Faget sign explained

Differential:	Yellow fever,Typhoid fever, Brain abscess, Tularaemia, Brucellosis, COVID 19 Omicron

In medicine, the Faget sign—sometimes called sphygmothermic dissociation—is the unusual pairing of fever with bradycardia (slow pulse). (Fever is usually accompanied by tachycardia (rapid pulse), an association known by the eponym "Liebermeister's rule".) The Faget sign is named after Louisiana physician Jean Charles Faget, who studied yellow fever in Louisiana.^[1]

Faget sign is often seen in:

• Yellow fever
• Typhoid fever
• Brain abscess
• Tularaemia
• Brucellosis
• Colorado tick fever
• Some pneumonias - Legionella pneumonia and Mycoplasma pneumonia
• Drug fever (e.g. beta-blockers,^[2] known as the Beta-Faget sign)

Of note, the Faget sign in bacterial infections is consistently associated with bacteria that have an intracellular life cycle.

Notes and References

1. Jean-Charles Faget. Études médicale de quelques questions importantes pour la Louisiane, et exposé succinct d’une endémie paludéenne de forme catarrhale qui a sévi à la Nouvelle-Orléans, particulièrement sur les enfants, pendant l’epidémie de fièvre jaune de 1858. New Orleans, 1859.
2. Neuroimmunomodulation. 1999 Jul-Aug;6(4):305-17.Beta-adrenergic receptor subtype effects on stress fever and thermoregulation.Mayfield KP, Soszynski D, Kozak W, Kozak A, Rudolph K, Kluger MJ.