lung infection and immunity

Question 1

bacterial source of acute lung infection pneumoccocal pneumonia

Answer 1

Streptococcus pneumoniae

Question 2

pathogens associated with community acquired pneumonia (CAP)

Answer 2

presentation of acute pneuomonia result of cooperative bacteria and viruses

Question 3

are causes of hospital-acqiured pneumonia same as communtiy acquired pneumonia

Answer 3

no

Question 4

typical community acquired pneumonia pathogens

Answer 4

S. pneumoniae, H. influenzae, M. catarrhalis

Question 5

atypical community acquired pneumonia pathogens

Answer 5

M. pneumoniae, C. pneumoniae, L. pneumophilia

Question 6

risk factors for pneumonia

Answer 6

age, smoking, excess alcohol, contact with < 15 years, poverty, overcrowding, some medications, medical history (e.g. COPD, asthma, heart, liver, diabetes), animal contact, geographical variations

Question 7

diagnosing pneumonia

Answer 7

acute lower respiratory tract symptoms (coughing, green (neutrophil)/rusty (dead cell) sputum, dyspnoea as alveoli fill with pus), new focal chest signs, >1 systemic feature (fever, shivers, aches, high temperature), no other explanation for illness, CRB65 (confusion, respiratory rate, blood pressure, age) severity score, stabbing chest pain due to peripheral inflammation, X-ray with dense debris seen in lungs (fibrin, bacteria)

Question 8

supportive therapy for pneumonia

Answer 8

antibiotics, oxygen (hypoxia), fluids (dehydration), analgesia (pain), nebulised saline

Question 9

pneumonia antibiotic therapy examples

Answer 9

amoxicillin, clarithromycin, benzylpenicillin IV

Question 10

features and outcome of acute antibiotic therapy for pneumonia

Answer 10

rapid time of antibiotic administration to reduce septic shock; 1 week treatment leaving airways unscarred and some effort made to clear infections

Question 11

effect of viral infection on lung

Answer 11

mediator release, cellular inflamation, local immune memory; damage to epithelium - loss of cilia, bacterial growth, poor antigen barrier, loss of chemoreceptors

Question 12

common cold agents

Answer 12

many viruses (influenza, respiratory syncytial etc.), atypical bacteria

Question 13

features of severe viral disease

Answer 13

RNA sequence, viral load, DNA, environment - mediators, cell stress, epithelial damage, viral spread

Question 14

causes of severe flu

Answer 14

highly pathogenic strains (zoonotic), absence of prior immunity, predisposing illness/conditions

Question 15

feature of influenza infection and effect on vaccines

Answer 15

no re-infection by same strain; imperfect vaccines

Question 16

respiratory syncytial virus (RSV) features

Answer 16

unstable; recurrent re-infection (filamentous) with similar strains; no vaccine

Question 17

what does RSV cause in neonates

Answer 17

bronchiolitis

Question 18

is RSV likely to be present upon hospital admission

Answer 18

no

Question 19

viral load: influenza vs RSV

Answer 19

influenza - rapid viral load; RSV - delayed viral load

Question 20

why is lung susceptible to infection

Answer 20

not sterile - contains many organisms causing pneumonia

Question 21

define bronchiectasis as an example of a chronic lung infection

Answer 21

chronic condition where airways become abnormally widened, secondary to chronic inflammation, leading to build-up of excess mucus (more vulnerable to infection)

Question 22

pathogenesis of bronchiectasis

Answer 22

inflammation permanently destroying tissue and muscles surrounding bronchi, causing them to widen, become scarred, inflamed and filled with excess mucus; this triggering persistent coughing, SOB, chronic fatigue, and make the lungs more vulnerable to infection as they harbour bacteria

Question 23

causes of bronchiectasis

Answer 23

severe pneumonia, whooping cough, TB, measles, immunodeficiency, connective tissue diseases (e.g. rheumatoid arthritis), CF, cilia abnormalities

Question 24

treatment of bronchiecstasis

Answer 24

physiotherapy to empty phlegm, antibiotics to clear infection

Question 25

acute inflammation: neutrophils and anti-protease balance

Answer 25

neutrophils secrete proteases to destroy microbes during inflammation and infection, and normally this is balanced by anti-proteases in the airways

Question 26

chronic inflammation: neutrophils and anti-protease imbalance

Answer 26

number of neutrophils is so large that the anti-proteases are overwhelmed leading to increased free proteases causing damage to the airway epithelia (which in turn makes it easier to be infected, creating a vicious cycle)