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Pulmonary Total amount of air in the lungs at the end of normal expiration Total amount of air in a fully expanded lung Define Residual Volume, RV How do you calculate the A-a gradient? Difference in partial pressure of Oxygen, PO2, between the alveolar PO2 and arterial PO2 PAO2=FiO2(713) - arterial PCO2/0. What causes an A-a gradient and how is it useful in differentiating causes of hypoxemia? A-a gradient is caused by a mismatch between ventilation and perfusion. Hypoxemia of pulmonary origin causes an increased A-a gradient (>30). Hypoxemia of extrapulmonary origin has a normal A-a gradient. What are some causes of ventilation defects? Impaired O2 delivery to the alveoli for gas exchange, e.g. from airway collapse due to respiratory distress syndrome or atelectasis. What are some causes of perfusion defects? Decreased or absent blood flow to the alveoli, e.g. pulmonary embolus What are some causes of diffusion defects? O2 cannot diffuse across alveolar-capillary interface, e.g. pulmonary fibrosis or pulmonary edema. Causes decreased DLCO What are some causes of shunting? A shunt is technically blood going from right to left because of heart issues, e.g. right to left shunting from tetralogy of fallot. What are some causes of hypoxemia with a normal A- a gradient? Depression of the respiratory center in the medulla (barbiturates, brain injury); upper airway obstruction (epiglottitis, croup); Chest bellows dysfunction (paralyzed diaphragm, ALS with degeneration of anterior horn cells). Define Functional Residual Capacity, FRC (Refer to Pulmonary attachment 1). Define Total Lung Capacity, TLC Volume of air left over in the lung after maximal expiration: FRC- ERV
Define Tidal Volume, TV Volume of air that enters/exits the lungs during normal respiration Total amount of air expelled after maximal inspiration 70-80% Amount of air forcibly expelled at the end of normal expiration They're at the bifurcation of airways, larynx and distal esophagus Postnasal discharge Define Forced Vital Capacity, FVC Define Forced Expiratory Volume, 1 second, FEV Amount of air expelled from the lungs in 1 second after maximal inspiration What is the normal FEV1/FVC? Define Expiratory Reserve Volume, ERV Describe spirometry in restrictive lung disease TLC decreased, RV decreased, FEV1 decreased, FVC decreased, FEV1/FVC normal to increased, PaO2 decreased, A-a gradient increased (if disease of lungs, not just restriction of chest wall Describe spirometry in obstructive lung disease TLC increased, RV increased, FEV1 decreased, FVC decreased, FEV1/FVC decreased, PaO2 decreased, A-a gradient increased Define Dyspnea and list some causes. Difficulty breathing. Can be due to stimulation of J receptors causing decrease in full inspiration. Also decreased compliance, e.g. interstitial fibrosis; increased airway resistance, e.g. chronic bronchiti; chest bellows disease, e.g. obesity; kyphoscoliosis, interstitial inflammation or fluid accumulation, e.g. left sided heart failure. Where are cough receptors located? What is the most common cause of cough with a normal CXR? What causes nocturnal cough? GERD from acid refluxing into the bronchial tree at night. Bronchial asthma due to airway constriction
What is the origin and mechanism of normal breath sounds? Normal breath sounds come from the trachea and are caused by air velocity and turbulence inducing vibrations in airway walls Where does laminar air flow start? Terminal bronchioles where the increased surface area converts turbulent to laminar flow What are tubular breath sounds? Sound like air blowing through a tube-this is normal over the trachea but is always abnormal over the bronchi. Causes a loud, high pitched sound with a tubular or hollow quality. Expiration is longer than inspiration. Means that there is consolidation or patent but partially collapsed bronchi What are vesicular breath sounds? Tracheal sounds that are modified in the alveoli. Inspiratory to expiratory ratio is 3:1. Diminished in emphysema and asthma due to increased AP diameter. Absent in pneumothorax, atelectasis or effusion What are bronchovesicular breath sounds? Normal breath sounds over the main bronchi with an equal inspiratory and expiratory ratio. What are crackles and how are they caused? Extra sounds, usually inspiratory, that sound like (you guessed it), crackles! Early and midinspiratory crackles are due to secretions in proximal large to medium sized airways. These clear with coughing. Late inspiratory crackles are due to reopening of distal airways partially occluded by increased interstitial pressure (fluid, transudate, pus). These do not clear with coughing and vary from fine to course
