Acute viral nasopharyngitis overview

# Overview
Acute viral nasopharyngitis is a highly contagious viral infectious disease of the upper respiratory system primarily caused by rhinovirus and less commonly caused by picornaviruses or coronaviruses. Common symptoms are sore throat, runny nose, nasal congestion, sneezing, and cough sometimes accompanied by muscle aches, fatigue, malaise, headache, muscle weakness, or loss of appetite. Fever and extreme exhaustion are more common in influenza. The symptoms of a cold usually resolve after about one week, but can last up to 14 days. Symptoms may be more severe in infants and young children. Although the disease is generally mild and self-limiting, patients with the common cold often seek professional medical help, use over-the-counter drugs, and may miss school or work days. The annual cumulative societal cost of the common cold in the United States is billions of dollars. No vaccines are available. The primary method to prevent the infection is hand washing to minimize person-to-person transmission of the virus. There are no antiviral drugs approved to treat or cure the infection. Most available medications are palliative and treat symptoms only. Megadoses of vitamin C, preparations from echinacea, and zinc gluconate have been studied as treatments for the common cold, though none have been approved by the Food and Drug Administration or European Medicines Agency.

# Historical Perspective
Common cold was first considered a distinct diagnosis by Benjamin Franklin in the 18th century.

# Classification
There is no established classification system for acute viral nasopharyngitis.

# Pathophysiology
Rhinovirus (the most common cause of common cold) is usually transmitted via aerosols generated by coughing or sneezing. The entry point is usually the nose, however viruses can enter the body through the lacrimal ducts. Following transmission, the virus invades epithelial cells and causes a release of inflammatory cytokines, leading to the various symptoms of the common cold. The body responds using cellular and humoral immunity in addition to the role of bacterial flora in the defense against the organism.

# Causes
Acute viral nasopharyngitis is most commonly caused by an infection with rhinovirus. Other common causes include coronavirus, human parainfluenza viruses, and human respiratory syncytial virus (RSV).

# Differentiating Acute Viral Nasopharyngitis from other Diseases
Acute viral nasopharyngitis should be differentiated from other diseases that cause runny nose, cough, and constitutional symptoms such as influenza, allergic rhinitis, and acute sinusitis.

# Epidemiology and Demographics
Acute viral nasopharyngitis is the most common human infection worldwide, responsible for about half of all family physician visits. On average, adults get 2-3 common cold bouts per year and children get 6-10 infections per year and 500 out of every 1,000 family physician visits per year are due to acute viral nasopharyngitis. Males are more likely to be affected than females and Native Americans are more prone to develop complications.

# Risk Factors
Common risk factors for acute viral nasopharyngitis include having contact with an infected patient, spending time in daycare centers, presence of allergic rhinitis or immunocompromisation.
Despite that infection with common cold tend to have a seasonal pattern, there is no proven association between cold exposure or chilling and the occurrence of common colds.

# Natural History, Complications, and Prognosis
If left untreated, common cold resolves completely within 7-10 days. Common complications of acute viral nasopharyngitis include sinusitis, otitis media, and exacerbation of reactive airway disease. Prognosis is generally excellent. 50% of patients recover completely within 7 days and 90% of patients recover within 15 days.

# History and Symptoms
Symptoms of acute viral nasopharyngitis include runny nose, cough, and sore throat.

# Physical Examination
Patients with acute viral nasopharyngitis usually appear ill. Physical examination of patients with acute viral nasopharyngitis is usually remarkable for runny nose, hyperemic nasal mucosa, and mild cervical lymphadenopathy.

# Laboratory Findings
Laboratory findings consistent with the diagnosis of acute viral nasopharyngitis include positive viral culture, positive PCR, and leucocytosis in CBC.

# Imaging Findings
There are no X-ray, CT, MRI, or ultrasound findings associated with acute viral nasopharyngitis.

# Medical Therapy
The mainstay of therapy for acute viral nasopharyngitis is symptomatic treatment using palliative measures like fluids, rest and throat sprays. Analgesics, nasal decongestants and cough suppressants can be used to alleviate the symptoms. Antibiotics have no use in common cold as the disease is viral in origin and there is no approved antiviral drug for the common cold. Mega doses of vitamin C, Zinc and steam inhalation are not proved to be of benefit in treating common cold despite the wide belief of their use.

# Surgery
Surgical intervention is not recommended for the management of acute viral nasopharyngitis.

# Prevention
Effective measures for the primary prevention of acute viral nasopharyngitis include avoiding close contact with patients and washing hands regularly.