Erin A. Lyden
Pharyngitis and Tonsillitis
Immediate emergency department referral or physician consultation is indicated for pharyngeal abscess.
Definition and Epidemiology
Pharyngitis is a condition that encompasses inflammation of the pharynx from either infection or irritation.1 An illness affecting both children and adults, pharyngitis is a common reason for people to seek health care and accounts for around 6% of visits to health care providers.2 Pharyngitis can manifest as an acute illness or a chronic condition. The causes are numerous and include both infectious and noninfectious agents.1
Noninfectious causes of pharyngitis include referred pain, allergies, trauma from foreign bodies or burns, cancer, and irritation. Irritation of the pharynx may result from dust, smoke, dryness, or toxins, either inhaled or swallowed.1,2
Infectious agents responsible for pharyngitis include viruses, bacteria, and, uncommonly, fungi or parasites. Viral infection is the most common cause of pharyngitis in all age groups and can occur during any season.1–3 Viruses are responsible for 30% to 60% of cases in adults. In those cases the most common cause is the rhinovirus.1 Other responsible agents include Epstein-Barr virus (which causes mononucleosis), herpes simplex virus, influenza virus, parainfluenza virus, and coronavirus.1,4
Bacterial pharyngitis is more common in children (30% to 40%), peaking at ages 5 to 15, than in adults (5% to 10%).1,2 Streptococcus pyogenes is the etiologic agent for an estimated 15% to 30% of acute pharyngitis cases.5 S. pyogenes includes groups A, C, and G β-hemolytic streptococci. Group A β-hemolytic Streptococcus (GAS) is the most important to identify because it is responsible for acute rheumatic fever (ARF) and poststreptococcal glomerulonephritis. Infection with GAS typically peaks in the late winter and early spring, but it can be seen year-round.1,2,6 Group C disease is more common among college students and adolescents. Community-wide and food-borne causes of pharyngitis have been connected to group G organisms.1 Other offending agents include mycoplasmas, Arcanobacterium haemolyticum, chlamydiae, Neisseria gonorrhoeae, corynebacteria, and anaerobic bacteria.1
Tonsillitis and pharyngitis are similar in clinical presentation, physical findings, diagnosis, and management (Fig. 101-1). Tonsillitis is an acute or chronic inflammation of the tonsils and usually results from GAS infection, although it may be caused by other bacteria or viruses. Tonsillitis may not be a concern unless the patient is symptomatic.
Pathophysiology
The normal flora of the oral pharynx region consists of various and numerous microorganisms. These microorganisms are not harmful unless the immune system is weakened, resulting in increased susceptibility to illness. Pharyngitis or tonsillitis develops from exposure to a viral or bacterial agent, although some people can harbor or be colonized with pathogenic bacteria and remain free of infection.1
Clinical Presentation
The clinical presentation of pharyngitis or tonsillitis varies according to the offending agent. Noninfectious pharyngitis has an initial appearance somewhat different from that of infectious pharyngitis. Typically, with noninfectious pharyngitis the patient reports a sore throat and dryness; if environmental allergens are the cause, symptoms often include rhinorrhea, watery eyes, and postnasal drip. Patients receiving radiation therapy or chemotherapy may report pain, dryness, and dysphagia. Oropharyngeal candidiasis (thrush) may be present in these patients secondary to the immunosuppression.
The infectious causes of pharyngitis or tonsillitis are bacterial and viral. The presentation of symptoms can be similar. Viral causes are more common, and patients typically report the sudden onset of a sore throat, fever, malaise, cough, headache, myalgias, and fatigue. Patients may also report rhinitis, conjunctivitis (adenovirus), congestion, and a cough with sputum production.7
One of the most common causes of bacterial pharyngitis or tonsillitis is GAS. In the winter months, it is estimated that 15% to 25% of pharyngitis cases in children are caused by GAS.5,7 This disease is most prevalent in children younger than 15 years. The transmission of GAS is by direct contact with respiratory secretions or large droplets, and the incubation period can be 2 to 5 days. It is often spread in the classroom setting.5,7
Patients may report a sudden onset of sore throat, painful swallowing, fever (temperature higher than 38.5° C [101.3° F]), chills, headache, nausea, vomiting, and abdominal pain.1,5,7 With bacterial pharyngitis, rhinitis, cough, conjunctivitis, and myalgias are not typically present.6,7
Other bacterial causes should be investigated if indicated because N. gonorrhoeae and Chlamydia organisms can cause pharyngitis. Other bacteria, such as group C and G streptococci, Mycoplasma pneumoniae, and A. haemolyticum, can be involved.7 These patients often report mild throat discomfort in addition to urethritis or vaginitis.
