Infectious Diseases Flashcards
acute bronchitis
-Self-limited inflammation of large airways -> cough without pneumonia
- ≈10% ambulatory care visits -> increased winter and fall
-Viruses most common:
-Influenza A and B
-Parainfluenza
-Coronavirus (types 1-3)
-Rhinovirus
-RSV
pathophysiology acute bronchitis
-inflammatory response to infections of epithelium of the large bronchi
-inflamed areas of bronchial and tracheal mucosa thicken
-wide variations in anatomical distribution of many pathogens that cause acute bronchitis
-flemy cough (the epithelium)
acute bronchitis symptoms
-Primary manifestation is cough +/- sputum
-50% purulent sputum
-Sloughed tracheobronchial epithelium and inflammatory cells
-Coughing persisting >5 days is suggestive rather than URI -> prolonged cough*
-signs- +/- wheezing and rhonchi**
PFTs: acute bronchitis
-generally not indicated
-may become abnormal
-significant reductions in FEV1 -> obstructive pattern
-bronchial hyperreactivity
bronchitis/pneumonia lung sounds
-bronchitis- lung sounds (rhonchi) clears with a cough -> airway issue
-pneumonia- lung sounds dont clear with cough -> alveolar or interstitial issue
diff dx bronchitis
-URI- runny nose, sneezing, scratchy throat, headache
-bronchitis- no fever or systemic signs, no consolidations
-pneumonia- fever, consolidation
-post nasal drip- runny nose, need to clear throat
-GERD- heartburn, regurgitation, dysphagia
-asthma- wheezing, SOB, allergen exposure or exercise
-ACE inhibitors- nonproductive cough, scratchy throat
-heart failure- SOB, orthopnea, gallop rhythm, peripheral edema
-pulmonary embolism- tachy, SOB, pleuric chest pain, hemoptysis
-lung cancer- smoking hx, hemoptysis
acute bronchitis dx
-physical exam!
-cough WITHOUT fever, tachycardia and tachypnea suggests bronchitis, rather than pneumonia
-normal vital signs
- no rales and egophony (e sounds like A, 99 sounds like yelling)
-chest x-ray- if cant distinguish by physical exam
Acute bronchitis rapid tests
-Rapid dx tests for several pathogens linked to acute bronchitis -> COVID-19, Influenza, RSV
-Rapid tests should be used if:
-Suspected organism is treatable
-Infection circulating in the community
-pt has suggestive symptoms or signs
treatment of acute bronchitis
-Antimicrobial agents are NOT recommended in most acute bronchitis ** -> Supportive Care
-Antimicrobial therapy beneficial if treatable pathogen ID: Influenza agents, Pertussis, COVID-19
-inhaled or oral corticosteroids for 7-14 days -> reasonable for troublesome cough (cough for more than 20 days)
-mucolytic or antitussive agents
influenza
-Orthomyxovirus
-Highly contagious disease
-Transmitted by respiratory route via droplet nuclei
-Epidemics and pandemics appear at varying intervals, usually in fall or winter
-Affecting 10–20% of global population on average each year
Influenza incubation and types
-incubation period/viral shedding average 2 days -> contagious
-more contagious when symptomatic
-antigenic types: A and B produce clinically indistinguishable infections -> C is usually minor
influenza 2022-2023
-In US there were
-26 to 50 million illnesses
-12 to 24 million medical visits
-290,000 to 670,000 hospitalizati
influenza signs and symptoms
-ABRUPT onset of fever, headache, myalgia*, arthralgias, malaise
-Cough, sore throat (no rales/crackles)
-Other presentations:
-Afebrile respiratory illnesses similar to common cold
OR
-S&S with little indication of respiratory tract involvement
-physical findings are FEW in uncomplicated -> hot and flushed, oropharyngeal hyperemia, mild cervical lymphadenopathy, respiratory exam generally unremarkable
influenza diff dx
-Common cold
-Primary bacterial pneumonia
-Infectious mononucleosis
-Mycoplasma infection
-Early Legionnaires
-Chlamydophila pneumoniae infection
-Acute HIV infection
-Meningitis
-RSV, COVID
influenza dx/labs
-labs = not helpful
-leukopenia is common
-x-ray normal in uncomplicated illness
-Rapid lab tests for influenza antigens from nasal or throat swabs are widely available
-Reverse-transcriptase polymerase chain reaction (RT-PCR) is the most sensitive and specific modality
influenza maincomplication and risk group
-Pneumonia (MC)
-High risk groups:
-Cardiovascular or pulmonary ds
-Diabetes mellitus, renal disease, hemoglobinopathy, or immunosuppression
-Nursing homes or chronic care facilities
-Over age 50, pregnant, young kids
primary viral pneumonia
-from the influenza
-is the flu itself
-not alveoli affected -> interstitial tissue is affected
-Symptoms persist and increase **
-High fever, dyspnea, and progression to cyanosis can be seen
-x-ray - hazy everywhere; interstitial (not focused to an area)
secondary bacterial pneumonia
-from bacterial infection not from flu -> flu is getting better and then bacterial infection -> relapse (get better then worse)
-in addition to the viral flu
-Relapse **
-Higher fevers, cough, purulent sputum, and pulmonary infiltrates* (alveolar) on cxr
-consolidation
-Streptococcus pneumoniae (MC)
-Staphylococcus aureus(2nd MC): much worse infection
-H. influenzae
influenza complications
-pneumonia
-Acute sinusitis
-Otitis media
-Myositis
-Rhabdomyolysis
-Pericarditis
-Myocarditis
-Reye syndrome**- assoc with kids and aspirin use -> dont give aspirin to kids -> encephalopathy
-flu + aspirin = assoc with reye syndrome
prevention of influenza
-The trivalent inactivated influenza virus vaccine provides partial immunity (about 85% efficacy) for a few months to 1 year.
