Bacterial Respiratory Infections Lecture 18

Question 1

Background and organisms

Answer 1

• Presence of increased calcitonin signals bacteral etiology and not viral IL-1 induced calcitonin release.
• Step pneumo is the most common in all scenarios. Mycoplasma pneumonia is also very common in ambulatory. Can be legionella, especially in more severe. Chlamyida, H flu, other gm -,

Question 2

Strep Pneumo

Answer 2

• Most common cause in all scenarios
• Gm + lancet shaped diplococci
• Aids patients and asplenic patients are at increased risk. (all encapsulated bacteria)
• Often presents as lobar pneumonia, pain, chills, fever
• Polysacharide coat is major virulence factor.
• Currently vaccine for pneumococcal pneumonia. Poysacharide for adults and polysacharide attached to toxoid for infants.
• Many are susceptible to penicilin and is first line therapy, otherwise cephalosporins etc.

Question 3

Curb 65

Answer 3

• Confusion
• Urea (Renal dysfunction)
• Respirations (tachypnea)
• Blood Pressure (Hypotension)
• 65+
• 1 is mild, 3 is severe (ICU)

Question 4

Empyema

Answer 4

• Diffuse inflammation of pleural space, blurred costophrenic angle.
• Staph or strep pneumo
• Must drain and then treat with antibiotics. Broad spectrum (3rd gen cephalosporins)

Question 5

Abcess

Answer 5

• Always think TB on chest X-Ray abcess
• Anaerobic or gm negative
• Treat with broad spectrum antibiotics.

Question 6

Bordetella Pertussis

Answer 6

• 3 stages: Catarhall appears like a cold but is most infective and culturable stage. Cough stage is next and then convalesence.
• Highly communicable in respiratory droplets
• Gram negative rod
• Exotoxin increases cAMP and destroys ciliated epithelial cells.
• Must be cultured on calcium alginate swa gathered from nasopharynx
• Vaccination with acellular pertussis.
• Increasing prevalence due to adults infecting children, boosters are recommended for adults.
• Tx macrolides

Question 7

Aspiration Pneumonia

Answer 7

• Community acquired look for smell and may be anaerobes (Swallowing problem, PPI)
• Hospital acquired is most likely gram negatives (e coli, kleibsella, pseudomonas)
• Treat with broad spectrum and include metronidazole or anaerobe for CA

Question 8

Legionella

Answer 8

• Airborne source
• Pneumonia with cough, fever, chills, but also GI involvment
• Facultative intracellular
• Elderly, smokers/COPD
• Cultured on BCYE

Question 9

Mycoplasma

Answer 9

-Walking pneumonia, less severe
-Often presents as diffuse bronchial pneumonia.
-Cold agglutinins
Bullous Myringitis is pathoneumonic.

Question 10

Chlamydia psitcci

Answer 10

-Look for exposure to birds.

Question 11

Coxellia Burnetti

Answer 11

• Q fever, transported by placenta of goats/cattle/sheep

- Endospore, rickettsia

Question 12

Tularemia

Answer 12

-From rabbits

Question 13

Hospital Acquired

Answer 13

• Pseudomonas is very common along with other gram negatives

- Kleibesella, E coli

Question 14

Elderly

Answer 14

-Often present afebrile and have a worse porgnosis

Question 15

AIDS

Answer 15

• 10-20x increased risk of strep pneumo

- Pneumocystis jarovecii is a fungus that classically causes pneumonia.