Acute pharyngitis

Acute pharyngitis
Classification and external resources
Viral pharyngitis. The oropharynx is swollen and red.
ICD-10	J02., J31.2
ICD-9	462, 472.1
DiseasesDB	24580
MedlinePlus	000655
eMedicine	emerg/419
MeSH	D010612

Pharyngitis (pronounced /ˌfærɪnˈdʒaɪtɪs/) is an inflammation of the throat or pharynx.^[1] In most cases it is painful and the initial infection can extend for a lengthy time period. It is the most common cause of a sore throat.^[2]

Like many types of inflammation, pharyngitis can be acute – characterized by a rapid onset and typically a relatively short course – or chronic. Pharyngitis can result in very large tonsils which cause trouble swallowing and breathing. Pharyngitis can be accompanied by a cough or fever, for example, if caused by an upper respiratory tract infection.

Most acute cases are caused by viral infections (40–80%), with the remainder caused by bacterial infections, fungal infections, or irritants such as pollutants or chemical substances.^[2][3] Treatment of viral causes are mainly symptomatic while bacterial or fungal causes may be amenable to antibiotics and anti-fungals respectively.

Classification

Acute pharyngitis is one type of upper respiratory tract infection.

Cause

The majority of cases are due to an infectious organism acquired from close contact with an infected individual.

Viral pharyngitis

A throat infection which tested negative for streptococcus thus presumably of viral origin. Note the white exudate on the tonsils which frequently also occurs with a viral infection.

These comprise about 40–80% of all infectious cases and can be a feature of many different types of viral infections.^[2][3]

• Adenovirus – the most common of the viral causes. Typically the degree of neck lymph node enlargement is modest and the throat often does not appear red, although it is very painful.
• Orthomyxoviridae which cause influenza – present with rapid onset high temperature, headache and generalised ache. A sore throat may be associated.
• Infectious mononucleosis ("glandular fever") caused by the Epstein-Barr virus. This may cause significant lymph gland swelling and an exudative tonsillitis with marked redness and swelling of the throat. The heterophile test can be used if this is suspected.
• Herpes simplex virus can cause multiple mouth ulcers.
• Measles
• Common cold: rhinovirus, coronavirus, respiratory syncytial virus, parainfluenza virus can cause infection of the throat, ear, and lungs causing standard cold-like symptoms and often extreme pain.
• Primary HIV

Bacterial pharyngitis

A number of different bacteria can infect the human throat. The most common is Group A streptococcus, however others include Corynebacterium diphtheriae, Neisseria gonorrhoeae, Chlamydophila pneumoniae, and Mycoplasma pneumoniae.^[4]

Streptococcal pharyngitis

Streptococcal pharyngitis or strep throat is caused by group A beta-hemolytic streptococcus (GAS).^[5] It is the most common bacterial cause of cases of pharyngitis (15–30%).^[4] Common symptoms include fever, sore throat, and large lymph nodes. It is a contagious infection, spread by close contact with an infected individual. A definitive diagnosis is made based on the results of a throat culture. Antibiotics are useful to both prevent complications and speed recovery.^[6]

Fusobacterium necrophorum

Fusobacterium necrophorum are normal inhabitants of the oropharyngeal flora. Occasionally however it can create a peritonsillar abscess. In 1 out of 400 untreated cases Lemierre's syndrome occurs.^[7]

Diphtheria

Diphtheria is a potentially life threatening upper respiratory infection caused by Corynebacterium diphtheriae which has been largely eradicated in developed nations since the introduction of childhood vaccination programs, but is still reported in the Third World and increasingly in some areas in Eastern Europe. Antibiotics are effective in the early stages, but recovery is generally slow.

Others

A few other causes are rare, but possibly fatal, and include parapharyngeal space infections: peritonsillar abscess ("quinsy"), submandibular space infection (Ludwig's angina), and epiglottitis.^[8][9][10] Some medications may produce pharyngitis such as pramipexole and antipsychotics.^[11][12]

Other causes

Fungal infections

Some cases of pharyngitis are caused by fungal infection such as Candida albicans causing oral thrush.

Diagnostic approach

It is hard to differentiate a viral and a bacterial cause of a sore throat based on symptoms alone. Thus often a throat swab is done to rule out a bacterial cause.^[13]

Management

The majority of time treatment is symptomatic. Specific treatments are effective for bacterial, fungal, and herpes simplex infections.

Medications

• Analgesics such as NSAIDs and acetaminophen can help reduce the pain associated with a sore throat.^[14]
• Steroids ( such as dexamethasone ) have been found to be useful for severe pharyngitis.^[15][16]
• Viscous lidocaine relieves pain by numbing the mucus membranes of the throat.^[17]
• Antibiotics are useful if a group A streptococcus is the cause of the sore throat. For viral infections, antibiotics have no effect.^[18]

Alternative

Alternative medicines are promoted and used for the treatment of sore throats.^[19] They are however poorly supported by evidence, and UpToDate, an evidence-based peer-reviewed resource, recommends that they not be used to treat pharyngitis.^[19][20]

Epidemiology

Acute pharyngitis is the most common cause of a sore throat and is diagnosed in more than 1.9 million people a year in the United States.^[2]

References