Pulm physio Flashcards
What 3 events increase risk of pneumonia
impaired cough reflex, damaged mucocilary elevator, mucus plug
Three types of pneumonia
Lobar, broncho, interstitial (atypical)
Four gross phases of lobar pneumonia
- Congestion
- Red hepatization
- Gray hepatization
- Resolution
Describe red hepatization
Exudate, neutrophils and hemorrhage fill alveolar spaces, making spongy lung more solid
Describe gray hepatization
Degradation of red cells within exudate
Which cells are responsible for resolution after pneumonia?
Type 2 pneumocytes
Which pathogen is the most common cause of community-acquired pneumonia in adults and elderly?
Strep pneumo
Which pathogen is the second most common cause of acquired pneumonia in adults?
S. aureus
Klebsiella pneumonia commonly affects
malnourished in nursing homes, diabetics, alcoholics
What color is the sputum in Kleb pneumo?
Currant jelly (red)
COPD patients are at risk of pneumonia from which pathogens (most common to least)
H. Influenzae (secondary), Moraxella catarrhalis (community acquired), Legionella (Water source)
Cystic fibrosis patients get pneumonia from which pathogen?
Pseudomonas aeruginosa
which patients are at risk of developing aspiration pneumonia
Alcoholics and comatose patients
Which three agents most often cause aspiration pneumonia
Bacteroides, fusobacterium, peptococcus
Most common cause of interstitial pneumonia in young adults
Mycoplasma pneumoniae
Complications of mycoplasma pneumoniae
Autoimmune hemolytic anemia (IgM) and erythema multiforme
Second most common interstitial (atypical) pneumonia in young adults
Chlamydia trachomitis
Most common cause of atypical pneumonia in infants
RSV (respiratory synctival virus)
Most common cause of pneumonia in immunosuppressed (post-transplant, AIDS)
CMV
Which virus causes atypical pneumonia in elderly and increases risk of superimposed bacterial pneumonia infection?
Influenza virus
Most common cause of pneumonia in farmers and vets
Coxiella burnetii
How is coxiella different from other rickettsial organisms
- causes pneumonia
- does not require arthropod vector
- does not produce skin rash
Where is aspiration pneumonia commonly seen on XRAY
Right lower lobe
Why should a patient have PPD before starting TNF alpha inhibitors?
To avoid reactivating (secondary) tuberculosis
What is Pott’s disease
destruction of lumbar vertebrae by tuberculosis
What is Goodpasture syndrome?
Autoimmune disease against glomerular basement membrane and alpha chain of Type IV collagen that leads to restrictive lung disease and rapid kidney failure
What is Caplan syndrome?
pneumoconioses with rheumatoid arthritis (Associated with coal workers’ pneumoconioses)
Why does silicosis increase risk of TB?
Impairs phagolysosome formation in macrophages in upper lobe of lung (fibrotic nodules in UL)
Noncaseating granulomas are found in which two restrictive diseases?
Sarcoidosis and berryliosis
Asbestosis is typically found in
Shipyard workers, construction workers, plumbers
Asbestosis increases risk of which 2 malignancies?
Lung carcinoma and mesothelioma
Describe FEV1/FVC, TLC, FRC in restrictive diseases
FEV1/FVC >80% (FVC <
Describe FRC, RV, TLC, FEV1/FVC in obstructive lung diseases
FRC increases, RV increases, TLC increases, FEV1/FVC decreases
List 4 obstructive diseases
chronic bronchitis
emphysema
asthma
bronchiectasis
Classic presentation of primary pulmonary hypertension
Young adult female with exertional dyspnea
Mutation in primary pulmonary hypertension
Inactivating mutation of BMPR2, proliferation of vascular smooth muscle
Etiology of secondary pulmonary hypertension
Hypoxemia or increased pulmonary circuit volume; or recurrent pulmonary embolism
Who is at risk of developing small cell carcinoma?
Male smokers
Which cells are mutated in small cell carcinoma?
Neuroedocrine cells (Kulchitsky)
What co-morbidities can develop with small cell carcinoma?
