RESP 120 Pneumonia

Question 1

What are the two types of pneumonia and how do they present differently?

Answer 1

Atypical: gradual onset, dry cough, myalgias and headache
Typical: abrupt onset, high fever, purulent sputum and focal consolidation
(Also HAP and CAP)

Question 2

What criteria is used to define severe pneumonia?

Answer 2

CURB65 : confusion, urea >7, RR >30, BP 65 years of age

3+ criteria met = severe

Question 3

What investigations should be carried out in pneumonia?

Answer 3

SUBEC:
Sputum: acid fast bacilli, general culture, gram stain
Urine: legionella Ag, output (1st thing to deteriorate in sepsis)
Blood: Cultures, WBC, Urea and serology
ECG and CXR

Question 4

What is the most common infective cause of pneumonia?

Answer 4

Streptococcus pneumoniae

Question 5

Name two common infective causes of HAP

Answer 5

Klebsiella and pseudomonas aerginosa

Also: haemophillus influenzae, e.coli and legionella. Staph aureus –> MRSA

Question 6

What infective cause of pneumonia would indicate possible aspiration?

Answer 6

E.coli - poor prognosis, commonly infects lower lobe

Question 7

How would you treat an uncomplicated pneumonia?

Answer 7

P.o amoxicillin + p.o. clarithromycin/ p.o cephalosporin

Question 8

How would treat a complicated pneumonia?

Answer 8

iv cefuroxime/iv augmentin + p.o. clarithromycin

Question 9

How would you treat an atypical pneumonia?

Answer 9

clarithromycin + i.v. rifampcin + tetracycline

Question 10

how would you treat a pneumonia that had cavitation or aspiration?

Answer 10

iv cefuroxime + iv metronidizole/ iv flucloxacillin

Question 11

What is the concentration of dissolved 02 in arterial blood?

Answer 11

3ml/L at 100mmHg

Question 12

What is Henrys Law?

Answer 12

The concentration of a dissolved gas in a liquid = solubility x partial pressure

Question 13

In the deoxygenated state how are Hhb subunits held together?

Answer 13

By salt bridge interactions

Question 14

How does 02 binding change haemoglobin?

Answer 14

It causes a conformational change in the globin molecule and increases the likelihood of salt bridges break allowing further o2 binding

Question 15

What is the normal Pa02 and paCO2 in arterial blood?

Answer 15

100mmHg and 40mmHg

Question 16

What is the normal Pv02 and PvCO2 in mixed venoud blood?

Answer 16

35mmHg and 45 mmHg

Question 17

How many haem and how many globin subunits are there in one molecule of Hb?

Answer 17

4 of each

Question 18

What binds the O2 in Hb and how many can bind maximally?

Answer 18

The Fe2+ iron and 4

Question 19

What will shift the O2 dissociation curve to the right? (decreased affinity for O2)

Answer 19

Increased [H+] and [CO2]
Increased temperature
= Bohr effect of Cl- shift and increased salt bridge formation to allow O2 to be released more easily

BPG - present in all RBC

Question 20

What is 90% of your CO2 carried as?

Answer 20

Carbonic acid in RBC

Question 21

What enzyme catalyses the dissolution of CO2 in RBC’s?

Answer 21

Carbonic anhydrase

Question 22

What is the Haldane effect?

Answer 22

Where deoxyHb takes up H+ ions allowing more dissolution of CO2 in plasma = increased CO2 carriage at low pO2

Question 23

What 4 processes does pulmonary gas exchange depend on?

Answer 23

Ventilation, diffusion of gases, perfusion of the lung and correct V/Q matching

Question 24

Where is V/Q greatest?

Answer 24

At apices of lungs

Question 25

Where is V/Q lowest and why?

Answer 25

At bases of lungs where there is the biggest difference between ventilation and perfusion

Question 26

How does strep pneumoniae infection present?

Answer 26

Typically - fever, productive cough, dyspnoea, pleuritis pain
RUST COLOURED sputum
Lobar pneumonia

Question 27

Name some atypical pathogens that cause pneumonia

Answer 27

Mycoplasma Pneumoniae
Chlamydiae pneumoniae
Legionella pneumophillia (aircon - immunocompromised)
Coxiella Burnetti ( animals)
Chlamydia psittaci (birds)