Respiratory Infections Flashcards
Objectives
1
Q
Define acute bronchitis
A
- Inflammation of the bronchi due to upper airway infection
- Cough lasting > 5 days
- Usually 1-3 weeks
- Usually with sputum production
2
Q
Acute bronchitis eitology
A
- Typically viral
- 60-90% of patients who receive care for bronchitis are given antibiotics
3
Q
acute bronchitis incidence/risk factors
A
- 44 per 1000 adults per year (5% of adults)
- Winter/Fall higher incidence
- Chronic lung disease at greater risk
- Chronic illness at greater risk
4
Q
acute bronchitis Etiology/infectious agents
A
- Etiology: Viral
- Influenza A & B
- Parainfluenza
- Coronavirus
- Rhinovirus
- RSV
- Human metapneumovirus
- Difficult to establish exact agent (13-29%)
- Other pathogens:
- Mycoplasma Pneumoniae
- Severe URI symptoms for 4-6 weeks (cough, pharyngitis)
- Chlamydia Pneumoniae
- Pertusis
5
Q
acute bronchitis clinical presentation (signs and symptoms)
A
- URI type symptoms initially
- Congestion
- Nasal drip
- Facial pressure
- Develop a cough that persists > 5days
- Not critical to distinguish acute bronchitis from Viral URI
- It is critical to distinguish acute bronchitis from pneumonia
- Sputum Production: 50% of patients
- Bronchospasm
- Reduced FEV1
- Can occur for up to 5 weeks
- Cough for 10 to 20 days
- Fever unusual
6
Q
Acute bronchitis DX
A
- Diagnosis typically made during your H&P
- “Clinical Diagnosis”
- Labs
- CXR
- Sputum culture
7
Q
acute bronchitis dx labs
A
CBC results
- WBCs typically normal, occasionally slightly elevated
- Significant Leukocytosis
- Bandemia
- A large elevation in WBC’s or a “left shift/bandemia” should prompt CXR to rule out pneumonia
- Procalcitonin
- Cytokine stimulation by bacterial infections
- Helps distinguish bacterial vs viral
- Reduce Abx exposure in multiple settings
- Use if can be obtained in a timely manner - may not be possible in a lot of clinics
- Big idea: Not getting in the office only in hospital, mostly useful in bronchitis and pneumonia
8
Q
acute bronchitis Dx CXR
A
- Clear “no acute process” infiltrates or anything else on CXR should raise suspicion for PNA
- Should get a CXR when:
- Elevation of WBCs
- Abnormal vital signs
- Tachycardia OR bradycardia
- Tachypnea
- Fever
- Physical Exam suggestive of pneumonia
- AMS
9
Q
acute bronchitis dx sputum culture
A
- Takes time, bacterial typically not cause would see polymorphonuclear cells and/or bacterial pathogens if bacterial
10
Q
actue bronchitis management plan
A
- Symptom management
- Pain Relief: NSAID, ASA, Acetaminophen
- Cough suppressants: codeine, dextromethorphan
- Short Acting Beta Agonist – if bronchospastic
- Don’t give bronchitis abx – especially broad spectrum abx
- Antibiotics
- Large meta-analyses of 15+ RCT’s showed only a reduction of 0.6 days of cough.
- This is a marginal reduction considering the potential adverse effects and potential antibiotic resistance
- “Post infectious bronchospasm”
- Persistent dry cough for 4-6 weeks
- Treat with BD’s, sometimes corticosteroids
11
Q
acute bronchitis special considerations
A
- Chronic lung disease
- Episodes of acute bronchitis
12
Q
pertussis definition
A
- “Whopping cough”
13
Q
pertussis incidence/risk factors
A
- Primarily children pre-vaccine era
- Resurgence with anti-vaccine movement
- Highly contagious
14
Q
pertussis Etiology/infectious agents/basic pathophysiology
A
- Longer incubation period
- 1-3 weeks
- Catarrhal phase
- Early phase
- Malaise, rhinorrhea, mild cough
- Early phase
- Paroxsymal Phase
- 2nd week of illness
- Hallmark whooping cough
- Convalescent Phase
- Gradual reduction of cough
- Total Duration of Phases: up to 3 months
15
Q
pertussis Clinical presentation: signs and symptoms
A
- Hallmark:
- Inspiratory whoop
- Paroxysmal cough
- Posttussive emesis
16
Q
pertussis dx
A
- Clinical definition
- Cough lasting two weeks without cause + one of these:
- Paroxysmal coughing
- Inspiratory whoop
- Posttussive emesis
- Cough lasting two weeks without cause + one of these:
- Tests
- Nasopharyngeal Culture
- PCR
- Serology
- Antibody titers
17
Q
