Parainfluenza infection

Disease Description (Causes and Symptoms)

• Cause: A respiratory infection caused by parainfluenza viruses (of the Paramyxoviridae family). It is mainly transmitted through droplets and contact.
• Pathophysiology: It causes upper respiratory tract infection and, in children, may cause laryngeal involvement (laryngospasm, croup), leading to airway obstruction; when it spreads to the lower respiratory tract, it may progress to bronchiolitis or pneumonia.
• Main symptoms: Fever, cough (barking cough), wheezing, inspiratory noise (stridor), runny nose, sputum, loss of appetite, vomiting, enlarged tonsils, and erythematous tympanic membranes. In severe cases, tachypnea, intercostal retractions, hypoxemia, and altered consciousness may occur.
• Diagnostic summary: Detection of the virus in respiratory secretions (nasopharyngeal swabs/aspirates/laryngeal secretions)—nucleic acid amplification testing (PCR) or cell culture is used. In cases of severe respiratory symptoms, chest imaging, oxygen saturation measurement, blood tests, and other tests may be added.

Treatment Methods

• General principles: Most cases can be managed with symptomatic treatment (supportive care). Provide fluids, use antipyretics if necessary, and encourage rest.
• Medications/Procedures:
  • For laryngitis (croup) and breathing difficulties in children: Short-term administration of inhaled epinephrine (via nebulizer) and oral or injectable corticosteroids (e.g., dexamethasone) to relieve airway swelling.
  • In cases of hypoxemia: Oxygen therapy.
  • If bacterial complications (such as sinusitis, otitis media, or secondary bacterial pneumonia) are suspected, administer appropriate antibiotics.
  • In cases of severe airway obstruction or respiratory failure: Airway management (endotracheal intubation) and mechanical ventilation may be necessary.
• Lifestyle management: Use a humidifier to relieve airway mucus, drink sufficient fluids, rest, and use antipyretics when fever occurs (acetaminophen/ibuprofen).
• Precautions:
  • If inspiratory noise or breathing difficulties worsen in infants or young children, immediate emergency evaluation is necessary.
  • Steroids and epinephrine must be used according to a doctor's instructions; repeated administration or long-term use may cause side effects.
  • Antibiotics are ineffective against viral infections and should be used only when complications are suspected.

Checklist Before an Outpatient Visit (Including Example Questions)

Items/Information to Prepare:

• List of medications and supplements currently being taken (including doses and administration times)
• Medical history (especially asthma, heart disease, and whether the patient is immunocompromised), and records of recent hospitalizations or surgeries
• Recently measured temperature, respiratory rate and oxygen saturation (if available), and the timing and course of symptoms (factors that worsen or improve them)
• Frequency and timing of breathing difficulties (such as at night or during exercise), changes in feeding and sleep, and changes in food intake
• Copies of previous test results (chest X-ray, PCR, etc.), if available

Examples of Symptoms to Report to Healthcare Professionals First During an Outpatient Visit:

• Breathing difficulties (rapid breathing, chest/intercostal retractions), bruising or cyanosis, decreased consciousness
• Inability to eat or markedly reduced fluid intake

Examples of Questions to Prepare Before an Outpatient Visit (for the Patient):

• When did the symptoms begin, and what was the first symptom?
• Are there any circumstances associated with worsening or improvement of the symptoms (for example, are they worse at night)?
• Is anyone in the family experiencing similar symptoms, or has anyone recently had a respiratory infection?

Examples of General Questions to Ask the Doctor

• What are the side effects of this medication (e.g., steroids or nebulized epinephrine)?
• What is the prognosis for this infection? Is there a possibility of recurrence or long-term complications?
• What are the criteria for going to the hospital immediately if symptoms worsen at home (emergency signs)?
• If there is an underlying condition (such as asthma), what additional measures should be taken for management and prevention?

Examples of Disease-Specific Questions

• Our (or our child's) cough is worse at night, and inspiratory noise can be heard. When should we consider visiting the emergency room or endotracheal intubation?
• How quickly will symptoms improve after administering steroids (or nebulized epinephrine), and what are the criteria for additional doses or hospitalization?

(Emergency signs: Persistent or worsening chest retractions, oxygen saturation of 92% or lower, severe lethargy or a comatose state, or inability to maintain hydration due to repeated vomiting require an immediate visit to the emergency room.)