Acute Coryza And Parainfluenza As Common Viral Infections Of The Respiratory Tract

Several viruses cause the clinical picture of coryza. Of these, rhinoviruses are the most important and common. The disease spreads by droplet infection and the portal of entry is the upper respiratory tract. Epidermis are seen in early autumn, mid-winter and spring. Incubation period varies from a few hours to 3 or 4 days. Hyperemia and edema of the mucosa of the nose and rhinopharynx are the early lesions. Copious amounts of watery fluid rich in glycoproteins exude. After a short course, the disease spontaneously subsides completely without any residual damage.

Clinical features: Onset is abrupt with headache nasal congestion and obstruction. It is followed by sneezing and watery discharge from the nose, which becomes mucopurulent and tenacious later on. Mild fever (37.5 to 38⁰C) and muscle pains set in within a few hours. The whole course lasts for 2 to 3 days. Coryza predisposes to the development of secondary bacterial infection. Physical examination is negative except for nasal congestion, conjunctival injection and pharyngitis. Complications are sinusitis, infection of the lower respiratory tract and otitis media.

Diagnosis: Clinical diagnosis is easy. Secondary bacterial infection should be looked for. Coryza has to be distinguished from allergic rhinitis in which nasal congestion may be prominent. In this, there may be other signs of allergy like pruritus and asthma extending for long periods. The causative organisms of coryza can be cultures from throat washings or nasal swabs.

Treatment: Treatment is symptomatic. Confinement to home and avoidance of contact with others help to shorten the course of the illness and limit its spread. Aspirin, 600 mg given thrice daily provided asymptomatic relief of aches and pains. Medicated inhalations, throat lozenges and decongestant nasal drops are all helpful. Specific protection using vaccines which contain a few strains of rhinoviruses has been attempted on a limited scale.

This is caused by parainfluenza viruses which belong to the group of paramyxoviruses. These viruses are 80 to 120 nm in size. They cause respiratory infection. Based on antigenic differences, parainfluenza has nothing in common with influenza virus. Parainfluenza viruses affect mostly children. Mainly the respiratory tract is involved.

Clinical manifestations: After an incubation period of 5 to 6 days, it starts with fever which is a constant feature. Type I infection causes laryngotracheobronchitis of croup. Type II infection causes tracheobronchitis, bronchiolitis and bronchopneumonia in infants and children. Submandibullar lymph nodes may become enlarged and tender.

Complications: Include secondary bacterial infection leading to otitis media, sinusitis and bronchiectasis.

Treatment: There is no specific drug against this virus. Secondary bacterial infection has to be treated with antibiotics.