Respiratory Path 7 - SRS Flashcards
Pneumonia is?
Inflammation of the lung parenchyma from any cause, infectious, radiation, chemical exposure, etc.
What organ system is more often than any other involved in infections?
Respiratory tract!
Riddle me seven pneumonia agents!
- • Bacterial
- • Mycobacterial
- • Fungal
- • Pneumocystis
- • Viral
- • Chemical
- • Physical (radiation)
If a pneumonia patient has elevated CRP and/or procalcitonin then what is the likely cause?
Bacterial more likely than viral pneumonia
What are the major predisposind conditions that cause compromise in the conducting airway defenses?
3
- Accumulation of secretions
- Loss or supression of normal cough reflex
- Injury to mucociliary apparatus
What major predisposing factors cause problems in the lower respiratory tract’s defense mechanisms?
- Edema and congestion
- Complement defects
- Abnormalities of phagocytosis or bactericidal activities (EtOH, tabacco, O2)
- HIV, immunosuppression
What is the one huge thing that majorly increases a patients risk of infection by encapsulated organisms?
What are two ways this can happen?
- Splenectomy (encapsulated pneumoccocus a big deal)
- surgical splenectomy
- Autosplenectomy via sicke cell anemia
What is the most common community aquired pneumonia?
Streptococcus pneumoniae G+ diplococci, (MOST COMMON, ↑risk with splenectomy/sickle cell need vaccine)
2?
In COPD patients what is the most common community acquired pneumonia?
Haemophilus influenzae
Moraxella catarrhalis G- diplococci, #2 in COPD
What is the most common post viral pneumonia/influenza?
Staphylococcus aureus. Also most common in IV drug abusers
What is the most common community acquired pneumonia in those with cystic fibrosis and neutropenia?
Pseudomonas aeruginosa G- coccobacilli
What are the three big community-acquired atypical bacterial pneumonias?
- Mycoplasma pneumoniae
- chlamydia species
- coxiella burnetti (Q fever)
What shoud you look for in a patient with a suspected mycoplasma pneumoniae infection?
Cold agglutanins
Aspiration pneumonia can be anaerobic oral flora admixed with aerobic bacteria. What are four anaerobic oral flora that can lead to this?
- bacteriodes
- prevotella
- fusobacterium
- petpostreptococcus
What are the 7 distinct categories of pneumonia syndromes?
- Community-acquired acute pneumonia
- community-acquired atypical pneumonia
- health care associated pneumonia
- Aspiration pneumonia
- Necrotizing pneumonia and lung abscess
- chronic pneumonia
- pneumonia in the immunocompromised host
If you see an immunocompromised patient presenting with pneumonia, what is the most likely organism?
Probably still just going to be S. pneumoiniae.
These patients will still get all the regular ones, they will just also sometimes present with the wierd ones like pneumocystis jirovecii.
Gomez made a point about this, might see him make it again on the exam. If you see an immunocompromised patient with pneumonia don’t jump to a wierd one. If you see a patient with a wierd one, think that they might be immunocompromised.
What shape is streptococci?
What formation do they assume?
What is the exception to the shape rule?
Gram positive cocci that form chains/
The exception is S. pneumoniae which is lancet shaped.
Pretty important distinction for this section
Which of the streptococci are encapsulated?
S. pneumoniae
S. Pyogenes
S. agalactiae
What is the number one cause of bacterial pneumonia in adults?
What makes this virulent?
S. pneumoniae α hemolysis- virulent because of the capsule
What else besides bacterial pneumoniae is S. pneumoniae the number one cause of?
2
- Otitis media in children
- meningitis in adults
After culturing S.pneumoniae, how would you differentiate it from the also α hemolytic S. viridans?
S. pneumoniae is optochin sensitive
What shape is haemophilus? Gram stain?
Gram negative coccobacilli
What is the major virulence factor of haemophilus?
