RESP 120 Pneumonia Flashcards
What are the two types of pneumonia and how do they present differently?
Atypical: gradual onset, dry cough, myalgias and headache
Typical: abrupt onset, high fever, purulent sputum and focal consolidation
(Also HAP and CAP)
What criteria is used to define severe pneumonia?
CURB65 : confusion, urea >7, RR >30, BP 65 years of age
3+ criteria met = severe
What investigations should be carried out in pneumonia?
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
What is the most common infective cause of pneumonia?
Streptococcus pneumoniae
Name two common infective causes of HAP
Klebsiella and pseudomonas aerginosa
Also: haemophillus influenzae, e.coli and legionella. Staph aureus –> MRSA
What infective cause of pneumonia would indicate possible aspiration?
E.coli - poor prognosis, commonly infects lower lobe
How would you treat an uncomplicated pneumonia?
P.o amoxicillin + p.o. clarithromycin/ p.o cephalosporin
How would treat a complicated pneumonia?
iv cefuroxime/iv augmentin + p.o. clarithromycin
How would you treat an atypical pneumonia?
clarithromycin + i.v. rifampcin + tetracycline
how would you treat a pneumonia that had cavitation or aspiration?
iv cefuroxime + iv metronidizole/ iv flucloxacillin
What is the concentration of dissolved 02 in arterial blood?
3ml/L at 100mmHg
What is Henrys Law?
The concentration of a dissolved gas in a liquid = solubility x partial pressure
In the deoxygenated state how are Hhb subunits held together?
By salt bridge interactions
How does 02 binding change haemoglobin?
It causes a conformational change in the globin molecule and increases the likelihood of salt bridges break allowing further o2 binding
What is the normal Pa02 and paCO2 in arterial blood?
100mmHg and 40mmHg
What is the normal Pv02 and PvCO2 in mixed venoud blood?
35mmHg and 45 mmHg
How many haem and how many globin subunits are there in one molecule of Hb?
4 of each
What binds the O2 in Hb and how many can bind maximally?
The Fe2+ iron and 4
What will shift the O2 dissociation curve to the right? (decreased affinity for O2)
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
What is 90% of your CO2 carried as?
Carbonic acid in RBC
What enzyme catalyses the dissolution of CO2 in RBC’s?
Carbonic anhydrase
What is the Haldane effect?
Where deoxyHb takes up H+ ions allowing more dissolution of CO2 in plasma = increased CO2 carriage at low pO2
What 4 processes does pulmonary gas exchange depend on?
Ventilation, diffusion of gases, perfusion of the lung and correct V/Q matching
Where is V/Q greatest?
At apices of lungs
Where is V/Q lowest and why?
At bases of lungs where there is the biggest difference between ventilation and perfusion
How does strep pneumoniae infection present?
Typically - fever, productive cough, dyspnoea, pleuritis pain
RUST COLOURED sputum
Lobar pneumonia
Name some atypical pathogens that cause pneumonia
Mycoplasma Pneumoniae Chlamydiae pneumoniae Legionella pneumophillia (aircon - immunocompromised) Coxiella Burnetti ( animals) Chlamydia psittaci (birds)
