Organic solvent intoxication – affecting the nervous system

To illustrate how organic solvents may affect the nervous system, we will tell you about a worker who experienced a typical chronic intoxication of such chemicals. This is about a 29 year old man, referred to the hospital because he had become very forgetful. He was working in a paint factory, in the production line. The company was located in an old house with no specific ventilation. He did not use any respiratory protective mask during his work. This man had worked in this company since he was 18 years old, meaning 11 years. The past five years he had become more and more forgetful, receiving complaints from his colleagues as well as from his wife. He often forgot very important issues, like what kind of colors he was working on and how much paint he should make, and this had become a problem at his work place.

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He also had developed an extreme tiredness. He slept all afternoon and most of the weekends. He also had problems in concentrating, and could for instance not watch television anymore, or read a newspaper. In addition to these problems, he had developed difficulties in walking. During medical examination, he had paralyses in some of the muscles of the leg. This man was examined carefully in our hospital, with blood tests, x-rays and brain function test. We found he had a minor brain damage and a polyneuropathy (reduced function of several nerves in the leg). The most likely reason for this was the organic solvent exposure at his work place. There was no other explanation for his problem.

We decided that he had to stop working in this factory so his organic solvent exposure could stop completely. After a year with no such work, he felt much better, but he will never fully regain his previous health. This is a sad story, and the saddest thing is that this could have been prevented.

This young man developed a chronic organic solvent intoxication, which means he has a brain damage which cannot be cured. With proper ventilation, information and use of respiratory protective equipment, he could have avoided the development of this disease.

By this story, we have described to you an organic solvent intoxication. A chronic organic solvent intoxication is a permanent damage in the nervous system, caused by exposure to organic solvents. The damage may occur both in the brain and in peripheral nerves. Many such patients must stop working. However, if the conditions at work can be improved so further exposure to organic solvents does not occur, the patient can continue working, if he is well enough to perform the job.

Organic solvents and health effects in general

Organic solvents can cause adverse health effects in other parts of the body than the nerves and brain, but these side effects differ between the different organic solvents. Most important is to remember the effects in the nervous system. It can be useful to divide these health effects in acute and chronic.

Acute effects
Acute effects of organic solvents that work on the brain have been known for hundreds of years. Low or moderate concentrations of organic solvents can cause transient symptoms as euphoria, irritability, headache, dizziness, ataxia, and sleepiness. The euphoria is well known, as for instance the effect of drinking alcohol; which is the organic solvent ethanol. High exposures to organic solvents can provide lack of consciousness and life-threatening respiratory and circulatory disorders. Acute effects are known from both occupational exposure, and from sniffing (abuse) and drinking (ethanol) organic solvents.

The nervous system consists of the brain, spinal cord and the peripheral nerves. Organic solvents may influence the nervous system, for instance by affection of the myelin sheath around the nerves, as well as by a direct effect on the nerve cells. ^{© Colourbox}

Chronic effects
Chronic organic solvent effects of the nervous system develop gradually as a result of regular low level exposure to organic solvents over many years. Gradual development, starting with symptoms like fatigue and headaches, is very common. Thereafter, symptoms like reduced ability to concentrate and to remember things develop. Depression, sleep problems and various forms of anxiety often occurs. It is unclear whether these symptoms are a part of the effect from the organic solvents, or if some of the symptoms come as a secondary effect as the patient feel like he/she comes up short in many situations. The workers have symptoms similar to light dementia. Serious dementia symptoms with loss of disease insights, an inability of abstract and constructive thinking, aphasia, apraxia, or delusions are very unusual.

A clinical neurological examination may reveal weaknesses in tests of concentration and immediate memory, and sometimes unsteady gait and ataxia. Some patients develop polyneuropathy in arms and/or legs, with reduced sensitivity and motor skills.

It can be difficult to diagnose these patients, as the disease resembles many others. It is important to examine the patients thoroughly, to avoid a wrong diagnosis. The diagnosis should ideally be set by cooperation between a neurologist, a neuropsychologist and an occupational physician. Differential diagnoses are for instance: Alzheimer’s disease, vascular affection of the brain, alcohol related diseases, intracranial tumor, chronic fatigue syndrome, depression, panic anxiety, diabetes mellitus and anemia.