One of the first outpatient problems a primary care trainee learns to manage is sore throat.  The current algorithm is fairly simple.  Most sore throats are caused by viruses and will not improve with antibiotics.  Symptomatic medication for pain and fever is the best we can offer.  But a significant minority of sore throats is caused by a bacterium called group A β-hemolytic streptococcus.  These cases are more commonly known as “strep throat”.  In strep throat antibiotics shorten the duration of symptoms by a day or two, but more importantly antibiotics prevent acute rheumatic fever, a potentially dangerous complication of untreated strep throat.

So the algorithm for evaluating sore throats is: decide if it’s strep.  If it is (or has a reasonable likelihood of being) strep then treat with antibiotics; otherwise don’t.

An article in this issue of Annals of Internal Medicine suggests that this algorithm is inadequate in adolescents and young adults.  The reason is that about 10% of sore throats in patients between 15 and 24 years old is caused by a bacterium called Fusobacterium necrophorum.  (Please memorize that name and mention it at your next holiday party.)  F. necrophorum also causes Lemierre Syndrome, a bacterial infection of the internal jugular vein that results in the bacteria spreading elsewhere in the body.  Lemierre Syndrome frequently results in permanent harm and is sometimes fatal.  Though much remains unknown about F. necrophorum, it appears to cause sore throats as commonly as strep in adolescents and young adults, and Lemierre Syndrome in this age group appears to be more common than acute rheumatic fever.

Diagnosing F. necrophorum pharyngitis is problematic.  F. necrophorum doesn’t grow on a standard throat culture.  (It’s anaerobic, meaning it only grows in the absence of oxygen.)  And specific molecular tests for it are not commercially available.

So the author recommends that antibiotics be prescribed for 15 to 24 year olds with sore throats and at least 3 of the following 4 findings.

  • history of fever
  • pus on the tonsils
  • swollen tender lymph nodes in the neck
  • absence of cough

(Note for doctors: use penicillins or cephalosporins.  Macrolides are ineffective against F. necrophorum.)

In that age group worsening symptoms or neck swelling should be alarm signs that F. necrophorum is present.

Our simplest clinical problem just got more complicated.  That’s a good sign that we’re learning something.

Learn more:

Annals of Internal Medicine article:  Expand the Pharyngitis Paradigm for Adolescents and Young Adults