pertussis management plan
A
- Catarrhal phase antibiotics effective - decrease duration/severity of cough
- Antibiotics in later phases
- May not reduce duration or severity but may be useful in reducing spread of disease
- Use if < 2 weeks of symptoms
- Persistent symptoms at 4 weeks
- CDC: Empiric antibiotic therapy early
- Empiric antibiotic therapy early if suspicious for pertussis even while diagnostics are ongoing
- Antibiotics
- Macrolides
- Azithromycin 5 days
- Clarithromycin 500 mg PO BID x 7 days
- Bactrim DS alternative
- Macrolides
- Cough suppressants ineffective
18
Q
pertussis complications
A
- Pneumonia
- Otitis Media
- Cough complications
- Subconjunctival hemorrhage
- Hernia
- Rib fractures
- Lumbar strain
- Rare: Intracranial hemorrhage
- Time lost in school/work
19
Q
pertussis vaccination recommendation
A
- Postvaccine: adults 50% of the time
- DTaP: diptheria, tetanus, pertussis, acellular pertussis
- Tdap booster
20
Q
influenza definition
A
- On Boards the clinical scenario will have short period of time for illness with high fevers typically
21
Q
influenza incidence/risk factors
A
- Yearly winter season outbreaks/epidemics
22
Q
Influenza Etiology/infectious agents
A
- Acutely debilitating
- Self-limiting
- Transmission
- Large droplets: sneezing, coughing
- Small particle possible
- Droplet precautions
- Incubation period
- 1-4 days
- Epidemiology:
- Distinct outbreaks every year
- Hemagglutinin glycoprotein
- Neuraminidase glycoprotein
- Antigenic Shifts
- Epidemics
- Antigenic Drifts
- Influenza A: high propensity for antigenic changes
- H1, H2, H3 and N1, N2
- Influenza B only H changes
23
Q
Influenza Clinical presentation: signs and symptoms
A
- Abrupt onset fever
- General symptoms: headache, myalgias, malaise
- URI symptoms
- NP cough, sore throat, nasal discharge
- Physical Exam
- Feverish/hot feeling
- Flushed
- Cervical lymphadenopathy
- Improve after 2-5 days
- Residual symptoms for weeks
24
Q
Influenza Dx
A
- Clinical Diagnosis
- Rapid Antigen: screening: <15 minutes
- Identifies Influenza A and B
- Sensitivity 62%, Specificity 98%
- LAIV false positive
- Reverse Transcriptase PCR (most sensitive and specific): 2 day, send out lab
- Timing of tests
- High viral load 24-48 hours into illness
- Viral Culture
- 48-72 hours
25
Influenza management plan
* Neuraminidase inhibitors:
* Zanamivir: inhaled/intranasal version
* Oseltamivir (Tamiflu) 75 mg PO BID x 5 days
* Resistance already exists
* Duration \< 1 day
* Benefit best within first 24 hours of fever
* Typically Rx limited to within first 48 hours
* Treat high risk populations first
* Do not delay treatment
* Treatment:
* Severe illness: double dose of Tamiflu: 150 mg PO BID
* Avoid cough suppressants
* NSAIDs for myalgias
* Antibiotics if secondary bacterial pneumonia expected
* Infection Control: stay at home!
26
influenza vaccination recommendation
* Formulations:
* IM Inactivated Influenza vaccine (IIV)
* Fluarix/Fluzone
* Intranasal live-attenuated influenza vaccine (LAIV)
* Flumist
* Protects against Influenza A (H3N2, H1N1) and Influenza B
* Allergic reaction potential
* Immunizing agent itself
* Other proteins introduced in the production process
* Animal proteins, antibiotics, preservatives, stabilizers, virus-inactivating compounds, latex
* Not all allergic reactions to flu vaccine are egg allergy
* Flu vaccine constituents
* Gelatin: stabilizer
* h/o allergy to ingestion of gelatin/gelatin containing foods (marshmallows, gummy candy)
* Test for gelatin allergy
* High incidence in Japan
* Antimicrobials
* Gentamycin, neomycin, streptomycin, polymyxin B
* Latex
* Rubber vial stopper, syringe plunger contacts liquid
* Flu vaccine produced in fluid from embryonated eggs
* Egg protein content
* All current vaccines contain \< 1 mcg per 0.5 mL dose
* Required to list this information
* Large studies (\>4000 patients) have reported safe administration of injective trivalent flu vaccine to patients with egg allergy and included 500 patients with anaphylactic reaction to egg ingestion
* Flu vaccine alternatives:
