Respiratory tract infections

Question 1

Describe the infections that affect the following areas:

1. Upper respiratory tract
2. Lower respiratory tract

Answer 1

1. Upper respiratory tract:

• Sinusitis
• Tonsillitis

2. Lower respiratory tract:

• Bronchitis
• Pneumonia
• Empyema
• Bronchiectasis
• Lung abscess

Question 2

Describe how the following can cause a compromise to normal host defences:

1. Muscle weakness
2. Cystic fibrosis
3. Smoking/Kartagener’s
4. Bronchiectasis
5. HIV/immunosuppression

Answer 2

1. Muscle weakness/alcohol - can lead to poor swallow
2. Cystic fibrosis leads to thick/abnormal mucous - so poor removal of bugs
3. Smoking and Kartagener’s can lead to abnormal ciliary function, and reduce clearance of any infection in the airways
4. Bronchiectasis leads to dilated airways
5. HIV/immunosuppression leads to general defects in host immunity

All of these cause a higher risk of an infection, and often rare conditions

Question 3

Case 1:

18 year old woman presents with fever, cough and malaise

Diagnosed with flu by GP. No abx given. Now presents to A&E

Obs:

• Temp 38 degrees
• Sats 87% OA
• RR 24
• Chest - clear
• Bloods: WCC=40.8, Neutrophils = 36.3 and CRP = 63

1. What do the images show?
2. What she is likely to have?
3. What is the likely organism out of the following:

a) Pseudomonas aeruginosa
b) Mycobacterium tuberculosis
c) Legionella pneumophilia
d) Streptococcus pneunomiae
e) Staphylococcus aureus

Answer 3

1. The CT shows densely consolidated and collapsed lower lobe
2. She has developed a left lower lobe pneumonia
3. d) Streptococcus pneumoniae is the most likely causative organism

Question 4

Describe the following about s.pneumonia

1. Type of bacteria
2. Onset
3. ABx

Answer 4

1. Gram positive streptococcus and accounts for 30-50% of CAP
2. Acute onset

• Severe pneumonia
• Fever, rigors
• Lobar consolidation

3. Almost always penicillin sensitive

Question 5

Describe pneumonia

1. What is it?
2. Mortality
3. Presentation

Answer 5

1. Pneumonia is inflammation of the lung alveoli
2. Patients are sick - mortality is 5-10%, 20-40% for those that are admitted to hospital
3. Presentation:

• Fever
• Cough
• Pleuritic chest pain
• Shortness of breath

Often localized signs and abnormal CXR

Question 6

What are the main organisms that cause community aquired pneumonia?

Answer 6

• Streptococcus pneumoniae - gram positive
• Haemophilus influenzae - gram negative coccobacillary
• Moraxella catarrhalis - (neisseria) - gram negative diplococcus
• Staphylococcus aureus - gram positive cocci
• Klebsiella pneumoniae - gram negative, encapsulated

Question 7

What are the main pathogens that cause respiratory infections in the following age groups:

1. 0-1months
2. 1-6 months
3. 6months - 5 years
4. 16-30 years

Answer 7

1. E.coli, GBS, Listeria
2. Chlyamydia trachomatis, S aureus, RSV
3. Mycoplasma, influenza
4. M.pneumoniae, S. pneumoniae

Question 8

1. What are the main causes of typical CAP?
2. What are the causes of atypical CAP?

Answer 8

1. Typical accounts for 85%

• S. pnuemoniae
• H. influenzae

2. Atypical 15%

• Legionella
• Mycoplasma - epidemics every 4-6 years
• Coxiella burnetti (Q-fever) - farm animals, hepatitis
• Chlamydia psittaci - exposure to birds - causes splenomegaly, rash and haemolytic anaemia

Question 9

What are the symptoms of pneumonia?

Answer 9

• SOB
• Cough +/- sputum
• Fever
• Rigors
• Pleuritic chest pain
• Malaise
• Nausea and vomiting

Question 10

What are the signs on examination of pneumonia?

Answer 10

• Pyrexia
• Tachycardia
• Tachypnoea
• Cyanosis
• Dullness to percussion, tactile vocal fremitus - consolidation
• Bronchial breathing
• Crackles

Question 11

What are the investigations for pneumonia?

Answer 11

• FBC, U&E, CRP
• Blood cultures, sputum MC&S
• ABG
• CXR

Question 12

1. What is the CURB-65 score?
2. Treatment of pneumonia

Answer 12

1. CURB-65

• Confusion
• Urea >7mmol/l
• Respiratory rate >30
• BP<90 systolic, <60 diastolic
• >65 years

A score of up to 2, think about admitting. However if the score is 2-5 - treat as severe pneumonia

2. Treat supportively - oxygen, anti-pyrexials, and fluids if dehydrated.

ABx - take a blood culture to make sure the right ABx is being used. However, usually responsive to broad spectrum penicillin e.g. Levofloxacin

