Complications
Often associated with overconfidence or risk-taking while under the influence of psychostimulant drugs. Signs of traumatic injury are important to see in amphetamine overdose, as they may complicate the clinical picture and management.[58]
Acute kidney injury in the clinical setting of hyperthermia is thought to be multifactorial. Muscle injury releases myoglobin, uric acid, and myocyte cytosol contents into the plasma. Pigmented casts form in renal tubules, which results in obstruction, and direct toxicity to tubules occurs through the heme components of myoglobin. Renal ischemia results from the vasoconstriction of renal arterioles in an underperfused state. Hydration is paramount to management, and diuretics may be helpful in maintaining urine output. Severe cases may require temporary hemodialysis for management. Full recovery is the norm.
Hyperthermia may lead to a clinical picture similar to that of severe heat stroke, with rhabdomyolysis, metabolic acidosis, renal failure, disseminated intravascular coagulation, or acute respiratory distress syndrome.[6][7][8] Management of DIC consists of hydration, control of hyperthermia, and blood product support only if active bleeding is taking place (balance risk of precipitating clotting cascade versus benefit of use of products). Consultation with a hematologist is best sought when disseminated intravascular coagulation is diagnosed.[54]
Acute dyspnea and hypoxemia, which progress to respiratory failure, and bilateral infiltrates on chest x-ray may follow hyperthermia. Hypoxemia with PaO₂ to inspired oxygen ratio ≤200 and no clinical evidence of heart failure are characteristic. Low tidal volume with plateau pressure-limited mechanical ventilation is the only therapy that has been shown to reduce mortality.
Sympathetic overstimulation and hypertension are implicated in cerebral and intracranial bleeding of amphetamine toxicity. CT and MRI scans, with high sensitivity for intracerebral hemorrhage, are definitive in differential diagnosis.
Nausea and malaise are the earliest findings, and may be seen when the plasma sodium concentration falls below 125-130 mEq/L.[87] This may be followed by headache, lethargy, and obtundation. If untreated, seizures, coma, and respiratory arrest may ensue. Treatment with fluid restriction is adequate in most cases, with hypertonic saline an option if urgent intervention is necessary. Vasopressin receptor antagonists are an alternative to fluid restriction and hypertonic saline solution.
Severe neurologic symptoms, such as altered mental status, seizure, and coma, may result. These are treated with hypertonic saline, with close monitoring to avoid overcorrection of serum sodium.
Very rarely reported, thought to be due to ingestion of MDMA (ecstasy). It is usually self-limited and managed expectantly.[89]
Can occur after chronic exposure to amphetamines. It is characterized by breathlessness and fatigue, and may be diagnosed by transthoracic echocardiography. Treatment with diuretics and afterload reduction is the norm. Drug cessation may resolve early cardiomyopathy; otherwise, this complication is permanent and a cause of significant morbidity in users of amphetamines.[24][50][51][52][53][88]
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