What type of toxins can inflict damage on the brain?
As I mentioned before in Metabolic and Toxic Disorders, the list of toxins that are either mildly or severely damaging to the brain is huge. Because of this, I’ll only be addressing the most commonly encountered ones here. Most of these toxins are cumulative in nature: the more you are exposed to them, the greater risk you are at of developing unwanted side effects. In many workplaces, especially within the medical, metallurgy, engineering and power industries, there is a chance of exposure to such chemicals on a daily basis. Some of these you may take by choice, but other ones you don’t.
If you’ve been out partying on the weekends or just having fun with your mates, chances are you’ve met this toxin before. Yes: I’m referring to alcohol. Your drink of choice may be beer, vodka, champers, scotch, wine, liqueur, or anything else that’s on the market: I’m actually partial to vodka with cranberry juice, champers with OJ and white wine myself, but these days, I just cook with alcohol rather than drink the stuff. The effects of alcohol on the brain are minimal if you only drink once in a blue moon, and at mild doses such as a few glasses on a night out, the damage that it does to the brain in these circumstances is reversible. However, as well as damaging your liver and potentially causing cirrhosis, alcohol can lead to irreversible brain damage if taken excessively. Acute alcohol poisoning from having way too many drinks in matter of hours is a serious issue, at it can lead to brain swelling and even death if you’re not careful. In chronic cases of alcoholism, the cerebellum may shrink, leading to dysfunctional movement as well as nystagmus (eyes moving from side to side rapidly: this only normally happens during your dream cycles or REM sleep, in other words). Additionally, research has found that not only can alcohol affect the mind of the person ingesting the alcohol, but if a pregnant mother is drinking to excess, her baby may become born with foetal alcohol syndrome.
Do you recognize this place from the photo?
I’ll give you a hint… it was a nuclear power plant that went into meltdown in the early morning of 26th of April, 1986, causing an immense release of ionising radiation (radioactivity) that reached as far as the United States, and there is still an exclusion zone around Pripyat, Ukraine to this day. You may have also heard of the recent Fukushima Diiachi disaster that happened in 2011, which was caused by a combination of an earthquake and a following tsunami which flooded the plant. More information about this disaster can be found in the following Youtube documentary: Fukushima Disaster: 2011.
Despite the fact that the both disasters were very traumatic to their respective populations, when it comes to ionising radiation released into the atmosphere, the Fukushima disaster rates second to the one in the photo.The photo was taken as part of the 25th anniversary of the Chernobyl nuclear plant accident. It took place in Ukraine, which was at that time part of the Soviet Union, and a chain of events led to the explosion of nuclear reactor number 4. More information about the accident can be found in this documentary on Youtube: Chernobyl Disaster: 1986
Anyway, I drifted off a little, back to the brain…
The symptoms that ionising radiation have on the brain are various, and ma ny of them are nasty: during the two disasters I mentioned above, many of the workers unfortunately succumbed to radiation sickness. Symptoms of this condition include the following: headaches, nausea, vomiting and swelling of the optic discs in the eyes, also known as papilledema, as shown in the picture alongside. These symptoms can be acute or may occur even months or years after the exposure has happened, due to the presence of coagulative necrosis (death of brain tissue due to blood clotting) in the white matter with brain swelling and thickened blood vessels often accompanying it.
Heavy Metal Toxicity
There are multiple types of heavy metals which can lead to heavy metal poisoning. The most common by far is Pb or lead, as seen in the picture alongside. Here’s a funny fact for you to ponder: although we often use lead pencils, pencils don’t contain any lead whatsoever: they actually contain graphite, which is a form of carbon. Other metals which often lead to heavy metal poisoning include mercury (Hg) and arsenic (As). Ironically, mercury in ancient times was used as a medicine to attempt to treat syphilis. Unfortunately, it was more likely to kill the poor patient rather than heal them. Other heavy metals have a similar effect, and this can be used as a weapon. If you were watching House on TV regularly, you may remember an episode where a woman was poisoning her husband using gold (Au) and it was House’s deduction that led to the woman being busted for attempted murder. The heavy metals affect the brain by causing encephalopathy (disorder of the brain).
Industrial phosphates such as organophosphates can affect the brain by leading to damage within the retinas of the eyes. Examples of organophosphates include pesticides and methanol (CH3OH). As the picture alongside suggests, pesticides are used to keep insects at bay when food products are growing. Methanol has multiple uses, including as a cleaning agent (in the form of methylated spirits), fuel for vehicles, an antifreeze in pipelines and a carbon food source in wastewater plants.
The main environmental pollutant which can lead to damage within the brain is carbon monoxide (CO). This is often expelled as a result of incomplete combustion in cars. What is incomplete combustion you may ask?
(liquid petroleum gas):every hydrocarbon must contain at each one hydrogen and one carbon atom. The difference between complete and incomplete combustion is the amount of oxygen present in the air. If there is sufficient oxygen, the combustion will be complete and the above reaction happens, but if there is not, incomplete combustion takes place and often carbon monoxide is released instead of carbon dioxide. Same thing happens in your body: aerobic respiration happens during exercise with adequate oxygen, but lactic acid builds up as a byproduct of insufficient oxygen. In the brain, the presence of carbon monoxide in high doses is deadly: it can lead to lack of oxygen because of carbon monoxide competing for the areas where oxygen is carried on red blood cells (as shown in the picture above) and selective injury to the globus pallidus in the basal ganglia.
Methotraxate is a medication which is used in the treatment of tumours. Ironically, it can lead to damage of the brain as a side effect: this tends to happen when a patient is being given radiation and systemic therapy at the same time. There are multiple things seen under the microscope, including calcification (excess calcium), gliosis, necrosis (cell death) and demyelination, which involves stripping of crucial myelin from neurons.