Abstract Lithium is indicated for treatment of bipolar disorder (BD). It has a variable half-life of 12-24 hours, which can extend to 36 hours in elderly patients or with acute changes to renal function. This results in difficulty maintaining serum levels within the therapeutic range of 0.6 to 1 mmol/L. Lithium may cause decreased collecting tubule sensitivity to antidiuretic hormone and reduction of aquaporin-2 water channels within the collecting duct. This inability to concentrate urine and reabsorb water is characteristic for lithium induced nephrogenic diabetes insipidus. A 68-year-old female with a medical history of bipolar disorder, on daily lithium, presented for sublingual tenderness and swelling. The patient had associated agitation and confusion. Vitals were significant for tachycardia. Labs were significant for leukocytosis (16,900 per uL). CT soft tissue neck showed a 11 mm dilation of the right submandibular duct without a definite stone. The patient received early antibiotics and 2.4 L NS bolus to treat sialadenitis, per sepsis protocol. The following morning, the patient’s sodium level had increased to 165 mmol/L and the patient had developed output of 5.5 L to 6 L of dilute urine daily. Lithium induced nephrogenic diabetes insipidus was suspected early, and the patient’s serum lithium level was found to be 1.116 mmol/L. Despite infusion of D5W at 270 cc/h the patient had persistent hypernatremia and required subcutaneous desmopressin. The patient was weaned from IV fluids and desmopressin after her serum sodium levels and urine output normalized. The patient was briefly admitted to the ICU for respiratory failure secondary to hypoxemic respiratory failure as the patient developed pulmonary edema, although pneumonia could not be excluded. The patient experienced severe agitation and required restraints so noninvasive positive pressure ventilation could not be utilized. The patient was not able to wean from her high flow nasal cannula, until dexmedetomidine infusion was started for treatment of her severe agitation. The patient required intramuscular fluphenazine decanoate and a regimen of oral valproic acid with as needed olanzapine in order to wean from the dexmedetomidine infusion. Current recommendations for monitoring serum lithium levels include weekly checks upon titration, and every three to six months when in maintenance. In elderly patients, more frequent serum lithium level checks may be warranted as acute changes to renal function is common. Discontinuing the medication in place of an alternative should be considered in patients who experience severe adverse effects. This abstract is funded by: None
Thota et al. (Fri,) studied this question.