Lemierre Syndrome Following Acute Oropharyngeal Infection in a Young Adult

Introduction

Lemierre syndrome is a rare but potentially life-threatening complication of an oropharyngeal infection. It is classically characterised by septic thrombophlebitis of the internal jugular vein, bloodstream infection, and septic embolisation to distant organs. The lungs are the most frequently affected site, although the joints, liver, spleen, central nervous system, and other tissues may also be involved.

The condition most commonly affects previously healthy adolescents and young adults. Fusobacterium necrophorum, an anaerobic Gram-negative bacillus, is the organism most frequently implicated. The infection usually begins as pharyngitis or tonsillitis and subsequently spreads into the lateral pharyngeal space, where inflammation and thrombosis of the internal jugular vein may develop.

Early symptoms can resemble uncomplicated bacterial or viral pharyngitis. Diagnostic delay may occur when persistent fever, neck pain, respiratory symptoms, or clinical deterioration are attributed to the original throat infection. Awareness of the characteristic clinical progression is therefore essential.

Case Report

A 22-year-old previously healthy man presented with a seven-day history of fever, severe sore throat, painful swallowing, and progressive fatigue. He had initially developed fever and throat discomfort and had been treated symptomatically with antipyretics at a local clinic.

During the following four days, his throat pain intensified, and he developed swelling and tenderness along the left side of his neck. He also reported chills, reduced oral intake, and two episodes of vomiting. On the day before admission, he developed pleuritic pain over the right side of his chest and a productive cough.

There was no history of recent surgery, dental extraction, intravenous drug use, central venous catheterisation, malignancy, tuberculosis, or known immunodeficiency. He was not receiving corticosteroids or other immunosuppressive medication.

On examination, he appeared acutely unwell and dehydrated. His temperature was 39.4°C, heart rate was 126 beats per minute, respiratory rate was 26 breaths per minute, blood pressure was 102/64 mmHg, and oxygen saturation was 93% while breathing room air.

Oropharyngeal examination revealed enlarged and erythematous tonsils with left-sided exudates. There was mild deviation of the uvula towards the right. No significant airway obstruction or drooling was observed.

Tender swelling was present below the angle of the left mandible and extended along the anterior border of the sternocleidomastoid muscle. Neck movement was restricted because of pain. There was no overlying skin discolouration, fluctuance, or crepitus.

Respiratory examination demonstrated reduced air entry and scattered inspiratory crackles over the right lower lung field. Cardiovascular and abdominal examinations were otherwise unremarkable.

The combination of recent severe pharyngitis, unilateral neck swelling, persistent high-grade fever, and new respiratory symptoms raised concern for a deep neck infection complicated by internal jugular vein thrombophlebitis and septic pulmonary embolisation.

Investigations

Initial laboratory investigations demonstrated a total leucocyte count of 19,800 cells/mm³ with 89% neutrophils. C-reactive protein was markedly elevated at 286 mg/L, and the erythrocyte sedimentation rate was 72 mm/hour.

The platelet count was reduced to 108,000 cells/mm³. Haemoglobin was 13.2 g/dL. Serum creatinine was mildly elevated at 1.4 mg/dL, while alanine aminotransferase and aspartate aminotransferase were 68 U/L and 74 U/L, respectively. Serum lactate was elevated at 3.1 mmol/L.

A chest radiograph demonstrated multiple bilateral patchy opacities, with a small right-sided pleural effusion.

Contrast-enhanced computed tomography of the neck revealed inflammatory changes in the left peritonsillar and parapharyngeal spaces, with a 2.6-cm peritonsillar collection.

A filling defect with peripheral enhancement and expansion of the left internal jugular vein was identified, extending from the level of the angle of the mandible to the lower neck. The findings were consistent with septic thrombophlebitis.

Computed tomography of the chest demonstrated multiple bilateral peripheral pulmonary nodules, several showing central cavitation. Wedge-shaped pleural-based opacities and a small right pleural effusion were also present. These findings were considered highly suggestive of septic pulmonary emboli.

Two sets of blood cultures were obtained before antibiotic administration. After approximately 48 hours of anaerobic incubation, both sets grew Fusobacterium necrophorum. The organism was susceptible to metronidazole and beta-lactam/beta-lactamase inhibitor therapy.

Echocardiography showed no valvular vegetation or other evidence of infective endocarditis.

Based on the preceding oropharyngeal infection, internal jugular vein thrombosis, F. necrophorum bacteraemia, and septic pulmonary emboli, Lemierre syndrome was diagnosed.

Differential Diagnosis

Deep Neck Space Infection

A peritonsillar or parapharyngeal abscess could explain the fever, throat pain, neck swelling, and restricted neck movement. However, internal jugular vein thrombosis and multiple cavitating pulmonary lesions indicated systemic extension beyond an isolated deep neck infection.

Infective Endocarditis

Infective endocarditis may cause persistent fever, bacteraemia, and septic pulmonary emboli, particularly when the right side of the heart is involved. The absence of predisposing factors, negative echocardiographic findings, and demonstration of internal jugular vein thrombophlebitis made this diagnosis less likely.

Community-Acquired Pneumonia

Pneumonia was initially considered because of the cough, pleuritic chest pain, hypoxaemia, and pulmonary opacities. However, the presence of multiple peripheral cavitating nodules was more characteristic of septic embolisation than primary lobar pneumonia.

Cervical Lymphadenitis

Acute cervical lymphadenitis can produce unilateral neck pain and swelling following an upper respiratory infection. Nevertheless, the swelling in this patient followed the course of the internal jugular vein, and imaging directly demonstrated venous thrombosis.

