Respiratory Tract Infections

• the normal upper respiratory tract is colonised with bacteria. Some of these are potentially pathogenic.

  • staphylococcus
  • streptococcus
  • s. pneumoniae
  • viridans streptococcus
  • haemophilus
  • anaerobes

  The alveoli also contain a microbiome of normal microbes.
• Viral rhinosinusitis

  • less than 10 days
  • self-resolving
  • rhinovirus
  • influenza
  • parainfluenza
• Bacterial rhinosinusitis

  • bi-phasic illness
  • more than 10 days
  • secondary infection to allergic/viral rhinitis
  • streptococcus pneumoniae
  • haemophilus influenzae
  • moraxella catarrhalis
• Red flags for rhinosinusitis

  • severe/persistent headache
  • periorbital oedema
  • visual changes
  • ophthalmoplegia
  • cranial nerve palsy
  • altered mental state
  • neck stiffness
  • papilloedema
• Complications of rhinosinusitis

  • pre-orbital/orbital cellulitis
  • subperiosteal abscess
  • osteomyelitis of sinus
  • meningitis
  • intracranial abscess
  • septic cavernous sinus thrombosis
• Viral rhinosinusitis will self-resolve. Supportive therapy with analgesics, intranasal steroids (> 10 days) and decongestants.
• Bacterial rhinosinusitis will self-resolve. Supportive therapy:

  • can give back up antibiotics to be taken if not resolving in 5-7 days.
  • evidence is poor
  • follow up 3-5 days following treatment or not improving
• Common Cold - a benign self-limiting syndrome caused by 200+ subtypes of virus. Most common are rhinovirus (50%), coronavirus (25%), influenza (15%), parainfluenza (5%) and RSV (5%).
• Common cold is spread by direct transmission.

  • hand contact - survives up to 2 hours on skin
  • sneezing or coughing - tissues do not support virus transmission
  • large droplets - from close contact or 8 hours on external surface
• The common cold is normally self-limited and uncomplicated. Effective treatments include supportive, nasal decongestant/antihistamine combination and analgesics.
• Ineffective treatments for common cold

  • antibiotics
  • antivirals
  • vitamin C
  • echinacea
  • codeine
  • intranasal glucocorticoid
• Potential complications of common cold

  • acute rhinosinusitis
  • lower respiratory tract infection
  • asthma exacerbation
  • acute otitis media
• Acute pharyngitis (tonsillitis)

  • examination will often reveal swollen tonsils and lymph glands
• Tonsillitis caused by adenovirus/rhinovirus/coronavirus

  • 25-45% of cases
  • fatigue
  • nasal congestion
  • cough
• Tonsillitis caused by Group A (or C/G) streptococcus

  • 10-25% of cases
  • acute onset sore throat and fever
  • patchy tonsillar exudate and pharyngeal oedema
  • tender anterior cervical lymphadenopathy
  • scarlatiniform rash
• Tonsillitis caused by infectious mononucleosis (Epstein-Barr virus)

  • high fever
  • prominent posterior cervical lymphadenopathy
  • splenomegaly and atypical lymphocytosis
• Viral tonsillitis will self-resolve with supportive measures. GBS tonsillitis will need penicillin antibiotics.
• Bronchiolitis

  • viral infection of the small airways
  • URTI prodrome followed by secondary inflammation of bronchi/bronchioles
  • caused by RSV
  • seasonal outbreaks in autumn and winter
  • leading cause of admission for young children
• Risk factors for severe bronchiolitis

  • prematurity
  • low birth weight
  • age < 12 weeks
  • chronic lung disease
  • anatomic defects
  • congenital heart disease
  • immunodeficiency
  • neurological disease
• Clinical course of bronchiolitis

  • day 0 - URTI symptoms
  • day 2 - LRTI symptoms
  • day 3-5 - peak illness
  • day 15 cough resolves

  90% fully resolve within 3 weeks
• Bronchiolitis will normally self-resolve. NICE guidance promotes supportive care and NIV for respiratory failure. Discharge when clinically stable, taking oral fluids and SpO2 sats > 92%
• Bronchiolitis should NOT be treated with:

  • antibiotics
  • hypertonic saline
  • adrenaline (nebulised)
  • salbutamol
  • montelukast
  • ipratropium bromide
  • systemic or inhaled corticosteroids
• Infectious pneumonia symptoms

  • high fever and chills
  • clamminess and blueness
  • cough with sputum or phlegm, shortness of breath, pleuritic chest pain and haemoptysis
  • headaches, loss of appetite and mood swings
  • low blood pressure
  • high heart rate
  • nausea and vomiting
  • joint pain
• CURB 65 severity score

  • confusion
  • urea > 7.0 mmol
  • respiratory rate > 30
  • blood pressure < 90 systolic or < 60 diastolic
  • > 65 years old

  score = 1-2 admit to hospital

  score 3-5 admit to intensive care
• Typical causes of community acquired pneumonia

  • can be viewed on gram stain
  • sensitive to beta-lactams (penicillin)
  • streptococcus pneumoniae
  • haemophilus influenzae
  • moraxella catarrhalis
  • staphylococcus aureus
  • Group A strep
  • Aerobic gram -ve
  • Anaerobes (associated with aspiration)
• Atypical causes of community acquired pneumonia

  • cannot be viewed on gram stain
  • often require non beta-lactam (doxycycline or clarithromycin)
  • legionella
  • mycoplasma pneumoniae
  • chlamydia pneumoniae
  • chlamydia psittaci
  • coxiella burnetii
• Viral, fungal and tuberculosis account for 1/3 of cases of community acquired pneumonia.

  • influenza A + B
  • rhinovirus
  • parainfluenza
  • RSV
• Hospital acquired pneumonia

  • pneumonia that occurs after > 48 hours after admission to hospital
  • risk increased by mechanical ventilation
  • pathogens
  • s. aureus (including MRSA)
  • pseudomonas aeruginosa
  • klebsiella
  • enterobacter
  • acinetobacter
  • e. coli
• Treatment for community acquired pneumonia

  • penicillin e.g. amoxicillin (covers typical)
  • tetracycline e.g. doxycycline or macrolide e.g. clarithromycin (covers atypical)
• Treatments for hospital acquired pneumonia

  • broad spectrum penicillin or carbopenum e.g. co-amoxiclav
  • aminoglycoside e.g. gentamicin
• Complications of pneumonia

  • pleural effusion
  • empyema (pus in the pleura)
  • respiratory failure
  • acute respiratory distress syndrome
  • cavitating disease
  • abscess