-3 formulations
-October and November
-immunity about 2 weeks after vaccine
-Vaccine recommended FOR ALL > 6 mos of age
-immunity takes about 2 weeks after vaccine
-Especially:
-50 & older
-Children receiving long-term aspirin therapy
-Nursing home residents
-Patients with chronic medical problems
-Including lung or heart disease, diabetes, renal failure and immunodeficiencies (such as HIV); pregnant
-Contacts of these high-risk groups including health care workers, service personnel, and caretakers of children younger than 2 years
influenza:chemoprophylaxis
-oseltamivir**, zanamivir, baloxavir
-given to high risk OR unvaccinated individuals if begun within 48 hours after influenza exposure
influenza treatment
-Bedrest, Analgesics (no ASA)
-Cough meds
-The neuraminidase inhibitors:
-Zanamivir (two 5mg inhalations twice daily for 5 days) - cant give to pts with asthma
-Oseltamivir (75 mg twice daily for 5 days) -> tamaflu
-Baloxavir (40 mg single dose*)
-Most effective when within 48 hrs of symptom onset
who to treat: influenza
-Illness requiring hospitalization
-Progressive, severe, or complicated illness, regardless of previous health or vaccination status
-High risk pts: children under 2, over 65, comorbid ds, immunosurpressed, ASA users
influenza prognosis
-Duration of uncomplicated illness is up to 7 days
-Prognosis is excellent in healthy, nonelderly adults
-Most fatalities are due to bacterial pn (secondary):
-Pneumococcal pneumonia MC
-Staphylococcal pneumonia most severe
bordetella pertussis infection
-whooping cough
-Acute infection of respiratory tract by B pertussis
-Transmission: respiratory droplets
-Incubation period: 7–21 days
-50% < 2yo
-Adults are important reservoir (waning immunization)
-vaccine or past disease does not give lasting immunity to pertussis**
bordetella pertussis stages
-symptoms of classic pertussis last about 6 weeks
-divided into 3 consecutive stages
-1. Catarrhal stage- feels like a respiratory infection
-2. Paroxysmal stage- whooping cough
-3. Convalescent stage- recovery
bordetella pertussis: Catarrhal stage
-7-10 days
-insidious/gradual onset
-Lacrimation, sneezing, coryza, anorexia, malaise, and hacking night cough that becomes diurnal (during day) -> like URI
bordetella pertussis: paroxysmal stage
-1-6 wks but up to 10
-fits of coughing that you need to gasp for breath
-Bursts of rapid, consecutive coughs followed by a deep, high-pitched inspiration (whoop), posttussive emesis & fatigue
-“whoop”: coughing so much that they are SOB and take a deep high pitched breath (whoop)
bordetella pertussis: convalescent stage: 1-3 weeks
-Decrease in frequency and severity of paroxysms of cough
bordetella pertussis: diff dx
-The differential diagnosis of a prolonged cough includes:
-1. Viral infections — Adenovirus, Parainfluenza virus, Influenza A and B, Respiratory syncytial virus, Coronavirus, Rhinovirus
-2. Bacterial infections — Bordetella parapertussis, Bordetella bronchiseptica, Chlamydophila (formerly Chlamydia) pneumoniae, Mycoplasma pneumoniae, tuberculosis, acute exacerbations of chronic bronchitis
-3. Noninfectious causes — Asthma, foreign body, postnasal drip, GERD, and malignancy
bordetella pertussis labs and CXR
-WBC usually 15,000–20,000/mcL
-CXR: Subtle changes
-Peribronchial cuffing (walls of bronchi are edematous -> donut sign), perihilar infiltrates, interstitial edema, or atelectasis
-Pulmonary consolidation (20 %)
-primary or Secondary bacterial pneumonia
bordetella pertussis complications
-Pneumonia (primary and secondary)
-Reactive airway disease
-Lumbar strain, rib fracture, inguinal hernia
-Syncope, pneumothorax/pneumomediastinum
-Subconjunctival hemorrhage, subdural hematoma
-Encephalopathy (secondary to diffuse hypoxia)
-Seizures
-Wt loss/failure to thrive
-Pulmonary hypertension
-Hearing loss
pertussis diagnosis
-Diagnosis: combinations of diagnostic tests to identify persons with pertussis, based upon the duration of cough
- Wk 0-2: culture + PCR
- Wk 2-4: PCR + serology
- Wk 4+: serology
pertussis prevention
-Acellular pertussis vaccine: infants, combined with diphtheria and tetanus toxoids (DTaP)
-Booster vaccination: for adolescents/adults
-Post exposure prophylaxis with an oral macrolide (azithromycin/Z-pack)
-Even if vaccinated*
tx and post exposure tx for pertussis
-adults - ZPAC- azithromycin
respiratory panel
-done in ER usually bc expensive
-tests for various diseases
-viruses- pertussis, RSV, influenza
-bacterial- mycoplasma pneumonia, chlamydophila pneumonia
