Substance abuse

Question 1

What is substance abuse?

Answer 1

Any continued pathological use of a prescription medication, illicit drug or toxin
This abuse results in repeated adverse social consequences, dependence or addiction is characterized by physiological and behavioural symptoms

Question 2

What are substances that are abused?

Answer 2

Alcohol, amphetamines, cannabis, cocaine, hallucinogens, inhalants, opoids (morphine, heroin, codeine, methadone), phenycyclidine sedative, hypnotic and anxiolytic (anti anxiety drugs), nicotine and anabolic-androgenic steroids

Question 3

What are common properties of depressants?

Answer 3

Slurred speech, lack of coordination, unsteady gait, memory impairment, stupor, aggressive behaviour, mood volatility and impaired functioning

Question 4

What are the common properties of stimulants?

Answer 4

Rapid heart beat, elevated or depressed blood pressure, dilated (enlarged) pupils, weight loss, excessively high energy, inability to sleep, confusion, occasional paranoid psychotic behaviour

Question 5

What is overdosing?

Answer 5

This is a common complication of substance abuse and can be a life threatening emergency

Question 6

What are the effects of overdosing in substances with depressing effects?

Answer 6

These may dangerously slow the breathing and heart rate; drop the body temperature; result in a general unresponsiveness

Question 7

What are the effects of overdosing in substances with stimulatory effects?

Answer 7

These may dangerously increase the heart rate and blood pressure; produce abnormal heart rhythms; increase body temperature; induce seizures; cause erratic behaviour

Question 8

What complications can intravenous drug use cause?

Answer 8

Track marks, cutaneous necrosis and necrotising ulcers, localised cutaneous infections as well as systemic infections

Question 9

What are track marks?

Answer 9

these are visible signs of redness and swelling of the vein at the site of an injection, this damage can lead to blood clots where there is damage/inflammation and collapsed veins, they occur due to physical damage caused by the needle due to frequent use of the same site and also the presence of solids in the injected material

Question 10

How can intravenous drug use cause cutaneous necrosis and necrotising ulcers?

Answer 10

These may result from the toxicity of the drug itself and/or the irritant properties of adulterants used to cut the drug
For example quinine is often used as an adulterant and has caustic effects while cocaine has potent vasoconstrictive and thrombotic effects
Cutaneous necrosis also results from arterial thrombosis after direct intra-arterial injection

Question 11

How can drug use result in localised cutaneous infections?

Answer 11

The combination of compromised epithelium and injections of drugs with non-sterile needles leads to a wide variety of potential infections including abscesses which are a localized collection of pus encapsulated within the inflamed tissue, cellulitis (a painful spreading inflammation of the dermis with oedema), non sterile injections can also lead to systemic bacterial, viral and fungal infections

Question 12

What factors associated with intravenous drug use can increase the risk of infection?

Answer 12

Absence of skin asepsis, use of unsterile equipment. Poor hygiene behaviours such as licking needles, using saliva to clean skin, to moisten cotton wool or to dilute the drug

Question 13

How can intravenous drug use lead to systemic infections?

Answer 13

Injection of drugs with non-sterile needles causes the potential for a wide variety of these infections including endocarditis, acute bacterial meningitis, tuberculosis and viral infections causing hepatitis and HIV

Question 14

What is adulteration in drug abuse?

Answer 14

This is mixing the drug with an inert substance like talcum powder to dilute it
It can potentially lead to granulomatosis as the inorganic material collects in the tissues particularly the liver, spleen, lymph nodes, bone marrow and lungs to form a foreign body granuloma

Question 15

What is common of the kidney of drug addicts?

Answer 15

It is often damaged with a spectrum of glomerular, interstitial and vascular disease being observed frequently with chronic and irreversible effects
The high rates of infection associated with iv drug use results in glomerulonephritis
Local pyogenic abscesses can also be formed in the kidney due to S. Aureus infections
The drug an metabolite may be excreted through the kidney causing it to be upconcentrated here where it can have directly nephrotoxic effects or trigger immune-complex-mediated glomerulonephritis

Question 16

What is the relationship between heroin and nephropathy?

