Respiratory Tract Infections

Question 1

What are the URTIs?

Answer 1

o Sinusitis

o Tonsillitis

Question 2

What are the LRTIs?

Answer 2

Bronchitis
Pneumonia
Empyema
Bronchiectasis
Lung abscess

Question 3

What effects on the body does respiratory defence compromise have?

Answer 3

Question 4

· 18yo female; fever, cough and malaise

· Diagnosed with flu by GP (no ABx given)

· Attended A&E with…

o T 38C 87% sats on room air

o Chest clear, RR 24 Bloods (WCC 40.8, Neut 36.3, CRP 63)

What investigations wold you do?

Answer 4

o CXR double heart border (‘Sail’ sign)

o CT densely consolidated and collapsed lower lobe

Question 5

o CXR double heart border (‘Sail’ sign)

o CT densely consolidated and collapsed lower lobe

Diagnosis?

Answer 5

LL pneumonia

Question 6

What is streptococcus pneumonia?

Answer 6

o Alpha-haemolytic and optochin-sensitive

o Gram-positive cocci (chains and pairs)

o 30-50% of CAP

o Acute onset

§ Severe pneumonia Fever and rigors Lobar consolidation

o Almost always penicillin-sensitive

o Penicillin-resistance strains may be imported from Southern Europe

Question 7

What is pneumonia?

Answer 7

inflammation of the lung alveoli

Question 8

What is the presentation of pneumonia?

Answer 8

Fever

Cough

Abnormal CXR

Pleuritic chest pain

SoB

Question 9

What are the types of pneumonia?

Answer 9

§ Community-acquired

§ Hospital-acquired/nosocomial (i.e. ventilator-associated)

Question 10

What underlying factors contribute to pneumonia?

Answer 10

§ Pre-existing lung disease

Immunocompromise

§ Geography, seasons, epidemics

Travel, exposure to animals

Question 11

What causes CAP?

Answer 11

· Streptococcus pneumoniae

· Haemophilus influenzae

· Moraxella catarrhalis

· Staphylococcus aureus

· Klebsiella pneumoniae

Question 12

Which pathogens affect which agre group?

Answer 12

Question 13

What are the cauess of CAP?

Answer 13

· TYPICAL (85%)

o Streptococcus pneumoniae

o Haemophilus influenzae

· ATYPICAL (15%)

o Legionella

o Mycoplasma

o Coxiella burnetii (Q fever) from exposure to farm animals

§ Hepatitis

o Chlamydia psittaci (Psittacosis) from exposure to birds

§ Splenomegaly, rash, haemolytic anaemia

Question 14

What are the clinical features of CAP?

Answer 14

§ Symptoms:

· SoB Cough ± sputum Fever

· Rigors Pleuritic chest pain Malaise, N&V

§ Examination:

· Pyrexia Tachycardia Tachypnoea

· Cyanosis Bronchial breathing Crackles

· Dullness to percussion/tactile vocal fremitu

Question 15

What Ix should you do for CAP?

Answer 15

· FBC, U&E, CRP BCs, Sputum MC&S

· ABGs CXR

Question 16

What is the CURB 65?

Answer 16

· Confusion

· Urea > 7 mmol/L

· RR > 30

· BP < 90 systolic, < 60 diastolic

· 65+ years

2 = consider admitting

2-5 = manage as severe / consider ITU

Question 17

What is bronchitis?

Answer 17

inflammation of medium-sized airways

Question 18

What is the presentation of bronchitis?

Answer 18

§ Cough

§ Fever

§ Increased sputum production

§ Increased shortness of breath

CXR is usually NORMAL

Question 19

What organisms cause bronchitis?

Answer 19

§ Viruses

§ Streptococcus pneumoniae

§ Haemophilus influenzae

§ Moraxella catarrhalis

Question 20

What is the treatment of bronchitis?

Answer 20

§ Bronchodilation

§ Physiotherapy

§ Antibiotics

Question 21

· 56yo man; flu-like illness

· Presented with cough, fever, haemoptysis, pyrexia (but not severely unwell)

CXR shows cavitation

Differentials?

Answer 21

o Staphylococcus aureus

o Klebsiella pneumoniae

o Haemophilus influenzae

o TB

Question 22

What is H influenzae?

Answer 22

o Gram-negative cocco-bacilli (stain on chocolate agar)

o 15-35% of CAP

o More common with pre-existing lung disease

o May produce beta-lactamase

Question 23

· 62yo man; SOB

· Confusion, smoker, 91% saturation on room air, chest exam normal, hyponatraemia

· CXR showed bilateral interstitial change

Ddx?

Answer 23

§ Mycoplasma

Legionella

§ Chlamydia

Coxiella

Question 24

What is Legionella?

Answer 24

o Spread via inhalation of infected water droplets

o It is grown on a buffered charcoal yeast extract

o Can cause multi-organ failure

Question 25

Which antibioitcs are used for atypicals?

