Exam 2 - respiratory infections Flashcards
What are the two classifications of Pneumonia
-community acquired (CAP)
(typical and atypical)
-nosocomial (aka hospital acquired)
typical CAP: most commonly caused by
bacterial: strep pneumoniae
- in top 10 causes of death in US
Typical CAP: bronchopneumonia
- bronchitis -> pna
- locations = lower lobes, RML
- patchy consolidations (microabscesses)
Typical CAP: lobar pneumonia
consolidation of lobe (complete or incomplete)
typical CAP: pathogenesis
most common: microaspiration of oropharyngeal contents during sleep
second most common: aerosol inhalation
uncommon: blood stream infection
typical CAP: clinical findings
- sudden high fever
- productive cough
- CP
- tachycardia
Consolidation signs =
- dullness to percussion
- inspiratory crackles
- bronchial breath sounds
typical CAP: chest X-ray (CXR), labs
- screen
- patchy infiltrates (bronchopneumonia)
- lobar consolidation
labs: gram + stain, leukocytosis, blood cultures
Nosocomial pneumonia: risk factors
- **respirators = most common
- underlying disease
- antibiotics
- immunosuppression
Nosocomial pna bugs
Gram (-) = pseudomonas, E.coli
Gram (+) = staph. aureus
Rhinovirus
most common cause of common cold
transmission: hand-to-eye/nose
Coxsackievirus
-acute chest syndrome
fever, pleuritis
Parainfluenza
-most common cause of CROUP!!
CXR: steeple sign (mucosal edema in trachea)
treatment: cold water humidifiers, aerosolized racemic epinephrine
Cytomegalovirus (commonly cause, pathology, treatment)
- common cause of pna in immunocompromised
- pathology: enlarged macrophages and pneumocytes
- Treatment: anti-virals
What are the 2 classifications of influenza?
- Type A (most common, worldwide epidemics)
- Type B (major outbreaks)
Hemagglutinins vs neuraminidase
- hemagglutinins: protein on virus. how it binds to cells in nasal passages
- neuraminidase: disolves mucus. facilitates release of virus
Influenze: clinical findings and associations
clinical finding: fever, headache, cough, muscle/chest pain
associations:
- guillain-barre syndrome
- Reye syndrome
Influenza treatment
- prevention = vaccinate
- neuraminidase inhibitors
(i. e., tamiflu - within 48 hrs of sx)
Rubeola: Measles (pathology and clinical findings)
- patho: Warthin-Finkeldey multinucleated giant cells
- clinical findings: Koplik spots in mouth before rash, rash, fever, cough, conjunctivitis, nasal mucus)
Respiratory syncytial virus
- **Most common cause of pna and bronchiolitis in infants
- winter illness
- pathology = fusion protein
- you want to vaccinate high risk kids
Mycoplasma pneumoniae
- most common cause of atypical pna (***“walking pna”)
- patient pop = teens, military recruits
- symptoms: insidious onset, low-grade fever
- other pathology = cold agglutinins in blood
Chlamydia trachomatis
***NEWBORN PNA (infected during birth)
-symptoms: afebrile, choppy cough, conjunctivitis, wheezing
Coxiella burnetii
- associated with: birthing process of infected animals, milking, handling of animal waste (vets, dairy farmers)
- clinical findings: atypical PNA, myocarditis, hepatitis
Streptococcus pneumoniae
- most common cause of typical CAP
- Gram (+) diplococcus
- rapid onset of sx = productive cough, consolidation signs
Staphylococcus aureus
- Common pts: influenza, measles, CF, IVDA
- yellow sputum
pathology: Gram (+), ABSCESSES!!!, pneumatoceles, hemorrhagic pulmonary edema
Bacillus anthracis: classifications
Cutaneous anthrax
- direct contact with contaminated animal products
- eschar formation with central necrosis
Pulmonary anthrax
- “first sign is death”
- inhalation of spores
- findings = necrotizing PNA, meningitis, splenomegaly
Bacilus anthracis (pathology)
- Gram (+) rod
- EXOTOXINS!!: edema factor, lethal factor, protective antigen
Bordetella pertussis
WHOOPING COUGH!!!
patho:
- Gram (-) rod
- droplet transmission
- bacteria pili attach to cilia in resp tract
- toxin (blahhhh)
Haemophilus influenzae
***most common bacterial cause of COPD exacerbations
- Gram (-) rod
causes: epiglottitis, sinusitis, otitis media, conjunctivitis
Moraxella catarrhalis
- common cause of typical PNA (especially elderly!)