Question 13

Bronchitis

1. What is it?
2. Signs and symptoms
3. CXR results
4. Organisms that can cause it
5. Treatment

Answer 13

1. Bronchitis is inflammation of medium sized airways, occurs mainly in smokers
2. Signs and symptoms:

• Cough
• Fever
• Increased sputum prodction
• Increased SOB

3. Chest X-ray is normal
4. Organisms:

• Viruses
• S.pneumoniae
• H.influenzae
• M. catarhalis

5. Treatment

• Bronchodilation
• Physiotherapy +/- Abx

Question 14

Case

56 year old man with a flu-like illness presents with cough and fever. Blood stained sputum, pyrexial but not severely unwell

1. What does the x-ray show?
2. What does he have?
3. What is the likely causative organism? One of the following:
   a) Streptococcus pneumonia
   b) Haemophilus influenzae
   c) Staphylococcus aureus
   d) Klebsiella pneumoniae
   e) any of the above

Answer 14

1. Cavitation on X-ray in the left lower lobe
2. Left lower lobe pneumonia
3. b) haemophilus influenzae

Question 15

Describe Haemophilus influenzae

Answer 15

• Gram -ve coccobacillus
• 15-35% of CAP
• more common in pre-existing lung disease
• May produce Beta - lactamase

Question 16

Case

62 year old man, presents with SOB and the family also reported recent confusion. He is a smoker

O/E:

• Sats 91% OA
• Chest examination normal
• Na = 124

1. What does the x-ray show?
2. What is the likely causative organism out of the following?

​a) Moraxella catarrhalis

b) Mycobacterium tuberculosis
c) Legionella pneumophilia
d) Cytomegalovirus (CMV)
e) Staphylococcus aureus

Answer 16

1. Bilateral interstitial change
2. c) legionella pneumophilia

Question 17

1. How is legionella pneumophila spread?
2. What special culture is needed for it?
3. Describe the associated symptoms of L.pneumophila
4. How is it diagnosed?

Answer 17

1. Inhaled of infected water droplets
2. Requires buffered charcoal yeast extract for culture

May cause multi-organ failure

3. Associated with confusion, abdominal pain and diarrhoea. Has a flu-like syndrome before develops pneumonia
4. Diagnosis by antigen in urine/serum

Question 18

Describe what makes a pneumonia atypical

Answer 18

• Pneumonia caused by organisms without a cell wall
  
  • Mycoplasma
  • Legionella
  • Chlamydia
  • Coxiella
• Cell-wall active antibiotics e.g. penicillins won’t work
• Need agents that work on protein synthesis
  
  • Macrolides (clarithromycin/erythromycin)
  • Tetracyclines (doxycycline)
• Extrapulmonary features
  
  • Hepatitis
  • Low sodium
• Makes up 20% of CAP
• Flu-like prodrome before fever and pneumonia

Question 19

Describe coxiella burnetii

1. Where does it come from/
2. How it is transmitted?
3. Diagnosis?
4. Abx used

Answer 19

Coxiella burnetii

1. Common in domestic/farm animals
2. Transmitted by aerosol or milk
3. Diagnosis by serology
4. Sensitive to macrolides

Question 20

Chlamydia psittaci

1. How is it spread
2. Diagnosis
3. Sensitive to which type of antibiotics?

Answer 20

1. Spread from birds by inhalation
2. Diagnosis by serology
3. Sensitive to macrolides

Question 21

Case

74 year old woman, presented with SOB, fever and right sided pleuritic chest pain.

PMHx of - ischaemia HD, CABG and atrial fibrillation

Drug Hx = Warfarin

Otherwise well

O/E

• Temperature 38.5 degrees C
• reduced percussion note and decreased air entry in the right base

1. What does the X-ray show and what does she have

Admitted and started on cefuroxime and doxycycline but fevers continued to spike. Not getting better.

2. On standard antibiotic and not getting better, what is the probable diagnosis?
   a) Tuberculosis
   b) Empyema
   c) Mesothelioma
   d) MRSA pneumonia
   e) Aspiration pneumonia

Answer 21

1. Consolidation in the right lower lobe, likely to have a right lower lobe pneumonia
2. b) empyema - not responsive to drugs!

Question 22

A 74 year old with suspected RLL who is not responding to standard antibiotics, and continues to spike fevers

1. What does the CT show
2. What should be done next?

Answer 22

1. Large empyema with collapsed lung underneath
2. If they fail to improve on treatment, and RLL suspected, think alternative causes:

• Empyema/abscess
• Proximal obstruction (tumour)
• Resistant organism
• Not recieveing/absorbing Abx
• Immunosuppression
• Other diagnoses = lung cancer, crpytogenic organising pneumonia

Question 23

Case

21 year old male from Ecuador presents with cough and weight loss

Ix:

• U&Es are normal
• Hb = 10.4
• WCC: 9.8
• HIV negative
• CRP = 173
• Albumin = 31

1. What does the X-ray show?
2. What is the likely causative organism?
   a) Staphylococcus aureus
   b) Aspergillus fumigatus
   c) Mycobacterium tuberculosis
   d) Haemophilus influenzae
   e) Pneumocystis jiroveci

Answer 23

1. Right upper zone shadowing
2. c) Mycobacterium tuberculosis

Question 24

Describe Tuberculosis

Answer 24

• Known as the ‘white plague’ and must always be considered as a differential
• Spread by droplets
• CXR - classically upper lobe cavitation but can vary
• Clues that it is TB:
  
  • Ethnicity
  • Prolonged prodome
  • Fevers (especially at night)
  • Weight loss
  • Haemoptysis

Question 25

1. How is a hospital acquired pneumonia defined? 2. What increases the risk of developing a HAP?

Answer 25

1. Pneumonia that is acquired from hospital, when in hospital for \>48 hours 2. Risk factors: * Often previous antibiotics +/- * ventilator infection * Reduced lung function

Question 26

What is the most common causative organism for HAP?

