RNPedia PNLE Nursing Practice 2 Test 7 Practice Test

Lithium has a narrow therapeutic window, so small increases in its level can produce toxicity. Tremor and confusion are classic early signs of lithium toxicity, reflecting how elevated lithium interferes with neuronal signaling in the central nervous system. In a patient taking lithium, these symptoms strongly point to toxicity rather than a unrelated issue, because the drug’s clearance is sensitive to hydration status and kidney function, and certain interactions or dehydration can raise lithium levels quickly. While other problems like vitamin deficiencies or unrelated renal issues could cause cognitive changes, they don’t align as directly with the tremor–confusion presentation in the setting of lithium therapy. The most likely cause is lithium toxicity from elevated levels within this narrow therapeutic window.