Answer 16

This drug is particularly associated with nephropathy where focal glomerulosclerosis (fibrotic change or hardening) that occurs leads to nephrotic syndrome which progress rapidly to end stage renal failure
Animal studies have suggested that this drug may have a direct effect on the glomerulous to increase proliferation of fibroblasts and decrease degradation of type 4 collagen, however heroin may act as an antigen leading to renal deposition of immune complexes in the kidney

Question 17

What can result from cocaine intoxication?

Answer 17

This may lead to a state of psychosis called excited delirium where the individual becomes markedly agitated and combative resulting in traumatic injuries being common
Over dose can cause severe hyperthermia and organ damage can occur particularly rhabdomyolysis of muscle and hepatotoxicity and renal failure

Question 18

What si the mechanism of action of cocaine?

Answer 18

This prevents reuptake of catecholamines such as epinephrine, norepinephrine and dopamine at presynaptic terminals causing an increased effect of the catecholamine resulting in tachycardia, hypertension, vasoconstriction and increased myocardial oxygen consumption

Question 19

What is associated with cocaine abuse?

Answer 19

Acute haemorrhage and infarction in the brain as well as chest pain, palpitations and myocarditis. There is both focal necrosis and ischemic damage to the myocardium as well as infarcts and thickening of coronary arteries this is due to increased oxygen demand of the myocardium plus vasoconstriction resulting in an increased risk of myocardial infarct and sudden death

Question 20

How can the ischemic changes in the heart which occur with cocaine abuse be observed?

Answer 20

Small artery narrowing and sclerosis, contraction band necrosis of the myocardium can be observed as loss of cross striations, nuclei which are not clearly visible and also irregular dark pink wavy contraction bands

Question 21

How can cocaine use have an effect on bleeding?

Answer 21

One complication is disseminated intravascular coagulation as the proteins that control blood clotting are abnormally active and small blood clots form throughout the body, this is also results in a depletion of these proteins so they are unavailable at times of injury resulting in severe bleeding

Question 22

What affects can cocaine abuse have on unborn babies?

Answer 22

It can cause abnormalities of placental function leading to low birth weight and an increased risk for placental abruption -when blood clots compress the placenta, this acute condition occurs near term and the baby in utero is at risk due to the separation of the placenta and disruption of the blood supply

Question 23

What inhalation damage can occur with drug abuse?

Answer 23

This can cause necrosis of the cartilage and bone with erosion of the nasal septum
When cocaine is snorted throughout the nose causes frequent nosebleeds, erosion of the nasal septum, nasal saddling due to the extensive necrosis of the cartilage and bone in the nasal septum and paranasal sinuses this can lead to naso-oral fistulae

Question 24

How can cocaine cause pulmonary toxicity?

Answer 24

This can occur regardless of method of use with an acute toxicity within 48 hours causing fever and eosinophilia
Diffuse alveolar infiltrates are observed and there is alveolar damage and hyaline membrane formation
Chronic pulmonary toxicity may occur in which case diffuse alveolar damage and haemorrhage, interstitial pneumonitis, intra aveolar oedema, chronic interstitial pulmonary fibrosis as well as hypertrophy of the pulmonary arteries and bulbous emphysema may also be seen

Question 25

What is the mechanism through which cocaine causes lung damage?

Answer 25

This is not known but it could be due to direct cellular toxicity- for example biotransfomation of cocaine could lead to formation of ROS in type 2 pneumocytes- this could be receptor mediated damage, it has known vasoconstrictive effects of cocaine may cause constriction of pulmonary vasculature leading to ischemia
There could also be an abberant inflammatory response and a hypersensitivity reaction
The mechanism of alveolar haemorrhage is unknown as the type 1 pneumocytes are intact and the type 2 pneumocytes are increased

Question 26

Why is cocaine toxicity and its associated pathologies unpredictable?

Answer 26

This may relate to differences in the metabolic biotransformation of cocaine, most of the drug is hydrolysed by a serum esterase enzymes but a small amount undergoes demethylation by CYP enzymes ultimately forming norcocaine nitroxide which is a reactive species
So a poor metabolizer may exist causing these individuals to have an altered risk of development of addiction and/or a lower risk of toxicity