* Trivalent inactivated influenza vaccine (Optaflu) is produced using cultured mammalian cells
* Approved in EU, Iceland, Norway in 2007
* Approved in USA in 2012 for individuals \> 8 years of age (Flucelvax)
* Flublok (RIV)
* Recombinant hemagglutinin influenza vaccine (trivalent egg free)
* Approved by FDA in 01/2013
* For patients 18-49
* **Do not miss opportunity to immunize patients with an egg allergy**
27
influenza complications
* Pneumonia
* Primary Viral Pneumonia
* Secondary Bacterial Pneumonia
* Hallmark: worsened fevers and symptoms after initial improvement (relapses)
* S. Pneumoniae, H. Flu, Staph A., CA-MRSA
* ARDS
* Myositis/Rhabdomyloysis
* Rare, but seen in children
* Tenderness, swelling in legs
* CNS involvement
* Encephalopathy (AMS), encephalitis, Guillain-Barre
* Cardiac
* ACS/MI, myocarditis, pericarditis
28
Define “chronic cough” + list ddx
* Cough:
* Acute \< 3 weeks
* Subacute 3-8 weeks
* Chronic \> 8 weeks
* Irritation of cough receptors
* Upper Respiratory
* Lower Respiratory
* Pericardium
* Esophagus
* Diaphragm
* Stomach
* Mechanical Receptors
* Triggers such as touch or displacement
* Chronic cough:
* At least 3 months cough in 2 consecutive years
* Upper Airway Cough Syndrome (PND): #1
* Allergic
* Rhinitis
* Sinusitis
* Acute nasopharyngitis
* Asthma: #2 (MCC In Children)
* “cough variant asthma”
* GERD
* Laryngopharyngeal reflux (LPR)
* Post-infectious (subacute)
* ACE Inhibitors
* Chronic Bronchitis
* Bronchiectasis
* Lung Cancer
* Nonasthmatic Eosinophilic Bronchitis
* Dysphagia/Silent Aspiration
29
Distinguish between upper and lower respiratory tract infections
* Upper respiratory tract:
* Contains:
* Nasal cavity
* Pharynx
* Larynx
* Upper respiratory tract infections: Infections of nasal, sinuses, pharynx, larynx
* Lower respiratory tract:
* Contains:
* Trachea
* Primary bronchi
* Lungs
* Lower respiratory tract infections: bronchitis, pneumonia, lung abscesses
30
**Epiglottitis**
* Inflammation of the epiglottis
* Life threatening airway obstruction
31
**Epiglottitis: Etiology/Patho**
* Infection: essentially cellulitis
* Viral or Bacterial
* Healthy children = bacterial: Haemophilus influenzae B (Hib) MCC: vaccine
* Other bacteria: staph, Group A strep, MRSA
* Adults: broad range of viruses or bacteria
* Trauma: foreign body, caustic ingestion
32
Epiglottitis Incidence
* Declined rapidly after Hib vaccine
* Previously 5 per 100,000 children
* Now 0.6 to 0.8 per 100,000 children
* 1.6 cases per 100,000 adults
33
Epiglotitis Clinical presentation (signs and symptoms)
Medical Emergency!
Objective: make diagnosis before airway obstruction occurs
Young Children:
* **3 D’s: Dysphagia, Drooling, Distress**
* Respiratory distress, anxiety, tripod/sniffing posture, drooling
* No cough typically
* Sudden onset high fever
* Appear toxic
* “hot potato voice” muffled speech
Adults:
* Rapidly developing sore throat ***or***
* Odynophagia is _out of proportion_ to clinical findings
Physical Exam:
* Stridor
* Oropharynx benign
34
**Epiglotitis Work Up Algorithm**
**Likely**?
* Stridor, distress
* Get experts stat! ENT + Anesthesia + Intensivist
**Unlikely**?
* Mild symptoms; no stridor or distress
* Lateral neck radiographs
* Direct pharyngoscopy (tongue blade)
* Fiberoptic visualization (expert still needed)
35
**Epiglottitis DDx**
* Croup (laryngotrachetitis)
* Uvulitis
* Peritonsilar/Retropharyngeal Abcesses
* Foreign body
* Angioedema
* Diptheria
36
Epiglotitis Dx
* Blood cultures
* 70% of Hib in children
* 0-17% in adults
* Throat cultures: negative
* Epilglottic culture: 33-75%
* Direct Visualization!
* Fiberoptic Laryngoscopy
* CBC
* Lateral Neck X-ray
* You’ll see a thumb print sign on Xray
37
epiglotitis tx
* #1: Airway Maintenance
* Experts! ENT + Anesthesia + Intensivist
* Location of intubation?
* Milder Cases? Observe in ICU
* Daily direct visualization
* Antibiotics:
* 3rd gen Ceph: ceftriaxone or cefotaxime AND
* Antistaph: vanco (if MRSA likely)
* Duration: 7-10 days
* **\*Steroids? No benefit, no longer recommended**
* **\*Racemic Epinephrine? Not helpful**
* Afterwards?
