What are the symptoms of lithium toxicity?

Lithium toxicity is classified into 3 types: acute lithium toxicity, chronic lithium toxicity, and acute-on-chronic lithium toxicity. The main symptoms associated with acute lithium toxicity include: weakness, dizziness, nausea, diarrhea, vomiting, muscle twitches, poor concentration, seizures and hand tremors. Neurological symptoms occur following intestinal symptoms and occur in more severe cases of acute lithium toxicity. The main symptoms of chronic lithium toxicity include: increased reflexes, slurred speech, and tremors. When chronic lithium toxicity is severe, there may be additional nervous system and kidney issues including: kidney failure, memory problems, coma, issues regulating salt in the body, psychosis, and movement disorders. There are typically no intestinal symptoms during this type of lithium toxicity. During acute-on-chronic lithium toxicity, an individual experiences both acute and chronic symptoms. 

Acute lithium toxicity occurs after one takes a single large dose of lithium intentionally or inadvertently. Chronic lithium toxicity occurs overtime after one takes slightly too much of a lithium dose everyday over an extended period of time. Acute-on-chronic toxicity occurs after one takes an extra amount of lithium after a normal dosage. This may occur from as little as a few pills.