Lithium induced neuropathy is a rare side effect of lithium. We will discuss this adverse event in the following sections:
- Underlying mechanism.
- Clinical Presentation: onset, localization, recovery and prognosis.
(1) Underlying Mechanism:
- intracellular accumulation of lithium and interference with the propagation of action potentials.
(2) Clinical Presentation:
- Delayed in most cases: 3-7 days.
- from slight paresis to complete quadriplegia.
- symmetrical involvement.
- mostly distal involvement, but proximal limbs can get affected.
- Recovery can take weeks to months in some cases.
- Good prognosis: most case reports described a good prognosis with clinical recovery upon discontinuation of lithium.
(a) Rule out medical causes of neuropathy:
- Electrolytes: basic metabolic panel (ex: hypernatremia)
- B12 and folate levels.
- HbA1c: rule out diabetes as cause of peripheral neuropathy.
- Urine and serum examination for heavy metal (mercury, lead, copper) levels
- porphyria (porphyrin studies), if indicated
- pseudocholinesterase levels, and immune marker, if indicated
- Cerebrospinal fluid for anti-GQ1b (if indicated to rule out Guillain-Barré syndrome)
(b) Differentiate from lithium toxicity:
- Check lithium level
Lithium toxicity is associated with:
- increased muscle tone
- hyperactive tendon reflexes
- presence of Babinski sign
- note that sensation is normal
Important clinical fact:
- Brain lithium level is not always accurately reflected in serum lithium level.
- Cases have documented the worsening of neurological symptoms even after discontinuation of lithium level and with therapeutic or normal lithium levels.
(c) EMG and Nerve Conduction Studies:
- mostly represents axonal neuropathy.
(1) Discontinue Lithium level if signs of lithium toxicity.
(2) Evaluate for peripheral neuropathy in every patient on chronic lithium treatment.
(3) If re-challenging with lithium after neuropathy resolution:
- be mindful of delayed onset and slow resolution of neuropathy side effect.
- Consider lower dose of lithium with lower therapeutic level, if clinically possible.
- Switch to another mood stabilizer: positive case of switch to quetiapine.
For Physician’s Guide for Clinical Psychiatry Subscribers:
Course subscribers will have access to the following six chapters discussing the management of both common and rare lithium’s adverse events:
Management of Lithium’s Adverse Events
(1) Lithium and Acute Kidney Injury (Evaluation): read chapter 2.25
(2) Lithium induced Polyuria/polydipsia (nephrogenic diabetes insipidus): read chapter 2.26
(3) Lithium and Risk of Hypercalcemia & Hyperparathyroidism: read chapter 2.27
(4) Lithium induced Tremors: read chapter 2.28
(5) Lithium induced Hypothyroidism: read chapter 2.29
(6) Lithium induced Neuropathy: read chapter 2.30
- Total chapters= 236 and counting
- Chapters and Sections are frequently updated.
- Each chapter includes references: with either pdf article or pubmed link for each article.
- Triweekly Email Clinical Summary: subscribers receive 3 emails/week.
- Goal: is to have all important clinically relevant topics in one course.
- Annual Subscription of $65/year: for continued access to course on an annual basis.