Substance Use Disorders

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• The Chronic Disease Model: Severe substance use disorders (SUDs) share core features with chronic illnesses like asthma and diabetes, including a strong genetic component, problems with medication adherence, and a cycle of relapses and exacerbations requiring integrated treatment.
• Hepatic Glycogen Depletion: In chronic alcohol use disorder, patients develop profoundly depleted hepatic glycogen stores and impaired gluconeogenesis. When intoxicated or fasting, this mechanical breakdown completely prevents the body from autoregulating glucose, frequently resulting in life-threatening hypoglycemia.
• The Polysubstance Masking Effect: Concomitant use of opposing substances (e.g., opioids and sympathomimetics) dangerously alters the clinical picture. The profound central nervous system (CNS) depression of the opioid can completely mask the catecholamine excess of the stimulant. When the opioid is reversed, massive unmasked sympathomimetic toxicity (tachycardia, hypertension, severe agitation) rapidly emerges.
• Receptor-Specific Toxidromes: MDMA (ecstasy) drives profound hyponatremia and altered mental status. Acetaminophen (frequently co-formulated in abused "pain pills") rapidly depletes hepatic glutathione, driving toxic accumulation of NAPQI and fulminant liver failure.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Stabilization: Assess ABCs; comatose or stuporous intoxicated patients often lose airway reflexes and may require assisted ventilation or endotracheal intubation.
• The Mandatory Glucose Check: Always document a bedside capillary glucose before empirical administration of IV dextrose. Treat confirmed hypoglycemia with IV D50W or a D5W infusion.
• The Alcohol Resuscitation Cocktail:
• Thiamine: Administer 100 to 250 mg IV or IM daily for 3 to 5 days to prevent Wernicke's encephalopathy.
• Magnesium: Administer 2 g IV, as it acts as an essential cofactor for thiamine metabolism.
• Targeted Reversal: For suspected opioid toxicity causing respiratory depression, administer Naloxone (e.g., 2 mg IV) for diagnostic and therapeutic reversal. Caution: Be prepared for immediate vomiting or acute agitation.
• SUD Medication Initiation (Naltrexone): If initiating Naltrexone in the ED for alcohol cravings, explicitly ask about recent opioid use. Administer a 0.4 mg IV naloxone challenge; if no precipitated withdrawal occurs, safely start 50 mg PO or 380 mg IM Naltrexone and arrange outpatient follow-up.
• Safety First: When interviewing an intoxicated or agitated patient, position yourself near the exit, maintain a safe physical distance, and wear a breakaway badge clip to prevent choking.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

Trainees must never prematurely ascribe altered mental status solely to intoxication.

• Critical "Can't-Miss" Differentials:
• Profound hypoglycemia (mimics intoxication perfectly).
• Intracranial hemorrhage or diffuse axonal injury (common in "found down" patients).
• CNS Infections (Meningitis, Encephalitis).
• Endocrine collapse (Thyrotoxicosis, Myxedema coma).
• Prioritized Diagnostic Workup:
• Bedside Glucose: The absolute first diagnostic test in any altered patient.
• Acetaminophen & Salicylate Levels: Mandatory in undifferentiated overdoses or "pain pill" abuse, as these are frequently co-formulated with opioids and require immediate, specific antidotal therapy (N-acetylcysteine).
• Creatine Kinase (CK), LFTs, & Coags: Order immediately if the patient is highly agitated or hyperthermic (>104°F/40°C) to rule out rhabdomyolysis and early organ failure.
• Chemistry Panel: Screen for severe anion gap acidosis or MDMA-induced hyponatremia.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• 12-Lead ECG: Obtain immediately for any patient presenting with chest pain in the setting of stimulant (cocaine/methamphetamine) use to screen for acute ischemia or infarction. Patients placed in the Clinical Decision Unit (CDU) require continuous QT monitoring.
• Non-Contrast CT Head: Routinely indicated for patients presenting with an altered mental status or coma in the setting of drug/alcohol abuse to rule out occult traumatic intracranial hemorrhage or structural mimics.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• SASQ (Single Alcohol Screening Question): "How many times in the past year have you had X or more drinks in a day?" (X = 5 for men, 4 for women).
• CRAFFT Screening Tool: Useful for adolescents/young adults (Relax, Alone, Forget, Friends, Trouble).
• mMINDS Score: Utilized for severe alcohol withdrawal when the traditional CIWA-Ar score breaks down or is difficult to apply.
• CDU Disposition Criteria:
• Discharge Home: Stable vital signs, asymptomatic, no physical or laboratory evidence of continued toxicity, and cleared by toxicology.
• Hospital Admission: Unstable vital signs, persistent symptoms (vomiting, ataxia, hypoglycemia, altered mental status), or new laboratory abnormalities (elevated LFTs, CPK, or electrolyte shifts).

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• The "Kitchen Sink" Pitfall: Applying a shotgun approach to ordering labs and imaging rather than specifically tailoring the diagnostic workup to the toxidrome.
• Anchoring & Premature Closure: Ascribing agitated, combative, or depressed behavior exclusively to drugs or alcohol without considering traumatic, infectious, or metabolic etiologies.
• The Reassessment Trap: Failing to frequently reassess the intoxicated patient. One-third of severe intoxications are missed initially, and lethal withdrawal or delayed overdose symptoms can develop while the patient is boarding in the ED.
• CRITICAL ACTION: You must document a bedside blood glucose before assuming an intoxicated patient is simply "sleeping it off".
• CRITICAL ACTION: In an undifferentiated "pain pill" overdose, you must order an acetaminophen level, even if the patient exhibits a classic opioid toxidrome that reverses with naloxone.

7. MCQ MASTERCLASS (Written Exam Tips)

• The "Pain Pill" Distractor: A patient presents somnolent with pinpoint pupils after taking unknown "pain pills." Naloxone is given, and the patient wakes up. The question asks for the next best test. Do not pick urine drug screen; the correct answer is an Acetaminophen level, as opioids are often co-formulated with APAP.
• The Glucose Distractor: An alcoholic is brought in confused and smelling of liquor. Distractors will offer "Serum blood ethanol level" or "Urine toxicology." The absolute correct first action is Bedside Glucose, due to depleted glycogen stores.
• High-Yield Buzzword: If a patient presents with agitation, hyponatremia, and altered mental status after a rave or club, suspect MDMA (Ecstasy) intoxication.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• Securing the Room: "Examiner, before approaching this agitated, intoxicated patient, I am ensuring scene safety. I am locating the exit, maintaining a safe distance, and removing any lanyards or a non-breakaway badge clip to prevent injury."
• The Resuscitation: "The patient is comatose with a respiratory rate of 6. I am immediately assessing the ABCs, preparing airway equipment, and ordering a STAT fingerstick glucose. I will administer 2 mg of IV Naloxone to reverse potential opioid toxicity, but I will have suction ready as this often precipitates vomiting or unmasks a sympathomimetic toxidrome."
• The Motivational Interview (BNI): "Now that the patient is sober and medically cleared, I will use a brief negotiated interview. 'On a scale from 1 to 10, how ready are you to change your drinking?' I want to help the patient make a direct connection between their alcohol use and this ED visit today. I will offer a prescription for PO Naltrexone after confirming a negative naloxone challenge."