Doctors are taught that a really bad sore throat should be cultured to determine whether it is caused by a group A beta-hemolytic streptococcal infection (aka strep throat).
If the test comes back positive, the patient is treated with an antibiotic because untreated strep sometimes triggers rheumatic fever. If the test is negative, the patient is often sent home and told to wait for the discomfort to disappear.
Why Should You Worry About F-Throat?
Many physicians are not aware of another kind of sore throat caused by Fusobacterium necrophorum (aka F-throat). A study in the Annals of Internal Medicine (Feb. 17, 2015) suggests this F-throat infection is more common than strep throat among adolescents and young adults. It is not as easily diagnosed because the routine throat culture carried out in a doctor’s office will not catch it. Untreated, F-throat can cause severe illness or even death.
How Common is F-Throat?
The researchers recruited 312 students at a university health clinic who arrived complaining of a “sore throat.” The scientists used a sophisticated PCR (polymerase chain reaction) test to tell what kind of bacteria might be causing the sore throat symptoms. What they found was a game changer.
One fifth of the students had F-throat. Half as many (10 percent) had strep infections. What this means is that a surprisingly high number of sore throats in young adults are caused by F. necrophorum bacteria. In fact, it was the most common bacterium triggering sore throat symptoms in this college population.
Diagnostic Disaster
What this means is that current diagnostic practices will not catch this common and potentially deadly infection. Doctors have guidelines for treating strep throat. As far as we can tell, there are no guidelines for treating F-throat. That means that most physicians do not know what the best antibiotic treatment is for F-throat; that lack of knowledge could be disastrous.
Deadly Lemierre’s Disease from F-Throat
Let us tell you a story we heard from Lisa Sanders, MD. She writes the “Diagnosis” column for the New York Times Magazine. In one of her articles (and also in an interview on our radio show) she related the case of a 17-year-old boy who developed a fever and sore throat. Because he was so sick, his mother took him to the family physician promptly after his symptoms worsened.
The doctor diagnosed strep throat (without a culture) and prescribed a macrolide antibiotic called azithromycin (Zithromax, Zmax). It usually works well for strep throat. But instead of getting better, the young man continued to run a fever with shaking chills and his sore throat got substantially worse, localizing on one side of his neck.
The parents took him to the emergency room of the local hospital, but the ER physicians didn’t consider F-throat either. The antibiotics they prescribed didn’t work against F-throat. By the time the doctors figured out that the infection was caused by F. necrophorum and he had developed Lemierre Syndrome, it was too late. The young man died because of a misdiagnosis and inadequate treatment.
Should you be Worried about F-Throat?
Physicians have been taught that F-throat is relatively rare and that if it occurs it primarily affects teenagers or young adults up to the age of 30. But Lisa Sanders described a case of a 44-year-old mother who developed F. necrophorum. The only reason she was correctly diagnosed was because her ear, nose and throat specialist couldn’t figure out what was happening and consulted an infectious disease expert. This specialist recognized F-throat and recommended the antibiotic that saved her life.
The study in the Annals of Internal Medicine established that F-throat is twice as common as strep throat, at least in a college-age population. Although Lemierre syndrome is relatively rare, it is such a serious condition that it must be diagnosed promptly and treated correctly. Penicillin or metronidazole are more appropriate than antibiotics like azithromycin, ciprofloxacin, erythromycin or tetracycline.
How to Recognize F-Throat
As we have already described, the traditional diagnosis with a routine throat swab and culture is not going to catch F-throat. Clues to report to a physician include:
- A bad sore throat that does not get better after a few days
- A fever
- Night sweats and shivering
- Pus in the back of the throat
- Swollen glands in the neck
- Swelling in the neck, especially on one side
If you suspect that you or someone you love has F-throat, encourage your physician to consider this diagnosis. Make sure that she does her homework on Fusobacterium necrophorum and knows how to treat it appropriately.
Sinusitis and F. necrophorum:
The throat is not the only place this bad actor can show up. An article in The Pediatric Infectious Disease Journal (Jan. 31, 2018) discuses cases of serious sinusitis linked to F. necrophorum.
In one instance a 15-year-old young man ended up in the ER with:
“…acute altered mental status, photophobia, speech difficulty, right upper extremity weakness, and sinus pressure. For the past week, he had experienced headache, fever, and occasional emesis [vomiting].”
The infection had penetrated into his skull and brain. A brain scan after treatment showed the severity of the infection:
“CT one month later revealed new moth-eaten changes of the frontal bone, suggestive of chronic osteomyelitis. Paranasal sinuses were significantly improved and well aerated. The patient had neurologic recovery, with slight difficulty with speech and right hand coordination difficulty.”
Fortunately, this young man survived. The authors note that Fusobacterium can cause sinusitis without any symptoms of sore throat. It also means that physicians will need to be alert for this kind of infection since it requires a different antibiotic approach.
There is also evidence that the bacteria can invade the middle ear (The Pediatric Infectious Disease Journal, July, 2008). The authors note that:
“Inappropriate antibiotic treatment may seriously compromise clinical outcome.”
Beware Misdiagnosis:
Misdiagnosis can cause serious harm or death. Surprisingly, misdiagnosis is far more common than most people realize. Some experts estimate that diagnostic error rates are as high as 15 percent in clinical medicine.
You will read about the “Top 10 Reasons Why Doctors Screw Up Diagnoses” in our book, Top Screwups Doctors Make and How to Avoid Them. You will also discover the “Top 10 Questions to Ask to Reduce Diagnostic Disasters.” And you will find out the about the most common diagnostic errors to watch out for in Top Screwups.
Do not let F-throat or other common conditions go misdiagnosed. Protect yourself and those you love with knowledge.
Please share your own story below and vote at the top of this article.
Revised: 3/15/18
