Drug Misuse - Unusual Presentations

Managing people with drug misuse problems in primary care involves not only treating patients who admit to their dependency but also recognising the signals in those who are reluctant to share this information. Not infrequently, you will also be approached by temporary patients attempting to obtain drugs by deception. GPs need to be alert to the possible significance of the following:

• Temporary residents just passing through the area.
• Patients with an overly familiar knowledge of medications, demanding analgesia for renal colic, sickle-cell crises, etc.
• Patients giving evasive answers.
• Signs of heavy smoking, strange smoke smells (cannabis, cocaine, heroin).
• Acetone or glue smell on breath (solvent abuse).
• Small pupils (opiates).
• Needle tracks on arms, groin, legs, between toes; intravenous access difficult.
• Abscesses and lymphadenopathy in nodes draining injection sites.
• Signs of drug-associated illnesses (eg, endocarditis, AIDS, chronic viral hepatitis).

See also the articles on Assessment of Drug Dependence, Drug Misuse and Dependence, Opioid Misuse and Dependence, Crystal Methamphetamine Drug Abuse, Dual Diagnosis (Drug Abuse with Other Psychiatric Conditions), and Alcoholism and Alcohol Misuse - Recognition and Assessment.

Medical conditions presenting in drug misusers

Patients may present with a variety of medical conditions but the doctor may not be aware of the history of drug dependency. The following is a list of some of the possible scenarios:

• Patient found unconscious - consider narcotics, barbiturates, solvents and benzodiazepine as well as alcohol (see also Opiate Poisoning).

Mental health:

• Psychosis - consider methylenedioxymethamphetamine (MDMA, or 'ecstasy'), lysergic acid diethylamide (LSD), amphetamine, anabolic steroids^{[1, 2]} .
• Agitation - common with benzodiazepines.

Respiratory:

• Asthma/dyspnoea - consider opiate-induced pulmonary oedema, asthma (may follow the smoking of heroin).
• Reduced lung density, lung cysts and chronic obstructive pulmonary disease (COPD) - may be related to cannabis use^[3] .
• Lung abscess - may be a complication of right-sided staphylococcal endocarditis (common in intravenous drug users)^[4] .
• Airway burns, pneumothorax, pneumomediastinum, 'crack lung' - these can all be complications of crack cocaine, due to its method of delivery^[5] .

Infection:

• Fever/pyrexia of unknown origin (PUO)/shivering - may be the only sign of endocarditis.
• Shivering and headache - due to chemical/organism contamination of intravenous drug. If suspicious, outline risks and offer immediate referral to secondary care - may need blood cultures, and antibiotics - eg, gentamicin.
• Hyperpyrexia - consider 'ecstasy'^[6] ; be wary of associated myoglobinuria, disseminated intravascular coagulation, renal failure.
• Abscesses - if over an injection site, then often of mixed organisms.
• Pneumonia - pneumococcus, haemophilus, tuberculosis, pneumocystis.
• Symptoms suggestive of glandular fever - may actually be HIV seroconversion illness.
• Pain in a limb or back pain with fever - consider osteomyelitis.

Cardiovascular:

• Tachyarrhythmia - in young patients consider cocaine, amphetamines, endocarditis.
• Myocardial infarction - may be associated with:
  • Cocaine^[7]
  • Cannabis use^[8]
  • MDMA^[9]
• Stroke or transient ischaemic attack (TIA), spinal infarction - consider:
  • Cocaine use^[10]
  • MDMA^[11]
• Myocarditis, hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic dissection - all noted in cocaine users^[7] .

Others:

• Deep vein thrombosis - may result from injecting suspension of tablets into a groin; consider acute compartment syndrome; organise a creatinine kinase test.
• Jaundice - hepatitis B, C, or D, anabolic steroids (cholestasis).
• Severe constipation - unusual in a young patient, and may be sign of opiate abuse.
• Cystitis - ketamine abuse can cause inflammation of the bladder lining, leading to frequency, urgency and nocturia (ketamine bladder syndrome).^[12]
• Severe sight impairment - may be secondary to fungal or bacterial endophthalmitis with or without endocarditis, or talc or other particulate emboli.
• Rhinitis - consider opiate withdrawal; other features may be colic/diarrhoea, lacrimation, dilated pupils, insomnia, piloerection, myalgia, low mood; (rhinitis may also be a sign of cocaine use).
• Signs of sensory or motor neuropathy - consider solvent abuse.

General management

• Essential elements of treatment provision.
• Psychosocial components of treatment.
• Pharmacological interventions.
• Criminal justice system.
• Health considerations.
• Specific treatment situations and populations.
• Advice on writing prescriptions.
• Interactions.
• Travelling abroad with controlled drugs.
• Drugs and driving.