Answer 25

Protein synthesis inhibitors: ## Footnote § Macrolides (clarithromycin/erythromycin) § Tetracyclines (doxycycline)

Question 26

o Extra-pulmonary features (e.g. hepatitis, hyponatraemia) – characteristic of atypical pneumonias o Account for 20% of CAP o Often have a flu-like prodrome before fever and pneumonia

Answer 26

o Extra-pulmonary features (e.g. hepatitis, hyponatraemia) – characteristic of atypical pneumonias o Account for 20% of CAP o Often have a flu-like prodrome before fever and pneumonia

Question 27

What is legionella?

Answer 27

o Aerosol spread and associated with environmental outbreaks o Associated with: § Confusion Abdominal pain Diarrhoea § Lymphopaenia Hyponatraemia o Investigation: urinary antigens o Sensitive to macrolides

Question 28

What is coxiella?

Answer 28

o Common in domesticated farm animals o Transmitted by aerosol or milk o Investigation: serology o Sensitive to macrolides

Question 29

What is Chlamydia?

Answer 29

o Spread from birds by inhalation o Investigation: serology o Sensitive to macrolides

Question 30

Why might empyema not improve?

Answer 30

Failure to improve on treatment: o Empyema/abscess Proximal obstruction (tumour) o Resistant organisms (travel hx) Not receiving/absorbing antibiotics o Immunosuppression Other diagnosis (lung cancer, cryptogenic organising pneumonia

Question 31

How is TB diagnosed?

Answer 31

o Clues -\> Ethnicity, Prolonged prodrome, Fevers, Weight loss, Haemoptysis o CXR -\> classically upper lobe cavitation (but can vary) o Staining: § An auramine stain and a Ziehl-Neelsen stain will be done § Red rods are the acid-fast bacilli

Question 32

What is HAP?

Answer 32

o A pneumonia onset \>48 hours in hospital o Patients have often had previous antibiotics and maybe even ventilation o Bronchial lavage is desirable (differentiate upper respiratory from lower respiratory flora) o Aetiology of HAP § Enterobacteriaciae (e.g. E. coli, K. pneumoniae) – 31% Staphylococcus aureus – 19% § Pseudomonas spp – 17% Haemophilus influenzae – 5% § Acinetobacter baumanii – 4% Fungi (Candida spp) – 7%

Question 33

What would pneumocystis pneumonia cause on CXR?

Answer 33

bilateral ground-glass shadowing (“bat’s wing”)

Question 34

What is Pneumocystic Jirovecii?

Answer 34

o Protozoan o Ubiquitous in the environment o Insidious onset § Dry cough Weight loss § SOB Malaise

Question 35

How do you manage Pneumocystis pneumonia?

Answer 35

· Investigations: bronchoalveolar lavage · Treatment: co-trimoxazole (septrin) · Prophylaxis: co-trimoxazol

Question 36

What can aspergillus cause?

Answer 36

o Allergic bronchopulmonary aspergillosis § Chronic wheeze § Eosinophilia § Bronchiectasis o Aspergilloma § Fungal ball, often in pre-existing cavity § May cause haemoptysis o Invasive aspergillosis § Immunocompromised § Treatment: amphotericin B

Question 37

What LRTIs can different immnosuppressed groups get?

Answer 37

Question 38

How do you diagnose LRTIs?

Answer 38

o Sputum/induced sputum Blood cultures BAL o Pleural fluid Antigen tests Antibody tests o Immunofluorescence PCR o Antigen Tests § Limited urine antigen tests available for: Legionella pneumophila Streptococcus pneumoniae § Send in severe CAP

Question 39

What are antibody tests?

Answer 39

§ Only useful on paired serum samples (one acutely unwell and another when getting better) · Usually collected on presentation and 10-14 days later § Looks for a rise in antibody level over time § Most useful organisms to send antibody tests for because they are difficult to culture: · Chlamydia Legionella

Question 40

What is immunofluorescence?

Answer 40

§ Antibody is labelled with fluorescent dye § Often used in virology § PCP immunofluorescence is the most commonly used one in microbiology labs § PCP may also be detected by Silver stain in cytology labs

Question 41

How do you treat CAPs?

Answer 41

§ Mild-Moderate: Amoxicillin [OR erythromycin/clarithromycin] § Moderate-Severe · Needing hospital admission: Co-amoxiclav (augmentin) AND clarithromycin · Allergic: Cefuroxime AND clarithromycin

Question 42

How do you treat HAPs?

Answer 42

§ 1st Line -\> Ciprofloxacin ± vancomycin § 2nd Line/ITU -\> Piptazobactam AND vancomycin § Specific Therapy: · MRSA: Vancomycin · Pseudomonas: Piptazobactam OR ciprofloxacin ± gentamicin

Question 43

What is the treatment of general pneumonia?

Answer 43

o Cefuroxime and clarithromycin (hypotensive -\> query allergic) o Fluid resuscitation o Supplemental O2 o Senior support requested

Question 44

How can you prevent pneumonia?

Answer 44

o Smoking cessation o Vaccination: § Childhood immunisation schedule § Adults -\> influenza annually, pnemovax every 5 years