Mechanism of severe typhus: systemic vasculitis
Features of severe murine typhus:
(1)
The patient presents with a febrile illness and findings compatible with murine typhus (which often are nonspecific).
(2) The patient develops hypotension or shock with one or more organ failures including:
(2a) renal failure
(2b) neurologic involvement with change in mental status
(2c) acute respiratory distress syndrome (ARDS) with respiratory failure.
(2d) coagulopathy
(3) There is laboratory evidence for infection with Rickettsia typhi.
(4) Other causes of hypotension with organ failure are excluded.
Barriers to the diagnosis:
(1) The initial presentation is often nonspecific.
(2) Clinicians unfamiliar with typhus.
(3) Serologic testing may be unreliable and there are delays entailed in seroconversion. Molecular testing can be helpful if available.
Failing to treat appropriately with doxycycline (failure to start, early discontinuation, inadequate dosing) may increase risk of a poor outcome.
