Summarizing Cases: Lower Respiratory Disease

Question 1

1. List the common etiologic agents causing pneumonia in the elderly and the predisposing factors of exposure for each.

Answer 1

most common in elderly 
Klebsiella- drinking
S. pneumonia- CAP
M. pneumoniae- CAP
H. influenza- CAP
several viruses: influenza

Legionella- water from air conditioners, showers or hot tubs, immunosuppressed, compromised lung function

Question 2

2. Associate the clinical signs/symptoms and laboratory tests that allow diagnosis for each of
   the above agents.

Answer 2

S. pneumonia: gram stain, urine antigen test
Klebsiella- mucoid colonies, urine antigen test
H. flu- non-typable
dx: sputum samples are no longer routinely recommended, in patients gram stain and culture are still recommended

Mycoplasma: mild , dry cough (dx. serology), cold agglutinins (before specific Ab)
Chamydaphila: clinical diagnosis, DFA- rise in antibody titer
Legionella: culture on BCYE, urine antigen testing

viral, atypicals: interstial CXR
typical: lobar CXR

blood culture may be indicated in more severe/refractory cases

consider wet prep and fungal culture for coccidioides
TB skin test
flu rapid test

Question 3

3. List and explain the major approaches to diminishing the incidence of lower respiratory disease in the elderly and explain why such measures are of limited usefulness.

Answer 3

atypical: doxycycline, a macrolide, fluoroquinolone
Washing hands
stay home when you’re sick
immunizations: H. flu, S. pneumonia, Influenza, TB

Question 4

4. List the common etiologic agents causing pneumonia in infants and young children and explain the potential of immunization with currently available vaccines for decreasing the incidence of each.

Answer 4

S. pneumoniae: culture
H. Flu type b: culture
viral (respiratory syncytial virus, adenovirus, influenza and parainfluenza virus)
RSV: young boys esp; dx with DFA

Question 5

5. Discuss the pros and cons of immunizing children and the elderly to prevent lower respiratory tract infections caused by influenza, Mycobacterium tuberculosis, and Streptococcus pneumoniae.

Answer 5

pros: often low side effects, decrease transmission, fewer lost school/works, less severe disease
cons: variable levels of protection (antigenic variation), egg allergy, expensive; PPD positivity, if not killed can revert back to infectious disease