Lecture 3: Lower Respiratory Infections Flashcards
What environmental factor is one of the biggest contributors to childhood cough?
Secondhand smoke/air pollution
What CV symptoms could result in cough?
- Chest pain
- Dyspnea
- Palps
What are the 4 aspects of a respiratory exam?
- Inspection
- Palpation
- Percussion
- Auscultation
What are the 3 primary etiologies of acute bronchitis?
- Bacterial/viral infection
- Heavy smoking
- Allergy
What qualifies as acute bronchitis?
- 5-30 days
- Self-limiting inflammation of the bronchus
90-95% are viral in nature.
What is the pathophysiology of acute bronchitis?
- Infection of conducting airway
- Inflammation of airway
- Exudate production
- Bronchospasms
What are the two phases of acute bronchitis pathophysioogy?
- Direct inoculation of tracheobronchial epithelium (typical symptoms)
- Hypersensitivity of airway receptors (persistent symptoms, such as sputum production)
What are the main bacterial causes of acute bronchitis?
- Strep pneumo
- H flu
- M cat
What is the primary atypical that causes acute bronchitis?
Bordetella pertussis
Also has a similar strain called bordetella bronchiseptica (kennel cough)
What is the primary viral cause of acute bronchitis?
Influenza A/B
If a patient has no cough, can they still have acute bronchitis?
Yes
What are the primary symptoms of acute bronchitis?
- Cough (nonproductive/mucopurulent)
- Substernal pain
- Wheezing
- Minor fever (38.3-38.9)
- Fatigue
- Malaise
- Chest tightness
- SOB
- Dyspnea
- PND
- Cyanosis
No URI symptoms like coryza or congestion
What are the general PE findings for acute bronchitis?
- Cough w or w/o bronchospasm
- Wheezing variable (wheezing might be bronchiolitis)
- Rhonchi (clears with cough)
- Sputum variable
- Fever
- Chest wall tenderness
- Symptoms suggestive of URI
Rales/crackles does not clear with cough.
Define stridor vs wheezing
- Stridor is inhalation (#1 is croup, #2 is foreign body)
- Wheezing is exhalation
Stridor implies an obstructed airway.
What does a sustained heave across the left sternal border suggest?
RVH secondary to chronic bronchitis.
What does clubbing of the digits and peripheral cyanosis suggest?
Cystic fibrosis or chronic bronchitis
What does bullous myringitis have as an atypical cause?
Mycoplasma
What virus can cause conjunctivitis, adenopathy, and rhinorrhea?
Adenovirus
What would suggest a LRI is pneumonia over acute bronchitis?
- Fever (acute is low fever)
- Productive cough w/ sputum
- Isolated crackles/rales
- Chest pain
- Tachycardia
What are the emergent DDx for acute bronchitis?
- PNA
- PE
- Pulmonary edema
- Status asthmaticus
- Pneumothorax
- Foreign body aspiration
- CHF
How do we diagnose acute bronchitis?
Clinical exam, since CXR is probably going to be inconclusive or unremarkable.
CXR is mainly for infants, elderly, or an unclear exam.
What lab would suggest bacterial vs non-bacterial etiology for acute bronchitis?
Procalcitonin
Elevated above 0.5mcg = ICU and highly likely to be bacterial.
Greater than 0.25mcg suggest bacterial.
How does CBC w/ diff typically present for a viral acute bronchitis?
Normal to low, since viral.
What are the two indications for sputum culture?
- PNA pt being admitted to hospital.
- PNA pt failing standard therapy.
What are the recommended treatments for acute bronchitis?
- Supportive
- Antitussives/expectorants
- Antihistamines
- Decongestants
- B2 agonists for wheezing.
If cough > 2 weeks with no improvement, consider ABX.
What is dextromethorphan’s class and MOA?
Delsym, Robitussin
Centrally-acting non-opioid that elevates the threshold to cough.
It is an antitussive.
Equal efficacy to codeine for cough.
What happens if dextromethorphan is taken in high dosages?
Dissociative hallucinogen effects, similar to ketamine.
DXM junkie
What age is dextromethorphan contraindicated in?
Ages 4 and under.
How are codeine and dextromethorphan similar and different?
Codine is an opiate, whereas DXM is not.
Both have similar antitussive effects and efficacy.
Codeine has many more drug interactions than DXM.
What is benzonatate’s drug class and MOA?
Tessalon pearls
Peripheral acting antitussive derived from procaine (anesthetic)
Hinders the sensation to cough by numbing pulmonary stretch receptors.
What is the main counseling regarding benzonatate?
DO NOT CHEW
Cannot be used in children under 10.
What is guaifenesin’s drug class and MOA?
