Ten Things That Really Annoy Me About Lithium

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Ten Things That Really Annoy Me About Lithium

• Kent R. Olson, MD
• Medical Director, SF Division
• California Poison Control System

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10 It Has a Narrow Therapeutic Window, and it
can be Nasty

• Commonly used for bipolar disorder
• Therapeutic levels 0.6-1.2 mEq/L
• Toxicity with levels as low as 1.5-2
• Lethargy, confusion, tremor, ataxia, muscle
  jerking or rigidity
• Agitated delirium, coma, convulsions
• Symptoms may persist for days to weeks

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9 It Doesnt Bind to Activated Charcoal

• Alternatives
• Emesis, lavage - ? value
• Kayexalate?
• Whole bowel irrigation preferred method

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8 It Elevates the White Blood Count

• Usually mild, but dont be surprised to see WBC
  15,000 or more
• Mostly granulocytes
• Enhanced PMN production
• Could lead to needless workup for infection

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7 The ECG is Nonspecific

• Kinda looks like hypokalemia
• T-wave flattening or inversion common
• NSSTTW changes common
• QT interval may be prolonged
• Bradycardia, sinus node arrest - rare

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6 It Can Mess up your Sodium Level

• Nephrogenic Diabetes Insipidus
• Can occur with therapeutic use
• Lack of renal response to ADH
• Loss of free water in the urine
• Clinical findings
• Volume loss, leads to Li retention
• Elevated serum Na

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5 It can Mess with the Anion Gap
Anion Gap (10 mmol/L)
Na
HCO3-
Cl-
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5 It can Mess with the Anion Gap
Li
Anion Gap (4 mmol/L)
Na
HCO3-
Cl-
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4 Funky Pharmacokinetics

• Two-compartment model Li level reaches
  equilibrium slowly
• Initial extracellular fluid 15 L
• Later total body water 50 L

4-6 hrs
Li 4
Li 1.4
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4 Kinetics, continued . . .

• Slowly enters brain cells
• Difficult to get it back out
• Rebound after hemodialysis

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3 Its Only Way Out is Through Your Kidneys

• Expect toxicity if
• Worsening renal function
• Sudden volume depletion (eg, GI flu)

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So where are we so far?

• Patient with Altered MS
• NSSTTW changes
• Li Level 4.5 mEq/L
• What do we do?

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2 History is Usually Not Available or is
Incomplete

• Is this an acute OD or chronic use with
  accidental toxicity?
• What is the pre-existing baseline Li? BUN? Cr?

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Consider

• Our patient with ALOC, Li 2.5 mEq/L is not on Li
  routinely, took an acute OD of 14 LiCO3 (8 mEq
  each) tablets 2 hrs ago
• BUN/Cr 10/1.1
• Is this a serious Li OD?

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Or . . .

• Our patient is on Li chronically, has been
  increasingly confused and weak for several days,
  has had vomiting and diarrhea.
• BUN/Cr 30/2.2

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Or, how about this scenario?

• A patient was seen to take an acute overdose of
  Li tablets, is brought to the ED where Li 9
  mEq/L
• Is emergency hemodialysis indicated?

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1 Reason Why I Find Lithium Annoying Dialysis
Isnt So Hot

• Acute OD with high Li level patients do okay
  anyway, without dialysis
• Chronic intoxication with moderate level, altered
  mental status it takes days to weeks to recover
  anyway, despite dialysis

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So What Do We DO?

• Give IV fluids (NS initially)
• Try to get good Hx
• Follow Li levels
• Consider hemodialysis if
• Acute OD with level gt 10-11 mEq/L
• Chronic intoxication with level gt 4 and Sx