* Immune Deficiency workup if vaccinated
38
epiglititis mortality
* Children \< 1%
* Adults \< 3.3%
* Death is due to airway obstruction
* Most occur en route to hospital or soon after arrival
39
Bronchiectasis: CF
* Most common cause
* 30,000 in US
* Caucasian/Northern European Descent
40
CF: Etiology
* Mutation to large gene on chromosome 7
* CFTR (cystic fibrosis transmembrane conductance regulator)
* Changes the electrolytes in the respiratory epithelium (Na/Cl)
* Leads to thicker secretions in the airways
* Recurrent infections
41
Bronchiectasis: PREVALENCE
* Difficult to assess
* Estimated 110,000 in US
* Increases with age
* Require extensive healthcare resources
42
Bronchiectasis: Pathophys.
* Two factors
* Infectious insult
* Host defense defect, impaired drainage, airway obstruction
* Response causes inflammation, edema, cratering, ulceration, neovascularization of airways
* Permanent dilation, destruction of major bronchi and bronchiole walls
* Recurrent infections leads to further scarring
43
Bronchiectasis - Etiology
* \*First step, figure out cause of bronchiectasis if able
* Post-obstructive PNA
* Airway obstruction
* Foreign body aspiration
* Carcinoid Tumor
* Chronic Aspiration
* Immune Deficiency
* Hypogammaglobulinemia
* Low levels of IgG, IgA, IgM
* Can get replacement therapy (IVIG)
* Immunosuppression (transplant)
* Cystic Fibrosis
* 7% diagnosed in adulthood
* Upper lobe involvement
* Young’s syndrome
* Bronchiectasis, sinusitis, obstructive azoospermia
* Decline, close to nonexistent
* Young’s related to mercury
* Rheumatic Disease/Autoimmune
* RA, sjorgren’s syndrome
* Dyskinetic cilia
* Primary Ciliary Dyskinesia
* Pulmonary infections
* Nontuberculous Mycobacterial infection
* MAC
* Enlarged lymph nodes/damaged airways
* AIDS patients
* Mycoplasma
* GERD association/?Causal
* Allergic bronchopulmonary aspergillosis (ABPA)
* Asthma resistant to bronchodilator
* Central airway bronchiectasis
* Hyperimmune response
* Smoking: no true causation found although patients with COPD or reduced lung function may accelerate disease
* Tracheobronchomalaci
44
Bronchiectasis – signs/symptoms
* Frequent “bronchitis”/cough
* Months to years
* Daily cough of purulent sputum
* Thick sputum
* Hemoptysis – can be massive in acute infection with injury to superficial mucosal neovascular bronchial arterioles
* Pleurisy
* Shortness of breath
* Single episode of severe infection also possible presentation
45
Bronchiectasis – physical exam
* Crackles
* Rhonchi
* Wheezing
* Digital clubbing is rare – 2%
46
Bronchiectasis - CXR
* Platelike atelectasis
* Dilated thickened airways (tram or parallel lines, ring shadows on cross-section)
47
Bronchiectasis - HRCT
* HRCT (high resolution computed tomography)
* 1.0 – 1.5 mm cross sectionals
* Airway dilation
* Tram lines
* Lack of tapering airways toward periphery
* Bronchial wall thickening
* ‘Tree-in-bud”: linear branching markings
* Varicose constrictions
* Ballooned cysts at the end of the bronchus
48
Bronchiectasis: WORK UP
* HRCT
* Sputum Culture
* Swallow evaluation
* Autoimmune panel
* Bronchoscopy with BAL, biopsy if able
* Ig Levels (all classes and subclasses)
* Alpha1 Antitrypsin
* Test for CF in right patient groups
* Aspergillus IgE and IgG
* Spiro with Pre and Post Bronchodilator
* 6MWT
* PPD
49
Bronchiectasis – bronchoscopy
* Identify obstruction
* Foreign body, tumor, structural deformity, extrinsic compression by lymph nodes
* Broncheoalveolar lavage (BAL)
* Confirms Mycobacterium avian infection (MAI)
* Biopsy can confirm ciliary dyskinesia
* Can localize bleeding
50
Bronchiectasis – PFT/Spiro
* Provides a functional assessment
* Obstructive impairment most common, but sometimes low FVC is seen in advanced disease
* low FEV1
* preserved FVC
* FEV1/FVC ratio \< 70%
* \*Most commonly obstructive but you can see restrictive as well
* \*Not a specific test
51
DDX - Bronchiectasis
* Acute Bronchitis
*
