Other than Group A Beta-Hemolytic Streptococcus (GABHS), what are 5 other causes for ‘sore throat’?
What are FOUR common symptoms that accompany a viral etiology of pharyngitis?
What is the gold standard for diagnosis of GABHS pharyngitis?
What are three complications from GABHS infections?
Which complication from a GABHS infection can be prevented by treating with antibiotics?
When should GABHS be treated with antimicrobial therapy and what is the first line treatment? What class can be used if patient has a penicillin allergy?
Answers can be found below.
“I have a sore throat; it must be strep”, is a common phrase heard by primary care doctors. Yet, this is not a trap you will fall into when writing your exam because you read the study tips e-mail newsletter from The Review Course!
When treating a patient with acute pharyngitis, it is important to keep a broad differential diagnosis. Some etiologies to remember are:
Viral Etiologies (Can you list three before reading on? Answer at the end of this list!)
Corynebacterium Diphtheriae - worth knowing - in November 2017, Edmonton reported their first case in over a decade!
Oropharyngeal Sexually Transmitted Infections - Gonorrhea
Viral causes from above: Herpes Simplex, Cytomegalovirus, Influenza, Coxsackie etc.
Suspect a viral etiology of pharyngitis when the patient has the presence of rhinorrhea, hoarseness, cough and conjunctivitis. In these patients, throat cultures do NOT need to be done.
Although a popular clinical prediction tool, the Centor criteria are only aimed to improve clinical accuracy. The gold standard for diagnosis of GABHS pharyngitis is not Centor - it’s a throat culture.
Fever (subjective or measured in office) - 1 point
Absence of cough - 1 point
Tender anterior cervical adeopathy - 1 point
Tonsillar swelling or exudates - 1 point
< 15 years - + 1 point
15 – 45 - 0 points
> 45 years - - 1 point
Yet, in patients will all four of the classic symptoms, they still have a 44% of NOT having GABHS pharyngitis.
Only treat pharyngitis when a throat culture has been done, even when it delays treatment, and if the patient is willing to take antibiotics after hearing about the risks and benefits. Antibiotics decrease the severity of symptoms, the duration of symptoms by ~ 1 day, the risk of transmission and the likelihood of developing acute rheumatic fever (though the number needed to treat for prevention of rheumatic fever is 15,000!). Antibiotics do NOT prevent post-streptococcal glomerulonephritis, and the number needed to harm with side effects is about 10.
Some other nonsuppurative complications are poststreptococcal reactive arthritis, scarlet fever, streptococcal toxic shock syndrome and PANDAS syndrome.
Some of suppurative complications, which can also be prevented by antibiotic treatment, are peritonsillar abscess, retropharyngeal abscess, streptococcal bacteremia, or meningitis / brain abscess.
Penicillin VK 40 mg/kg day PO BID for 10 days
Penicillin VK 300mg PO TID for 10 days or Penicillin VK 600mg PO BID for 10 days
PCN Allergy = Macrolide (Erythromycin) or Lincosamide (Clindamycin)
Blondel-Hill E, Fryters S. Bugs and Drugs. Capital Health Authority, 2006.
Guideline for The Diagnosis and Management of Acute Pharyngitis. Towards Optimized Practice, Alberta Medical Association, 2008.
Shulman et al. Clinical Practice Guideline for the Diagnosis and Management of Group A Streptococcal Pharyngitis: 2012 Update by the Infectious Disease Society of America. Clinical Infectious Diseases 2012;55(10):e86-102
Vincent MT, Celestin N and Hussain AN. Pharyngitis. Am Fam Physician. 2004 Mar 15;69(6):1465-1470.
Worral GJ. Acute sore throat. Can Fam Physician. 2011 Jul; 57(7): 791–794.