What is a flow volume loop? What is wheezing and how is it caused? High pitched musical sound usually in expiration. Caused by inflammation of segmental bronchi and small airways by asthma or chronic bronchitis; pulmonary edema constricting airway (cardiac asthma); pulmonary infarction (release of TXA from platelets in the embolus causes bronchoconstriction What are Rhonchi and how are they caused? Low pitched snoring sounds during inspiration or expiration. Due to secretions in large airways (bronchus or trachea). Usually clear with coughing, common in chronic bronchitis What is inspiratory stridor and how is it caused? High pitched inspiratory sound. Indicates upper airway obstruction. Caused by epiglottitis (H. Influenzae), croup (parainfluenza) What is a pleural friction rub and how is it caused? Two inflamed surfaces (pleural and parietal) rubbing against each other. Usually happens at the end of inspiration and beginning of expirations when things are changing direction. Caused by pleuritis due to cancer, infarction, pneumonia, serositis (SLE). Disappears with alrge effusion bc separates layers and stays with holding breath. What does grunting in a newborn mean? Newborns should not grunt after 24 hours. It's a sign of respiratory distress syndrome. What is bronchophony and egophony? Caused by alveolar consolidations. Spoken numbers, syllables are heard more distinctly through stethoscope. Egophany is when the patient says E and you hear an A through the stethoscope. Plot of inspiratory and expiratory flow rate(L/sec) versus lung volume(L)
Define Laryngeal Carcinoma. What causes obstructive sleep apnea? Most commonly a result of obesity causing the pharyngeal muscles to collapse under the weight of the tissue. Can also result from tonsilar hypertrophy or nasal septum deviation. What is the pathogenesis and clinical findings in sleep apnea? Airway obstruction causes CO2 retention resulting in hypoxemia. Decreased PO2 and O2 saturation during apnea with increase in PCO2. See excessive snoring with apneic periods and excessive daytime somnolence. Can cause pulmonary arterial hypertension leading to Right Ventricular Hypertrophy and polycythemia secondary to hypoxemia. Define Sinusitis and describe its causes. Inflammation of the sinuses, most often maxillary or ethmoid sinuses. Caused by URI blocking drainage of sinuses into nasal cavity. Can be caused by a deviated nasal septum, allergic rhinitis, barotrauma, or cigarettes. Pathogens implicated are rhinovirus, strep pneumoniae, anaerobes (chronic sinusitis), systemic fungi (diabetics due to Mucor species). What is a Nasopharyngeal Carcinoma? Most common malignant tumor of the nasopharynx, more common in males and increased incidence in the Chinese and African populations. Closely related to EBV. Often causes squamous cell carcinoma or undifferentiated cancers which can metastasize to cervical lymph nodes. Carcinoma most commonly located on the true vocal cords. Mostly keratinizing squamous cell carcinomas, mostly in med. Related to cigarette smoking, alcohol (synergistic with cigarettes), HPV 6 and 11 and squamous papillomas and papillomatosis. Persistent hoarseness from cervical lymphadenopathy is common.
What is Atelectasis? Loss of lung volume due to inadequate expansion of the airspaces (collapse). Collapse happens because of lack of air and distal resorption of air through pores of Kohn in the alveolar walls. May see ipsilateral elevation of the diaphragm and tracheal deviation. Treat with incentive spirometry, CPAP or PEEP. What is resorption atelectasis? Airway obstruction in bronchiols, segmental bronchi or bronchi, by thick secretions which prevents air from reaching the alveoli. Can be caused by mucus or mucopruluent plug after surgery, aspiration of foreign material or centrally located bronchogenic carcinoma. What is compression atelectasis? Air or fluid in the pleural cavity under increased pressure collapses small airways beneath the pleura. What is atelectasis due to loss of surfactant? Synthesized by Type II pneumocytes starting in the 28th week of gestation. Stored in lamellar bodies. Major component is phosphatidylcholine (lecithin). Synthesis is increased by cortisol and thyroxine but decreased by insulin. Surfactant reduces surface tension so airways don't collapse. Without surfactant, airways can collapse causing atelectasis. What is Respiratory Distress Syndrome? Decreased surfactant in lungs results in atelectasis and respiratory distress from massive intrapulmonary shunting. Collapsed alveoli are lined by hyaline membranes (from protein leaking out of damaged alveoli). Causes respiratory difficulty, grunting, tachypnea, intercostal retractions and hypoxemia with respiratory acidosis.
