+

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