Mucinex, Tussin
It is an expectorant that reduces chest congestion by increasing mucus secretion and sputum volume to clear up the airways.
Lower sputum viscosity so you can cough it out better.
What is the only contraindication to guaifenesin?
Allergy
What kind of virus is influenza?
Encapsulated single-stranded RNA.
What are the two surface proteins that are significant to the influenza virus’s virulence?
- Hemagglutinin: binds to respiratory epithelial cells
- Neuraminidase: cleaves bonds to allow infection to spread
When is influenza transmissible?
1 day prior to onset to 10 days.
Most virulent in first 3 days.
What is the most pathogenic strain of influenza?
Influenza A
What are the common symptoms of influenza?
- Fever, HA, fatigue
- Sore throat, rhinorrhea, nasal congestion
- Cough, dyspnea
- N/V/D
- Myalgia, joint pain, body aches
What are the common signs of influenza?
- Lethargic
- Clear lungs 9/10 (could hear bilateral rales rarely)
What is the standard for confirming the presence of a flu virus?
- RT-PCR
- Viral culture of NP or throat secretions
What might prompt us to order a CXR for influenza?
- Presence of rales on PE
- R/o pneumonia.
What CBC findings are typical of influenza?
- Leukopenia
- Lymphocytopenia
How should influenza be managed?
- Supportive care
- NSAIDs and acetaminophen
- Antivirals
What antivirals are indicated for influenza management?
- Tamiflu/oseltamivir 75mg BID x 5 days
- Zanamivir/Relenza Inhaler
- Rapivab/peramivir IV
- Baloxavir marboxil/Xofluza for high-risk.
Active against both strains if given within 48hrs of onset.
Also works vs H1N1
All of these are neuraminidase inhibitors.
How long does it take the flu vaccine to being working well?
10-14 days.
What is the current standard flu vaccine?
Quadrivalent flu vaccine
2 strains of A, 2 strains of B
What is flumist?
Live, attenuated virus.
Only for use in healthy 2-49.
Why is pertussis such an important vaccine?
Pertussis is highly contagious and can be fatal in < 2yo.
What are the two causative organisms for pertussis and what kind of bacteria is it?
- Bordetella pertussis and parapertussis.
- Gram-neg, aerobic, encapsulated, coccobacilli
How does bordetella pertussis work?
- Toxin B which attaches to cell surface.
- Toxin A which inactivates cAMP regulation.
Increased mucus production and decreased phagocytic activity, aka can’t get rid of the bacteria.
Describe the 6 week disease course of pertussis.
Exposure/Incubation (4-24 days)
- Stage 1: Catarrhal stage (1-2 weeks)
- Stage 2: Paroxysmal stage (1-10 weeks)
- Stage 3: Convalescence stage (2-3 weeks)
How does the catarrhal stage of pertussis typically present?
Viral URI symptoms
How does the paroxysmal stage of pertussis present?
- Paroxysms of intense coughing, aka the whooping.
- Posttussive vomiting and turning red from couging.
The iconic stage that whooping cough is named for.
How does the convalescence stage of pertussis present?
Chronic cough lasting for weeks.
If a patient tests positive for pertussis, what should we document?
Must submit a report to health department so they can screen all contacts.
What are some PE findings that are specific to pertussis?
- Coughing spells/incessantly
- Facial petechiae from coughing
Infants < 3mo have more gasping and reddened face over coughing.
What criteria should make us highly suspicious of whooping cough?
- Cough > 2 weeks
- Posttussive emesis
- Endemic areas
- No vaccination history.
How does a CXR for pertussis present?
Clear
What CBC findings are typical of pertussis?
- Leukocytosis
- Lymphocytosis
What is the gold standard to diagnose pertussis?
Bacterial culture of NP secretions.
What diagnostic testing has the smallest window to obtain samples to diagnose pertussis?
Cultures must be done within 3 weeks of onset.
Also must be done before ABX given.
What would be elevated in a serological test for a positive acute pertussis patient?
IgM
What is the preferred drug class to treat pertussis? Alternative?
Macrolides, preferably Azithromycin in infants under 1mo.
Bactrim is alternative, unless under < 2mo.
Must be started early to reduce symptom severity.
Who should be treated for pertussis?
Current sick patient and ALL close contacts.
What are the contraindications to azithromycin?
QT prolongation or proarrhythmic conditions.
What is the main complication we are concerned about with pertussis in infants?
Pneumonia
Inability to cough out sputum properly.
When is Tdap indicated vs DTap?
Tdap is for 11+ years old and for pregnant women.
DTap is for 2,4,6, 15-18, and 4-6y.
Pertussis vaccine may only last 5 years.