Differentials
Thyrotoxicosis
SIGNS / SYMPTOMS
Weight loss may be prominent. May be suggestive findings on physical examination of the thyroid, such as tenderness to palpation, goitre, and thyroid bruit.
INVESTIGATIONS
Elevated thyroxine, suppressed thyroid-stimulating hormone.
Amfetamine and methamphetamine use disorder
SIGNS / SYMPTOMS
Reported history of amfetamine or methamphetamine use. Significant dental erosion and skin ulcerations/other skin lesions from scratching and picking may be present. Medical and psychiatric adverse effects may be longer-lived (days to weeks) than those due to cocaine (typically lasting hours to 2-3 days) due to longer half-life of amfetamines versus cocaine.
INVESTIGATIONS
Urine toxicology screening positive for amfetamine or methamphetamine.[39]
Mood disorder
SIGNS / SYMPTOMS
Can be difficult to distinguish clinically and may be comorbid. Somatic symptoms, such as insomnia, weight loss, or psychomotor agitation may be more prominent.
INVESTIGATIONS
Clinical interview.
Use of Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) criteria.[1]
The Primary Care Evaluation of Mental Disorders (PRIME-MD) may indicate presence of symptoms suggestive of mood disorders.[40]
The Mood Disorder Questionnaire may indicate presence of symptoms indicative of elevated mood states (hypomania and mania).[41]
Urine toxicology screening is negative for cocaine or metabolites, unless there is concomitant cocaine use.
Psychotic/paranoid disorder
SIGNS / SYMPTOMS
History positive for similar states unrelated to episodes of cocaine use.
INVESTIGATIONS
Urine toxicology screening is negative for cocaine or metabolites, unless there is concomitant cocaine use.
Personality disorder
SIGNS / SYMPTOMS
Patients with borderline personality disorder may experience transient paranoid ideation in response to stress; patients with schizotypal personality disorder may experience ideas of reference (but not delusions), as well as odd beliefs or magical thinking. May be a comorbid condition.
INVESTIGATIONS
Clinical interview.
Use of Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR) criteria.[1]
Urine toxicology screening is negative for cocaine or metabolites, unless there is concomitant cocaine use.
Synthetic cannabinoid/cathinone derivatives use
SIGNS / SYMPTOMS
May exert the same symptoms as cocaine intoxication: for example, hyperactive delirium syndrome with severe agitation (psychotic hyperarousal, hyperthermia, cardiac arrest) or hyperadrenergic syndrome.
INVESTIGATIONS
Patient history of drug use is key. Not detected by normal urine toxicology screening, so should be suspected (along with psychosis) if a patient with suggestive symptoms and signs tests negative for cocaine and amfetamine or methamphetamine use. Detectable using time of flight spectroscopy, only available in selected large tertiary centres. Results are available after at least 24 hours (too slow to be of clinical value). The distinction is largely academic and treatment should be given for hyperactive delirium syndrome with severe agitation or hyperadrenergic syndrome (if present).
There are currently no commercial kits or devices for the routine screening of these drugs.[42][43][44]
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