Eaton-Lambert Syndrome and ADH/ACTH increase
A man with gradually worsening proximal muscle weakness, fatigue, weight loss, hypertension, high cortisol levels and a smoking history likely has
small cell carcinoma Eaton-Lambert
Histology of small cell carcinoma
Poorly differentiated cells (extremely dark nuclei, pleomorphic)
What is the most commmon lung cancer in male smokers?
Squamous cell carcinoma
Which co-morbidity develops from Squamous cell carcinoma?
Pancoast tumor (PTHrP–> Hypercalcemia)
Histology of squamous cell carcinoma
Keratin pearls and intercellular bridges
Who is at risk of developing Adenocarcinoma?
nonsmokers and female smokers
Histology of Adenocarcinoma
glands/mucin in alveolar spaces
prognosis for adenomarcinoma
likely lymphatic mets, poor
Which lung cancer presents with paraneoplastic syndrome and gynecomastia
Large cell caricnoma
What is the prognosis of large cell carcinoma
Very poor, extremely malignant
Which cells are mutated in broncheoalveolar carcinoma?
Clara cells
Which lung cancer hows pneumonia-like consolidation on imaging
Bronchoalveolar carcinoma
Which lung cancer is chromogranin positive
Carcinoid tumors
How does carcinoid tumor present on biopsy
polyp-like mass on bronchus
Two most common locations for metastasis
breast or colon
Define cyanosis
Bluish tinge of skin due to unsaturated Hgb >5g/dl
Define hypoxemia
Decreased oxygen tension (PaO2)
How do anemic patients present cyanosis different from normal patients?
Anemic patients may be hypoxemic before presenting with cyanosis because they have less hemoglobin and become cyanotic at a lower oxygen tension
What causes Horner syndrome (ptosis, anhidrosis, miosis) in squamous cell carcinoma?
Pancoast tumor in apical lung can compress sympathetic chain
Ipsilateral tracheal shift is seen in
spontaneous pneumothorax
Contralateral tracheal shift is seen in
tension pneumothorax
physical exam of a pleural effusion
dullness to percussion, decreased tactile fremitus, egophony, decreased breath sounds
What causes transudative pleural effusion
CHF, hepatic hydrothorax, chronic renal disease all lead to imbalance in absorption and formation of fluid
What are the pH, glucose, LDH and protein levels in transudative effusion?
Normal
Increased wbc, LDH, protein in fluid of pleural effusion implies
Exudative effusion due to infection or malignancy
what is SPARTAS of ARDS
Sepsis Pancreatitis, pneumonia Aspiration uRemia Trauma Amniotic fluid embolism Shock
What is found on histology of ARDS?
Hyaline membrane formation around alveoli
How can nocturnal hypoxia in sleep apnea cause death?
systemic/pulmonary hypertension, arrhythmias
What is another name for spontaneous pneumothorax?
Atelectasis
What physiological abnormalities lead to transudate effusions?
Increased hydrostatic pressure or decreased oncotic pressure
How does a lymphatic effusion present?
Milky fluid, increased triglycerids, due to duct injury from trauma or malignancy
Who is at greatest risk of primary spontaneous pneumothorax?
Tall, thing young males
Best treatment for lung abscess
Clindamycin
Histology of mesothelioma
Psammoma bodies
Cytokeratin and calretinin + indicates
Mesothelioma
What are signs of SVC syndrome?
Edema of upper extremities, facial plethora, jugular venous distension, increased ICP (headaches, dizziness)
What increases the production of surfactant?
Cortisol and thyroxine
Which hormone decreases production of surfactant?
Insulin
What are three risk factors for developing neonatal respiratory distress syndrome?
Prematurity, C-section, maternal diabetes
Is ARDS hypoxemia responsive to oxygen therapy (ventilation)?
No
Where do majority of pulmonary emboli originate from?
Lower extremities (usually below knee)
Which lung volumes are NOT measured directly by spirometry?
TLC, FRC, RV
Which cells are responsible for fibrosis in interstitial lung diseases?
Leukocytes release cytokines to stimulate fibrosis
What happeens to compliance and elasticity in restrictive lung diseases?
Decreased compliance, increased elasticity
What causes an increase in PaCO2 in chronic bronchitis?