Describe the pathogenesis of typical pneumonia. Most caused by bacterial pathogens, particularly Strep Pneumoniae. Pathogenesis is via inhalation of aerosol from infected person or aspiratin of nasopharyngeal flora while sleeping. Describe the pathogenesis of bronchopneumonia. Begins as acute bronchitis and spreads locally into the lungs, usually lower lobes or right middle lobes. Causes patchy consolidations and may have microabscesses. Describe clinical findings in lobar pneumonia. Complete or almost complete consolidation of a lobe of the lung. Can be complicated by lung abscesses, empyema or sepsis. See sudden onset of fever with productive cough, chest pain, tachycardia, dullness to percussion, increased tactile fremitus, late inspiratory crackles, bronchial breath sounds, bronchophany and egophany. Describe clinical findings in atypical pneumonia. Usually caused by mycoplasma pneumoniae, also chlamydophilia pneumoniae, RSV, influenzavirus, and adenovirus. Contracted by inhalation of droplets. Causes patchy, mononuclear infiltrate but the alveolar spaces are usually free of exudate. Insidious onset with nonproductive cough, low grade fever, chest pain, flu like symptoms including pharyngitis, laryngitis, myalgia and headache. No consolidation. Describe clinical findings in nosocomial pneumonia. Happens in patients with severe underlying disease, immunosuppresion, or who are on antibiotic therapy. Respirators are the most common source of infection. Usually gram (-) bacteria, often pseudomonas, E coli, or gram (+) like staph aureus. In immunocompromised, can be opportunistics like CMV, Pneumocystis Jirovecis, Aspergillus-fumigatus.
Acute chest syndrome: fever with pleuritis Describe pneumonia from Tuberculosis. From inhalation of Mycobacterium Tuberculosis. Infects phagosomes of alveolar macrophages and produces a protein that prevents fusion of the lysosome with the phagosome. Strict aerobe, acid fast. Cord factor is major virulence factor. Drug resistance by mutations in mycolic acid or catalase peroxidase (activates Isoniazid). Describe Primary TB Infection. Subpleural location, usually upper part of lower lobes or lower part of upper lobes. Causes Ghon focus (caseous necrosis) in periphery and Ghon complex in hilar lymph nodes. Produces a calcified granuloma or area of scar tissue Describe Secondary TB Infection. Due to reactivation of primary TB. Usually involves apices in upper lobes b/c increased V/Q ratio. Causes cavitary lesions from release of cytokines by T Cells. Causes fever, drenching night sweats, weight loss. May cause miliary TB with invasion into bronchus, lymphatics or extrapulmonary sites like the kidney. Spread to vertebra is called Pott's disease. Describe pneumonia from Mycobacterium Avium Intracellulare Atypical mycobacterium causing atypical pneumonia in AIDS patients. Happens when CD4+ T Cell count falls below 50 cells/mm3. Often disseminates and co-occurs with systemic fungal infection. What is the most common cause of the common cold? Rhinovirus, transmitted by hand to nose/eye contact. Less common are coronavirus, adenovirus, influenza C and coxsackievirus What does Coxsackievirus cause?
What is a common bacterial cause of newborn pneumonia? Chlamydia trachomatis from passage through infected birth canal. Afrebile with staccato cough, conjunctivitis and wheezing. Treat with erythromycin. What is the most common baterial cause of atypical pneumonia? Mycoplasma Pneumoniae. Insidious onset with low grade fever. Can cause bullous myringitis(inflamed Tympanic membrane), cold autoimmune hemolytic anemia from anti-IgM antibodies. Describe the signs and symptoms of Coxiella Burnetti infection Atypical pneumonia, myocarditis, granulomatous hepatitis. Associated with dairy farmers and vetrinarians. What is the most common cause of community acquired lobar pneumonia? Strep pneumoniae. Rapid onset, productive cough and signs of lobar consolidation. Can test with urine screen. What are signs/symptoms of pneumonia from Staph Aureus? Commonly superimposed on measles or influenza pneumonia or in CF or IV drug users. Hemorrhagic pulmonary edema, yellow sputum, abscess formation and tension pneumatocysts (intrapleural blebs) which can rupture and produce tension pneumothorax. Describe signs and symptoms of infection with Corynebacterium Diptheriae. Causes toxin-induced pseudomembranous inflammation producing a shaggy gray membrane in the oropharynx and trachea. Can cause toxic myocarditis from impaired B oxidation of fatty acids in the heart. What are signs and symptoms of infection with Bacillus Anthracis? Cutaneous anthrax initially looks like a scab but swells to form a black scab (eschar) with an area of central necrosis. Pulmonary anthrax causes necrotizing pneumonia, meningitis, splenomegaly and systemic dissemination. What are signs and symptoms of Actinomyces infection? Normal flora in tonsils and adenoids. Can produce draining sinuses in the jaw, chest cavity and abdomen. Pus contains yellow specks (sulfur granules) which contain the bacteria.
