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Symptoms: Loss of Consciousness and Altered Mental Status

Smalley, Courtney M. MD

doi: 10.1097/01.EEM.0000655024.53792.a3
    Figure
    Figure:
    locked-in syndrome
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    Figure:
    influenza

    A 70-year-old man with a past medical history of end-stage renal disease on dialysis, diabetes, COPD, hypertension, atrial fibrillation, and seizures presented after being found unconscious with altered mental status. A family member reported last seeing the patient two days earlier when he was alert and oriented and able to hold a conversation and drive himself to dialysis. The family member had arrived at the patient's house on the day he was brought to the ED, and found him on the floor. The patient could open his eyes, but he was unable to speak or move, so his family called 911. His family mentioned that he had a history of falls, and was unsure if he was taking anticoagulation medication. His last dialysis was believed to have been five days earlier.

    The patient was lying in bed, eyes open but nonverbal, on ED arrival. His initial vital signs were a blood pressure of 147/68 mm Hg, a heart rate of 122 bpm, a temperature of 35.5°C, and a normal respiratory rate and pulse oxygenation. A physical exam demonstrated no evidence of head trauma, and he had dry mucous membranes, tachycardia (otherwise regular), clear lungs, and a soft abdomen. A neurological exam demonstrated an alert patient cooperating with vertical eye movements but unable to perform horizontal eye movements. His pupils were equal, round, and reactive to light. The patient generated incomprehensible sounds, could follow motor commands, but was unable to lift his extremities from the bed.

    A full laboratory workup was initiated, and a head CT without contrast was performed, which was read by radiology as no acute intracranial hemorrhage and no change from a head CT performed two months earlier.

    Find the diagnosis and case discussion on the next page.

    Diagnosis: Locked-in Syndrome

    Locked-in syndrome, also known as pseudocoma, is a condition in which an ischemic or hemorrhagic stroke causes the inability to speak or move, though the patient is cognitively intact. (BMJ. 2005;330[7488]:406; http://bit.ly/35dqMLP.) A basilar artery embolism or thrombosis causes infarction of the ventral pons area of the brain. Other causes include hypertensive pontine hemorrhages, abscesses, tumors, trauma, and toxins.

    The clinical features of locked-in syndrome were first introduced by Plum and Posner in 1966. (Plum and Posner's Diagnosis of Stupor and Coma. New York: Oxford University Press; 1983.) There are three varieties: classic, incomplete, and total. (BMJ. 2005;330[7488]:406; http://bit.ly/35dqMLP.) The total variant is the most debilitating because patients have total immobility and are unable to communicate yet have preserved consciousness. (See table.) The classic and incomplete variants have preserved consciousness with vertical eye movement, allowing a trained clinician to use eye movements as a method of communication.

    Table
    Table

    The differential diagnosis for locked-in syndrome should include disorders of consciousness (DOC), upper cervical spinal cord injury, and akinetic mutism. DOC can be ruled out by determining whether the patient is alert and aware. Upper cervical spinal cord injury can present with quadriplegia and must also be excluded. Lastly, akinetic mutism is a syndrome of silent, alert immobility with a decrease in speech output, which can present similarly to locked-in syndrome. (Case Rep Neurol Med. 2017;2017:6167052; http://bit.ly/2E5yYlr.) A neurologist should be consulted for an in-depth evaluation to exclude these disorders and help make the diagnosis of locked-in syndrome.

    Our patient was admitted to the hospital for further workup with a neurologist and definitive imaging. He was also started on broad-spectrum antibiotics for potential sepsis because of the hypothermia and tachycardia without a clear history, and nephrology was consulted for urgent dialysis for his encephalopathic state.

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    Dr. Smalleyis associate staff and the associate ultrasound director at the Emergency Services Institute at the Cleveland Clinic. Follow her on Twitter@SmallsSono. Read past Quick Consult columns athttp://bit.ly/EMN-QuickConsult.

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