Malignancy-Associated Internal Jugular Vein Thrombosis

Internal jugular vein thrombosis may occur in association with malignancy or a hypercoagulable state. The acute onset following tonsillitis, marked inflammatory response, positive anaerobic blood cultures, and septic embolic lesions strongly favoured an infectious cause.

Management and Outcome

The patient was admitted to a high-dependency unit and received intravenous fluids, oxygen, analgesia, and close haemodynamic monitoring. Empirical intravenous piperacillin–tazobactam was started to provide broad coverage for anaerobic organisms, streptococci, and other potential pathogens.

An otorhinolaryngology consultation was obtained. The left peritonsillar abscess was drained, producing approximately 8 mL of foul-smelling purulent material. The specimen was submitted for aerobic and anaerobic culture.

Following identification of F. necrophorum, antimicrobial treatment was changed to intravenous ceftriaxone combined with metronidazole. This combination was continued during the initial phase of hospitalisation.

The role of anticoagulation was discussed with infectious disease, haematology, and otorhinolaryngology specialists. Because the thrombus was confined to the internal jugular vein, showed no intracranial extension, and the patient demonstrated clear improvement with antibiotics and drainage, therapeutic anticoagulation was not initiated. Repeat imaging and clinical monitoring were planned.

Within 72 hours, the fever began to resolve, neck pain decreased, and haemodynamic parameters stabilised. Repeat blood cultures obtained after initiation of treatment were sterile. His oxygen requirement gradually declined, and the inflammatory markers showed a consistent downward trend.

A repeat ultrasound examination after ten days showed persistent but non-progressive thrombosis of the left internal jugular vein. No new pulmonary, neurological, or musculoskeletal complications developed.

After two weeks of intravenous treatment, the patient was discharged on oral metronidazole with an additional beta-lactam antibiotic to complete a total antimicrobial course of six weeks. He was advised to return immediately if he developed recurrent fever, breathlessness, chest pain, headache, visual symptoms, or increasing neck swelling.

At the six-week review, he was asymptomatic and had returned to his usual activities. C-reactive protein and leucocyte count had normalised. Follow-up chest imaging demonstrated marked resolution of the pulmonary nodules and pleural effusion. Doppler ultrasonography showed partial recanalisation of the left internal jugular vein without thrombus extension.

Discussion

This case demonstrates the characteristic progression of Lemierre syndrome from an apparently localised oropharyngeal infection to internal jugular vein thrombophlebitis, bacteraemia, and septic pulmonary embolisation.

The syndrome should be considered when a young, previously healthy patient develops persistent or recurrent fever after pharyngitis, particularly when unilateral neck pain, swelling, respiratory symptoms, or systemic toxicity is present. Clinical improvement in the throat does not exclude ongoing extension into the deep neck spaces.

Blood cultures should include anaerobic incubation and ideally be obtained before antibiotics are administered. Nevertheless, cultures may remain negative because anaerobic organisms can grow slowly and patients may have received prior antimicrobial therapy.

Contrast-enhanced computed tomography of the neck is particularly useful for demonstrating internal jugular vein thrombosis and identifying associated peritonsillar or parapharyngeal collections. Chest imaging is important because septic pulmonary emboli frequently produce multiple peripheral nodules, cavitation, pleural effusion, pulmonary abscesses, or empyema.

Treatment requires prompt administration of antibiotics with reliable anaerobic coverage. Therapy is generally prolonged because infection may be protected within the thrombus and metastatic lesions. Surgical or image-guided drainage is required when a drainable abscess, empyema, septic joint, or another infected collection is present.

Anticoagulation remains controversial and is not universally required. It may be considered when thrombosis progresses despite appropriate antibiotics, extends towards the cerebral venous sinuses, produces extensive clot burden, or is associated with persistent septic embolisation. Decisions should be individualised according to the location and progression of thrombosis, bleeding risk, clinical response, and multidisciplinary assessment.

Conclusion

Lemierre syndrome is an uncommon but serious complication of oropharyngeal infection that can progress rapidly in otherwise healthy young adults.

Persistent fever, unilateral neck pain or swelling, respiratory deterioration, and cavitating pulmonary lesions following pharyngitis should prompt urgent investigation for internal jugular vein septic thrombophlebitis.

In this patient, blood cultures, contrast-enhanced neck imaging, and chest computed tomography established the diagnosis. Early anaerobic antimicrobial therapy, drainage of the peritonsillar abscess, supportive care, and careful assessment of the thrombosis resulted in complete clinical recovery.

Early recognition remains the most important factor in preventing delayed treatment, progressive septic embolisation, multiorgan complications, and death.

References

1. Tiwari A. Lemierre’s syndrome in the 21st century: A literature review. Cureus. 2023;15(8):e43650. https://pmc.ncbi.nlm.nih.gov/articles/PMC10505273/
2. Allen BW, Bentley TP. Lemierre syndrome. StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK499846/
3. Tromop-van Dalen C, Mekhail AM. Lemierre syndrome: Early recognition and management. Canadian Medical Association Journal. 2015;187(16):1229–1231. https://pmc.ncbi.nlm.nih.gov/articles/PMC4627880/
4. Gore MR. Lemierre syndrome: A meta-analysis. International Archives of Otorhinolaryngology. 2020;24(3):e379–e385. https://pmc.ncbi.nlm.nih.gov/articles/PMC7394644/
5. Johannesen KM, Bodtger U. Lemierre’s syndrome: Current perspectives on diagnosis and management. Infection and Drug Resistance. 2016;9:221–227. https://pmc.ncbi.nlm.nih.gov/articles/PMC5028102/
6. Lavalle S, et al. Pediatric Lemierre’s syndrome: A comprehensive literature review. Pediatric Reports. 2024;16(1):173–186. https://www.mdpi.com/2036-7503/16/1/18

Read more such content on @ Hidoc Dr | Medical Learning App for Doctors