CHAPTER 38
Pharyngitis
(Sore Throat)
Presentation
The patient with bacterial pharyngitis complains of a rapid onset of throat pain worsened by swallowing. There is usually sudden onset of the following: fever; pharyngeal erythema; edematous uvula; palatine petechiae; purulent, patchy yellow, gray, or white exudate; tender anterior cervical adenopathy; headache; and absence of a cough. Children who are younger than 3 years of age more often have coryza and are less likely to present with exudative pharyngitis. Viral infections are typically accompanied by conjunctivitis, nasal congestion, hoarseness, cough, aphthous ulcers on the soft palate, and myalgias. Children with viral pharyngitis can present with mouth breathing, vomiting, abdominal pain, and diarrhea. It is helpful to differentiate pain on swallowing (odynophagia) from difficulty swallowing (dysphagia); the latter is more likely to be caused by obstruction or abnormal muscular movement.
What To Do:
Obtain important historical information, including onset, duration, and progression of symptoms as well as the presence of associated fever, cough, respiratory difficulty, or swollen lymph nodes.
First, examine the ears, nose, and mouth, which are, after all, connected to the pharynx and often contain clues to the diagnosis. The pharynx should be evaluated for erythema, hypertrophy, foreign body, exudates, and petechiae (using a tongue blade). It is also important to assess the patient for fever, rash, cervical adenopathy, and coryza. Also, listen for the presence of a heart murmur and evaluate the patient for hepatosplenomegaly.
Patients usually fall into three clinical categories: those who appear to have Streptococcus pharyngitis, those who clearly have a viral illness, and those with symptoms of both. Scoring systems have been developed that can aid in decision making.
There are other uncommon causes of pharyngitis that should be kept in mind, such as primary human immunodeficiency virus (HIV) infection, diphtheria, as well as noninfectious causes, such as gastroesophageal reflux, postnasal drip, thyroiditis, allergies, and foreign bodies.
The Centor scoring system has been validated for adults and places people into high-, moderate-, and low-risk groups (for Streptococcus pharyngitis), based on four criteria: tonsillar exudates, tender anterior cervical lymphadenopathy, absence of a cough, and history of fever. High-risk patients have three or four positive criteria. Low-risk patients have zero or one positive criterion.
Patients in the low-risk category, in either scoring system, should be neither treated nor tested. Patients in the high-risk category may be treated empirically with antibiotics or tested and then treated if positive. Patients with moderate risk should be tested and only treated if positive for group A Streptococcus (GAS) infection.
Testing can be done with the rapid streptococcal test or with a throat culture. The throat culture will take at least 1 day to get results. According to some studies, the practice of treating high-risk patients without testing leads to significant overprescribing of antibiotics. Doing a culture or rapid streptococcal test on all moderate- to high-risk adult patients leads to the most appropriate use of antibiotics.
Children should be handled differently than adults when it comes to testing for GAS. Children have a higher risk of rheumatic fever and are much more likely to transmit GAS to others. Therefore, if rapid strep testing is used at the initial test and it is negative, a follow-up streptococcal culture is recommended. For this reason, initial testing with a throat culture may be the most cost effective practice in children.
When antibiotics are indicated, the first choice is penicillin V potassium (Pen-Vee K), 500 mg bid × 10 days, or oral solution 50 mg/kg/day divided bid × 10 days. If there is concern about compliance, give the penicillin IM, using penicillin G benzathine (Bicillin L-A), 1.2 million units IM × 1, or for the pediatric patient less than 27 kg, give 25,000 units/kg IM × 1.
In the penicillin-allergic patient, prescribe erythromycin base, 333 mg tid × 10 days or erythromycin ethyl succinate (EES) suspension 40 mg/kg/day divided bid × 10 days.
Cephalosporins can also be used, such as cefadroxil (Duricef), 500 mg bid × 10 days, or suspension 30 mg/kg/day divided bid × 10 days. Refractory cases may be treated with clindamycin 300 mg qid × 10 days or, for pediatric patients, 30 mg/kg/day divided qid × 10 days.
If mononucleosis is suspected, draw a test for atypical lymphocytes, and perform a heterophil antibody (monospot) test to confirm the diagnosis (see Chapter 32).
Relieve pain with acetaminophen or ibuprofen given on a regular basis rather than on an “as needed” basis. Warm saline gargles, and gargles or lozenges containing phenol as a mucosal anesthetic (e.g., Chloraseptic, Cepastat), may be soothing. Tessalon Perles may be bitten, with the anesthetic liquid held in the back of the throat and then swallowed. Gargling a 1:1 mixture of diphenhydramine and kaolin-pectin suspension can also provide temporary relief of throat pain.
For severe pain, in patients without contraindications, one dose of dexamethasone, 10 mg (0.6 mg/kg) IM or PO, or prednisone, 60 mg PO (in adults), has been used in conjunction with antibiotics and can provide a more rapid onset of pain relief. Narcotics can be considered for patients with severe pain.
