Lyme disease, an illness that can be quite serious if left untreated, affects people living in many parts of the United States. Since it was described in 1975 after being identified in Lyme, CT, the infection has grown in both real frequency and myth. Tranmitted by the tick Ixodes scapularis, commonly known as the deer tick, the causative organism is Borrelia burgdorferi, a type of bacteria. Following attachment by the tick, 24 to 36 hours are required for B.burgdorferi to be transmitted to its host, and often a characteristic rash known as erythema migrans develops at the site of tick attachment. Now there's good news, as Rick and I discuss this week on PodMed: turns out that contrary to much popular opinion and the word on the street, most if not all cases of recurrent Lyme disease in people who've already had it and been treated are new infections, not recrudenscence of an existing infection. That's as reported in the New England Journal of Medicine. So why is that good news? First let's take a look at the study.
A total of 17 patients in whom there were 22 paired consecutive episodes of erythema migrans were reported in this study. Specimens of skin and blood were obtained from each patient and the organism cultured and genotyped. Additional molecular tests were also performed on the specimens. Interestingly, only 27% of the subjects recalled a tick bite at the site of erythema migrans development in the previous 30 days.
The same genotype was not identified in any of the paired infections, indicating clearly that each episode was caused by a different strain of the bug. Additional factors such as the time of year during which infection occured and the length of time between infections were consistent with this conclusion. The take home message for people who receive a diagnosis of Lyme disease is that when they complete their antibiotic treatment, they can feel confident the infection has been eradicated and not worry about the constellation of negative sequelae that can develop when an infection isn't properly diagnosed and/or treated. YAY!
Lyme disease, of course, has a lot of panic attached to it among many, and that's because the symptoms of tertiary disease are dire indeed. Thus rabid advocacy groups have stridently proclaimed that Lyme requires a complex and prolonged treatment course during which hypervigilance is required. Maybe now that this study has been published some of the fever will die down. It is true, as Rick points out in the podcast, that sometimes even when the treatment course has been completed and the organism eradicated, symptoms such as arthritis, that may be severe, remain. The current explanation for this seems to be that Borrelia ramps up the immune response, which then takes some time to return to baseline. Tough for those who are living with it to deal with but much less serious than disseminated Lyme.
Other topics this week include steroid injections for sciatica, fungal infections secondary to steroid injection, and probiotics for Clostridium difficile infection, all in Annals of Internal Medicine. Until next week, y'all live well.