A patient shows which of the following symptom of overdose of lithium?

Appeared in: AIIMS Rishikesh & Jodhpur NO - 2017

Explanation

Slurred speech, also known as dysarthria, is a classic sign of central nervous system toxicity from an overdose of lithium.
It indicates that the serum lithium level has surpassed the therapeutic range and is affecting neurological function, particularly coordination and motor control of speech.
According to psychiatric references, slurred speech typically appears in the mild-to-moderate stage of lithium intoxication, with serum levels between 1.5 and 2.0 mEq/L.
This symptom is a clear warning sign of a developing medical emergency that requires immediate intervention.

Option A: Polyuria (excessive urination) is a very common side effect of lithium, even at therapeutic levels. It is not a specific sign of acute overdose, although it can contribute to dehydration, which worsens toxicity.
Option B: Weight loss is not associated with lithium use. In fact, weight gain is a common and often distressing side effect for patients taking lithium.
Option C: Leukocytopenia is a decrease in white blood cells. Lithium therapy actually causes the opposite effect, leukocytosis (an increase in white blood cells).

Clinical Relevance

Nursing practice connection: Use the key finding related to Signs and symptoms of lithium toxicity to guide bedside assessment, documentation, and the next nursing action.
Lithium has a very narrow therapeutic index (0.6-1.2 mEq/L), meaning the dose that is effective is close to the dose that is toxic. This makes vigilant nursing assessment for toxicity crucial.
Recognizing slurred speech as a sign of neurotoxicity is a critical patient safety intervention. The nurse's first actions should be to hold the next dose and immediately notify the provider for an urgent serum lithium level test.
Patient education is vital. Patients must be taught to recognize early signs of toxicity (e.g., worsening tremor, nausea, diarrhea) and to maintain consistent salt and fluid intake to prevent dehydration, which can rapidly increase lithium levels.

How to Approach the Question

First, identify the keywords in the question: "lithium" and "overdose." This directs you to recall or look up the signs of toxicity, not just common side effects.
Second, mentally separate lithium's effects into two categories: common/therapeutic side effects (e.g., fine tremor, thirst, weight gain) and toxic/overdose symptoms (e.g., coarse tremor, confusion, slurred speech, seizures).
Third, evaluate each option against these categories. Polyuria is a common side effect. Weight loss is incorrect (weight gain is common). Leukocytopenia is incorrect (leukocytosis occurs).
Fourth, recognize that slurred speech is a neurological symptom. Neurological impairment is a hallmark of moderate to severe lithium toxicity.
Finally, select slurred speech as the most definitive sign of overdose among the choices provided.

Concept Tested & Keywords

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E6 Kaplan Sadock's Synopsis of Psychiatry-2022 (pp 1-3768 of 3768) pp. 2058-2060, 2054-2056

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