Physical Examination
In viral pharyngitis, findings include fever, cough, nasal symptoms, and mild erythema with little or no pharyngeal exudate, although the pharynx may appear swollen, boggy, or pale. Painful or tender lymphadenopathy is not typically present. Infectious mononucleosis typically produces headache, fatigue, high fever, pharyngeal erythema, tonsillar hypertrophy, white to gray-green exudate, petechiae at the junction of the hard and soft palate, and posterior cervical adenopathy. Hepatomegaly and splenomegaly may be identified in less than 50% of patients. Jaundice may be present, but that is unusual.1,4,6
In GAS infection, the physical examination reveals marked erythema of the throat and tonsils; patchy, discrete, white or yellowish exudate; pharyngeal petechiae; and tender anterior cervical adenopathy (see Fig. 101-1). Patients with previous exposure to GAS may exhibit the typical diffuse exanthem of scarlet fever, a sandpaper-type rash, and erythematous (strawberry) tongue.1,6
Pressure on the tonsillar pillars may produce purulent drainage. The uvula may also be edematous, and temperature higher than 38.3° C (101° F) is typical. On occasion, GAS infection may be seen with an erythematous, persistent sore throat with little fever and no exudate.1,6
Diagnostics
Although it is sometimes difficult to differentiate between viral and bacterial pharyngitis and tonsillitis, clinical presentation may indicate the diagnosis. No specific diagnostic test exists for viral pharyngitis.1
Diagnostic studies used to detect GAS infection include a throat culture, a rapid antigen detection test (RADT), and sometimes an antistreptolysin O (ASO) titer. The ASO titer is not used during initial diagnostic screening but is obtained to identify or to confirm a diagnosis of GAS infection weeks to months later. The RADT is often used because it is rapid and convenient. However, the RADT is less sensitive (true positives) than a throat culture. If the diagnosis of GAS infection is suspected and the RADT result is negative, a throat culture is performed for confirmation. A complete blood count (CBC) often reveals leukocytosis with GAS infection.
Many studies have evaluated the efficacy of a clinical scoring system in the diagnosis of GAS pharyngitis. Many medical societies have recommended various clinical indicators in an attempt to standardize diagnosis. The Centor criteria—tonsillar exudates, swollen and tender anterior cervical lymph nodes, lack of cough, and history of fever—have proved to be predictive of a positive diagnosis in adult patients.5 To calculate a Centor score for an individual patient, 1 point is added for each of the following findings: absence of cough, tonsils with exudates or swelling, tender and swollen anterior cervical nodes, and temperature higher than 38° C (100.4° F); thus the score can range from 1 to 4.8 Some sources use age to modify the score, subtracting 1 point if the patient is over 45.3,5
There remains disagreement concerning the precise use of the Centor score to guide diagnosis and testing. The differences in recommendations arise from concern about potential sequelae of rheumatic fever.3 Some U.S. guidelines (Infectious Diseases Society of America, American Heart Association [AHA], American Academy of Pediatrics, and Institute for Clinical System Improvement) recommend culture and RADT testing based on presence of history of exposure to streptococci, previous history of rheumatic fever or poststreptococcal glomerulonephritis, or clinical signs and symptoms suggestive of streptococcal infection.3 In addition, the AHA guidelines recommend throat culture, even if the RADT is negative.3 The American College of Physicians–American Society of Internal Medicine (ACP-ASIM) guidelines use a Centor score of 2 to 3 to recommend testing with RADT with throat culture. In the ACP-ASIM guidelines, a Centor score of 4 indicates a presumptive diagnosis of GAS and confirmatory testing is not necessary.3
An investigation conducted in a large retail health system found that use of local biosurveillance data on the recent local proportion positive (RLPP) streptococci results on throat culture or DNA probe test to modify the Centor score improved the score’s ability to predict GAS infection.9 American College of Physician guidelines do not recommend testing adults with Centor scores of 0 or 1; the retail health system study found that in times of high RLPP, those patients with a Centor score of 0 typically have only a 15% risk for GAS, yet those with a Centor score of 1 when there is high RLPP should be tested because their risk is increased.9
Diagnostics
Pharyngitis and Tonsillitis
