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Acute KeelpijnPublished by: Werkgroep Ontwikkeling Richtlijnen Eerste Lijn (Worel)Last published: 2017Mal de gorge aiguPublished by: Groupe de Travail Développement de recommmandations de première ligneLast published: 2017Diagnosis begins with history and physical exam.[4] Patients with clear viral symptoms do not need to undergo testing for Group A Streptococcus (GAS).[4] In the absence of viral symptoms, a rapid antigen detection test and/or throat culture with specific microbiologic testing is required to confirm group A Streptococcus (GAS) infection.[4][17][25]
Individuals who are GAS carriers have a positive throat culture or positive rapid antigen test result but do not have clinical symptoms or an immunologic response to GAS antigens on laboratory testing. In children, negative rapid antigen tests are confirmed with throat culture.[17][26] Treatment is usually not required for such asymptomatic individuals.[4]
History
Several key elements of the presentation may help determine the causative organism:
Acute GAS pharyngitis is common in children and adolescents ages 5-15 years.[4][26] It is most frequent in the winter (or early spring) in temperate climates.[1] Enteroviral infection is most common in summer and fall.[1][2] Diagnostic studies for GAS pharyngitis are not indicated for children ages <3 years because acute rheumatic fever is rare and the incidence of streptococcal pharyngitis is uncommon in this age group.[4] However, if they have a sibling with GAS infection then it may be worth considering testing.[1]
Tularemia is suggested if there is a history of ingestion of undercooked wild animal meat.[7][9][13] History may also include a previous failure of response to a course of penicillin as treatment.[8]
HIV, chlamydia, and gonorrhea should be considered as causative organisms in sexually active or abused individuals with pharyngitis, especially in those with negative cultures for GAS.[10]
Immunocompromise may follow local tissue damage (e.g., irradiation for oropharyngeal cancer) or have a systemic cause (e.g., chemotherapy, post-transplant immunosuppression, HIV). Candida pharyngitis (e.g., thrush, an oral infection usually by Candida albicans) may be encountered in this clinical context. Culture for the suspected organism is diagnostic.
Lack of immunization may be a finding in diphtheria or measles.
Symptoms:
Sore throat is a common symptom.[4]
Pain with swallowing.[4]
Fever is common in pharyngitis and is a nonspecific symptom.
Headache, nausea, vomiting, and abdominal pain may be present in children.[1][4]
Rhinorrhea, nasal congestion, hoarseness, oral ulcers, conjunctivitis, and cough may be present in viral pharyngitis but are generally absent in bacterial pharyngitis.[4]
Physical exam
The physical evaluation of acute pharyngitis requires little more than a penlight and tongue depressor.
[Figure caption and citation for the preceding image starts]: Intraoral view of a patient with group A Streptococcus pharyngitisCDC/Heinz F. Eichenwald, MD; public domain [Citation ends].
Other important points to consider:
Absence of cough (with the presence of cervical adenopathy) has the highest specificity for predicting streptococcal etiology.[27]
Viral infections can be distinguished by the presence of rhinorrhea, nasal congestion, and cough.[4]
Diphtheria should be considered if a gray membrane is identified in the pharynx or nares. Culture for the suspected organism is diagnostic.[Figure caption and citation for the preceding image starts]: Typical pseudomembrane of diphtheria pharyngitisCopyright Department of Pediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong; used with permission [Citation ends].
Tularemia is suggested in the presence of ulcerations, exudates, and a history of ingestion of undercooked wild animal meat.[7][9][13] Historical failure of response to penicillin therapy should also raise suspicion. Culture for the suspected organism is diagnostic.
A scarlatiniform rash may be present, especially in children, and is suggestive of GAS.[1][4][Figure caption and citation for the preceding image starts]: Scarlatiniform rash on the forearm due to group A Streptococcus bacteriaCourtesy of the CDC Public Health Image Library [Citation ends].
Koplik spots (bluish-white, raised lesions on an erythematous base on the buccal mucosa) are pathognomonic for measles.[6] A characteristic maculopapular rash or conjunctivitis may also be seen in measles.
In children ages <3 years, GAS rarely manifests as acute pharyngitis. Fever, irritability, and anorexia may be seen, in addition to mucopurulent rhinitis. This presentation in young children is subacute, and high fever is rare.[4]
Laboratory
Rapid antigen detection tests for GAS and traditional throat culture are immensely helpful in the primary care setting and can avoid inappropriate antibiotic use.[14][28] Throat culture is considered the gold standard and may be helpful if the clinical suspicion of GAS is high or disease is caused by other streptococci or other bacterial pathogens such as Achanobacter hemolyticum.[4][25] However, there are some caveats to their use:[29]
GAS rapid antigen detection tests allow immediate point-of-care assessment.