Mucus plugs in lumens block CO2 exit from tissue
Which cytokine stimulates IgM -> IgE class switch?
IL-4
Which cytokine recruits eosinophils?
IL-5
Which T cell secretes IL-4, IL-5 and IL-10?
TH2 CD4+ T cell
Describe the biopsy of chronic bronchitis
Thickened bronchial walls, neutrophilic and lymphocytic infiltrates, mucus gland enlargement with increased mucus production and patchy squamous metaplasia of bronchial mucosa
What is the most common mutation in CF?
3-base pair deletion of phenylalaline at 508 (delta F508). Causes impared post-transcriptional processing
Which CF mutation is seen in the Askenazi jewish population?
Premature termination of transmembrane protein (nonsense, frameshift), leading to complete absence of membrane CFTR
An African American presenting with constitutional symptoms (weight loss, fevers), bilateral hilar adenopathy and pulmonary complaints is at concern for which malignancy
Sarcoidosis
Biopsy of sarcoidosis shows
Non-caseating granulomas
What are 3 key clinical features of Legionella pneumonia?
High fever with bradycardia
Headache and confusion
Watery diarrhea
Lab findings of Legionella pneumonia
Hyponatremia
Sputum gram stain shows neutrophils but no bacteria
Best test to dx Legionella
Urine test
How to identify cryptococcus neoformans infection
Stains red with mucicarmine
Symptoms of cryptococcal lung disease
IC patient with cough, pleuritic chest pain, dyspnea and hemoptysis
Best treatment for aspiration pneumonia (anaerobic bacteria)
Clindamycin or macrolides
Alcoholics are at increased risk of developing pneumonia from which pathogens?
Anaerobic oral flora (Bacteroides, Prevotella, Fusobacterium, Peptostreptococcus); best treated with clindamycin
Air fluid levels in CXR indicates
pneumonia
How does cyanide poisoning affect PaO2, SaO2 and CaO2
All normal (CN only affects ETC, lowering peripheral oxygen consumption)
Mechanism of cyanide poisoning
inhibits Fe3+ in cytochrome c oxidase in ETC, thus inhibiting cellular oxphos and tissue oxygen consumption falls–> decreases arterial-venous oxygen gradient since venous oxygen increases
How does high elevation affect PaO2, SaO2 and CaO2
Decreases all three
Which ion helps maintain erythrocyte electroneutrality as HCO3- (CO2) diffuses out?
Cl-
Chest tube placement through 4th/5th intercostal space in midaxillary line traverses through which 3 anatomic structures?
Serratus anterior, intercostal (external, internal, innermost), and parietal pleura
Aspiration while supine likely leads to pneumonia in which lung regions?
posterior segments of upper lobe
superior segments of lower lobes
Aspiration while upright leads to pneumonia in which region of lung
basilar segment of lower lobes (R > L)
Transplant patients are at increased risk of pneumonitis from which pathogen?
CMV (dsDNA)
How does CMV present on biopsy
enlarged cells with intranuclear and intracytoplasmic inclusions (owl’s eye)
Which compounds induce bronchospasm?
Leukotrienes C4, D4, E4 and acetylcholine
How do you minimize work of breathing in restrictive lung disease?
Minimize tidal volume, maximize respiratory rate (fast, shallow breaths)
Restrictive diseases have increased
elastic resistance
Which diseases cause high airflow resistance
COPD, asthma
How is work of breathing minimized in conditions with increased airflow resistance?
deep, slow breaths (increase tidal volume, decrease rate)
Which structures store and transport surfactant
Lamellar bodies
Which condition results from excessive activity of intra-alveolar proteases released by locally infiltrating leukocytes?
Emphysema
What is the etiology behind chronic bronchitis
Cells secrete a lot more mucus to protect against irritants
What accounts for the rubber-like properties of elastin?
Desmosine cross-links between lysines
Which part of the lungs does Klebsiella pneumonia commonly infiltrate?
Right upper lobes (due to supine aspiration)
How long does it take for kidneys to compensate for alkalosis/acidosis via bicarb?
~48 hours
How is PaO2 affected in pulmonary embolism?
