar adenopathy and pleural effusion Treat with erythromycin for 3 weeks
+Tuberculosis
Leading cause of death worldwide
Humans are sole reservoir
TB can remain dormant for years in granulomas
Risk factors Immunocompromised (HIV, malignancy, DM, extremes of
age) Close contacts or occupational exposure Medically underserved, low-income populations
+TB symptoms and signs
Primary TB Only 10% of exposed individuals develop primary TB Constitutional symptoms
Coughmost common symptoms of pulmonary TB Initially nonproductive or nonspecific sputum Hemoptysis may be presenting complaint Pleuritic chest pain Night sweats “classic” presentation is uncommon
+TB
Postprimary TB (reactivation TB) Lifetime risk in immunocompetent individual is 10% to 15% In HIV-positive patients
37% with disease in 6 months 10% incidence of disease per year Signs and symptoms similar to primary TB
+TB extrapulmonary Lymphadenitis (scrofula)
Most common EPTB, enlarging, painless, erythematous firm mass near cervical nodes, do NOT I and D
Pleural effusion Small and unilateral, diagnosis through pleurocentesis
Bone and joint infection Pott’s disease (spinal)spinal cord injury possible, lumbar infection may
lead to psoas abscess
acute disseminated Generalized systemic illness, typically in elderly and HIV patients, fever,
weight loss, anorexia, weakness, SIADH is common, often associated with meningitis
CNS 6% of cases, peak in newborn to 4 years, SIADH, tuberculosis meningitis CSF analysislowest glucose CSF levels of any meningitis
+TB diagnosis
TB skin testingread 48-72 hours later, induration not erythema 15mm in low-risk, immunocompetent patients 10mm in high-risk immunocopetent patients 5mm in HIV, Close contacts infectious TB, abnormal CXR,
immunocompromised from steroids
+TB medical therapy
Latent TBinfections without active disease, chemoprophylaxis with isoniazid for 9 months
Active TBtreated for 6 months, 4 drugs until resistance pattern determined, after 2 months may discontinue pyrazinamide if TB isolates do not demonstrate resistance
Extrapulmonary TB->treat for 6 months CNS infection (tuberculous meningitis) is the exception,
requires 9-12 months of treatment Consider steroids for CNS and pericardial TB
+Treatment of TBdrugs First line agents
Isoniazid (INH) 8% resistance rate Prevent INH-related seizures: supplement with pyridoxine
(B6) Rifampin
Orange discoloration of bodily fluids Oral contraception failure
Pyrazinamide (PZA) Hepatotoxicity, polyarthralgias
Ethambutol (ETH) Prevents emergence of RIF resistance Retrobulbar neuritisdecreased visual acuity or red/green
color blindness
+Treatment cont.
Noncompliant patients Uncooperative and potentially infectious patients may be
compelled to comply Court-ordered directly observed therapy (DOT) Incarceration as last resort
In pregnancy INH, RIF, ETH cross placenta and are safe
+Viral Pneumonia
Influenza
Varicella
Cytomegalovirus
hantavirus
+influenza
Often associated with bacterial superinfection (s. aureus)
Diagnosis: nasopharyngeal swab culture for influenza aid diagnosis
CXR shows diffuse bilateral infiltrates
+Varicella
Symptoms and signs: pneumonia may present with chest pain and hemoptysis preceded by a rash
More severe in adults
Managementmandates admission for treatment with acyclovir
+cytomegalovirus
Most common in solid organ transplant and bone marrow transplant recipients
Often presents simultaneously with pneumocystis pneumonia
Management IV ganciclovir or foscarnet plus immunoglobulin therapy
CXR Bilateral interstitial pattern
+Hantavirus
Aerosolized contaminated material from rodent feces or urine Southwest US
Symptoms and signsflu-like symtpoms that progress to respiratory distress and shock
DiagnosisCXR reveals bilateral infiltrates
+Fungal Pneumonia
Histoplasma capsulatum, blastomyces dermatitides and coccidioides present in the soil in various geographic areas of the US Histoplasma capsulatum in the mississippi and Ohio River
valleys Coccidioides immitis in desert areas of the Southwest Symptoms and signs vary from acute or chronic pneumoina
to asymptomatic granulomas on CXR Diagnosishilar adenopathy