LRTI Flashcards
What structures make up the lower respiratory tract?
- Trachea
- Primary bronchi
- Lungs
What are the most common LRTIs?
- Bronchitis
- Bronchiolitis
- Pneumonia
- Influenza
Which viral and bacterial pathogens can causes acute bronchitis?
Virus:
- adenovirus
- coronarvirus
- parainfluenza
- influenza
- rhinovirus
Bacteria:
- bordetella pertussis
- mycoplasma pneumonia
What is the most common cause of severe bronchiolitis (children <2 y/o)?
RSV
What are the symptoms of acute bronchitis?
- 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
How is acute bronchitis diagnosed and managed?
- Cough = 3wks +/- sputum
- If there are signs of consolidation, airway obstruction, fever, increases RR + HR then consider pneumonia, asthma, or pulmonary diseases
- 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
Define pneumonia.
Inflammation of the alveoli in either one or both lungs
What is the most common cause of community-acquired pneumonia?
Most common = strep pneumoniae (nearly 50%)
Other bacterial causes:
- Haemophilus influenzae in 20%,
- Chlamydophila pneumoniae in 13%
- Mycoplasma pneumoniae in 3%
What viruses commonly cause pneumonia?
viruses account for approximately a third and in children for about 15% of pneumonia cases.
- rhinoviruses
- coronaviruses
- influenza virus
- RSV
- adenovirus
- parainfluenza
In what cases would HSV cause pneumonia?
- newborns
- people with cancer
- transplant recipients
- people with significant burns
Other viruses that cause pneumonia in immunocompromised host:
- measles
- CMV
- HHV-6
Which agents that cause pneumonia would be considered typical and atypical?
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
What S+S would CAP caused by ‘typical’ organisms present with?
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
What S+S would CAP caused by ‘atypical’ organisms present with?
- insidious onset
- non-productive cough
- fever
- headache
- vague symptoms
How are x-ray presentations of pneumonia classified? How would CAP caused by bacteria appear on x-ray?
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
How would viral pneumonia appear on x-ray?
- may appear normal
- appear hyper-inflated
- bilateral patchy areas
- or present similar to bacterial pneumonia with lobar consolidation
What is Legionnaires’ disease? What is the pathophys?
- 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
What are the S+S of Legionnaires’ disease? (include lab findings + CXR)
- 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
How is Legionnaires’ disease treated?
- respiratory tract quinolones (levofloxacin, moxifloxacin, gemifloxacin)
- newer macrolides (azithromycin, clarithromycin, roxithromycin)
- antibiotics used most frequently: levofloxacin, doxycycline, and azithromycin.
How is bacterial CAP treated?
- 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
How is HAP treated?
- third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and vancomycin
- -> give intravenously
What is CURB 65?
- 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
State which CURB scores are low/moderate/severe and how a patient should be managed according to their score.
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
What vaccines against pneumonia are available?
- Pneumococcal polysaccharide vaccine (PPV) = Pneumovax
- 23 different strains
- 2-3 weeks for strain specific antigen to develop - Pneumococcal conjugated vaccine = Prevenar
- 13 different strains
How often should the vaccine be taken? Who should be given the vaccine?
Take every 5 years Indications for vaccination: - >/=65 y/o - DM not controlled by diet - immunosuppression - CHF, liver, renal or lung conditions
