Pulmonary Infections

Empyema

* * * * * * *

Which type of pneumonia has a characteristic sputum that is said to resemble "red-currant jelly"

Klebsiella pneumonia

Which pathogen is most commonly associated with the Bulging fissure sign?

Klebsiella pneumoniae The bulging fissure sign refers to lobar consolidation where the affected portion of the lung is expanded, causing the fissure to "bulge" towards the unaffected region. MCC = K. Pneumoniae. Also associated with H.Influenzae and S. Pneumoniae

Which organisms are prone to causing significant necrotising pneumonia resulting in cavitation and abscess formation

Klebsiella, Type 3 pneumococci, S. Aureus

What percent of individuals with primary TB develop secondary TB?

Less than 5% of individuals with primary TB develop secondary TB.

What is the most common mechanism/pathogenesis of Community Acquired Pneumonia?

Microaspiration of oropharyngeal contents during sleep is the MCC Most bacteria that cause pneumonia are normal inhabitants of the oropharynx and nasopharynx that reach alveoli by aspiration of secretions

What is the 2nd most common bacterial cause of acute exacerbation of COPD?

Moraxella Catarrhalis

What is the most common cause of Atypical pneumonia?

Mycoplasma Pneumoniae

List Six organisms that cause atypical community acquired pneumonia

Mycoplasma pneumoniae Chlamydia pneumoniae Legionella spp Coxiella burnetii Chlamydia psittaci Viruses (RSV, CMV, influenza, adenovirus)

What three bacteria are most commonly associated with Atypical pneumonia?

Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila

Most common Opportunistic infection in patients with AIDS?

PCP Pneumocystis jiroveci (carinii) Pneumonia

What is the most common severe complication of Measles and accounts for most measles associated deaths?

Pneumonia

Pneumonia

Pneumonia is an inflammatory process of infectious origin affecting the pulmonary parenchyma. occurs when the normal defenses are impaired -mucocilliary escalator -cough reflex -static fluid -immunoglobulin production -etc

As a general rule, Klebsiella infections are seen mostly in people with

Predisposing conditions such as advanced age, chronic respiratory disease, diabetes, or alcoholism.

Primary TB occurs at _____ of lung Secondary TB occurs at ______ of lung

Primary: Gravity assisted entry into lower lung lobes Secondary: Apex of lung due to high oxygen tension

Name two biomarkers that may be useful in differentiating bacterial from viral pneumonia

Procalcitonin and C-Reactive Protein are significantly elevated in bacterial more than in viral infections

What is the most common cause of Ventilator Associated Pneumonia?

Pseudomonas Aeruginosa (RX)

Pulmonary Tb is spread by? Nonpumonary TB is most often caused by?

Pulmonary TB is spread by respiratory droplets Nonpulmonary TB is most often caused by ingestion of in infected milk

Match the characteristic with the stage of inflammation in Lobar Pneumonia *Red, firm lobe (liver-like consistency) *Red, heavy, boggy lobe *Fibrinosuppurative Exudate *Enzymatic digestion of exudate *Exudate of RBCs + Fibrin + Neutrophils *Alveolar exudate contains mostly bacteria

*Red, firm, air-less lobe (liver-like consistency): Red Hepatization *Red, heavy, boggy lobe: Congestion *Fibrinosuppurative Exudate: Gray Hepatization *Enzymatic digestion of exudate: Resolution *Exudate of RBCs + Fibrin + Neutrophils: Red Hepatization *Alveolar exudate contains mostly bacteria: Congestion

Predisposing Conditions for Aspiration Pneumonia

*Reduced level of consciousness *Alcoholism *Seizures *General anesthesia *Tracheostomy *Presence of NG tube or Endotracheal tube *Stroke *Dysphagia

Match the characteristic with the pattern of Pneumonia *Scattered foci of consolidation in the same or several lobes *Non-lobar patchy or interstitial infiltrates. Often diffuse and bilateral *Consolidation of a large portion of a lobe or an entire lobe

*Scattered foci of consolidation in the same or several lobes: Bronchopneumonia *Non-lobar patchy or interstitial infiltrates. Often diffuse and bilateral: Interstitial/Atypical Pneumonia *Consolidation of a large portion of a lobe or an entire lobe: Lobar Pneumonia

What are the 4 classic gross phases of inflammation in Lobar Pneumonia?

