Two individuals are brought into the emergency department, one night. One
is 28 year old Brian who was brought in by his friend with complaints of
altered consciousness and vomiting.
The friend recalls that Brian had a habit of binge drinking on weekends. On
examination, he was disoriented, and had slurring of speech, loss of
coordination, and nystagmus.
The second is 2 year old Michelle who’s brought by the mother who reported
a seizure episode an hour ago.
Upon further questioning, the mother reveals that Michelle was born 2
months prematurely, was always crying and irritable, and was slow in
reaching developmental milestones.
On examination, Michelle has reduced height and weight, a small eye
opening, smooth philtrum, and thin lips. A neurological exam shows reduced
muscle tone and coordination.
When you obtain a more focused history regarding the mother's pregnancy,
she reported drinking 3-5 glasses of wine each night during the 1st and 2nd
trimester.
Okay, both Brian and Michelle’s symptoms are due to alcohol. Alcoholic
drinks contain the chemical ethanol, which mainly acts in two ways in the
brain, one, it acts as an agonist to GABA, which is the brain’s major inhibitory
neurotransmitter; and two, it acts as an antagonist of glutamate, which is an
excitatory neurotransmitter.
Both these actions produce an overall inhibitory action on the brain’s
neuronal circuits. Now, ethanol’s effects vary based on the blood alcohol
concentration, or BAC, which is the percentage of ethanol in a given volume
of blood.
At a blood alcohol concentration of 0.0 to 0.05%, ethanol produces a relaxed
and happy feeling, along with slurred speech and some difficulty with
coordination and balance.
, At a blood alcohol concentration of 0.06 to 0.15%, there is increased
impairment to speech, memory, attention, and coordination, and some
individuals can get aggressive and even violent.
Complex tasks like driving can become dangerous, which is why it is illegal to
drive in some countries with a blood alcohol concentration of 0.08% or
higher.
At a blood alcohol concentration of 0.16 to 0.30%, individuals can
experience alcohol poisoning where they blackout or experience periods
of amnesia.
Finally, at a blood alcohol concentration above 0.31%, the effect
of alcohol can severely suppress breathing and even lead to death.
Now, the use of alcohol can be assessed by direct and indirect tests. Direct
tests measure the alcohol content in bodily fluids like blood, urine, saliva and
the air breathed out.
In contrast, the indirect tests assess the effect of alcohol on organs like the
liver. Cellular damage causes the release of liver enzymes into the blood.
Gamma-glutamyltransferase, or GGT, is the most sensitive indicator
of alcohol use. In addition, aspartate aminotransferase or AST, alanine
aminotransferase or ALT, are also elevated in chronic alcohol use, although
AST values rise to about twice as much as ALT.
This is because alcohol use decreases ALT activity in the liver. And, that’s
high yield! Over time, in people with prolonged alcohol consumption, neurons
adapt by decreasing their number of GABA receptors, while increasing the
number of NMDA glutamate receptors.
These individuals develop tolerance to the effects of alcohol, and therefore
an increased dose is needed to achieve the original response.
Moreover, if the individual suddenly stops drinking, this receptor imbalance
leads to overactivity of the central nervous system, which can result
in withdrawal symptoms.
is 28 year old Brian who was brought in by his friend with complaints of
altered consciousness and vomiting.
The friend recalls that Brian had a habit of binge drinking on weekends. On
examination, he was disoriented, and had slurring of speech, loss of
coordination, and nystagmus.
The second is 2 year old Michelle who’s brought by the mother who reported
a seizure episode an hour ago.
Upon further questioning, the mother reveals that Michelle was born 2
months prematurely, was always crying and irritable, and was slow in
reaching developmental milestones.
On examination, Michelle has reduced height and weight, a small eye
opening, smooth philtrum, and thin lips. A neurological exam shows reduced
muscle tone and coordination.
When you obtain a more focused history regarding the mother's pregnancy,
she reported drinking 3-5 glasses of wine each night during the 1st and 2nd
trimester.
Okay, both Brian and Michelle’s symptoms are due to alcohol. Alcoholic
drinks contain the chemical ethanol, which mainly acts in two ways in the
brain, one, it acts as an agonist to GABA, which is the brain’s major inhibitory
neurotransmitter; and two, it acts as an antagonist of glutamate, which is an
excitatory neurotransmitter.
Both these actions produce an overall inhibitory action on the brain’s
neuronal circuits. Now, ethanol’s effects vary based on the blood alcohol
concentration, or BAC, which is the percentage of ethanol in a given volume
of blood.
At a blood alcohol concentration of 0.0 to 0.05%, ethanol produces a relaxed
and happy feeling, along with slurred speech and some difficulty with
coordination and balance.
, At a blood alcohol concentration of 0.06 to 0.15%, there is increased
impairment to speech, memory, attention, and coordination, and some
individuals can get aggressive and even violent.
Complex tasks like driving can become dangerous, which is why it is illegal to
drive in some countries with a blood alcohol concentration of 0.08% or
higher.
At a blood alcohol concentration of 0.16 to 0.30%, individuals can
experience alcohol poisoning where they blackout or experience periods
of amnesia.
Finally, at a blood alcohol concentration above 0.31%, the effect
of alcohol can severely suppress breathing and even lead to death.
Now, the use of alcohol can be assessed by direct and indirect tests. Direct
tests measure the alcohol content in bodily fluids like blood, urine, saliva and
the air breathed out.
In contrast, the indirect tests assess the effect of alcohol on organs like the
liver. Cellular damage causes the release of liver enzymes into the blood.
Gamma-glutamyltransferase, or GGT, is the most sensitive indicator
of alcohol use. In addition, aspartate aminotransferase or AST, alanine
aminotransferase or ALT, are also elevated in chronic alcohol use, although
AST values rise to about twice as much as ALT.
This is because alcohol use decreases ALT activity in the liver. And, that’s
high yield! Over time, in people with prolonged alcohol consumption, neurons
adapt by decreasing their number of GABA receptors, while increasing the
number of NMDA glutamate receptors.
These individuals develop tolerance to the effects of alcohol, and therefore
an increased dose is needed to achieve the original response.
Moreover, if the individual suddenly stops drinking, this receptor imbalance
leads to overactivity of the central nervous system, which can result
in withdrawal symptoms.