What are signs and symptoms of Nocardia infection? Granulomatous microabscesses in the lungs. Often disseminates to CNS and kidneys. What are signs and symptoms of infection with Bordatella Pertussis? Produces whooping cough-inspiratory whoop between coughing fits. Catarrhal phase is 1-2 weeks and involves mild coughing, rhinorrhea and conjunctivitis. Paroxysmal phase lasts 2-5 weeks and involves coughing in succession followed by inspiratory whoop and absolute lymphocytosis (20,000-50,000). Convalescent pahse lasts 1-2 weeks or more and involves a slow decline in lymphocytosis and coughing. Can cause hemorrhage into skin, conjunctiva, bronchus, brain or rectal prolapse from coughing. Also otitis media and meningoencephalitis. What are signs and symptoms of infection with H. Influenzae? Common cause of sinusitis, otitis media, conjunctivitis, epiglottitis with inspiratory stridor. Swelling of epiglottis produces a thumbprint sign on lateral xray of the neck. Can cause COPD exacerbation. What are signs and symptoms of Moraxella Catarrhalis infection? Causes typical pneumonia, especially in the elderly. Causes acute COPD exacerbation, chronic bronchitis, sinusitis and otitis media. What are signs and symptoms of infection with Pseudomonas Aeruginosa? Green sputum (pyocyanin), nosocomial pneumonia and pneumonia in CF patients. Often associated with infarction from vessel invasion. What are signs and symptoms of Klebsiella Pneumoniae infection? Most common gram negative that causes lobar pneumonia and typical pneumonia in nursing home patients and alcoholics. Associated with blood tinged, thick, mucoid sputum, lobar consolidations and abscesses.
What are signs and symptoms of infection with Coccidoides Immitis? Contracted by inhaling arthrospores in dust in arid areas (increased after earthquakes). Causes flu-like symptoms and erythema nodosum and granulomatous inflammation of the lungs with caseous necrosis. What are signs and symptoms of infection with Histoplasma Capsulatum? Most common systemic fungal infection, endemic in Ohio and Mississippi river valleys. Causes granulomatous inflammation with caseous necrosis, simulating TB. Produces coin lesions, consolidations, milary spread and cavitation. Causes marked dystrophic calcification of granulomas and multiple calcifications in the spleen. What are signs and symptoms of infection with Blastomyces Dermatitidis? Male dominant disease, common in Great lakes, central and southern US. Causes skin disease that simulates squamous cell carcinoma and lung disease with granulomatous inflammation and caseous necrosis. What are signs and symptoms of infection with Pneumocystis Jiroveci? Cysts and trophozoites attach to Type I pneumocytes. Most common AIDS-defining infection, CD4+ count <200. Fever, dyspnea and severe hypoxemia, diffuse intra-alveolar foamy exudates with cup chaped cysts (under silver or Giemsa stain). Diffuse alveolar and interstitial infiltrates. What are the common causes of lung abscesses? Aspiration of oropharyngeal material. Risk factors are alcoholism, loss of consciousness and recent dental work. Can also be a complication of pneumonia, a result of septic embolism or from an obstructive lung neoplasia. What are the most common pathogens in lung abscesses? Aerobic and anaerobic streptococci, staph species, prevotella, fusobacterium
What is Hampton's Hump? Wedge shaped area of consolidation/infarction from PE Where are most lung abscesses due to aspiration located? Right side because the bronchi going to the right lobes are more direct (straight) so it's easier to aspirate crap into there. Usually in the upper portion of the right lower lobe, but it depends on the position of the person when they aspirated. What are clinical findings in a lung abscess? Spiking fever with productive cough and foul smelling sputum. CXR shows cavitation with an air/fluid level. What is the pathophysiology of a pulmonary thromboembolism? Venous clot, most commonly from the femoral vein. Risk factors are Virchow's triad-stasis of blood flow, hypercoagulable