Substance Abuse

Alcohol

Alcohol abuse is defined as the regular or binge consumption of alcohol which can lead to physical, neuropsychiatric or social damage.

– 1 unit (10mL) of alcohol is about equivalent to a small glass of wine, or a single peg of spirits.

– Units = Volume (L) * ABV (%)

– e.g. a 750ml bottle of wine, strength 12% has 750/1000 *12 = 9 units

– Both men and women should drink no more than 14 units a week. If you do, it is best to spread this evenly over 3 days or more.

There are several problems of alcohol abuse, both in the short and long term: 

Acute intoxication

This is a fairly common state which can resemble other causes of acute confusion, especially head trauma.

Symptoms: Slurred speech, impaired coordination and judgement but can lead to hypoglycaemia and coma

Management – Effects usually wear off in 24 hours, provide supportive management 

Alcoholic Ketoacidosis

This is a complication of alcoholism which leads to raised ketone level in the blood causing an acidosis

– When alcoholics miss meals or vomit, this can lead to episodes of starvation, and so the body switches from carbohydrate to fat metabolism generating ketone bodies.

Symptoms: Nausea, vomiting and abdominal pain

– Tachypnoea, tachycardia and hypotension

– However, in contrast to diabetic ketoacidosis, patients are usually alert and lucid

Diagnosis:

– Blood gas –> metabolic acidosis with a raised anion gap and high ketones

– However, the glucose levels will be normal showing it is not a diabetic ketoacidosis

Management – IV saline with dextrose and thiamine (to prevent Wernicke encephalopathy)

Alcohol Dependence

This is defined as a strong compulsion to drink alcohol despite awareness of the physical/psychological harms

– The main psychological problem is that it leads to thiamine (Vitamin B₁) deficiency in alcoholics

To address the problem of chronic alcoholism, there are several screening tests available:

i) CAGE questionnaire – Have you tried to Cut down drinking?

– Have people Annoyed you by suggesting you do so?

– Have you felt Guilty about drinking?

– Have you needed an Eye-opener (early morning drink)?

ii) Fast alcohol scoring test (FAST) – This is a quick test, used to assess for levels of hazardous drinking

Management – Patients are often referred to an alcohol dependence programme to help them quit.

– They can use a mixture of behavioural interventions (e.g. CBT) and pharmacological treatment

– Disulfiram –> this inhibits acetaldehyde dehydrogenase, so people feel hungover as soon as they drink alcohol (avoid in ischaemic heart disease)

– Acamprosate –> this is a weak NMDA antagonist which is used to reduce alcohol craving  

If alcoholism is left untreated, it can lead to some complications:

Wernicke’s encephalopathy

Lack of Vitamin B₁ causes a peripheral neuropathy and leads to cerebellar degeneration giving ataxic signs

Symptoms: Ataxia, nystagmus, ophthalmoplegia and acute confusion

Investigations:

–  MRI shows cerebellar degeneration

– Decreased red cell transketolase –> this is an enzyme that catalyses transfer of alcohol group between sugars

Management:

– IV infusion of thiamine (Vitamin B₁)

Korsakoff’s Syndrome

This is the consequence of untreated Wernicke’s encephalopathy which leads to irreversible brain changes.

Symptoms: Same as Wernicke’s plus both antero/retrograde amnesia

– Confabulation –> symptom of memory dysfunction where patients make up stories to fill in gaps in memory 

Alcohol Withdrawal

Alcohol consumption enhances GABA-inhibition in the CNS and inhibits NMDA glutamate receptors

– In withdrawal is thought that the opposite occurs (less GABA and more NMDA transmission)

Symptoms – Together they are called delirium tremens – Early on –> increased anxiety, with sweating and agitation

– After 24 hours –> Seizures with visual hallucinations

– From 48-72 hours –> Course tremors, agitation, delusions and severe visual hallucinations

Management – 1st line is benzodiazepine chlordiazepoxide 

Stimulants

e.g. Cocaine + Amphetamine

These drugs block the reuptake of dopamine and noradrenaline (and 5-HT) increasing transmission at synapses

– They are usually snorted excepted crack cocaine which is smoked

– They are classified as stimulants as they clinically resemble a state of increased sympathetic activity.

Main effect – Increased energy and concentration, euphoria and hyperactivity

Side effects:

– Cardiovascular –> Increased pulse, blood pressure, hyperthermia, can lead to aortic dissection

– Heart –> QRS widening and QT prolongation

– GI –> Reduced appetite and ischaemic colitis

– Psychological –> Insomnia, agitation and hallucinations e.g. formication (sensation of ants under the skin)

 – If you take a prolonged large dose, the euphoria can turn to depression and anxiety

– Can get psychosis –> delusions, visual and auditory hallucinations

N.B. Many of the withdrawal effects are clinically the opposite of the dose effects:

– Mood –> Depression with irritability and agitation

– GI –> Craving and hyperphagia

– Psychological –> Hypersomnia 

Management – IV benzodiazepines + treat complications (heart attack, aortic dissections) + antipsychotics

MDMA (Ecstasy)

This is a psychoactive drug which blocks the reuptake of monoamines, particularly serotonin (and Na)

– It is commonly used at  parties and gives people a “high” with a feeling of euphoria

Main effect – Increased energy, empathy, as well as pleasure, mild hallucinogen

Side effects:

– Cardiovascular –> Hyperthermia causing sweating, tachycardia, hypertension

– Dehydration –> patients can then drink a lot of water giving hyponatreamia and death

– Psychological –> Insomnia, increased psychomotor activity, trismus (locked jaw), impulsivity

Cannabinoids

Cannabis is grown from the plant strains cannabis sattiva and Indica

– The active stimulatory ingredient is tetrahydrocannabinol which binds CB1 receptors causing a high

– The other component is CBD (cannabidiol) which is known to dampen the THC effects

Main effect – Euphoria and relaxation, with a distortion of sense of time and place.

Side effects:

– Respiratory –> red eyes, dry mouth and coughing

– Psychological –> Leads to paranoid thinking, anxiety and increases risk of depression and schizophrenia

– GI –> Increased appetite after the high