Tick-borne relapsing fever

This code represents a systemic bacterial infection caused by spirochetes of the genus Borrelia, transmitted by ticks. It is characterized by recurrent episodes of fever, headache, myalgia, and arthralgia, interspersed with afebrile periods. The disease course typically involves multiple relapses due to antigenic variation of the spirochetes.

Assign this code when documentation confirms a diagnosis of tick-borne relapsing fever, often supported by a history of tick exposure and characteristic clinical symptoms. Laboratory confirmation, such as visualization of spirochetes in peripheral blood smears during febrile episodes or positive serology, further supports its use.

• Differentiate from louse-borne relapsing fever (A68.0), which has a different vector and epidemiological profile.
• Ensure documentation specifies "tick-borne" to accurately assign this code.
• Consider co-coding for associated manifestations or complications, such as meningitis or myocarditis, if present and documented.