1) Congestion 2) Red Hepatization 3) Grey Hepatization 4) Resolution

Describe each stage of inflammation in Lobar Pneumonia

1) Congestion (<24 hour) *Protein-rich edema fluid containing numerous organisms fills the alveoli; Few neutrophils *Marked congestion/engorgement of capillaries *Lung is heavy, boggy, and red 2) Red Hepatization (2-3 days) *Massive exudation with RBCs, Fibrin, and Neutrophils 3) Grey Hepatization (4-6 days) *RBCs disintegrate *Color change to Gray/Brown *Persistence of Fibrin and Neutrophils (Fibrinosuppurative) Exudate 4) Resolution (>6 days) *Enzymatic digestion of exudate *Resorption of exudate and restoration of pulmonary architecture

What are the three morphologic and clinical patterns of Pneumonia?

1) Lobar Pneumonia 2) Bronchopneumonia/ Lobular 3) Interstitial Pneumonia

Clinical Presentation of Typical vs Atypical Pneumonia

Typical *Abrupt onset *Productive cough with purulent sputum *Pleuritic chest pain *Signs of consolidation (alveolar exudate) * * Atypical *Subacute onset *Nonproductive cough *Lower fever than in Typical **Extrapulmonary manifestations are common* *No response to common antibiotics *Patient looks better than the symptoms suggest **No signs of consolidation on physical exam* *Can be associated with "pulse-temperature dissociation"—temperature is elevated, but pulse is normal

What is the character of a cough due to a typical pneumonia? Explain the pathophysiology of each type of cough.

Typical: Productive Atypical: Non-Productive Typical: Presence of an exudative accumulation in the alveoli = Productive Atypical: Interstitial inflammation and an absence of exudative inflammation = Non-Productive

When a pulmonary abscess is discovered in an older individual, what other diagnosis must be ruled out?

Underlying carcinoma. Lung Carcinoma causing bronchial obstruction, leading to abscess formation is the cause in 10-15% of cases

Pneumonia due to Mycoplasma is seen more often in which demographic?

Usually affects young adults (classically military recruits/ college kids in dorms)

Most common cause of atypical pneumonia due to Rickettsial Organism

Q Fever Coxiella burnetii - The typical incubation period is usually 2 to 3 weeks. - Cattle, goats and sheep are most commonly infected, and can serve as a reservoir for the bacteria. - Found in the birth products (i.e. placenta, amniotic fluid), urine, feces, and milk of infected animals - Acute febrile illness, hepatitis, and atypical pneumonia are the three most common manifestations. - It is a zoonotic disease caused by Coxiella burnetii—an obligate, Gram-negative, intracellular bacteria. Q Fever is QUEER because unlike other rickettsial species -does not cause rash -does not require arthropod vector http://www.usmleforum.com/files/forum/2012/1/710540.php

What four viruses are most commonly associated with Atypical pneumonia?

RSV, CMV, influenza, adenovirus

In order from highest to lowest frequency, the pathogens most often responsible for secondary bacterial pneumonia are?

S. pneumoniae, S. aureus, and H. Influenza Secondary Pneumonia = bacterial pneumonia that is superimposed on a viral upper respiratory tract infection

Pneumatoceles are thin-walled air-filled cysts that develop in the lung parenchyma, usually after pneumonia. Which pathogen is most commonly associated with Pneumatocele formation?

Staphylococcus Aureus

What is the most common cause of community-acquired pneumonia?

Streptococcus Pneumoniae (AKA Pneumococcus)

Patients older than 65 are particularly prone to Secondary bacterial infections T/F?

T!

Typical Pneumonia is more often associated with pleuritic chest pain T/F?

T!

What is the mechanism behind the formation of caseous necrosis and cavitary lung lesions seen in Tuberculosis infections?

The activated macrophages increase phagolysosome acidification and secretion of proteass, NO, and ROS in an attempt to destroy mycobacteria. However this response results in extensive collateral tissue damage resulting in caseous necroses and cavitary lung lesions

About 2 months after visiting dying aunt from a respiratory tract infection, a healthy 6 y/o girl develops a fever along with wheezing. On PE, her temp is 38 C/100.4 F. Her lung fields are clear to auscultation but there are expiratory wheezes. A chest X-ray reveals a solitary 2.5 cm peripheral mid/lung nodule & marked hilar lymphadenopathy. Lab; Hg b: 13.5 g/dL Platelet: 183,599/uL WBC: 5379/uL The following finding is due to which of the following virulence factors? a) Coagulase b) Toxin A c) Large slimy capsule d) Trehalose dimycolate e) Wax D f) Toxin B

d) Trehalose dimycolate

Aspiration Pneumonia usually contain which bacteria?

Anaerobic Oral Flora : Bacteroides, Fusobacterium, and Peptostreptococcus, Prevotella; Mixed with Aerobic Bacteria : S. pneumoniae, S. aureus, H. influenzae, P. aeruginosa

Atypical pneumonia with post-transplant immunosuppressive therapy

CMV

What is the most common opportunistic infection in lung-transplant recipients?

