Lecture 22 Repiratory infections Flashcards
How are respiratory infections usually transmitted?
Airborne transmission (droplets between humans
What are the portals of entry for respiratory infections?(3)
Conjunctiva(eye); Nose; mouth
Structures commonly involved in Lower Respiratory Tract (LRT): (5)
Larynx (voice box); Bronchi; Bronchioles; Alveoli; Pleura (membranes surrounding lungs)
Structures commonly involved in Upper Respiratory Tract (URT):
Conjunctiva(eye); Tear ducts (nasolacrimal duct); Middle ear; Sinuses; Mastoid air cell; Nose; Throat
What defenses do our bodies have to protect against respiratory tract infections?
Mucociliary escalator: Mucus;Goblet cells;Cilia
Rheumatic fever
Inflammation and damage of tissue in joints; heart; skin and brain; Onset occurs 3 weeks after recovery from strep throat;Pathogenesis is poorly understood.
Upper Respiratory Tract Diseases (3)
Strep Throat; Common cold; Otitis media (middle ear infections)
Strep Throat (Streptococcal Pharyngitis) Etiology; Pathogenesis; Symptoms
- Etiology : Group A Streptococcus pyogenes (GAS) (Gram+ coccus); ?-hemolytic 2. Pathogenesis Strep throat and possible complications caused by virulence factors; inc. toxins 3. Symptoms : Sore throat; Difficulty swallowing; Fever; Redness in throat; Patches of pus; Enlarged and swollen lymph nodes in neck
Strep Throat (Streptococcal Pharyngitis) Epidemiolody; Treamtment; Prevention and complications
- Epidemiology Transmitted by direct contact; droplets; ingestion of contaminated food; Seasonal; (winter and spring); Asymptomatic carriers 5. Treatment Penicillin or erythromycin(10 days) 6. Prevention Avoidance of crowding; adequate ventilation 7. Possible complications ; Scarlet fever; Rheumatic fever
Common cold Etiology
> 100 types of rhinoviruses (30-50%);Other viruses; Sometimes bacteria (10%)
Common cold Pathogenesis
Infected cells die and slough; Sloughed cells stimulate nasal secretions; swelling and sneezing
Common cold Epidemiology
Viruses specific to humans; Americans have on average 2-3 colds a year; Transmitted by inhalation of airborne droplets; contact with nasal secretions; Seasonal (winter)
Common cold Treatment
Self-limiting within 1 week
Common cold Prevention
not practical; hand washing and keeping hands away from face; not having people cough on you
Otitis media (middle ear infections) Etiology and Pathogenesis
Etiology Streptococcus pneumoniae (Gram+ coccus); Hemophilus influenzae (Gram- rod); Other bacteria ; Some viruses Pathogenesis Often associated with nasal infection; Pressure behind eardrum
Otitis media (middle ear infections) Symptoms and Epidemiology
1)Symptoms Pain in eardrum; bulging eardrum 2)Epidemiology Asymptomatic carriers 85% of people get 1 ear infection a year
Otitis media (middle ear infections) Treatment and Prevention
1)Treatment Tubes if recurrent 2)Prevention influenza vaccines Removal of adenoids
Lower Respiratory Tract diseases 3
Pneumonia; Tuberculosis; Influenza
Pneumonia Etiology
Streptococcus pneumoniae (Gram+ coccus): pneumococcal pneumonia-most common Other bacteria inc. Mycoplasma pneumoniae: walking pneumonia; Various viruses; fungi
Pneumonia Pathogenesis
Infection develops when bacteria are inhaled into alveoli; Fluid; inflammation in alveoli
Pneumonia Symptoms and Epidemiology
1)Symptoms- Cough; Fever; Chest pain; Sputum production 2)Epidemiology - Disease of immune compromise; Asymptomatic carriers; Damage to mucociliary elevator allows bacteria to reach lungs
Pneumonia Prevention and Treatment
1)Prevention Polysaccharide vaccine; Prevention is aided by vaccine; Gives immunity to 23 strains; Conjugate vaccine against 7 types is available for infants 2)Treatment: Antibiotic treatment is generally successful if given early;Penicillin and erythromycin; More strains are becoming antibiotic resistant
Pneumonia Possible complications
Septicemia; Endocarditis; Meningiti
Tuberculosis Etiology
Tuberculosis Etiology - Mycobacterium tuberculosis (acid-fast rod)(Stains Red) ;Slow growth (12 hrs. generation time); Mycolic acid(resistant to most treatment)
