Altered level of consciousness (LOC): Nursing

An altered level of consciousness is characterized as a decreased wakefulness, awareness, or alertness, and includes a range of categories like hyperalert, delirious, lethargic, and comatose.

Now, let’s quickly review the physiology of consciousness. Normal consciousness is composed of alertness and awareness while awake, as well as arousal or the ability to be woken up from sleep. Consciousness and arousal are believed to be regulated by the reticular activating system, which is a network of neurons that’s located in the brainstem. Normally, these neurons ultimately act by activating parts of the brain cortex involved in wakefulness, attention, behavior, and thinking.

So, altered levels of consciousness can have many causes and risk factors, which can be broadly categorized as structural, metabolic, infectious, toxic, or other. Structural causes include cerebral edema, increased intracranial pressure, stroke, or traumatic brain injury; while metabolic causes include dehydration, hypo- or hyperthermia, hypo- or hyperglycemia, hypo- or hypernatremia, hypoxia, hypercapnia, or uremic encephalopathy. Infectious causes include meningitis, encephalitis, or sepsis. Toxic causes include carbon monoxide, alcohol, or medications, such as opiates, salicylates, barbiturates or benzodiazepines. Lastly, other causes include syncope, seizures, sleep deprivation, serious illness, sensory impairment, or intense pain.