Respiratory tract infections Flashcards
What are the most common URTIs ?
-Rhinitis
– Pharyngitis
– Laryngitis and epiglottitis
What are the most common LRTIs ?
-Tracheitis
– Bronchitis
– Parenchymal infection - pneumonia
What are the risk factors for LRTIs ?
- Age under 5 or over 65
- More common in winter than in summer
- Sick contacts
- Travel and smoking
- Immunosuppression
- Iatrogenic: such as steroids and Biologic agents.
- Stem cell transplant causing neurtopenia
- HIV with CD4 <500
- Anti-immunoglobuin antibodies
- Organ transplan.
what is acute bronchitis ?
It is acute bronchial infection and >90% cases are viral origin.
What is the presentation of acute bronchitis ?
The patients typically Present in GP setting with cough +/- small volume purulent sputum, mild systemic symptoms, and the natural course can be up to 8 weeks.
what is the management of acute bronchitis ?
No indication for antibiotics unless
– systemically unwell (Low blood pressure, fevers, signs of sepsis)
– evidence of pneumonia
– chronic lung disease eg COPD, bronchiectasis, asthma
What is the definition of pneumonia ?
An acute infection of the pulmonary parenchyma resulting in lung consolidation.
What are the aetiologies of pneumonia ?
Strep pneumoniae (60% of bacterial pneumonia)
– Mycoplasma pneumoniae (Younger people)
– Haemophilus influenza
– Staphylococcus aureus (MSSA)
– Other: Chlamydia pneumoniae, Legionella pneumophila
– Respiratory viruses (Influenza, COVID in older people)
What is the mortality rate in pneumonia ?
- Less than 1 to 5 % in out-patient setting.
- Patients with community acquired pneumonia who are hospitalized will have 10% mortality.
- In ICU cases the mortality approaches 40%.
What is Hospital-acquired pneumonia?
Hospital-acquired pneumonia (HAP) is pneumonia acquired after 48 hours of admission to hospital.
What is Ventilator-associated pneumonia?
Ventilator-associated pneumonia (VAP) is pneumonia occurring more than 48 hours after endotracheal intubation.
What are the aetiologies of HAP and VAP?
Aerobic gram negative bacilli: Pseudomonas aeruginosa,
Escherichia coli, Klebsiella pneumoniae,
– Resistant bacteria: MRSA
– Fungi – aspergillus or candida
What are the risk factors for pneumonia ?
- Smoking
- Alcohol
- Malnutrition
- ≥ 65 years
- Immunosuppression
- Altered level of consciousness (aspiration of food/vomit)
- Chronic lung disease eg. COPD/Bronchiectasis
What is the Dx criteria of pneumonia ?
evidence of lung consolidation+ pleuritic chest pain or focal crepitations on auscultation+ opacification on chest xray or on CT thorax.
What are the signs of pneumonia ?
- Tachypnoea
- Tachycardia
- Hypotension
What are the signs of consolidated lung ?
– Increased vocal fremitus on affected side
– Dull percussion over consolidated lung
– Bronchial breathing
– Crackles (crepitations)
– Increased vocal resonance
– Pleural rub
what are the ddx of Pneumonia ?
- Exacerbation of underlying lung disease
- Lung cancer with post-obstructive pneumonia
- Foreign body aspiration
- Opportunistic infection- eg. Pneumocystis jirovecii pneumonia in
HIV/AIDS - Mycobacterium tuberculosis
What are the blood findings in pneumonia ?
Venous Bloods
– FBC: elevated WCC (or decreased in elderly / HIV / COVID)
– Renal profile (U&E):
* Determine baseline renal function/acute kidney injury in setting of
sepsis.
* Urea is a component of CURB-65 score
* Hyponatraemia in legionella pneumonia
– CRP (Non-specific marker of inflammation)
– LFTs: mycoplasma and legionella associated with hepatic transaminitis
– Blood cultures
* Arterial blood gas
– Degree of hypoxia
– Elevated lactate if septic
What is CURB 65 score ?
- Confusion (AMTS ≤ 8 or new disorientation)
- Urea > 7 mmol/L
- Resp rate ≥ 30/min
- Systolic BP < 90 mmHg OR Diastolic BP ≤ 60 mmHg
- Age ≥ 65 years
What is the use of CURB 65 score in Community acquired pneumonia ?
CURB 65 score 0 to 1 = Low mortality suitable for home.
CURB 65 score 2= Intermediate mortality, consider hospital supervised Tx.
CURB 65 score 3 or more = High mortality Severe pneumonia ICU management.
What is the management approach in pneumonia ?
- Stabilise patient; assess and manage for sepsis
- Oxygen therapy as appropriate
- Anti-pyretics (Paracetamol / NSAIDS)
- Antimicrobial therapy
- Chest physiotherapy for clearance of secretions.
- Nebulised saline and bronchodilators may assist secretion clearance in some patients.
What is the antibiotic Tx in mild CAP?
Amoxicillin 500 mg – 1 gram TDS + Clarithromycin 500mg BD
What is the antibiotic Tx in Hospitalised patient with moderate to severe CAP and or cardiovascular or respiratory illness?
1st line: Co-amoxiclav 1.2g IV TDS AND Clarithromycin 500 mg BD PO
OR
– 3rd generation Cephalosporin eg Cefuroxime 1.5 g tds iv AND
Clarithromycin 500 mg BD PO.
– 2nd line if penicillin-allergic: Levofloxacin 500 mg OD PO OR Moxifoxacin 400 mg OD PO.
What is the Tx of Hospital-Acquired pneumonia ?
*Important to broaden gram-negative cover and in particular for
Pseudomonas +/- MRSA.
*1st line: Piperacillin/Tazobactam 4.5 g tds IV +/- Vancomycin 1g BD IV