Decrease; increased A-a gradient due to V/Q mismatch
Describe the three receptors epinephrine acts on in anaphylactic shock
alpha-1 on peripheral vasculature: causes constriction to increase blood pressure
beta-1 on heart: increases heart rate
beta-2 on bronchioles: causes bronchodilation
What is the Reid index
The ratio of the thickness of the mucous gland layer to the thickness of the wall between the epithelium and cartilage in bronchi/bronchiole
How do you measure the severity of chronic bronchitis?
Ratio of thickness of mucous gland layer to the thickness of the wall between epithelium and cartilage (nl = 0.4). Reid index increases in growing severity
Presence of anaerobic bacteria in lungs (Peptostreptococcus and Fusobacterium) is highly suggestive of
Lung abscess formation
Most common cause of lung abscesses
Oropharyngeal aspiration due to conditions with loss of consciousness or dysphagia (alcoholism, drug use, seizure disorders, prolonged anestheia, neuro dzes)
The presence of multiple lung abscesses in lungs due to septicimia or infectious endocarditis is likely due to
Staphylococcus or Streptococcus species
Three reasons why emphysema causes decrease FVC and increase in both TLC and RV
Destruction of intraalveolar walls, decrease in elastic lung recoil, distal airspace enlargement
Frequent respiratory infections is characteristic of which obstructive condition
Chronic bronchitis
Progressive exertional dyspnea is characteristic of which obsructive condition
Emphysema
A patient comes with in progressive exertional dyspnea and worsening cough. His lung XRays show bilateral, LL, diffuse pattern of small irregular opacities. Lung exams finds end-inspiratory crackles. findings most consistent with
Pulmonary fibrosis.
Diminished air volume in part of lung commonly due to obstruction of corresponding bronchus or bronchiole. Shows up as distinct opacification of a lobe/lobule on CXR
Atelectasis
Which gas is the major stimulator for respiration in healthy individuals?
PaCO2
What is the major stimulator of respiration in central chemoreceptors of the medulla?
PaCO2 levels, indicating pH (decreased pH increases RR)
Peripheral chemoreceptors in the aortic and carotid bodies are primarily driven by which gas in hypoxemic (PaO2 <60 mmHg) patients?
PaO2
Which chemoreceptors are important for responding to hypercapnia/hypocapnia?
Central chemoreceptors in the medulla
Reddish-pink granules in periportal hepatocytes stained with acid-Schiff reaction in a patient who complains of progressive dyspnea likely suggests
Alpha-1 antitrypsin deficiency (AD inheritance)
Emphysema results from
Destruction of alveoli (either induced by smoking or autoimmune by AAT deficiency)
Where is alpha-1-antitrypsin synthesized?
Liver
Bronchial hyperreactivity is a hallmark of
chronic asthma
Chronic rejection after lung transplantation causes damage to which part of the lung?
Small bronchioles (presents with dyspnea, nonproductive cough and wheezing years after transplantation)
Bilateral hilar adenopathy and elevated serum calcium and ACE levels are suggestive of
Sarcoidosis
Which immune cells will be elevated in sarcoidosis?
CD4+ T cells
Which cells carry elastase in the lungs?
Neutrophils and macrophages
Which enzyme protects alveoli elastin from degradation by elastase?
alpha-1-antitrypsin (damaged by smoking)
Causes of ARDS (SPARTAS)
Sepsis, Pneumonia, Aspiration, uRemia, Trauma, Amniotic fluid embolism, Shock
clinical presentation of ARDS
Acute onset shortness of breath (respiratory failure), hypoxemia, CXR with bilateral lung opacities but no evidence of HF/fluid overload
What causes initial alveolar damage in ARDS
Neutrophilic substances release substances toxic to alveoli, activate coagulation cascade and oxygen-derived free radicals
Etiology of ARDS
Endothelial cell damage–> increased permeability of alveolar capillaries–> protein leaks into alveolar spaces–> hyalinization–> decreased lung compliance, increased work of breathing, decreased oxygen diffusion capacity
Mechanism of cough-induced syncope
Increased intrathoracic pressure decreases venous return to heart, thus decreasing CO and cerebral perfusion