Lemierre Syndrome Presenting as Unilateral Neck Swelling with Coexisting Thyroiditis: A Rare Case Report

Lemierre syndrome (LS) is a rare but potentially life-threatening complication of oropharyngeal infection characterised by septic thrombophlebitis of the internal jugular vein, with or without metastatic septic embolisation. We report the case of a 54-year-old woman who presented with fever, painful left-sided neck swelling, and neck pain following a recent peritonsillar infection. Ultrasonography demonstrated a partially occlusive thrombus within the left internal jugular vein and diffuse thyroid enlargement with heterogeneous echotexture and increased vascularity, suggestive of coexisting thyroiditis. Contrast-enhanced computed tomography confirmed internal jugular vein thrombosis without deep neck abscess, mediastinal extension, or septic pulmonary emboli. A clinicoradiological diagnosis of LS was established, and the patient responded favourably to intravenous ceftriaxone without anticoagulation. This case highlights an uncommon presentation of LS with coexisting thyroiditis and emphasises the importance of early multimodality imaging and prompt antimicrobial therapy to prevent potentially life-threatening complications.

Keywords: Lemierre syndrome, Internal jugular vein thrombosis, Peritonsillar infection, Thyroiditis, Neck ultrasonography, Contrast-enhanced computed tomography.