Positive test results in the absence of characteristic symptoms (fever, lack of cough, tonsillar exudates, and tender cervical adenopathy) likely represent colonization that is not clinically relevant; therefore, testing should be used only when the clinical symptoms are consistent with GAS disease.
GAS rapid antigen detection tests are 70% to 90% sensitive and 95% specific compared with throat culture.[1][30][31] GAS rapid antigen detection tests may have a lower specificity in children recently treated for GAS.[32]
A negative GAS rapid antigen test should be followed by conventional throat culture when there is a high index of suspicion for bacterial pharyngitis, especially in children, given their increased risk of rheumatic fever.[4][17][26][33]
Nucleic acid amplification (via polymerase chain reaction) testing for GAS is comparable to throat culture in sensitivity and specificity but is more rapid. In addition, PCR use in children with GAS in primary care led to more appropriate antibiotic use.[34] However, rapid in-office PCR is not widely available.[34][35][36][37]
Throat culture is particularly useful when rapid antigen tests are negative for GAS but the clinical syndrome is consistent with GAS. Rapid antigen tests will not detect other streptococci or Arcanobacterium hemolyticum that can be clinically indistinguishable from GAS pharyngitis.
Haemophilus influenzae, Staphylococcus aureus, Neisseria meningitidis, and Streptococcus pneumoniae are not etiologic agents of acute pharyngitis and should not be identified or reported in throat cultures.[17]
The Centers for Disease Control and Prevention recommend that the Monospot test is not used. The antibodies detected by Monospot can be caused by conditions other than infectious mononucleosis and does not confirm the presence of EBV infection.[38]
Do not routinely order broad respiratory pathogen panels in adults or comprehensive viral testing in children.[39][40] Respiratory viruses are the most common cause of pharyngitis but it is unnecessary to determine a specific viral etiology as there is no available pathogen-directed therapy.[17]
Test of cure (with a follow-up throat culture or rapid antigen test for GAS) is not routinely required except in patients who are at high risk of acute renal failure or who have recurrence of symptoms compatible with GAS.[1] Test of cure is recommended for patients with gonococcal pharyngitis.
For adults with symptoms of pharyngitis, laboratory testing is not always indicated.[25] Instead, all adult patients with symptoms of pharyngitis should be screened using prediction rules (e.g., Centor criteria, McIsaac, or FeverPAIN).
Centor criteria:[41]
History of fever
Lack of cough
Tonsillar exudates
Tender anterior cervical adenopathy.
Adults with none or only one of these findings should not be tested or treated for GAS. Individuals who meet two or more Centor criteria should have a rapid antigen test.[25]
Treatment failure in a patient without laboratory confirmation of GAS should prompt culture for bacterial agents other than GAS, and examination for evidence of viral disease.
McIsaac scoring system
The McIsaac scoring system modifies the Centor algorithm to account for the increased prevalence of GAS in children.[42]
Tonsillar swelling or exudate (add 1 point)
Tender anterior cervical adenopathy (add 1 point)
No cough (add 1 point)
Temperature > 38°C (add 1 point)
Ages 3-14 years (add 1 point)
Ages 15-44 years (no points)
Ages ≥45 years (minus 1 point).
Like the Centor algorithm, a higher McIsaac composite score means greater risk of a GAS infection.
FeverPAIN:[43]
Fever (during previous 24 hours)
Purulence (pus on tonsils)
Attend rapidly (within 3 days after onset of symptoms)
Severely inflamed tonsils
No cough or coryza (inflammation of mucus membranes in the nose).
Each of the FeverPAIN criteria score 1 point (maximum score of 5). Higher scores suggest more severe symptoms and likely bacterial (streptococcal) cause. A score of 0 or 1 is thought to be associated with a 13% to 18% likelihood of isolating Streptococcus. A score of 2 or 3 is thought to be associated with a 34% to 40% likelihood of isolating Streptococcus. A score of 4 or 5 is thought to be associated with a 62% to 65% likelihood of isolating Streptococcus.
In the UK, the Centor and FeverPAIN scores are the two prediction rules recommended by the National Institute for Health and Care Excellence (NICE).[44] Although these scoring systems are not definitive, they can be used to increase pretest probability and limit detection of GAS carriage in pharyngitis due to other etiologies.[45]
Radiology
Acute pharyngitis does not usually require radiographic diagnosis. If clinical symptoms are concerning for retropharyngeal abscess (toxic appearance, neck stiffness/swelling, or vocal changes), then a computed tomography scan of the neck with intravenous contrast should be obtained.
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