I had a patient come in for follow up after we have been on treatment for lyme disease for 3 months. At first, I was in doubt of the diagnosis, and thought that the more likely condition was something related to stress, or adrenal fatigue. However, testing subsequently showed a very likely at least exposure to lyme, if not being absolutely clear for current infection. A cautious watch and wait, treat the stress approach was started, with no change.
We decided to start on antibiotic treatment with the most basic - doxycycline. After 2 months, there was significant improvement in target symptoms of dizziness, palpitations, fatigue, and cognitive impairment. We started on metronidazole to address the cystic and persister forms of lyme.
Notably, on starting the metronidazole, there was a significant flare in symptoms. All of them. There was a mild nausea that we could attribute to a drug side effect as well. We pulsed the metronidazole 7 days on 7 days off, and on the week off, symptoms again improved. On the second round of metronidazole, all symptoms flared again, but to a much lesser extent.
The patient was worried that she was regressing, as she did not feel as well as she did compared to the first 2 months. However, this was not the case.
Usually, on first starting treatment, some patients experience the typical die-off symptoms which we call a herxheimer reaction. This is theoretically from a killing of susceptible lyme, and the subsequent inflammatory response that follows. Imagine the lyme as a mixed bunch of balloons - letting off a small amount of faint gas that causes symptoms. The treatement initially pops a great number of these balloons, and symptoms get worse. Then they improve.
When we add another medication, particularly flagyl, we provoke more symptoms since we target different balloons, or different morphologies of lyme. And... the flares tend to get less with each subsequent round since there are less of these balloons to pop.