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• Diseases of the Respiratory System


  • Upper Respiratory tract infection
  • Upper airway obstruction
• Upper Respiratory Tract Infections

  • Common cold
  • Acute pharyngitis
  • Otits media
• Common Cold


  More appropriately- rhino-sinusitis
• Common Cold


  • Commonly associated with rhinoviruses but a lot others can also give a similar syndrome
  • Occur year round
  • Average- 6 to 8 colds/year, 10-15% can have more than 12 attacks per year; 2-3/yr for adults
  • Out-of-home day care centers- 50% higher
• Portals of entry for Common Cold

  • Large aerosols
  • Small aerosols - influenza
  • Direct contact - rhinoviruses, RSV
• Pathogenesis of Common Cold

  Rhinoviruses and adenoviruses cause serotype specific protective immunity<|>Repeated infections because of the many serotypes<|>Influenza has antigenic variability – repeated infections with a single subtype<|>Parainfluenza and RSV have protective immunity that doesn't occur following infection
• Damage from Common Cold

  • No significant - rhinoviruses, RSV, and coronaviruses
  • Epithelial lining destruction-influenza viruses and adenoviruses
• Clinical features, diagnosis, & treatment of Common Cold


  Symptoms 1-3 days after viral infection, Sore or scratchy throat and rhinorrhea<|>Cough in 30% of cases<|>Influenza viruses, RSV, and adenoviruses- fever and other constitutional symptoms<|>Usual cold lasts for 1wk, 10%- 2 weeks<|>Treatment is symptomatic relief<|>Specific antiviral therapy is not currently available for rhinovirus infections
• Complications of Common Cold

  • Acute otitis media
  • Asthma exacerbation
  • Sinusitis
• Prevention of Common Cold

  Chemoprophylaxis or immunoprophylaxis is generally not available<|>Interrupting the chain involved in the spread of virus by direct contact may prevent colds
• Causes of Acute Pharyngitis


  • Viruses-adenoviruses, coronaviruses, enteroviruses, rhinoviruses, respiratory syncytial virus [RSV]
  • Group A β-hemolytic streptococcus (GABHS)
  • Other bacteria
• Streptococcal pharyngitis


  • Uncommon before 2–3 yr of age, has a peak incidence in the early school years, declines in late adolescence and adulthood
• Pathogenesis of Streptococcal pharyngitis

  Colonization with GABHS – asymptomatic carriage vs. acute infection<|>M-Protein is the major virulence factor, prevents phagocytosis by polymorphoneuclear neutrophils
• Scarlet Fever


  Circumoral pallor, strawberry tongue, sandpaper rash and resembles sunburn with goose pimples<|>Erythrogenic exotoxins A, B, C are responsible for development of scarlet fever<|>Result in fine papular eruptions<|>Scarlet fever can occur up to three times
• Clinical Features of Streptococcal pharyngitis

  Incubation period 2-5 days<|>Rapid onset, prominent sore throat<|>Headache and GI symptoms (abd. pain and vomiting)<|>Swollen, erythematous tonsils with exudate<|>Petechiae or "doughnut" lesions on the soft palate and posterior pharynx
• Clinical Features of Viral pharyngitis

  More gradual onset, and Symptoms more often include rhinorrhea, conjunctivitis, coryza, hoarseness, and cough
• Diagnosis of Streptococcal pharyngitis


  Throat culture remains an imperfect gold standard<|>The specificity of rapid tests to detect group A streptococcal antigen is high
• Treatment of Streptococcal pharyngitis

  GABHS remains universally susceptible to penicillin<|>Benzathine Penicillin<|>Oral Penicillin<|>Analgesics
• Complications of Streptococcal pharyngitis

  • Suppurative: Otitis media, Retropharyngal abscess, Peritonsillar abscess
  • Non-suppurative: Acute Glomerulonepheritis, Rheumatic Fever
• Otitis Media


  Inflammation of the middle ear nearly always preceded by an URTI
• Causes of Otitis Media in children


  • Haemophilus influenzae non type b (25%)
  • Moraxella catarrhalis (15%)
  • Streptococcus pneumoniae (25%)
  • Staphlococcus aureus (2%)
  • Viruses (min. 25%)
• Recurrent Otitis Media


