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Flashcards in Respiratory Tract Infections Deck (31):
1

What examples are there of compromise to respiratory defences?

Poor swallow- cva, muscle weakness, alcohol. Aspirating of salivary secretions
Abnormal ciliary function- smoking, viral infection, kartageners
Abnormal mucus- cf
Dilated airways- bronchiectasis
Defects in host immunity- HIV, asplenic, complement deficient

2

What is pneumococcus known as?

Old mans friend but actually one of the commonest caused of CAP.
Bacteraemic
Green alpha haemolysis
Bile soluble optochin sensitivity

3

What is s pneumonia?

Gram positive diplococci
30-50% of cap
Acute onset, severe pneumonia, fever, rigours, lobar consolidation
Almost always penicillin sensitive, know travel history
Resistance in Europe

4

What is pneumonia?

Inflammation of lung alveoli
Patients are sick, mortality of 5-10%
Fever, cough, pleuritic chest pain, shortness of breath
Often localising signs and abnormal cxr or normal in atypical

5

How is pneumonia classified?

Community acquired
Hospital acquired- ventilator associated
Pre existing lung disease, immunocompromised, geography, season, epidemics, travel, exposure to animals and contacts

6

What are the main organisms in cap?

S pneumonia
H influenzae
Moraxella catarrhalis- follows viral infection
S aureus
Klebsiella pneumoniae

7

What ages are various pathogens likely to infect people?

0-1 months- E. coli, gbs, listeria
1-6 months- chlamydia trachomatis, s aureus, Rsv
6 months-5 years- mycoplasma, influenza
16-30 years- m pneumoniae, s pneumoniae

8

What are the causes of cap?

Typical- s pneumonia, h influenzae
Atypical- legionella
mycoplasma (barking cough)
coxiella burnetti. (Q fever) , farm animals, hepatitis
Chlamydia psittaci- birds, splenomegaly, rash, haemolytic anaemia

9

What would you expect to find in examination of cap?

Pyrexia
Tachycardia, tachypnoea
Cyanosis, dullness to percussion, tactile vocal fremitus
Bronchial breathing
Crackles

10

What investigation would you ask for cap?

Fbc, u&e, crp
Bc, sputum and mc&S
Abg- useful in PCP, desaturate on exertion
Cxr

11

How do you manage cap?

CURB 65 score- confusion, urea more than 7, rr more than 30, bp less than 90 systolic, less than 60 diastolic, more than 65 years
Score 2- maybe admit
Score 2-5 manage as severe

12

What is bronchitis?

Inflammation of medium sized airways
Mainly in smokers
Cough, fever, increased sputum production, increased sob
Cxr is normal
Organisms- virus, s pneumonia, h influenza, m catarrhalis
Bronchodilation, physiotherapy, humidified oxygen

13

Which organisms can give cavitating pneumonia?

S aureus
Klebsiella
H influenza gram neg bacilli

14

What is h influenzae?

Gram neg coccobacillus
15-35% of cap
More common with pre existing lung disease
May produce b lactamase- augmentin plus or minus clarithromycin

15

What clincal signs point to legionella?

Confused
Smoker
Hyponatriaemic
Infected water droplets
Multi organ failure
Special culture- buffered charcoal yeast extract
Asymptomatic- Pontiac fever

16

What are atypical pneumonia caused by?

Organisms without a cell wall- mycoplasma, legionella, chlamydia, coxiella
Cell wall active abx eg pencillin don't work
Need agents that work on protein synthesis- clari, erithromycin, tetracycline like doxycycline
Extrapulmonary feature- hepatitis, low sodium, flu like

17

What is the respiratory tract split into?

Upper- sinusitis, tonsillitis
Lower- bronchitis, pneumonia, empyema, bronchiectasis, lung abscess

18

How is legionella spread?

Aerosol spread
Environmental breakouts
Associated with confusion, abdo pain and diarrhoea
Lymphopenia, hyponatraeima
Diagnosis by antigen in urine/serum serotype 1
Sensitive to macrolides

19

How are coxiella burnetti and chlarmyida psittaci spread?

Common in domestic farm animals
Transmitted by aerosol or milk
Dx by serology
Sensitive to macrolides
Psittaci- spreads by birds by inhalation
Dx by serology
Sensitive to macrolides

20

What should be done if empyema is found?

Send sample for microbiology, cytology, check ldh, low ph
Needs removal

21

What are the differentials for failing to improve on treatment?

Empyema
Proximal obstruction
Resistant organism
Not receiving/ absorbing abx
Immunosuppression
Other diagnosis- lung cancer, cryptogenjc organising pneumonia

22

How can s aureus lead to necrotising pneumonia?

Production of pvl, recurrent boils, cabuncles, young person
Want to know if colonised
Contacts

23

What is a hospital acquired pneumonia?

More than 48 hours in hospital
Often previous abx, plus or minus ventilator
Infectious vs non infectious causes of abnormal Cxr/lung function
Bronchial lavage- desirable to differentiate upper respiratory from lower flora

24

What pathogens would cause hospital acquired pneumonia?

Enterobacteriaciae
S aureus
Pseudomonas
Other
H influenza
Acinetibacter baumanii

25

What is PCP?

Pneumocystis carinii, Protozoa
Ubiquitous in environment
Insidious onset
Dry cough, weight loss, SOB, malaise
Cxr bat wings
Immunofluroscence on BAL
Treat with co amox and prophylaxis too
Apple green

26

What diseases can aspergillus fumigatus cause?

Allergic bronchopulmonary aspergillosis- chronic wheeze, eosinophilia, bronchiectasis
Aspergilloma- fungal ball often in pre existing cavity, may cause haemoptysis
Invasive aspergillosis- immunocompromised, treat with amphotericin B

27

What lower tract infections can be associated with immunosupression?

HIV- PCP, TB, atypical mycobacteria
Neutropenia- fungi, aspergillus
Bone marrow transplant- CMV
Splenectomy- encapsulated organisms, s pneumonia, h influenza, malaria

28

What can be done in the microbiology lab for diagnosis of lrti?

Sputum
Blood cultures
BAL
Pleural fluid
Antigen tests
Antibody tests
Immunofluroscence
PCR

29

What are antibody tests useful for?

Useful in paired serum samples
Usually collected on presentation and 10-14 days later
Look for rise in antibody level over time
Useful for organisms that are difficult to culture- chlaymida, legionella

30

What is empric therapy for cap?

Amoxicillin or erythromycin/clarithromycin
Admision- augmentin and clari
Allergic- cefuroxime and clari

31

What is the therapy for hospital acquired?

1st line- ciprofloxacin plus minus vanco/ tazocin
2ndline/ITU- piptazobactam and vanco
Specific therapy- mrsa- vanco
Pseudo- piptazobactam or ciprofloxacin plus minus gentamicin