Lemierre’s syndrome
Overview
Lemierre's syndrome (or Lemierre's disease, also known as postanginal sepsis and human necrobacillosis) is a disease usually caused by the bacterium Fusobacterium necrophorum, and occasionally by other members of the genus Fusobacterium (F. nucleatum, F. mortiferum and F. varium etc.) and usually affects young, healthy adults. Lemierre syndrome develops most often after a strep sore throat has created a peritonsillar abscess, a crater filled with pus and bacteria near the tonsils. Deep in the abscess, anaerobic bacteria (microbes that do not require oxygen) like Fusobacterium necrophorum can flourish. The bacteria penetrate from the abscess into the neighboring jugular vein in the neck and there they cause an infected clot (thrombosis) to form, from which bacteria are seeded throughout the body by the bloodstream (bacteremia). Pieces of the infected clot break off and travel to the lungs as emboli blocking branches of the pulmonary artery bringing the heart's blood to the lungs. This causes shortness of breath, chest pain and severe pneumonia. Fusobacteria are normal inhabitants of the oropharyngeal flora. This is a very rare disease with only approximately 160 cases in the last 100 years.[1]
Symptoms
* Headache (not related to meningitis) * Muscle pain * Jaundice * Trismus * Crepitations are sometimes heard over the lungs * Pericardial friction rubs as a sign of pericarditis (rare) * Cranial nerve paralysis and Horner's syndrome (both rare)
Diagnosis
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 the symptoms are found, physicians are cautioned to screen for Lemierre's syndrome. Laboratory investigations reveal signs of a bacterial infection with elevated C-reactive protein, erythrocyte sedimentation rate and white blood cells (notably neutrophils). Platelet count can be low or high. Liver function tests and renal function tests are often abnormal. Thrombosis of the internal jugular vein can be displayed with sonography. However, thrombi that have developed recently have low echogenicity and thus will not show up on ultrasound. A CT scan or an MRI scan is more sensitive in displaying the thrombus. Chest X-ray and chest CT may show pleural effusion, nodules, infiltrates, abscesses and cavitations. Bacterial cultures taken from the blood, joint aspirates or other sites can identify the causative agent of the disease. Other illnesses that can be included in the differential diagnosis are: * Q fever * Tuberculosis * Pneumonia
Treatment
Lemierre's syndrome is primarily treated with antibiotics given intravenously. However, because sore throats are most commonly caused by viruses, for which antibiotic treatment is unnecessary, such treatment is not usual in the first phase of the disease. Lemierre's disease proves that, rarely, antibiotics are needed for 'sore throats'.[12] Fusobacterium necrophorum is generally highly susceptible to beta-lactam antibiotics, metronidazole, clindamycin and third generation cephalosporins while the other fusobacteria have varying degrees of resistance to beta-lactams and clindamycin[11]. Additionally, there may exist a co-infection by another bacterium. For these reasons is often advised not to use monotherapy in treating Lemierre's syndrome. Penicillin and penicillin-derived antibiotics can thus be combined with a beta-lactamase inhibitor such as clavulanic acid or with metronidazole.[5][7] Clindamycin can be given as monotherapy. If antibiotic therapy does not improve the clinical picture, it may prove useful to drain any abscesses and/or perform ligation of the internal jugular vein where the antibiotic can not penetrate.[5][6][13] There is no evidence to opt for or against the use of anticoagulation therapy. The low incidence of Lemierre's syndrome has not made it possible to set up clinical trials to study the disease.[5] The disease can often be un-treatable, especially if other negative factors occur,i.e. various diseases occurring at the same time, such as meningitis, pneumonia.