CMV

Which organisms commonly cause pneumonia in Immunocompromised patients?

CMV Pneumocystis Jiroveci * * * *

Ghon Complex is characteristic of Primary or Secondary TB? Cavitation is characteristic of Primary or Secondary TB? Caseation is characteristic of Primary or Secondary TB? Granulomatous inflammation is characteristic of Primary or Secondary TB?

Ghon Complex: Primary TB Cavitation: Secondary TB Caseation: Both Granulomatous Inflammation: Both

Hospital Acquired Pneumonias are usually gram positive or gram negative?

Gram Negative including Klebsiella, Pseudomonas Aeruginosa, E. Coli

What is the most common causative agent of pneumonia in infants < 1 month?

Group B Streptococcus (E. Coli less commonly)

What is the most common bacterial cause of acute exacerbation of COPD?

Haemophilus Influenzae

Atypical pneumonia in the elderly, immunocompromised host, and those with preexisting lung disease. Also increases the risk for superimposed S. Aureus or H. Influenzae bacterial pneumonia

Influenza Virus

ghon focus vs ghon complex

ghon focus is SUBPLEURAL location of caseous necrosis whereas ghon complex is combination of ghon focus + hilar lymphadenopathy

Pneumonia due to Legionella is seen more often in which demographic?

middle-aged and older adults, SMOKERS, and those with chronic illnesses or a WEAK IMMUNE SYSTEM.

Decreased Breath sounds

what does it mean?? ***

Match the feature with the causative agent of Pneumonia * * * *Most commonly associated with Bulging fissure sign *Most commonly associated with Pneumatoceles and Abscess formation *Most commonly associated with underlying COPD *Blood-tinged, thick, mucoid sputum *Rust colored sputum *Green sputum *Pneumonia often associated with infarction due to vessel invasion *Pneumonia associated with animals at the time of giving birth

* * * *Most commonly associated with Bulging fissure sign: Klebsiella pneumoniae *Most commonly associated with Pneumatoceles and Abscess formation: Staph Aureus *Most commonly associated with underlying COPD: H influenzae or M catarrhalis *Blood-tinged, thick, mucoid sputum: Klebsiella *Rust colored sputum: Streptococcus Pneumoniae *Green sputum: Pseudomonas Aeruginosa *Pneumonia often associated with infarction due to vessel invasion: Pseudomonas Aeruginosa *Pneumonia associated with animals at the time of giving birth: Coxiella Burnetii

Chlamydia Pneumonia

**demographics

Complications of Pneumonia

*Abscess formation ( Klebsiella,Type 3 pneumococci, S. Aureus) *Spread of infection to pleural cavity => Empyema *Bacteremic dissemination

Mycobacterium tuberculosis

*Acid fact, facultative intracellular bacteria *Transmission: respiratory droplets *TB contains no endotoxins or exotoxins * * * * *

What are 4 common causes of lung abscesses?

*Aspiration (MCC) *Complication of pneumonia (Esp S. Aureus, Klebsiella) (Suspect in a patient with incompletely treated pneumonia) *Bronchial obstruction from cancer or bronchiectasis *Septic embolus from right sided bacterial endocarditis (Tricuspid valve)

What findings are found on physical examination of a patient with pulmonary consolidation?

*Dullness to percussion *Increased vocal tactile fremitus (sound is transmitted well through alveolar consolidations.) *Late inspiratory crackles *Bronchial breath sounds, bronchophony *Egophony (E->A)

Describe the pathogenesis of Mycobacterium tuberculosis

*Entry into macrophages by phagocytosis *Unchecked replication in macrophages (prevents fusion with phagolysosome *APCs migrate to lymph nodes and produce IL-12. *IL-12 => TH1 response (Occurs after ~3 weeks) *TH-1 cells release IFN-y and TNF *Activated macrophages increase phagolysososme acidification, secrettion of proteosomes, NO, and ROS to destroy mycobacteria *IFN-y causes macrophages to differentiate into epitheliod histiocytes which aggregate to form granulomas and wall off the organisms *

Aspiration pneumonia

*Inhalation of either oropharyngeal or gastric contents into the lower airways **More often seen in the right lung than the left (result of wider and straighter right mainstem bronchus)* *Most common site = Right lower lobe *Standing/Sitting => Basal Right Lower lobe *Supine => Superior Right Lower lobe *Lying on right side => Right middle lobe or posterior segment of right upper lobe