Capsule
Name as many things as you can that haemophilus influenzae is implicated in!
Gomez listed 11
- pneumonia
- acute epiglottitis
- bacteremia
- meningitis
- septic arthritis
- cellulitis
- otitis media
- purulent pericarditis
- endocarditis
- arthritis
- osteomyelitis
There are six serological types of H. influenzae, based on capsular polysaccharide antigens.
Which is the most common cause of bacterial meningitis in children from 6 months to 2 years?
H. influenza type B
Unencapsulated strains of H. influenza cause ear, sinus and respiratory infections in what three patient groups typically?
Chronic smokers
Alcoholics
Elderly
What is the gram status and shape of moraxella catarrhalis?
Gram-negative diplococcus
What are three common afflictions caused by M. catarrhalis?
- common cold
- otitis media
- sinusits
What are four less common afflictions associated with m. catarrhalis?
In children
- laryngitis
- bronchitis
- pneumonia
In adults
- chronic lung disease
What is the gram status, shape and arrangement for Staphylococci?
Gram positive cocci in clusters
Staph aureus is a non-motile, oxidase -, facultative anaerobe. What will a coagulase test reveal for S. aureus?
Coagulase positive
S. aureus can do major damage to the skin, what are some examples?
- furuncle=boil
- carbuncles
- scalded skin syndrome
- impetigo
Apart from the skin presentations, what are some other major issues that S. aureus is known to cause?
8 with four bolded
- Deep abcesses
- Sepsis
- pneumonia
- meningitis
- acute endocarditis
- osteomyelitis
- toxic shock syndrome
- food poisoning
What are the major virulence factors for S. aureus?
- resistance to penicillins and vancomycin
- clumping factor (fibrinogen receptors)
- surface protein A (disables Ig)
- Exfoliative A and B toxins (scalded skin)
- Superantigens
What are the two superantigens associated with S. aureus?
Toxic Shock Syndrome (TSST1) Toxin
Heat stable enterotoxin
What is the gram status and shape of legionella?
Gram negative bacilli
Legionellae are associated with aerosolized water, why?
They are ubiquitous saprophytes that can live in amoebae and biofilms.
Legionnaire’s disease is a severe lobar pneumonia, how does it present clinically?
What does it lead to if not treated?
- cough, non productive
- fever
If untreated, the fever will lead to multi-organ disease and death if untreated.
What is the virulence of legionella proportional to?
Its ability infect and multiply within macros
Pontiac fever was and epidemic flu like condition caused by L. Pneumophila, what was the course of the sickness?
fever, chills, headache and malaise that lasted 2-5 days and resolved.
What is the gram stain and shape of klebsiella?
gram negative bacilli
Klebsiella is an encapsulated gram-negative bacilli. What will you see if you culture it on McConkey’s agar?
Reddish colonies, indicating lactose fermentation
What is klebsiella the most common cause of?
Nosocomial respiratory tract infections
What is a pretty distinctive characteristic presentation of a K. pneumoniae pneumonia?
Hemorrhagic pneumonia with red currant jelly colored sputum.
What are the capsular types of K. pneumoniae that are associated with 3% of bacterial pneumonias?
Capsular types 1 and 2
What is the gram-stain and shape of pseudomonas?
Is it motile?
Is it a fermenter?
Oxidase status?
Gram-negative rods
non-fermenter
oxidase positive
motile
What is the major virulence factor that is associated wtih pseudomonas?
•Antiphagocytic exopolysaccharide (alginate) slime biofilm
What is a characteristic finding in a pseudomonas culture?
•Many strains produce pigments (fluorescent pyoverdin and pyocyanin)
Pseudomonas is a common nosocomial infectious organism. In what patients does it typically cause problems?
Commonly present in the lungs of cystic fibrosis patients
What is the treatment for a patient with pseudomonas?
Antibiotics… but, typically find resistant strains in cystic fibrosis patients. Suck.
Describe the cell wall of mycoplasmataseae!