- major cause of COPD exacerbations
- also causes (chronic bronchitis, sinusitis, otitis media
-Gram (-) diplococcus
Pseudomonas aeruginosa
“respirator PNA” ***
- most common cause of nosocomial PNA in CF
- green sputum
- vessel invasion (pulmonary infarctions)
Klebsiella pneumoniae
- typical PNA
- patho (gram (-) rod
- elderly nursing home pts
- ALCOHOLICS**
- blood-tinged sputum
Legionella pneumophilia (main info)
-atypical PNA
-sources (moist places)
-patho: **“Water loving bacteria”*
Gram (-)
risk factors: EtOH, smokers, immunosuppression
Legionella pneumophilia: clinical findings and screens
- clinical findings: high fever, dry cough, flu like sx
- screen: *****antigens in urine!
Yersinia pestis (the plague): transmission and reservoir
Transmission
- rat flea bite!!**
- person to person via droplet
reservoir
-***ground squirrels
Yersinia pestis: the plague (pathology)
- V and W antigens: provide protection and macrophages cannot kill it
- Gram (-) rod
Yersinia pestis: the plague (classifications)
- bubonic (most common, rat flea bite, infected lymph nodes, drain to surface)
- pneumonic (aerosol transmission)
- septicemic
Mycobacterium tuberculosis
- TB
- strict aerobe
- **ACID-FAST
- resides in phagosomes of macrophages
- produces CORD FACTOR (protein that prevents lysosome fusion, provides virulence)
TB screening
- purified protein derivative
- intradermal skin test
- CANNOT differentiate active vs inactive
-(+) test detected bacterium cell wall protein
Primary TB
location: * upper lower lobes and lower upper lobes!!!*
Secondary TB
- reactivation of primary TB
- location: ** apices of lungs! (greatest O2 saturation)
- cavitary lesion (release of cytokines by memory T cells)
TB: clinical findings
- fever
- night sweats
- weight loss
- hemoptysis
- bronchiectasis
- scar carcinoma
Extrapulmonary TB
- kidneys = most common
- adrenals = addison disease
- vertebrae = Pott disease
TB diagnosis and treatment
Diagnosis: screen
treatment: triple therapy
* Treat 9-12 months!!!**
Cryptococcus neoformans: what and where you find
- fungus (budding yeast)
- environmental locations:
- Pigeon waste, windows, bridges, near buildings
Cryptococcus neoformans: clinical findings
- lung disease (granulomatous inflammation, caseation)
- infects (immunocompetent and immunocompromised)
Aspergillus fumigatus: structure
-fungus (fruiting body)
Asperilloma: **fungus ball!
Aspergillus fumigatus: pathology
- invades vessels***
- necrotizing PNA***
Mucor species
- fungus (wide angled, no septa)
- pulmonary vessel invasion
- in people with DIABETES!!!***
Coccidioides immitis
- fungus (*SPHERULES)
- found in: **deserts (valley fever) and earthquakes **
- pulmonary granulomatous inflammation
- flu-like symptoms and erythema nodosum
Histoplasma capsulatum
- most common systemic fungal infection
- yeast found in macrophages
- -locations: mississippi river valley!!!!!*
Blastomyces dermatitidis
- yeast with broad-based buds
- found in *great lakes
- associated with outdoor activities
- skin lesions similar to SCC
Pneumocystis jiroveci
- similar to fungi in structure
- ***most common pathogen causing PNA in AIDS
- patho: produces cysts, produces tropozoites
P. jiroveci clinical findings
- fever
- dyspnea
- hypoxemia
- intra-alveolar exudates
Causes of lung abscesses (4)
- oropharyngeal material aspiration
- bacterial PNA
- septic emboli
- obstructive lung tumor
Aspiration
- **most common cause of lung abscess
- risk factors (alcohol, LOC, dental work)
Pathogens: mixed aerobic and anaerobic (anaerobes 60%)
Lung abscess: gross pathology
-size and location vary
aspiration abscesses generally on Right side
Lung abscess **
- productive cough (foul sputum)*
- CXR: cavitation with air fluid level
- treatment: abx and bronchoscopy
