Lower respiratory tract infections

Question 1

Categories of pneumonia

Answer 1

Community acquired =

• acute lobar pneumonia
• atypical pneumonia - arose at the beginning of the antibiotic era

Hospital acquired pneumonia=
-been in hospital for more than 72 hours

Ventilator associated pneumonia=
-Mechanically ventilated machines that have been used for more than 48 hours

Question 2

Age ranges for community acquired pneumonia

Answer 2

-Neonates=
Group B streptococci
Listeria monocytogenes
Strep pneumonia and haemophilus influenzae - rare

-Older children=
Mycoplasma pneumoniae

-Young adults=
Mycoplasma spp
Chlamydia pneumoniae

-Older adults=
Strep pneumonia
Legionella spp

-Aspiration=
Gram negative bacilli

-CF=
Staph aureus
P. aeruginosa

Question 3

Lobar pneumonia

Answer 3

Community acquired; affects the discrete lobe and is almost always caused by streptococcus pneumoniae

Strep p - gram positive coccus found in pairs or in short chains; fastidious and only grows on media the contains blood or serum. a haemolysis but is soluble in bile and sensitive to the antibiotic optochin

85 antigenic types of Strep pneumoniae.

In 50% of cases it is associated with bacteriaemia

Treated with penicillin or erythromycin

Question 4

Bronchopneumonia

Answer 4

Diffuse lung infection and infects entirety of the lobes

Often develops after people have a virus and can be caused by S.aureus but usually S. PNEUMONIAE

Clusters of gram positive cocci

Over 80% of strains produce a B lactamase so penicillin isn’t used

Klebsiella pneumonia causes rare bronchopneumonia often seen in alcoholics and the immunosuppressed.

Coliforms can cause it in ICU patients.

Question 5

Necrotising pneumonia

Answer 5

Rare and caused by S. aureus.

Production of panton valentine leukocidin forms pores in the membrane of host cells

Question 6

Atypical pneumonia

Answer 6

Non cultivable

Dry and unproductive coughs, fever and myalgia and headache

Caused by bacteria that don’t have a cell wall

Mycoplasma pneumoniae, chlamydophila pneumoniae, coxiella burnetti and chlamydophila psittaci - birds

Treat with erythromycin

Question 7

Legionnaires disease

Answer 7

Legionella pneumophilla - poorly gram staining, slow growing and need iron and cysteine in their growth medium.

smokers have a high risk of development.

Bad cough, joint pain and a white out, mortality rates can reach 50% in hospital endemics

Question 8

Pontiac fever

Answer 8

Totlockia - milder version of Legionnaires

Question 9

Pneumonia diagnosis

Answer 9

CURB65

Confusion
Urea over 7mmol/L
Respiratory rate over 30/min
Blood pressure lower than 90mm/Hg
Age over 65

An xray can be done as can NAAT and immunoassay

Question 10

Pneumocytis jirovecci

Answer 10

Fungus
Pneumonia with shortness of breath and a dry cough
AIDs defining

Question 11

Chronic bronchitis

Answer 11

Multifactoral disease caused by the overproduction of mucus

Haemophilus influenzae

Question 12

Whooping cough

Answer 12

Bordetella pertussis- small gram negative cocco bacilli
Adheres to lining of trachea and bronchi where it releases a toxin that interferes with ciliary movement
Leads to an increase in cAMP leading to mucus accumulation.
Blood charcoal agar
71% cases in children

Question 13

Mycobacterium tuberculosis

Answer 13

Cause tuberculosis
M. bovis and M. avium
Intracellular
Obligate aerobe
Can survive inside phagocytes 
Ziehl neelson