Question: can toxins pass through the blood brain barrier

Answer: Yes, The blood-brain barrier may become leaky in select neurological diseases, such as amyotrophic lateral sclerosis, epilepsy, brain trauma and edema, and in systemic diseases, such as liver failure. The blood--brain barrier becomes more permeable during inflammation, allowing antibiotics and phagocytes to move across the BBB. However, this also allows bacteria and viruses to infiltrate the blood-brain barrier. Examples of pathogens that can traverse the blood-brain barrier include toxoplasma gondii which causes toxoplasmosis, spirochetes like Borrelia (Lyme disease), Group B streptococci which causes meningitis in newborns, and Treponema pallidum which causes syphilis. Some of these harmful bacteria gain access by releasing cytotoxins like pneumolysin which have a direct toxic effect on brain microvascular endothelium and tight junctions.