A client says to the nurse, "You are the best nurse I've ever met. I want you to remember me." What is an appropriate response by the nurse?

Choice A reason: Aphasia, a language impairment, is not a hallmark of delirium but is associated with neurological conditions like stroke affecting Broca’s or Wernicke’s areas. Delirium involves acute cognitive dysfunction due to underlying causes like infection or hypoxia, primarily affecting attention and awareness, not specific language processing, making this choice scientifically inaccurate for delirium.

Choice B reason: Confusion is a core feature of delirium, characterized by disorientation and impaired attention due to acute brain dysfunction. It results from disruptions in cerebral metabolism, often triggered by systemic issues like electrolyte imbalances or sepsis. This symptom distinguishes delirium from dementia, as it reflects rapid, reversible cognitive changes, requiring immediate assessment.

Choice C reason: Impaired level of consciousness, such as fluctuating alertness or stupor, is a defining feature of delirium. It stems from diffuse brain dysfunction, often due to toxic, metabolic, or infectious causes affecting neurotransmitter balance or cerebral perfusion. This distinguishes delirium from dementia, which typically preserves consciousness, making this a critical diagnostic criterion.

Choice D reason: Long-term memory impairment is characteristic of dementia, not delirium. Delirium involves acute, reversible cognitive deficits, primarily affecting attention and short-term memory due to transient brain dysfunction. Long-term memory remains relatively intact in delirium, as the underlying pathology does not typically involve chronic neuronal loss, unlike Alzheimer’s or other dementias.

Choice E reason: Mood fluctuations occur in delirium due to acute brain dysfunction affecting emotional regulation, often linked to neurotransmitter imbalances or systemic stressors like infection. However, they are not a primary diagnostic criterion compared to confusion, impaired consciousness, and rapid onset, as they may also occur in other psychiatric conditions, reducing specificity.

Choice F reason: Rapid onset of symptoms is a hallmark of delirium, distinguishing it from dementia’s gradual progression. Symptoms develop over hours to days due to acute insults like hypoxia, infection, or medication toxicity, disrupting cerebral function. This rapid timeline is critical for diagnosis, as it indicates a reversible condition requiring urgent intervention.

Choice A reason: Lithium’s therapeutic range for maintenance in bipolar disorder is 0.5–1.2 mEq/L, balancing mood stabilization via sodium channel modulation and neuroprotection with safety. This range minimizes toxicity risks like tremors or renal damage, ensuring effective serotonin and dopamine regulation while maintaining safe serum concentrations.

Choice B reason: A 10–50 mEq/L lithium level is far above the therapeutic range, causing severe toxicity, including seizures or coma, due to excessive sodium channel inhibition and neuronal dysfunction. This range is lethal, disrupting renal and neurological function, making it scientifically inaccurate for maintenance or safety.

Choice C reason: A 0.1–1 mEq/L range is partially subtherapeutic, as levels below 0.5 mEq/L are ineffective for mood stabilization in bipolar disorder. Lithium requires 0.5–1.2 mEq/L to modulate sodium channels and serotonin, making this range inadequate for therapeutic efficacy while still posing minor toxicity risks.

Choice D reason: A 50–100 mEq/L lithium level is exponentially above safe limits, causing fatal toxicity, including renal failure and neurological damage, due to extreme sodium channel disruption. This range is not viable for maintenance, as it far exceeds the therapeutic window, leading to severe neurobiological and systemic harm.