WHAT IS TBRD??
The TBRD is a really sweet classic auto known and loved by generations of car lovers.
But the more ominous designation of TBRD – Tick Borne Rickettsial Disease – is something that you should also be aware of because of its similarity to other types of insidious infections such as Lyme disease and because prompt treatment can mean the difference between dealing with a fairly mild and annoying condition versus a lifetime of suffering the late stage consequences.
The main types of TBRDs are RMSF (Rocky Mountain Spotted Fever), Ehrlichiosis anaplasmosis, Human Monocytic Ehrlichosis and Ehrichia ewingii. They are all found throughout the United States but particularly in the region from New England to Florida. They are all spread by tick bites including the common dog tick and the Lone Star tick.
Perhaps the most important factor leading to prompt and potentially life-saving treatment is a high index of suspicion. If the doctor or the patient even thinks of the possibility of TBRD under the appropriate circumstances, then treatment should be started with the appropriate antibiotic pending confirmatory tests. Failure of a classic Lyme “bull’s eye” rash to appear and blood tests for Lyme antibodies coming back as negative should not deter the patient or doctor from treating with medication if an unexplained fever, chills, malaise, headache or nausea occurs after a tick bite has been noticed or even if the person has been in the appropriate area prior to the onset of symptoms.
Only RMSF is quite commonly associated with a rash; with the others rash is much less common. The antibiotic of choice to kill Rickettsia is doxycycline 100mg twice each day for five to ten days. Fortunately this drug is also commonly effective against Lyme disease and is often administered pending confirmatory testing for Lyme. Thus the likelihood is that many cases that would have gone on to be TBRDs are cured by someone suspecting Lyme exposure and treating for this. Laboratory testing for TBRDs is nowhere near as sophisticated as that for Lyme disease and thus it can be much more challenging to confirm the diagnosis. Because the organism is extremely tiny and an obligate intracellular parasite, it cannot readily be seen on a blood smear or grown in a laboratory culture medium. It must be grown in a tissue or embryo medium to be identified.
Recommended treatment for tickborne rickettsial diseases
- Doxycycline is the drug of choice for treatment of all tickborne rickettsial diseases in children and adults; empiric therapy should be initiated promptly in patients with a clinical presentation suggestive of a rickettsial disease.
- Tickborne rickettsial diseases respond rapidly to doxycycline, and fever persisting for >48 hr after initiation of therapy should prompt consideration of an alternative or additional diagnosis, including the possibility of coinfection
- Doxycycline is recommended by the American Academy of Pediatrics and CDC as the treatment of choice for patients of all ages, including children aged <8 yr, with a suspected tickborne rickettsial disease.
- Delay in treatment of tickborne rickettsial diseases can lead to severe disease and death
Being aware of these conditions may save you or your patient a great deal of avoidable suffering. Emergency room personnel should be on the lookout for the symptom complex and perhaps have a lower threshold for prescribing doxycycline, attempting to ensure that no cases are inadvertently missed.