Pharyngitis.
Pharyngitis is defined as an infection or irritation of
the pharynx and / or tonsils. The etiology is usually infectious, with 40-60%
of cases being of viral origin and 5-40% of cases being of bacterial origin.
Other causes include allergy, trauma, toxins, and neoplasia.
The main concerns with pharyngitis are to rule out more
serious conditions, such as epiglottitis or peritonsillar abscess, and to
diagnose group A beta-hemolytic streptococcal (GABHS) infections. GABHS
infections can have serious sequelae.
Pathophysiology:
In infectious pharyngitis, bacteria or viruses may
directly invade the pharyngeal mucosa, causing
a local inflammatory
response. Other viruses,
such as rhinovirus, cause irritation
of pharyngeal mucosa secondary to nasal secretion.
Streptococcal infections are characterized by local
invasion and release of extracellular toxins and proteases. In addition, M
protein fragments of certain serotypes of GABHS are similar to myocardial
sarcolemma antigens and are linked to rheumatic fever and subsequent heart
valve damage.Acute glomerulonephritis may result from antibody-antigen complex
deposition in glomeruli.
Mortality / Morbidity:
·
One in 400 cases of
untreated GABHS infections can be expected to result in acute rheumatic fever.
·
Other sequelae of a
streptococcal pharyngitis include acute glomerulonephritis, peritonsillar
abscess, and toxic shock syndrome.
·
Mortality from
pharyngitis is rare but may result from one of its complications.
·
Age: The peak
incidence of bacterial and viral pharyngitis occurs in the school-aged child
aged 4-7 years.
·
Pharyngitis,
especially GABHS infection, is rare in children younger than 3 years.
Causes:
·
Bacterial
pharyngitis
* Group A beta-hemolytic streptococci (15% of
all pharyngitis)
·
The classic clinical
picture includes high fever of greater than, tonsillopharyngeal erythema and
exudates, swollen tender anterior cervical adenopathy, elevated WBC count,
headache, emesis in children.
·
A scarlatiniform
rash also is associated with GABHS infection (scarlet fever), ie, a sandpaper
like erythematous rash over the trunk and extremities with circumoral pallor
and a strawberry tongue.
* Group C, G, and F streptococci (10%) may
be indistinguishable clinically from GABHS infection but do not cause the
immunologic sequelae of GABHS infection. They may be associated with food-borne
outbreaks. Group C streptococci have been reported to cause meningitis,
endocarditis, and subdural empyemas.
* Viral pharyngitis
§ Adenovirus (5%): The distinguishing feature of an
adenovirus infection is conjunctivitis associated with pharyngitis
(pharyngoconjunctival fever). It is the most common etiology in children
younger than 3 years.
§ Herpes simplex (< 5%): Vesicular lesions
(herpangina), especially in young children, are the hallmark. In older
patients, pharyngitis may be indistinguishable from GABHS infection.
* Coxsackieviruses
A and B: These infections present
similarly to herpes simplex and also may have vesicles. If vesicles are whitish
and nodular, it is known as lymphonodular pharyngitis. Coxsackie A16 may cause
hand-foot-and-mouth disease, which presents with 4- to 8-mm oropharyngeal
ulcers and vesicles on the hands and feet, and, occasionally, on the buttocks.
The oropharyngeal ulcers and vesicles resolve within one week.
* Epstein-Barr
virus (EBV): Clinically known as infectious mononucleosis, it is extremely
difficult to distinguish from GABHS infection. Exudative pharyngitis is
prominent. Distinctive features include generalized adenopathy and hepatosplenomegaly.
Atypical lymphocytes can be seen on peripheral blood smear. Viral cultures from
washings are about 20% sensitive in adults.
·
CMV: Presentation of
CMV is similar to the presentation of infectious mononucleosis. Patients tend
to be older, are sexually active, and have higher fever and more malaise.
Pharyngitis may not be a prominent complaint.
·
HIV-1: This is
associated with pharyngeal edema and erythema, common aphthous ulcers, and a
rarity of exudates. Fever, myalgia, and lymphadenopathy also are found.
Lab Studies:
·
GABHS rapid antigen
detection test
·
This is the preferred method for diagnosing GABHS
infection. Rapid antigen detection is not sensitive for Group C and G
streptococci or other bacterial pathogens.
·
Throat culture
·
This is the
criterion standard for diagnosis of GABHS infection (90-99% sensitive).
·
Antistreptolysin-O
(ASO) is a highly sensitive test
·
Peripheral smear may
show atypical lymphocytes in infectious mononucleosis.
·
A Full blood count
(FBC), erythrocyte sedimentation rate (ESR), and C- reactive protein have a low
predictive value and usually are not indicated.
Imaging Studies:
·
Imaging studies
generally are not indicated for uncomplicated viral or streptococcal
pharyngitis.
·
Lateral neck film
should be taken in patients with suspected epiglottitis or airway compromise.
Emergency Care:
·
Assess and secure
the airway, if necessary.
·
Assess patient for
signs of toxicity, epiglottitis, or oropharyngeal abscess.
·
Evaluate the
hydration status, as severe pharyngitis limits oral intake.
·
Appropriate measures
to rehydrate should be initiated, including intravenous hydration.
The objective of medical therapy in pharyngitis, usually
antibiotic therapy, is to (1) decrease the duration of the illness and
infective period,
(2) provide symptomatic relief,
(3) decrease the incidence of relapses and complications
(eg, rheumatic fever). Steroids may be used for airway compromise and
symptomatic relief.
(4) Penicillins remain effective treatment options.
July 07, 2015
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