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Emergency And Acute Medicine - GHB Poisoning
Basics Description
γ-Hydroxybutyrate (GHB) is a naturally occurring analog of γ-aminobutyric acid (GABA). It has limited medical use, most notably in narcolepsy. Nonmedical use includes bodybuilding, recreational euphoria, and use as a predatory or date-rape drug. Precursors such as γ-butyrolactone (GBL), 1,4-butanediol (1,4-BD), γ-hydroxyvalerate (GHV), and γ-valerolactone (GVL) produce similar clinical effects. Onset typically occurs 15–30 minutes after ingestion, with duration of effects lasting approximately 2–6 hours.
Etiology
GHB toxicity results from deliberate or accidental ingestion of GHB or its precursors.
Diagnosis Signs And Symptoms
Central nervous system findings include CNS depression, dizziness, ataxia, impaired judgment, aggressive behavior, clonic extremity movements, coma, and seizures. Pulmonary manifestations include respiratory depression, apnea, and rarely laryngospasm. Gastrointestinal symptoms include nausea and vomiting. Cardiovascular effects include bradycardia, atrioventricular block, and hypotension. Other findings include nystagmus and hypothermia.
Withdrawal may present with hypertension, tachycardia, hyperthermia, agitation, diaphoresis, tremors, nausea, vomiting, abdominal cramping, hallucinations, delusions, and psychosis.
Essential Workup
Diagnosis is primarily clinical and based on history and presentation. Coingestants should be excluded if the clinical picture is atypical for GHB intoxication.
Diagnosis Tests And Interpretation
Confirmatory GHB testing is usually a send-out laboratory test and does not affect emergency department management. Urine toxicology screening may help identify coingestants. Serum ethanol level should be obtained. Urinalysis and creatine kinase are indicated if rhabdomyolysis is suspected. ECG may demonstrate sinus bradycardia or atrioventricular block. Chest radiography is indicated if aspiration pneumonia is suspected. Head CT should be considered if occult head trauma is possible.
Differential Diagnosis
Alcohol intoxication, barbiturate overdose, benzodiazepine overdose, neuroleptic overdose, opiate overdose, alcohol withdrawal, and sedative–hypnotic withdrawal.
Treatment Prehospital
All pills, containers, and drug paraphernalia involved in the overdose should be transported with the patient for identification.
Initial Stabilization Therapy
Airway management is the priority. Supplemental oxygen should be administered, and intubation performed if indicated. In patients with depressed mental status, administer thiamine, check glucose with bedside testing, provide dextrose if needed, and administer naloxone.
Ed Treatment Procedures
Management is primarily supportive. Bradycardia may be treated with atropine or temporary pacing. Hypotension is managed with intravenous 0.9% normal saline boluses, Trendelenburg positioning, and dopamine infusion if needed. Seizures should be treated initially with benzodiazepines; refractory seizures may require phenobarbital. Withdrawal should be treated aggressively with benzodiazepines, with phenobarbital or propofol used if benzodiazepines are insufficient.
Medication
Dextrose 50–100 mL of D50 IV (pediatrics: D25 2 mL/kg). Diazepam 5–10 mg IV. Lorazepam 2–4 mg IV. Dopamine infusion 2–20 μg/kg/min. Naloxone 0.4–2 mg IV or IM. Phenobarbital loading dose 10–20 mg/kg IV. Propofol loading dose 0.5–1 mg/kg IV followed by infusion. Thiamine 100 mg IV or IM.
Follow-Up Disposition
Admission is required for intubated patients, those with hypothermia or hemodynamic instability, or suspected coingestions that prolong intoxication. Discharge may be considered after at least 6 hours of observation if the patient is asymptomatic and shows no signs of withdrawal.
Alert: GHB withdrawal is life-threatening and closely resembles alcohol withdrawal; prolonged inpatient treatment may be necessary.
Follow-Up Recommendations
Patients with recreational drug use should receive substance abuse referral. Accidental poisonings require poison prevention counseling. Intentional ingestions require psychiatric evaluation.
Key Clinical Insights And Common Errors
Persistent altered mental status should prompt evaluation for non-toxicologic causes. Routine hospital toxicology screens do not reliably detect GHB or many recreational drugs of abuse.