Lung Abscess

*Localized collection of pus within parenchyma that produces necrosis of lung tissue *Most patients will have fever and a productive, often foul smelling cough **Cavities have thick fibrous walls* *Histology: Suppurative destruction of the lung parenchyma within the central area of cavitation **CXR: Cavity with air fluid levels* *Unlike pleural collections, lung abscesses frequently have a fluid level which is approximately the same length on both the frontal and lateral projection *Complications: Rupture into pleural space causing empyema; Severe hemoptysis

A 45-year-old male alcoholic presents with fever, productive cough, and foul-smelling sputum for the past two weeks. Vital signs are T 38.3 C, HR 106, BP 118/64 and RR 16. Oxygen saturation on room air is 90%. Given a diagnosis of aspiration pneumonia, initial chest radiograph findings would most likely include: 1. Left lung abscess due to increased ventilation-perfusion ratio of the left lung 2. Left lung abscess due to the left main bronchus being located superior to the right main bronchus 3. Right lung abscess due to increased anterior-posterior diameter of the right lung 4. Right lung abscess due to the right main bronchus being wider and more vertically oriented 5. Mediastinal abscess located between vertebral levels T1-T3

4. Right lung abscess due to the right main bronchus being wider and more vertically oriented Aspirated material is more likely to lodge in the right main bronchus. This is due to the anatomy of the right bronchus, which is shorter in length, wider in diameter, and oriented in a more vertical position compared to the left main bronchus.

Ghon focus vs Ghon complex vs Ranke complex

A Ghon focus is an area of consolidation that most commonly occurs in the mid and lower lung zones. A Ghon complex is the addition of hilar lymphadenopathy to a Ghon focus. The Ghon complex undergoes progressive fibrosis, often followed by calcification and is referred to as a Ranke complex. Ranke complexes are benign and are not associated with reactivation http://library.med.utah.edu/WebPath/TUTORIAL/MTB/MTB.html

A 27 yrs old student is coughed on by a patient who suffers from active pulmonary TB, and she never been exposed to TB before. Which one would likely happen in first week. A. Intracellular proliferation B. Epitheloid transformation of monocyte C. Scattered area of caseous necrosis D. Interfron secretion by active T lymphocyte E. mounting response by B lymphocyte

A. Intracellular proliferation During the earliest stage of primary tuberculosis <3 weeks) in the nonsensitized individual, bacteria proliferate in the pulmonary alveolar macrophages and air spaces, resulting in bacteremia and seeding of multiple sites. Despite the bacteremia, most people at this stage are asymptomatic or have a mild flu-like illness.

A 29-year-old alcoholic college student with a history of multiple hospitalizations presents to the emergency room with self-described fevers and chills over the past 24 hours. He is concerned because he has no recollection of how he got to the park bench upon which he awoke yesterday morning. A chest x-ray is obtained and can be seen in figure A. Which of the following best explains this patient's current symptoms? A. Neurologic dysphagia from multiple sclerosis B. Alcohol-induced altered consciousness that led to aspiration pneumonia C. Mechanical obstruction of the glottis from epiglottitis D. Mycoplasma pneumonia from living in college dorms E. Pulmonary fibrosis from a previous tuberculosis infection

B. Alcohol-induced altered consciousness that led to aspiration pneumonia This patient is most likely suffering from aspiration pneumonia secondary to impaired consciousness due to his excessive alcohol use. Given his history of alcoholism, this patient was likely intoxicated which led to altered consciousness and aspiration of vomitus. Aspiration is an important condition to recognize as it often leads to a LOWER-lobe pneumonia. These patients are often infected with gram negative organisms that are normally present in the oral flora. Patients who are chronic users of alcohol or drugs and patients with neurologic impairment are especially susceptible. Patients undergoing surgery are also at risk due to the inability to protect their airway from aspiration during anesthesia, thus the general requirement for patients to be NPO prior to a scheduled procedure. aspiration pneumonia should be suspected in patients with conditions that impair consciousness or swallowing. Treatment should include antibiotic coverage for organisms of the mouth as well as gram negative organisms and anaerobes (organisms of the GI tract).

Which of the following is the most common organism causing pneumonia in alcoholics? A) Klebsiella pneumoniae B) Mycoplasma pneumoniae C) Streptococcus pneumoniae D) Chlamydia pneumoniae

C Klebsiella frequently causes pneumonia in alcoholics,diabetics,chronic lung disease patients BUT the most common organism causing pneumonia in alcoholics is still Streptococcus pneumoniae

A 34 year old male presents to the ER with complaints of high fever, chills and a cough productive of greenish sputum. He admits to heavy alcohol use recently. On physical examination, there are crackles over his right lower lung lobe. Which of the following account for the colour of this patient's sputum? A. Hemolysis B. High bacteria load C. Myeloperoxidase D. Mucopolysaccharides E. Bacterial capsule F. Epithelial necrosis

C. The reaction catalyzed by myeloperoxidase results in the characteristic green-colored sputum that is often found in respiratory infections.