Lacks a cell wall around their cell membrane
Mycoplasma pneumoniae is known as a cause of what three things?
- Atypical “walking” pneumoniae
- acute tracheobronchitis
- bronchiolitis
Mycoplasma pneumoniae can be a pain in the ass to dx, what is a key to identification?
Cold agglutinin production
What the hell are the cold agglutinins that mycoplasma pneumoniae produces?
anti-IgM
What is the gram-stain and shape of chlamydia species?
Are they free living?
Obligate coccoid to rod intracellular bacteria that are gram negative.
Describe how chlamydia enters the cells!
What are the replicative forms?
•Infectious elementary bodies attach and are internalized by susceptible host cells
•Intracellular reticulate (initial) bodies - replicative form
Why must chlamydia be in a cell to reproduce?
cannot produce their own ATP
What C. pneumoniae strain is associated with upper and lower (atypical pneumoniae)) respiratory tract infections?
Strain TWAR
C.Psittaci is associated with atypical pneumonia and associated systemic symptoms. What is the vector for the two presentations of this infection?
- Psittacosis - In psittacine birds (parrots, lovebirds, & parakeets)
- Ornithosis – In non-psittacine birds (domestic fowl, ducks, pigeons, turkeys, and many wild birds)
What is the gram stain, and living situation of coxiella burnetii?
Gram negative obligate intracellular bacteria that requires host ATP
How is C. burnetii contracted?
Worldwide zoonosis usually in cattle, sheep or goats and spread via inhalation of aerosolized organisms, unpasteurized milk products
What is a characteristic of C. burnetii that makes it hardy?
What does this organism can cause?
Has an endospore like state that makes it highly resistant to environmental factors.
Causes:
- Q fever (asymptomatic, flu-like syndrome, or atypical pneumonia)
What bacterium is shown here?
What is the vector?
What can happen if this is allowed to progress?
Bacillus anthracis
- Large gram + bacillus in chains
- Infection via dormant endospores
Will cause pulmonary anthrax and medastinitis.
What is the gram stain, and shape of yersinia?
Lactose fermenter?
Glucose fermenter?
- Gram negative, bipolar staining coccobacilli
- Non-lactose fermenter
- Glucose fermenter
What are the reservoirs for Y. pestis?
Transmitted by?
•Bubonic plague (black death) maintained among rodent populations (ground squirrels, prairie dogs, great gerbils/black rats for exam questions) transmitted by infected fleas (regurgitate biofilm from gut)
What antigens are required for Y. pestis to be virulent?
F1 antigen, and both the V and W antigens.
Pneumonic plague occurs under crowded conditions when contaminated respiratory droplets expelled by infected perons are directly inhaled by another person. How else does this differ from the black death?
Shorter incubation period
greater mortality (90% die in 1 day)
What is the gram stain for mycobacteria?
What must you use for identification?
- Mycobacteria are gram ? [gram (+) due to cell wall structure vs gram (-) via DNA]
- Mycobacteria and nocardia are acid fast, so must use Ziehl-Neelsen stain for identification
How is M. tuberculosis spread?
What can it cause?
Spread by airborne droplets and can cause prolonged productive cough
Tuberculosis has primary infection and secondary infection classes. What characterizes the primary infection?
- Ghon complex (parenchymal lesion & involved lymph node)
- Granulomatous response, usually asymptomatic and self-limiting but clinically symptomatic in 5%
What characterizes the secondary infection class of Tuberculosis?
- Reactivation of old walled-off lesions, usually apical (high ppO2)
- Variable course: cavitary caseous necrosis with subsequent scarring or progressive disease
When does “military TB” occur?
When a tubercle erodes into a vessel.
How might TB present differently in an immunocompromised host?
Will it disseminate?
Without granulomas
- Dissemination in 10-15% of mildly immunosuppressed
- Dissemination in >50% of severely immunosuppressed
I
How do you dx tuberculosis?