Basics Description
γ-Hydroxybutyrate (GHB) is a naturally occurring analog of γ-aminobutyric acid (GABA). It has limited medical use, most notably in narcolepsy. Nonmedical use includes bodybuilding, recreational euphoria, and use as a predatory or date-rape drug. Precursors such as γ-butyrolactone (GBL), 1,4-butanediol (1,4-BD), γ-hydroxyvalerate (GHV), and γ-valerolactone (GVL) produce similar clinical effects. Onset typically occurs 15–30 minutes after ingestion, with duration of effects lasting approximately 2–6 hours.
Etiology
GHB toxicity results from deliberate or accidental ingestion of GHB or its precursors.
Diagnosis Signs And Symptoms
Central nervous system findings include CNS depression, dizziness, ataxia, impaired judgment, aggressive behavior, clonic extremity movements, coma, and seizures. Pulmonary manifestations include respiratory depression, apnea, and rarely laryngospasm. Gastrointestinal symptoms include nausea and vomiting. Cardiovascular effects include bradycardia, atrioventricular block, and hypotension. Other findings include nystagmus and hypothermia.
Withdrawal may present with hypertension, tachycardia, hyperthermia, agitation, diaphoresis, tremors, nausea, vomiting, abdominal cramping, hallucinations, delusions, and psychosis.
Essential Workup
Diagnosis is primarily clinical and based on history and presentation. Coingestants should be excluded if the clinical picture is atypical for GHB intoxication.
Diagnosis Tests And Interpretation
Confirmatory GHB testing is usually a send-out laboratory test and does not affect emergency department management. Urine toxicology screening may help identify coingestants. Serum ethanol level should be obtained. Urinalysis and creatine kinase are indicated if rhabdomyolysis is suspected. ECG may demonstrate sinus bradycardia or atrioventricular block. Chest radiography is indicated if aspiration pneumonia is suspected. Head CT should be considered if occult head trauma is possible.
Differential Diagnosis
Alcohol intoxication, barbiturate overdose, benzodiazepine overdose, neuroleptic overdose, opiate overdose, alcohol withdrawal, and sedative–hypnotic withdrawal.
Treatment Prehospital
All pills, containers, and drug paraphernalia involved in the overdose should be transported with the patient for identification.
Initial Stabilization Therapy
Airway management is the priority. Supplemental oxygen should be administered, and intubation performed if indicated. In patients with depressed mental status, administer thiamine, check glucose with bedside testing, provide dextrose if needed, and administer naloxone.
Ed Treatment Procedures
Management is primarily supportive. Bradycardia may be treated with atropine or temporary pacing. Hypotension is managed with intravenous 0.9% normal saline boluses, Trendelenburg positioning, and dopamine infusion if needed. Seizures should be treated initially with benzodiazepines; refractory seizures may require phenobarbital. Withdrawal should be treated aggressively with benzodiazepines, with phenobarbital or propofol used if benzodiazepines are insufficient.
Medication
Dextrose 50–100 mL of D50 IV (pediatrics: D25 2 mL/kg). Diazepam 5–10 mg IV. Lorazepam 2–4 mg IV. Dopamine infusion 2–20 μg/kg/min. Naloxone 0.4–2 mg IV or IM. Phenobarbital loading dose 10–20 mg/kg IV. Propofol loading dose 0.5–1 mg/kg IV followed by infusion. Thiamine 100 mg IV or IM.
Follow-Up Disposition
Admission is required for intubated patients, those with hypothermia or hemodynamic instability, or suspected coingestions that prolong intoxication. Discharge may be considered after at least 6 hours of observation if the patient is asymptomatic and shows no signs of withdrawal.
Alert: GHB withdrawal is life-threatening and closely resembles alcohol withdrawal; prolonged inpatient treatment may be necessary.
Follow-Up Recommendations
Patients with recreational drug use should receive substance abuse referral. Accidental poisonings require poison prevention counseling. Intentional ingestions require psychiatric evaluation.
Key Clinical Insights And Common Errors
Persistent altered mental status should prompt evaluation for non-toxicologic causes. Routine hospital toxicology screens do not reliably detect GHB or many recreational drugs of abuse.
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