Lemierre's syndrome occurs most often when a bacterial (e.g., Fusobacterium necrophorum) throat infection progresses to the formation of a peritonsillar abscess.

When the abscess wall ruptures internally, the drainage carrying bacteria seeps through the soft tissue and infects the nearby structures.

[3] In 1936, André Lemierre published a series of 20 cases where throat infections were followed by identified anaerobic sepsis, of whom 18 died.

[4] The signs and symptoms of Lemierre's syndrome vary, but usually start with a sore throat, fever, and general body weakness.

Some cases will also present with meningitis, which will typically manifest as neck stiffness, headache and sensitivity of the eyes to light.

F. necrophorum produces hemagglutinin which causes platelet aggregation that can lead to diffuse intravascular coagulation and thrombocytopenia.

[13][14] Diagnosis and the imaging (and laboratory) studies to be ordered largely depend on the patient history, signs and symptoms.

If a persistent sore throat with signs of sepsis are found, physicians are cautioned to screen for Lemierre's syndrome.

[15] Laboratory investigations reveal signs of a bacterial infection with elevated C-reactive protein, erythrocyte sedimentation rate and white blood cells (notably neutrophils).

[citation needed] Bacterial cultures taken from the blood, joint aspirates or other sites can identify the causative agent of the disease.

The low incidence of Lemierre's syndrome has not made it possible to set up clinical trials to study the disease.

Approximately 10% of those with the condition experience clinical sequelae, including cranial nerve palsy and orthopaedic limitations.

[18] The estimated incidence rate is 0.8 to 3.6 cases per million in the general population, but is higher in healthy young adults.

[3] In 1936, André Lemierre published a series of 20 cases where throat infections were followed by identified anaerobic sepsis, of whom 18 patients died.