Lemierre’s syndrome occurs when you get a certain rare type of bacterial infection in your throat. When it’s not treated, the infection can spread to the vessels that carry lymph fluid throughout your body. When these vessels get infected, they can’t properly return fluids that have leaked from bloodstream back into your circulatory system.

Lemierre’s syndrome can also cause your jugular vein to swell. When this happens, you can get a potentially fatal blood clot in your jugular. This swelling is known as internal jugular thrombophlebitis. In some cases, you may need surgery to treat this condition. If it’s not treated, it can cause serious or life-threatening complications.

The symptoms of Lemierre’s syndrome may not appear right away after you get the infection. This condition starts in your throat, so the first symptom you notice will likely be a sore throat.

Other early symptoms of Lemierre’s syndrome include:

  • swelling in your neck around your lymph nodes
  • abnormal headaches
  • pains that feel like they’re shooting down your neck
  • high fever
  • feeling stiff, weak, or exhausted
  • feeling more sensitive to light than usual (known as photophobia)
  • trouble breathing
  • trouble swallowing
  • inflammation of your tonsils (known as tonsillitis), two lymph nodes in your throat that protect your body against infection
  • coughing up blood or bloody mucus
  • losing your appetite or feeling nauseous
  • throwing up

As the infection spreads, your symptoms may become worse over time. Seek emergency medical help right away if you notice one or more of these symptoms.

Lemierre’s syndrome is most commonly caused by the bacteria known as Fusobacterium necrophorum. Fusobacterium necrophorum is often found in your throat without causing infections. It’s possible that this syndrome happens when the bacteria get into the mucus membranes around your throat. These membranes are known as the mucosa. Other bacteria in the Fusobacterium family are known to cause this condition, too.

The Staphylococcus aureus bacteria is also known to cause Lemierre’s syndrome. This type of bacteria is also found on your body. It is common on the surface of your skin and inside your nose. These bacteria can cause staph infections when they get into your body’s tissues or into your bloodstream. Staph infections can be contagious. You can get a staph infection by sharing household objects that touch another person’s skin, such as towels or razors. You can also get it from food that hasn’t been washed or prepared properly to remove bacteria.

Other types of infections may also cause you to get this type of infection. Having the Epstein-Barr virus, a type of herpes virus, in your body may cause Lemierre’s syndrome. Having a bacterial infection in your pharynx, the area in the back of your throat right before your esophagus, may also cause you to get Lemierre’s syndrome. This condition is known as bacterial pharyngitis.

The first treatments that your doctor will give you for Lemierre’s syndrome are antibiotics to help fight the bacterial infection. Common antibiotics that are used to treat this condition (especially when it’s caused by a Fusobacterium) include:

Your doctor may use other antibiotics if you have another bacterial infection caused by staph or other bacteria.

If antibiotics can’t treat the infection before it begins to get worse, your doctor may need to perform surgery on your throat or neck. Any abscesses that may have formed because of the infection may need to be drained. Your doctor may also need to perform ligation on your jugular vein. A ligation closes off your jugular vein and may help treat the infection.

Your doctor may recommend several months of anticoagulation therapy to help manage Lemierre’s syndrome. This therapy involves taking blood thinners like warfarin (Coumadin) or clopidogrel (Plavix). Anticoagulation therapy is sometimes considered dangerous because it can cause you to bleed more easily and make it harder for cuts or wounds to scab over and heal. Talk to your doctor if you're concerned about these risks before you start this type of therapy.

The prognosis for Lemierre’s syndrome is good. Fewer than 5 percent of all people diagnosed with Lemierre’s syndrome die from complications due to the infection.

Lemierre’s syndrome is usually diagnosed after you show certain symptoms for an extended amount of time, especially a sore throat. Several lab tests can diagnose this syndrome, including:

  • C-reactive protein (CRP) test, a blood test that measures inflammation in your body
  • erythrocyte sedimentation rate (ESR, or sed rate) test, which also measures inflammation

If either of these tests suggest that you may have a bacterial infection, your doctor may then use imaging tests to look more closely at your throat and neck. Some imaging tests your doctor may use include:

  • computed tomography (CT) scan, which allows your doctor to look at a cross-section of the area where the infection is located
  • ultrasound test, which can let your doctor look at possible blood clots around your jugular vein
  • X-rays, which can help your doctor find any symptoms or complications of the syndrome inside your body

The outlook for Lemierre’s syndrome is good if it’s diagnosed and treated early on. This syndrome can be dangerous if the infection spreads beyond your throat to your lymph nodes, jugular vein, and your other organs. If untreated, this syndrome can cause sepsis. Sepsis happens when your body is harmed while your immune system tries to fight an infection.

Go to the emergency room right away if you notice any symptoms of Lemierre’s syndrome, especially if you have a sore throat, can’t breathe or swallow easily, or are throwing up blood or bloodstained mucus. The earlier you treat this infection, the more likely you are to avoid any complications or risks because of it.