Cocaine use as a rare cause of locked-in syndrome: a case report

Dr Osman Ali at the division of Pulmonary & Critical Care Medicine, University of Maryland School of Medicine, Baltimore, USA and colleagues have reported a rare case of locked-in syndrome due to Cocaine use. The case has appeared in the Journal of Medical Case Reports.

Cocaine is a commonly used drug of abuse that is a well recognized contributing factor for both hemorrhagic and ischemic strokes. However, cocaine-induced basilar artery thrombosis has rarely been reported in the literature. Locked-in syndrome is a rare neurological disorder in which there is complete paralysis of all voluntary muscles except for the ones that control the movements of the eyes. Individuals with locked-in syndrome are conscious and awake but have no ability to produce movements or to speak. Cognitive function is usually unaffected.

A 51-year-old African American woman with a limited medical history significant for depression and polysubstance abuse was brought to our emergency department by her boyfriend because of her bizarre behaviour, nonsensical communication, and listlessness. As per her boyfriend, the patient was seen inhaling cocaine on the night prior to admission to the hospital. Owing to her altered mental status, her history was obtained from her boyfriend and sister and was limited because of their limited knowledge of the patient's previous health issues. However, upon further questioning, it was discovered that the patient's family history was significant for maternal chronic kidney disease, diabetes mellitus, and hypertension. Furthermore, it was revealed that the patient was unemployed, used tobacco, had substance abuse issues specifically with cocaine and heroin, and had abstained from alcohol use for over 10 years. The patient's initial vital signs were significant for a body temperature of 36.7 °C, heart rate of 60–70 beats/minute, blood pressure of 113/73 mmHg, and respiratory rate of 20 breaths/minute. Her initial physical examination revealed that she was an awake and alert obese African American woman appearing to be her stated age, was confused and very agitated, and was not following commands. She had intact corneal and pupillary reflexes and clear lung sounds. She had regular heart sounds with no murmurs, rubs, or gallops and had a soft non tender abdomen. Additionally, the result of her neurological examination was negative for muscle rigidity, nystagmus, or diffuse hyperhidrosis. However, her examination revealed generalized confusion and agitation. Her pupils were round but sluggishly reactive to light bilaterally. She opened her eyes upon command and moved all four extremities spontaneously, withdrawing appropriately to noxious stimuli, and she exhibited dysarthria.

The result of her urine toxicology was positive for cocaine, opiates, and benzodiazepines. The results of her laboratory studies were unremarkable, with the exception of a potassium level of 3.1 mEq/L. After blood cultures were drawn, empirical intravenous vancomycin and cefepime were initiated for possible encephalomeningitis. The findings of initial unenhanced computed tomography (CT) of the brain were negative for any acute changes. Etomidate and rocuronium were administered for the patient's agitation, and she was intubated and started on a propofol infusion.

On day 3 of admission, when the patient had been weaned off sedation and paralytic therapy, she demonstrated decorticate posturing, intact gag and cough reflex, positive Babinski reflexes bilaterally, and intact pupillary reflexes. The patient's motor strength was dramatically decreased in both upper and lower extremities. She was obtunded, unable to follow commands, and opened her eyes spontaneously. On day 4 of admission, she was minimally responsive to commands and was able to communicate only with vertical eye movements. Repeat non-contrast CT showed hyperdensity in the basilar artery, suggestive of occlusion due to thrombosis, which was not present in the initial CT findings. Findings of lumbar puncture with cerebrospinal fluid examination and electroencephalography (EEG) were unremarkable. MRI showed large foci of abnormally restricted vessels of the brainstem with recent infarction, occurring bilaterally with no observed hemorrhage. MRA revealed complete loss of flow-related signal within the distal basilar artery.