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Toxicity, Lithium (Diagnosis)

eMedicine Emergency Medicine, 2011

Workup Laboratory Studies The extent of the laboratory workup depends upon the degree of toxicity suspected and other diagnoses under consideration.
Measure serum lithium concentration if any degree of toxicity is suspected; however, keep in mind that suspicion of toxicity should be high in any patient with known lithium use because early toxic symptoms are very vague and nonspecific.
Electrolyte disturbances, particularly hyponatremia, may predispose an individual to lithium toxicity.
Similarly, lithium treatment may predispose an individual to electrolyte (sodium) disturbances, which are usually mild.
Lithium toxicity is one of the few clinical entities that may be associated with a decrease in the anion gap.
BUN and creatinine measurements are important for determining the patient's ability to excrete lithium.
Imaging Studies Consider a CT scan of the head in individuals with severe movement disorders, seizures, stupor, or coma.
Other Tests Electrocardiogram Chronic lithium toxicity is frequently associated with depressed ST segments and T wave inversion unassociated with symptoms or significant sequelae.
Serious cardiac toxicity is uncommon and generally only occurs in individuals with underlying heart disease.
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