Lower Respiratory Tract Infections Flashcards
Common Infectious Agents
- Rhinoviruses: (cold; exacerbations of asthma or chronic bronchitis; pneumonia in children)
- Coronaviruses: (cold; exacerbations of asthma or chronic bronchitis; pneumonia and bronchiolitis; specific serotype caused SARS)
- Respiratory syncytial virus: (pneumonia and bronchiolitis; croup: LTB (larygotracheobronchitis); cold; pneumonia in geriatric and immunocomprised)
- Parainfluenza viruses: (croup, bronchiolitis, bronchitis, pneumonia; pharyngitis and cold)
- Adenoviruses: (cold and pharyngitis (peds), often with conjunctivitis; pneumonia in peds and immunocompromised)
- **Influenza A: ** (influenza; pneumonia)
- **Influenza B: ** (influenza; cold; pharyngitis; pneumonia, diarrhea)
- **Enteroviruses: ** (febrile illness; cold; pharyngitis; pneumonia)
- **Herpes Simplex Viruses: ** (pharyngotonsillitis; tracheitis and pneumonia in immunocompromised)
- Streptococcus pneumoniae
- Mycoplasma pneumoniae
- Chlamydophila pneumoniae (formerly Chlamydia species)
- Haemophilus influenza (“H. flu” not influenza; type B and non-typable)
- Pneumocystis jirovecci (formerly P. carinii)
Less Common Infectious Agents
- Mycobacterium tuberculosis
- Legionella pneumophila (and other species)
- Moraxella catarrhalis
- Histoplasma capsulatum
- hantavirus
- metapneumovirus
- cytomegalovirus
- Bacillus anthricis (anthrax)
- Yersinia pestis
Bacterial Tracheitis
Predominantly pediatric disease because of shape of subglottic airway–cricoid cartilage is narrowest portion of trachea
Has prodome similar to URI
Acute or subacute
Bacterial Tracheitis Etiology
MC: M. catarrhalis
Also: S. aureus, S. pyrogenes
Bacterial Tracheitis PE
Stridor
Hoarseness
Croupy cough
Respiratory distress
Sore throat
No positional changes of comfort
Bacterial Tracheitis Diagnostics and Management
Labs: elevated WBC; blood cultures; gram stain of sputum
Laryngotracheobronchoscopy only definitive means of diagnosis
Send to hospital: maintain airway and IV antibiotics
Acute Bronchitis
Inflmmatory process that may be caused by infection
Cough with purulent sputum production
Other sxs may include: rhinorrhea; nasal congestion; fever; mylagias and arthrlagias; dyspnea or SOB; sore throat
Acute Bronchitis PE
May have ronchi, wheezing, coarse breath sounds
Often unremarkable
Etiology of Acute Bronchitis
Numerous viral causes, often seasonal.
M. pneumoniae, C. pneumoniae, S. pneumoniae, H. flu, B. pertussis
Treatment and Complications for acute bronchitis
Supportive treatment
Inflammation of bronchial mucosa: corticosteroids
Mucus retention: water dilutes secretions
Airway reactivity: beta agonist or anticholinergic
Copmlications: pneumonia, chronic bronchitis, bacterial superinfection, reactive airway disease
Pneumonia Classification (3)
Community Acquired
- Treated as outpatient
- Treated as inpatient
Nosocomial pneumonia
- non-ventilator dependent
- ventilator dependent
PORT Scoring: based on demographics (age, gender), comorbidities, physical exam findings, lab and radiograph findings
CURB-65
- Confusion
- Uremia
- Respiratory Rate >30
- Blood Pressure (hypotensive)
- >65
- If 2 admit to hospital, if 3-5 admit to ICU
Pneumonia
Lower respiratory tract infection in a person with symptoms of an acute infection, with or without infiltrate on CXR
Results in abnormal pulmonary function
Typical pneumonia etiology
Strep pneumo
Atypical pneumonia etiology
M. pneumoniae
C. pneumoniae
Legionella pneumophila
Influenza virus
Adenovirus
MC in young adults
Indications for CXR in adults
One of:
- Temperature >100
- HR > 100bpm
- RR >20
Or two of:
- Decreased breath sounds
- Crackles
- Absence of asthma
Pneumonia RFs
Recent viral infection
Hx of pneumonia
Immunosupression
Disordered swallowing (aspiration)
EtOHism
Smoking
COPD
Illicit drug use
Recent major surgery
Seizures
Hospitalization
Clinical presentation of pneumonia
Temperature >110.4
Rigors, sweats
Cough (+/-sputum, +/-hemoptysis)
Dyspnea
Fatigue
Myalgias
Pleuritic chest pain
Typically have abnormal PE
Pneumonia PE
Ill appearing
febrile
tachypnea
tachycardia
abnormal chest exam: crackles, wheezing, rhonchi, signs of consolidation; bronchial breath sounds “hollow” b/c not surrounded by aerated lung tissue
decreased O2 sat
Very young may not have pulmonary symptoms
Elderly may have a paucity of sxs; change in cognitive status
Diagnostic Factors Pneumonia
Labs: WBC, sputum gram stain, PCR, antibody titers
CXR: establish diagnosis and identify complications
Conisder CT for those whose dx is questionable
Bronchiectasis
Bronchiectasis is the consequence of inflammation most commonly caused by infection.
Inflammatory mediators are released and damage epithelium, resulting in pathologic dilation of the medium sized airways.
Dilated airways serve as a reservoir for colonization which continues the cycle
Bronchiectasis Etiology
bacterial infection
aspiration
CF
autoimmune diseases
alpha 1 antitrypsin deficiency
viral infection (influenza and adenovirus)
Bronchiectasis PE
Coarse breath sounds, rhonchi, rales, wheezing
Advanced disease: right ventricular failure, cor pulmonale (R ventricular hypertrophy), clubbing
Bronchiectasis Dx
HRCT
CXR–occasionally diagnostic
PFTs–obstructive pattern
Lung Abscess
Subacute infection of the lung parenchyma (necrotic)
MC in elderly
MC secondary to aspiration; clinically signifciant 1-2 weeks later
Can also be a seondary abscess from comorbid infection
