LRTI

Question 1

What structures make up the lower respiratory tract?

Answer 1

• Trachea
• Primary bronchi
• Lungs

Question 2

What are the most common LRTIs?

Answer 2

• Bronchitis
• Bronchiolitis
• Pneumonia
• Influenza

Question 3

Which viral and bacterial pathogens can causes acute bronchitis?

Answer 3

Virus:

• adenovirus
• coronarvirus
• parainfluenza
• influenza
• rhinovirus

Bacteria:

• bordetella pertussis
• mycoplasma pneumonia

Question 4

What is the most common cause of severe bronchiolitis (children <2 y/o)?

Answer 4

RSV

Question 5

What are the symptoms of acute bronchitis?

Answer 5

• sore throat
• fatigue
• congested/runny nose
• body aches
• vomiting
• diarrhoea
• fever

Cardinal symptoms:

• acute illness <21 days
• cough (predominant symptom)
• at least one other resp symptoms: sputum, wheezing, chest pain

Question 6

How is acute bronchitis diagnosed and managed?

Answer 6

1. Cough = 3wks +/- sputum
2. If there are signs of consolidation, airway obstruction, fever, increases RR + HR then consider pneumonia, asthma, or pulmonary diseases
3. If none of these signs are present then consider whether or not there is a current outbreak of influenza pertussis
   - -> if not then the diagnosis is most likely acute bronchitis
   - -> if so, then the diagnosis is probably influenza pertussis and should be treated appropriately

Management of acute bronchitis:

• establish expectation that cough will last up to 14 days
• encourage high fluid intake and humidity
• recommend antipyretics, analgesics, antitussives for symptom relief
• do not give antibiotics
• might administer a SABA if there is significant wheeze

Question 7

Define pneumonia.

Answer 7

Inflammation of the alveoli in either one or both lungs

Question 8

What is the most common cause of community-acquired pneumonia?

Answer 8

Most common = strep pneumoniae (nearly 50%)

Other bacterial causes:

• Haemophilus influenzae in 20%,
• Chlamydophila pneumoniae in 13%
• Mycoplasma pneumoniae in 3%

Question 9

What viruses commonly cause pneumonia?

Answer 9

viruses account for approximately a third and in children for about 15% of pneumonia cases.

• rhinoviruses
• coronaviruses
• influenza virus
• RSV
• adenovirus
• parainfluenza

Question 10

In what cases would HSV cause pneumonia?

Answer 10

• newborns
• people with cancer
• transplant recipients
• people with significant burns

Other viruses that cause pneumonia in immunocompromised host:

• measles
• CMV
• HHV-6

Question 11

Which agents that cause pneumonia would be considered typical and atypical?

Answer 11

Typical:

• Streptococcus pneumonia
• Haemophilus influenza
• Staph aureus
• Group A strep

Atypical: (typically don’t have a cell wall; resistant to beta-lactams)

• mycoplasma pneumonia
• chlamydia pneumoniae
• C. pstticae
• Legionella pneumophilia
• Mycobacterium TB

Question 12

What S+S would CAP caused by ‘typical’ organisms present with?

Answer 12

Symptoms:

• sudden onset of chills/fever
• pleuritic chest pain
• productive cough (thick, purulent, may be rusty coloured)
• dyspnoea
• tachypnoea

Signs:

• raised WBC
• crackles
• consolidation or fluid –> dullness to percussion
• reduced breath sounds

Question 13

What S+S would CAP caused by ‘atypical’ organisms present with?

Answer 13

• insidious onset
• non-productive cough
• fever
• headache
• vague symptoms

Question 14

How are x-ray presentations of pneumonia classified? How would CAP caused by bacteria appear on x-ray?

Answer 14

Classifications:

• Lobar pneumonia
• Broncho/lobular pneumonia
• interstitial pneumonia

Bacterial CAP:
- classically show lung consolidation of one lung segmental lobe = lobar pneumonia
Other patterns:
- Aspiration pneumonia may present with bilateral opacities primarily in the bases of the lungs and on the right side

Question 15

How would viral pneumonia appear on x-ray?

Answer 15

• may appear normal
• appear hyper-inflated
• bilateral patchy areas
• or present similar to bacterial pneumonia with lobar consolidation

Question 16

What is Legionnaires’ disease? What is the pathophys?

Answer 16

• form of atypical pneumonia
• can be caused by any type of legionella bacteria

Pathophys:

• Legionella spp. enter the lungs either by aspiration of contaminated water or inhalation of aerosolized contaminated water or soil
• In the lung, the bacteria are consumed by macrophages inside of which the Legionella bacteria multiply, causing the death of the macrophage
• Macrophage dies, and bacteria are released from the dead cell to infect other macrophages
• Virulent strains of Legionella kill macrophages by blocking the fusion of phagosomes with lysosomes inside the host cell; normally, the bacteria are contained inside the phagosome, which merges with a lysosome, allowing enzymes and other chemicals to break down the invading bacteria

Question 17

What are the S+S of Legionnaires’ disease? (include lab findings + CXR)

Answer 17

• fevers + chills
• productive/non-productive cough
• muscle ache
• headache
• tiredness
• loss of appetite
• ataxia
• chest pain
• diarrhoea
• vomiting

Lab findings:

• hyponatraemia
• increased urea
• LFTs abnormal

CXR:
- consolidation in bottom portion of both lungs

Question 18

How is Legionnaires’ disease treated?

Answer 18

• respiratory tract quinolones (levofloxacin, moxifloxacin, gemifloxacin)
• newer macrolides (azithromycin, clarithromycin, roxithromycin)
• antibiotics used most frequently: levofloxacin, doxycycline, and azithromycin.

Question 19

How is bacterial CAP treated?

Answer 19

• Treatment before culture results: amoxicillin is recommended as the first line –> doxycycline or clarithromycin as alternatives
• Atypical CAP: macrolides (such as azithromycin or erythromycin), and doxycycline

Question 20

How is HAP treated?

Answer 20

• third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and vancomycin
• -> give intravenously

Question 21

What is CURB 65?

Answer 21

• Used to assess the severity of pneumonia
• Can predict mortality in CAP
• Each risk factor scores 1 point, max 5 points:
  1. Confusion of new onset (defined as an AMTS of 8 or less)
  2. Blood Urea nitrogen > 7 mmol/l (19 mg/dL)
  3. Respiratory rate >/= 30 breaths per minute
  4. BP < 90 mmHg systolic or diastolic blood pressure 60 mmHg or less
  5. Age >/= 65

Question 22

State which CURB scores are low/moderate/severe and how a patient should be managed according to their score.

Answer 22

0-1: Low –> treat at home; amoxicillin, doxycycline, clarithromycin

2: Moderate –> short stay in hosp/watch closely as outpatient; Amoxicillin or benzylpenicillin + clarithromycin OR doxycycline or levofloxacin as alternatives

3+: Severe –> requires hospitalisation; co-amoxiclav + clarithromcyin/ benzylpenicillin + levofloxacin/ ciprofloxacin/ cefotaxime

Question 23

What vaccines against pneumonia are available?

Answer 23

1. Pneumococcal polysaccharide vaccine (PPV) = Pneumovax
   - 23 different strains
   - 2-3 weeks for strain specific antigen to develop
2. Pneumococcal conjugated vaccine = Prevenar
   - 13 different strains

Question 24

How often should the vaccine be taken? Who should be given the vaccine?

Answer 24

Take every 5 years
Indications for vaccination:
- >/=65 y/o
- DM not controlled by diet
- immunosuppression 
- CHF, liver, renal or lung conditions