3
- PPD test,
- acid-fast stain on sputum,
- mycobacterial cultures
Tx for Tuberculosis?
3
•Rx - Isoniazid, rifampin and ethambutol (drug resistance has emerged)
How can Tb be prevented?
- bacillus Calmette–Guérin (BCG) vaccine
If inflammation and infection leads to pus in the pleural space, what is this called?
empyema
Identify the types of pneumonia shown
Left image: Bronchopneumonia
Right image: Lobar pneumonia
If you hear Lobar pneumonia you say it is what?
Pneumococcus
Classify the pneumonia you see here.
Lobar
Classify the pneumonia shown here
Bronchopneumonia
Classify the pneumonia you see here. Justify.
Bronchopneumonia
See inflammation primarily in a bronchus and surrounding alveoli, with neutrophil infiltration.
What organism should you think of when you see this pattern of hepatization?
Since this is lobar pneumonia you should be thinking pneumococcus (streptococcus pneumoniae)
(can also be from others, including H. influenze, but he said twice to think S. pneumo)
Of the two pictured hepatizations which comes early and which comes late?
Red is early
Gray is late
Which image is early and which is late?
On the right is early,
Left is late - more hemolysis and infiltration
Stage each of these bacterial pneumonias
Top left: Acute pneumonia with early red heptization
Top Right: early organization streaing through the pores of Kohn
Bottom left: Advanced organizing pneumonia
Orthomyxovirus; Influenza is an ssRNA, enveloped virus with three types A, B and C.
What surface antigens does the envelop have?
Surface glycoproteins hemagluttinin (H) and neuraminidase (N)
Influenza is transmitted in the air and leads to respiratory disease aided by hemagglutinin attachment to respiratory mucosa.
What does neuraminidase do?
Produces mucus liquefaction.
What are antigenic drift and antigenic shif?
- 1.Antigenic drift - mutations in the RNA → minor changes in the antigenic character of H and N molecules
- 2.Antigenic shift - rearrangement of genome segments →major changes in the antigenic character of the H and N molecules
What is Reye syndrome?
Child + flu (or chickenpox) + Aspirin = Reye’s
Paramyxovirus is an ssRNA with envelope. What are the types of paramyxoviruses?
four bold, one not
•Parainfluenza
•Mumps
•Measles
•Respiratory syncytial virus
•Human metapneumovirus
What does human metapnuemo virus cause?
- common cold
- bronchiolitis
- pneumonia
What are three sicknesses caused by parainfluenza?
- Cause 30-40% of acute respiratory infections in infants and children
- Mild cold-like to life-threatening (croup, bronchiolitis, pneumonia)
- Most common cause of croup laryngotracheobronchitis (barking cough, steeple sign)
What is this?
Steeple sign
RSV is an ssRNA with envelope, that causes local infection in ciliated epithelia (upper or lower respiratory tract), nose, eye and mouth.
What is this the major cause of?
- Major cause of bronchiolitis and pneumonia in infants (#1 cause in age < 6 months)
- Severe disease may present as bronchiolitis, pneumonia or croup
- Reinfection in adults usually involves the upper respiratory tract (common cold)
Measels enters oropharynx from human secretions followed by viremia to skin, mucosae, CNS, lymphatic & respiratory systems. What is the typical clinical presentation?
- Fever
- maculopapular rash
- +/- conjunctivitis leading to blindness
- +/- pneumonia
What are tht emiltinucleated ghiant cells with cytoplasmic and nuclear viral inclusions seen in measels called?
Warthin-Finkeldey cells
Adenovirus is a naked dsDNA with numerous serotypes that is transmitted by respiratory and fecal-oral routes. What types cause acute respiratory disease?
What else is adenovirus known to cause?