In a patient with a lung abscess, what characteristic finding would you expect to see on a chest x ray?

Characteristically shows a cavity with air-fluid levels Unlike pleural collections, lung abscesses frequently have a fluid level which is approximately the same length on both the frontal and lateral projection

Symptoms of Pneumonia

Chills and Fevers Productive cough Blood tinged or rusty sputum Pleuritic pain on INSPIRATION Hypoxia with shortness of breath Sometimes cyanosis Decreased breath sounds Elevated WBC

What is the 2nd most common cause of Atypical pneumonia?

Chlamydia Pneumoniae

What is the antibiotic of choice for treating lung abscesses?

Clindamycin Clindamycin has activity against oral anaerobes and also covers aerobic gram positive organisms such as S Pneumoniae

Name three virulence factors of Mycobacterium tuberculosis

Cord factor (Trehalose dimycolate) *Prevents fusion with lysosomes *Causes characteristic serpentine growth pattern *Inhibits macrophage maturation and induces release of TNF-α. Sulfatides *Prevents fusion with lysosomes *(some sources say cord factor prevents fusion (uworld) others say sulfatides) Tuberculin *A surface protein *Triggers cell-mediated immunity → caseation and granulomas *Triggers delayed hypersensitivity reaction

A 34 yo HIV patient develops pulmonary tuberculosis. No CD4+ lymphocytes are detected in his peripheral blood. Which of the following cellular components is most likely to have a deficient function in the tuberculoids lesions in this patient lungs? A) eosinophils B) fibroblasts C) langhans giant cells D) macrophages E) neutrophils

D) macrophages Primary method of killing mycobacterium tuberculosis is cell mediated Th1 response which releases INF-y and activates macrophages

A 69-year-old homeless man is admitted to the hospital with a nonproductive cough and malaise. CXR shows diffuse bilateral pulmonary interstitial infiltrates in all lung fields. A sputum gram stain reveals normal flora with few neutrophils. The patient is given supportive therapy and recovers spontaneously over the course of the next 10 days. What was the most likely cause of his illness? A.Asthma B.Mycobacterium tuberculosis C.Mycobacterium avium complex D.Influenza A virus E.Streptococcus pneumoniae

D.Influenza A virus Diffuse, bilateral pulmonary interstitial infiltrates in all lung fields with sputum containing few neutrophils is strongly suggestive of a viral lung infection. Viral lung infections usually resolve spontaneously, but can also cause a secondary (superimposed) bacterial pneumonia. This is because viral infections disable/hinder the "mucociliary elevator," which serves to clear the lung of debris and pathogens. It is important to remember that the most common causative pathogen implicated in SECONDARY bacterial pneumonia following viral infection (classically influenza) is S. aureus. Lobular consolidation is seen in Streptococcus pneumoniae whereas normal lung fields are seen in asthma. This is why asthma and lobar pneumonia could be ruled out in this patient. Mycobacterium would not be stained by a gram stain, as these organisms do not hold the stain used in gram staining. However, infection by these organisms can be ruled out by the fact that this patient's condition resolved spontaneously in a short period of time- something not characteristic of Mycobacterium infection. In addition, CXR typically will show cavitations or perihilar infiltrates.

What are the most common organisms causing pneumonia in cystic fibrosis patients?

During the first decade of life of CF patients, Staphylococcus aureus and Hemophilus influenzae are the most common bacteria isolated from the sputum, but in the second and third decade of life, Pseudomonas aeruginosa is the prevalent bacteria. 1st decade: H. Influenzae, S. Aureus 2nd & 3rd decade: P. Aeruginosa https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Cystic_Fibrosis_Respiratory_Infections_by_Age.svg/2000px-Cystic_Fibrosis_Respiratory_Infections_by_Age.svg.png

Granulomatous inflammation is characteristic of only Secondary TB T/F?

F Granulomatous inflammation is characteristic of BOTH primary and secondary TB

Typical Pneumonia is more often associated with Extrapulmonary manifestations T/F?

F! Atypical Pneumonia is more often associated with extrapulmonary manifestations

The most common pathogenesis of Community Acquired Pneumonia is the inhalation of aerosol drops T/F?

F! Microaspiration of oropharyngeal contents during sleep is the MCC

primary TB is usually symptomatic or asymptomatic?

asymptomatic BUT STILL RESULTS IN POSITIVE PPD