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<unk> . 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 and kidney function tests are often abnormal. Thrombosis of the internal jugular vein can be displayed with sonography. Thrombi that have developed recently have low echogenicity or echogenicity similar to the flowing blood, and in such cases pressure with the ultrasound probe show a non-compressible jugular vein - a sure sign of thrombosis. Also color or power Doppler ultrasound identify a low echogenicity blood clot. A CT scan or an MRI scan is more sensitive in displaying the thrombus of the intra-thoracic retrosternal veins, but are rarely needed. 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
Lemierre's syndrome
DAVID syndrome
Freshers' flu
Salmonellosis
Listeriosis
Boutonneuse fever
Periodic fever syndrome
Bacillary dysentery