Acute viral nasopharyngitis pathophysiology

Acute viral nasopharyngitis Microchapters
Home
Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating acute viral nasopharyngitis from other diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
X-ray
CT
MRI
Ultrasound
Other imaging findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Primary Prevention
Secondary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Acute viral nasopharyngitis pathophysiology On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Acute viral nasopharyngitis pathophysiology All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
National Guidelines Clearinghouse
NICE Guidance
FDA on Acute viral nasopharyngitis pathophysiology
CDC on Acute viral nasopharyngitis pathophysiology
Acute viral nasopharyngitis pathophysiology in the news
Blogs onAcute viral nasopharyngitis pathophysiology
Directions to Hospitals Treating Osteoporosis
Risk calculators and risk factors for Acute viral nasopharyngitis pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Ahmed Younes M.B.B.CH [2]

Overview

Rhinovirus (i.e., the most common cause of common cold) is usually transmitted via aerosols, generated by coughing or sneezing. Following transmission, the virus invades the epithelial cells and causes the release of inflammatory cytokines, leading to the various symptoms of common cold.

Pathophysiology

Virus

Common colds are most often caused via infection by one of the more than 100 serotypes of rhinovirus, a type of picornavirus. Other viruses causing colds are coronavirus, human parainfluenza viruses, human respiratory syncytial virus, adenoviruses, enteroviruses, or metapneumovirus.

Transmission

Cold viruses are spread by aerosols created when a patient sneezes

The common cold virus is transmitted between people by one of two ways:

• In aerosol form generated by coughing, sneezing.
• Contact with the saliva or nasal secretions of an infected person, either directly or from contaminated surfaces.

• Asymptomatic patients can transmit the infection.
• The infectious period (time during which an infected person can infect others) begins about one day before symptoms begin, and continues for the first five days of the illness.
• The virus enters the cells of the lining of the nasopharynx and rapidly multiplies.
• The virus enters the body mainly through the nose. Other entry points include the eyes (through drainage of tears from the lacrimal ducts into the nasopharynx).

{{#ev:youtube|GoRhRJXp0j8}}

Pathogenesis

• Viruses undergo frequent changes in their antigenic coat. This helps the viruses to evade the immune system and enables them to cause recurrent infections.
• Rhinovirus binds to ICAM-1 receptors on epithelial cells. Binding to ICAM-1 receptors releases inflammatory cytokines but does not cause damage to epithelial cells.
• Respiratory syncytial virus (RSV) does not cause any release of cytokines. Instead, it replicates in the nose and pharynx. In many occasions, it can spread to the lower respiratory tract.
• Human parainfluenza virus causes inflammation of the tract and subsequently, parainfluenza infection is much more severe than other viruses.
• The body responds using both humoral immunity (IgA in the epithelium) and cell mediated immunity (different inflammatory cells in the adenoids and tonsils) to fight the offending virus.
• Normal flora inhabitants in the nasopharynx also play an important role in eliminating the infection.