states and trauma to the vessel. Clot breaks off and goes to the lung-size of the embolus determines what it will block. Large embolus blocks major vessels (saddle embolus) while small emboli occlude medium and small vessels. What are consequences of pulmonary thromboembolism? Increase in pulmonary artery pressure, decreased flow to pulmonary parenchyma which can cause hemorrhagic infarct, see a red-blue, raised, wedge shaped area that extends to the pleural surface. Fibrinous exudate on the pleural surface and hemorrhagic pleural effusion. What are clinical signs of pulmonary thromboembolism? Sudden increase in PA pressure which can cause right ventricular failure, sudden onset of dyspnea and tachypnea, fever, pleuritic chest pain, plueral friction rub, pleural effusion, expiratory wheezing from release of TXA2 from platelets. What are lab findings of pulmonary thromboembolism? Respiratory alkalosis (PCO2<33mmHg), PaO2<80 mmHg, increased A-a gradient, increased D-Dimer Define Pulmonary Hypertension Mean pulmonary artery pressure >25 mmHg at rest or >30mmHg with exercise.
What is a pneumoconiosis? What is silicosis? What are clinical findings in restrictive lung disease? dry cough and exertional dyspnea, late inspiratory crackles in lower lung fields, potential cor pulmonale, equal decreases on PFT's. Inhalation of mineral dust into the lungs leading to interstitial fibrosis. Can be silica, asbestos, beryllium or others. Describe Coal Worker's Pneumoconiosis. "I think I've got the black lung pop…" Coal dust, aka aanthracotic pigment comes from coal mines, large cities, second hand smoke, etc. Deposits in alveolar macrophages creating "dust cells." Fibrotic opacities smaller than 1 cm in upper lobes and coal deposits adjacent to respiratory bronchioles producing centriacinar emphysema- simple CWP. Complicated CWP involves large fibrotic opacities, crippling lung disease (black lung), may have cor pulmonale or large cavitating rheumatoid nodules (Caplan Syndrome). No increase in TB or primary lung cancers. Common occupational disease from quartz/silicon dioxide, foundries, sandblasting and working in mines. Quartz is fibrogenic and deposits in the upper lungs, activates and is cytolytic to alveolar macrophages. Macrophages release cytokines resulting in fibrosis. Describe clinical findings in silicosis. Ground glass appearance on CXR or nodular opacities in more advanced disease (concentric layers of collagen w/wo central cavitation). Dystrophic calcification of lymph nodes. Can cause cor pulmonale or Caplan syndrome and increased risk of lung cancer and TB.
What is Berylliosis? What is Sarcoidosis? How do asbestos related diseases occur? Serpentine asbestos-interstitial fibrosis and lung cancer; amphilobe asbestos-interstitial fibrosis, lung cancer and mesothelioma. Deposits in respiratory bronchioles, alveolar ducts and alveoli. Comes from insulating pipes, naval shipyards, roofing material, ceiling tiles, old floor tiles and demolition of old buildings. What is the pathogenesis of asbestos related disease? Fibers are coated in iron and protein (ferruginous bodies) which are then pahgocytosed, coated with ferritin and look golden and beaded in sputum or distal small airways. Causes calcified pleural plaques which don't predispose to mesothelioma, diffuse interstitial fibrosis, primary bronchogenic carcinoma (esp if smoker), malignant mesothelioma of the pleura arising from serosal cells of the pleura. Can cause cor pulmonale or Caplan syndrome. Beryllium exposure from nuclear and aerospace industry causes diffuse interstitial fibrosis with noncaseating granulomas. Increased risk for cor pulmonale and primary lung cancer. Multisystem granulomatous disease of unknown origin. Common in Black women and nonsmokers and causes 25% of chronic interstitial lung disease. Granulomas in mediastinal/hilar lymph nodes and interstitium. Granulomas contain multinucleated giant cells, laminated calcium concretions (Schaumann bodies) and stellate inclusions (asteroid bodies). Dyspnea is the most common symptom.