Answer 26

* Enterobacteriaciae - 31% * Staphylococcus aureus - 19% * Psuedomonas spp = 17%

Question 27

Case ## Footnote 64 year old retired general, treated for lymph node tuberculosis. Has had increased SOB over one month, with a non-productive cough. Chest examination is normal 1. What does this X-ray show? 2. What is the likely organism? a) Aspergillus fumigatus b) H1N1 swine flu c) Mycoplasma pneumoniae d) Cytomegalovirus e) Pneumocystis jiroveci

Answer 27

1. Bilateral Ground glass shadowing 2. e) Pneumocystis jiroveci

Question 28

Pneumocystis jiroveci 1. What is it? 2. Presentation 3. Treatment

Answer 28

1. Pneumocystis is a protozoan and is ubiquitous in environment 2. Presentation * Insidious in onset * Dry cough * Weight loss * SOB * Malaise * CXR - bat's wing (ground glass shadowing) 3. Treatment * Septrin/Co-trimoxazole * Prophylaxis septrin

Question 29

Case ## Footnote 22 year old man has had chemotherapy for leukaemia, causing prolonged neutropenia (\<1). Has had ongoing fevers and raised inflammatory markers Started on the following Abx - meropenem, ciprofloxacin, vancomycin, Tazocin and gancyclovir 1. What does the CT show? 2. What is the likely causative organism? a) MRSA b) Aspergillus c) Tuberculosis d) CMV e) Drug reaction

Answer 29

1. Interstial change on CT bilaterally 2. b) Aspergillus

Question 30

Describe the following of aspergillus fumigatus: 1. Allergic bronchopulmonary aspergillosis 2. Aspergilloma 3. Invasive aspergillosis

Answer 30

1. Allergic bronchopulonary aspergillosis * Chronic wheeze * Eosinophilia * Bronchiectasis 2. Aspergilloma * Fungal ball often in pre-existing cavity * May cause haemoptysis 3. Invasive aspergillosis * Immunocompromised patients * Rx - Amphotericin B

Question 31

what organisms are the following most at risk from that may cause a LRTI? 1. HIV 2. Neutopenia 3. Bone marrow transplant 4. Splenectomy

Answer 31

1. HIV - PCP, TB, atypical mycobacteria 2. Neutropenia - Fungi e.g. Aspergillus spp 3. Bone marrow transplant - CMV 4. Splenectomy - encapsulated organisms e.g. S.pneumoniae, H.influenzae, malaria

Question 32

What organisms can be diagnosed by urine antigen tests?

Answer 32

* S.pneumonia * Legionella pneumophilia

Question 33

What organisms are antibody tests useful for and why?

Answer 33

* Chlyamydia * Legionella Antigen tests are useful for this as they are difficult to culture

Question 34

What test is used to identify PCP?

Answer 34

Immunofluoresence is used to check the presence of PCP

Question 35

What are the first line antibiotics for the following CAP: 1. Mild-moderate 2. Moderate - severe

Answer 35

1. Mild-Moderate * Amoxicillin * Or erthromycin/clarithromycin 2. Moderate-severe: * Needing hospital admission - Augmentin (co-amoxiclav) AND clarithromycin * Allergic: Cefuroxime AND clarithromycin

Question 36

What are the antibiotics for the following HAPs: 1. First line 2. Second line 3. MRSA 4. Pseudomonas

Answer 36

1. First line: Ciprofloxacin +/- vancomycin 2. Second line/ITU: Pipyazobactam AND vancomycin 3. MRSA: Vancomycin 4. Pseudomonas: Piptazobactam or Ciprofloxacin +/- gentamicin

Question 37

Case ## Footnote 21 year old man, No past medical history, however is a smoker and a drinker. Presented with a cough and SOB, sats 89% OA and hypotensive 1. What does the X-ray show? 2. What antibiotics would you prescribe from the following? a) Amoxicillin b) Tazocin and Vancomycin c) Co-amoxiclav d) Cefuroxime and clarithromycin e) Rifater, isoniazid, pyrazinamide and ethambutol

Answer 37

1. RUZ pneumonia 2. d) cerfuroxime and clarithromycin Also needed fluid resuscitation, supplemental O2 and senior help

Question 38

How can pneumonia be prevented?

Answer 38

* Smoking advice * Vaccination: * Childhood immunisation schedule * Adults: * Influenza annually * Pneumovax every 5 years