What is the recommended management approach for a patient with moderate traumatic brain injury and a positive screen for amphetamines?

Management of Moderate Traumatic Brain Injury in Amphetamine-Positive Patients

Manage amphetamine-positive patients with moderate TBI using standard TBI protocols focused on preventing secondary brain injury, as amphetamine intoxication does not fundamentally alter core management principles but requires specific attention to cardiovascular complications and potential for rapid neurological deterioration.

Initial Assessment and Stabilization

Perform immediate neurological assessment using Glasgow Coma Scale (GCS 9-13 defines moderate TBI) with particular attention to motor response and pupillary reactivity, as these are the most robust predictors of outcome. 1, 2, 3

• Obtain brain and cervical CT scan without delay to identify primary brain lesions and guide potential neurosurgical intervention 1, 2, 3
• Monitor for secondary neurological deterioration with frequent neurological examinations, as moderate TBI patients have significant risk of clinical worsening 3
• Assess for amphetamine toxicity manifestations including hypertension, tachycardia, hyperpyrexia, agitation, and potential for seizures 4

Prevention of Secondary Brain Injury

Maintain systolic blood pressure ≥110 mmHg and oxygen saturation >90%, as the combination of hypotension and hypoxemia carries a 75% mortality rate. 1, 2, 5

• Target mean arterial pressure ≥80 mmHg in severe cases to ensure adequate cerebral perfusion 2
• Avoid both hypoxemia (SaO₂ <90%) and hyperoxia after stabilization, as both worsen outcomes 2, 3
• Control ventilation with intubation if needed, maintaining EtCO₂ between 30-35 mmHg prior to arterial blood gas confirmation 1

Amphetamine-Specific Considerations

The acute amphetamine intoxication requires symptomatic management that may conflict with standard TBI care, necessitating careful balancing of competing priorities. 4

• Do NOT use chlorpromazine or other antipsychotics for amphetamine-induced agitation, as these lower seizure threshold and may worsen intracranial pressure 4
• Manage severe hypertension (if present) cautiously with short-acting agents like intravenous phentolamine, avoiding precipitous blood pressure drops that compromise cerebral perfusion 4
• Use benzodiazepines for sedation and seizure control rather than antipsychotics 4
• Monitor for hyperpyrexia and rhabdomyolysis, which can complicate both amphetamine toxicity and TBI 4

Monitoring and Advanced Care

Transfer immediately to a specialized center with neurosurgical capabilities, as moderate TBI patients require close monitoring for potential deterioration. 1, 3

• Consider ICP monitoring if neurological examination becomes unreliable due to sedation or clinical deterioration 1
• Maintain cerebral perfusion pressure ≥60 mmHg when ICP monitoring is available 1
• Use transcranial Doppler if available to assess cerebral perfusion, with concerning findings including diastolic velocity <20 cm/s and pulsatility index >1.4 1, 2

Neurosurgical Intervention Thresholds

Indications for emergency neurosurgery include symptomatic extradural hematoma, significant acute subdural hematoma, acute hydrocephalus, or displaced open skull fracture. 2

• For refractory intracranial hypertension despite medical management, consider decompressive craniectomy after multidisciplinary discussion 1, 2
• Use stepwise escalation of ICP management, reserving aggressive interventions for non-responders 1

Critical Pitfalls to Avoid

• Never acidify urine to enhance amphetamine excretion in TBI patients, as this increases risk of acute renal failure if rhabdomyolysis/myoglobinuria is present 4
• Do not use corticosteroids for TBI management, as they provide no benefit and may cause harm 2
• Avoid using antipsychotics for agitation management, as they lower seizure threshold and may worsen outcomes 4
• Do not delay CT imaging or transfer to definitive care while managing amphetamine toxicity 1, 3

Evidence Regarding Amphetamine Effects on TBI Recovery

While amphetamine use at time of injury has been associated with shorter posttraumatic amnesia duration (suggesting potential acute neuroprotective effects), patients with history of amphetamine use report significantly lower quality of life at 12 months post-injury. 6 However, this research on therapeutic amphetamines (methylphenidate) in the subacute/chronic phase should not influence acute management decisions. 7, 6, 8