What Not To Do:
Do not prescribe an antibiotic to patients with a clear viral infection (low-risk Centor or McIsaac scores). Treatment of viral pharyngitis with antibiotics is a major source of antibiotic resistance.
Do not miss scarlet fever, which is associated with group A beta-hemolytic Streptococcus (GABHS) pharyngitis and usually presents as a punctate, erythematous, blanchable, sandpaper-like exanthema. The rash is found in the neck, groin, and axilla and is accentuated in body folds and creases (the Pastia lines). The tongue may be bright red with a white coating (strawberry tongue).
Do not overlook acute epiglottic or supraglottic inflammation. In children, this presents as a sudden, severe pharyngitis, with a guttural rather than hoarse voice (because it hurts to speak), drooling (because it hurts to swallow), and respiratory distress (because swelling narrows the airway). Adults usually have a more gradual onset over several days and are not as prone to a sudden airway occlusion, unless they present later in the progression of the swelling and are already experiencing some respiratory distress.
Do not prescribe ciprofloxacin, tetracycline, doxycycline, and sulfamethoxazole/trimethoprim for acute pharyngitis. These drugs are considered to be ineffective.
Do not give ampicillin to a patient with mononucleosis. Although the resulting rash helps make the diagnosis, it does not imply ampicillin allergy and can be uncomfortable.
Do not overlook peritonsillar abscesses, which often require hospitalization and IV penicillin, incision and drainage, or needle aspiration. Peritonsillar abscesses or cellulitis causes the tonsillar pillar to bulge toward the midline. Patients typically have a toxic appearance and may present with a “hot potato voice.” With an abscess, there is a very tender, fluctuant, peritonsillar mass and asymmetric deviation of the uvula. Intraoral ultrasound examination or CT examination are diagnostic tests that can provide an accurate diagnosis if the clinical picture is unclear.
Do not overlook gonococcal pharyngitis in sexually active patients at risk. This can produce a clinical syndrome with fever, severe sore throat, dysuria, and characteristic greenish exudates that require special culture on Thayer-Martin medium or testing with a nucleic acid probe. This requires special treatment (see Chapter 83).
Do not overlook Kawasaki disease. A malady that most often affects children younger than 5 years of age, it has characteristic signs and symptoms that include sore throat, fever, bilateral nonpurulent conjunctivitis, anterior cervical node enlargement, erythematous oral mucosa, and an inflamed pharynx with a strawberry tongue. Within 3 days of the onset of fever, the patient will develop cracked red lips, a generalized erythematous rash with edema and erythema of the hands and feet, and periungual desquamation followed by peeling of the palms.
Do not overlook diphtheria. This acute upper respiratory tract infection is characterized by a sore throat, low-grade fever, and an adherent grayish membrane with surrounding inflammation of the tonsils, pharynx, and nasal passages with a serosanguineous nasal discharge.
Members of the general public know to see a doctor for a sore throat, but the actual benefit of this visit is unclear. Rheumatic fever is exceedingly rare in the United States and other developed countries (annual incidence less than one case per 100,000). Only 15% to 30% of cases in children and 5% to 15% of cases in adults are culture-positive GABHS pharyngitis. Poststreptococcal glomerulonephritis is usually a self-limiting illness and is not prevented with antibiotic treatment.
On the other hand, penicillin and other antibiotic therapies do prevent the rare development of acute rheumatic fever and may sometimes reduce symptoms or shorten the course of a sore throat. Antibiotics probably inhibit the infection from progressing into tonsillitis, peritonsillar and retropharyngeal abscesses, adenitis, and pneumonia.
Group A streptococcal infection cannot be diagnosed reliably based on clinical signs and symptoms. Typically, 25% of throat cultures grow group A Streptococcus, and 50% of those represent carriers who do not raise antistreptococcal antibodies and risk rheumatic fever.
Rapid streptococcal screens are less sensitive than cultures, but because of improvements in rapid streptococcal antigen tests, throat culture can be reserved for patients whose symptoms do not improve over time or who do not respond to antibiotics.
Clinical prediction rules have been developed that use several key elements of the history and physical examination to predict the probability of strep throat. Using a clinical prediction rule gives a clinician a rational basis for assigning a patient to a low-risk category (requires neither testing nor treatment), a high-risk category (empiric antibiotic may be indicated), or a moderate-risk category (may require further diagnostic testing). One of the best validated scoring systems is a simple four-item clinical prediction rule developed by Centor. The Centor score has been validated in three distinct adult populations. McIsaac modified the Centor score and validated it prospectively in a mixed population of adults and children. There is controversy surrounding these and other similar clinical prediction rules. Therefore clinical judgment and monitoring of the most recent literature on the subject are still advised when deciding whether or not to test or treat with antibiotics.
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