  Defined as 3 or more episodes in 6 months, or 4 or more in a year
• Incidence of Otitis Media

  • Approximately 40% of children suffer one or more episodes before the age of 10 years
  • More cases are seen in the winter months
• Symptoms of Otitis Media

  Pain<|>Discharge can occur<|>Fever, vomiting and loss of appetite may occur, especially in young children<|>Irritability may be the only indication in infants<|>Hearing loss occurs if accumulation of fluid has taken place
• Signs of Otitis Media


  Change of colour of the tympanic membrane to pink/red<|>Bulging drum<|>Loss of outline of drum and landmarks<|>Discharge in meatus<|>Perforation<|>There may be tenderness over the mastoid
• Risk Factors for Otitis Media

  • Passive smoker
  • Male
  • Family history of otitis media
  • In day care
  • On formula feed
• Pathogenesis of Otitis Media

  Eustachian tube obstruction<|>Viral or bacterial upper respiratory tract infection<|>IgA deficiency in some children with recurrent AOM<|>Alterations in mucociliary clearance
• Complications of Otitis Media


  • Perforation
  • Mastoiditis
  • Meningitis, intracranial abscess or facial nerve palsy
  • Recurrent episodes may lead to atrophy and scarring of the eardrum, chronic perforation and otorrhoea, cholesteatoma, permanent hearing loss, chronic mastoiditis and intracranial sepsis with meningitis , brain abscess
• Antibiotic Treatment of Otitis Media

  Amoxycillin limited to three to five days<|>Clarithromycin or azithromycin are both effective and are active against the common pathogen H influenzae<|>Erythromycin may be useful, although it lacks activity against H. influenzae
• Other Treatment of Otitis Media

  Simple analgesia: Paracetamol, Ibuprofen (some evidence superior)<|>Wicking the ear with dry cotton for discharging ear
• Upper Airway Obstruction


  • Croup
  • Epiglotitis
• Viral Croup (laryngotracheobronchitis)


  Most common cause of stridor after neonatal period<|>Age: 3 months – 5years, peak is in the second year of life<|>Males are more frequently affected, Common in winter<|>Recurrence common till 3-6yrs and decreases with age<|>15 %have strong family history of croup
• Etiology of Viral Croup

  • Parainfluenza virus type I,II,III(75% of the cases)
  • Influenza A or B
  • RSV
  • Rhinovirus
  • Measles
  • Adenovirus
  • Mycoplasma pneumoniae
  • Diphteria (rarely)
• Clinical Manifestations of Viral Croup

  Patients usually have rhinorrhea, pharyngitis, mild cough & low grade fever 1–3 days before the signs and symptoms of upper airway obstruction become apparent<|>The child then develops the characteristic "barking" cough, hoarseness, and inspiratory stridor<|>Symptoms are worse at night, resolve within a week<|>Other Family members may have mild respiratory illness
• Croup Score


  Used to assess the degree of severity, components include: Level of consciousness, Cyanosis, Stridor, Air entry, Retractions
• Diagnosis of Viral Croup


  Made clinically<|>X-rays: If other causes being considered or in atypical or prolonged cases<|>Obtain lateral neck films and PA CXR<|>PA CXR in croup shows "steeple sign"<|>Throat examination best deferred
• Differential diagnosis of Viral Croup

  • Epiglottitis
  • Bacterial trachiatis
  • Foreign body aspiration
  • Retropharyngeal abscess
• Treatment of Viral Croup

  Supportive: Oxygen, IV fluid, Close monitoring<|>Often improvement after child has been in cold night air or moist air from shower<|>Antipyretics if fever present<|>Antibiotics not indicated<|>IV fluid hydration only if necessary<|>Stridor at rest or child in respiratory distress- treat with epinephrine and steroids<|>Intubation if respiratory failure or pending
• Specific Treatments for Viral Croup

  Racemic Epinephrine: Recommended to watch patient for 3 hrs before considering discharge<|>Dexamethasone: Steroids used with moderate to severe episodes of croup, 0.3-0.6 mg/kg IM stat<|>Tracheostomy: for impending respiratory failure (20%)
• Acute Epiglottitis (Supraglottitis)


  Acute inflammatory (infectious) process involving the epiglotis & its surrounding structures