- Acute respiratory disease – serotypes 4,7 &21) upper respiratory infections in kids/young adults that can progress to pneumonia
- Pharyngoconjunctivitis – pink eye and sore throat
Picornaviruses are small naked ssRNA. Rhinovirus causes the common cold and spreads via the nasopharynx. What does this use for attachment?
•Attach via ICAM-1 receptor to respiratory epithelial cells
Name that cell and pathogen
Owl-eye basophilic intranuclear inclusion - CMV
What is SARS due to?
•Severe acute atypical respiratory syndrome due to a novel coronavirus
What are the sources of pulmonary abcesses?
- #1 Aspiration, usually right lower lobe
- Antecedent lung bacterial infection
- Septic embolism (thrombophlebitis or vegetations)
- Neoplasia (post obstructive pneumonia)
- Carcinoma found in 10-15% of cases
- Penetrating wounds
- Infection from adjacent organs
- Hematogenous spread of infection
- (Primary cryptogenic abscess if no source identified)
10.
What is RSV a common cause of?
- Most common cause of bronchiolitis and pneumonia in children < 12 month
- Also Otitis media
Chronic pneumonias are frequently a localized lesion in immunocompromised patients and often are granulomatous processes.
What are three examples of this?
TB
Leprosy
Funal
What are the three dimorphic fungal pneumonias?
Histoplasma capsulatum
Blastomyces dermatidis
Coccidioides immitis
Histoplasma capsulatum is 3-5 um in size and infectious in the micronidia and macronidia forms.
Where does this infection typically occur?
What is the source?
Ohio and Miss. River valleys and Caribbean
soil spores from bird (starlings) or bat feces
Blastomyces dermatidis is 5-15 um and infectious in the micronidia form. Where does this infection occur and via what route?
Central and SE USA, Canada, Mexico, Middle East, Africa, India
soil spores
Coccidioides immitis is 50-60 um and infectious in the arthroconidia form. What location are these infections typically seen? What are these patients exposed to?
Southwest (San Juaquin Valley), Far West and Mexico
soil spores
What is the infectious form of the organism that has afflicted this patient?
Histoplasmosis
Micronidia or macronidia
wiggled the image on the right
In the HE stain you see rounded budding yeasts larger than the infiltrating neutros. Note the thick wall and nuclei.
On silver stain you see broad-based budding.
Where was this person most likely infected by the micronidia form of this fungus?
Blastomyces
- Central and SE USA,
- Canada,
- Mexico,
- Middle East,
- Africa,
- India
These spherules are 50 to 60 microns and contain non-infectious endospores. What fungus are we looking at?
Where was this person likely exposed to the arthroconidia form of this fungus?
Coccidiomycosis
- Southwest (San Juaquin Valley),
- Far West
- Mexico
What are the common “unusual” diffuse pneumonias in the immunocompromised patient?
3
- Pneumocystis carinii (jirovecii is current favored name for human and carinii for pneumocystis in rats) (CD4<200)
- Cytomegalovirus (CMV) (CD4<50)
- Mycobacterium avium complex (CD4<50)
What are the common “unusual” focal pneumonias seen in HIV patients?
2
- Aspergillus sp.
- Candida albicans
This patient has been coughing up foamy “cotton candy” exudate. You do HE and see what appear to be empty air spaces. On silver stain you find the shown “cup and saucer” shaped organisms. What is this persons pneumonia?
Pnuemocystis pneumonia
wiggled and he said three times be able to recognize
What is this organism?
The morphology of Candida infections. C, Characteristic pseudohyphae and blastoconidia (budding yeast) of Candida
Wiggled!!!
What is this?
CMV
wiggled
Note the septate hyphae with acute-angle branching. What is this consistent with?
Aspergillus
wiggled!!!
What is this organism that was obtained from an AIDs patient’s lungs?
What stain would you use on this?
Cryptococcus - yeast form with variable size and NO pseudohypae.
Use a mucicarmine stain to highlight the capsule of the cryptococcosis yeast. (he said to be sure to remember this. Example shown in the image attached)
