Benzodiazepine Overdose

Benzodiazepine overdose is a common cause of hospitalization in the United States, associated with about 30% of overdose cases. Such incidences fixedly increase in quantity and are important to consider when dealing with patients who have a history of drug abuse or predisposing factors for a possible overdose. These comprise e.g. psychological disorders, post-traumatic stress syndrome in patients with a military background, depressive or suicidal states.

Benzodiazepines are a class of medication with anxiolytic, analgesic, sedative and hypnotic features marking them a target of drug abuse and subsequent overdose [1]. Illegitimate practices and 'doctor shopping', involving patients visiting multiple doctors, lead to the unreasonable prescription of benzodiazepines and consecutive abuse [2]. Psychiatric patients, on the other hand, are known to use benzodiazepines in an attempt of suicide or intentional self-harm [3].

Often, polydrug users execute the administration of benzodiazepines in combination with alcohol, antidepressants or opioids giving rise to the failure of cardiovascular and respiratory systems [4]. Other complications include neurological, renal impairment, muscular complications like hypotonia, and possible hearing loss.

Acute manifestations in overdosed patients usually involve collapse with seizures, cyanosis due to respiratory failure, loss of consciousness, coma and possible cardiac arrest [5]. On examination of the eyes, the patient might have fixed miosis or pinpoint pupil.

Benzodiazepine overdose is managed according to possible complications.

A magnetic resonance imaging (MRI) of the brain is a necessity if the patient appears unconscious, comatose and with a possible risk of acidosis. The MRI will expose herniations, edema and diffuse white matter injury (leukoencephalopathy) relatively excluding the lesions of the gray matter. The white matter injury may also be of connection with the use of chemotherapy agents and exposure to toxins e.g. carbon monoxide. Signs of edema and herniation may evolve and be the cause of death if not handled or monitored appropriately [6] [7].

A computed tomography (CT) examination findings include hypodensity in the affected area of the white brain matter, correlating to the clinical picture found in MRI. Reports suggest that early in the disease, the imaging of the patient's brain can appear normal which leads to discharge from the hospital. After about two weeks, a rapid deterioration of the white matter precedes and involves serious changes in consciousness, behavior, gait, parasympathetic system, etc., advancing to dramatic complications like coma or quadriparesis. Thus the importance of monitoring the affected patient is suggested [8].

Urine sample analysis may expose high levels of benzodiazepines [6].

Lumbar puncture with a collection of the cerebrospinal fluid is useful to exclude other diagnoses e.g. herpes simplex virus infection, Epstein-Barr virus disease or other infections associated with brain tissues that cause similar radiologic findings. The analysis includes cell count, protein, and glucose level determination [9].

Electroencephalography (EEG) is optional and used to discover electrical potential abnormalities if the patient experienced neurologic signs e.g. seizures. The EEG might reveal slowing of background in low frequencies [6].

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